Complete brake system on 69 cougar - now only 1 rear brake works

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  #1  
Old 09-06-08, 03:06 PM
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Complete brake system on 69 cougar - now only 1 rear brake works

Hello,

I am new to this forum but I have spent the last 1/2 hour searching for a possible idea on my brake problem with no luck. Please forgive the length of my post, I will try to keep it to the point and somewhat short.

I recently purchased my dream car. A 1969 Mercury Cougar xr-7 convertible. The car has been sitting for the last 14 years so one of the first things we needed to do was to revamp the brake system (the fluid was terribly contaminated, it had a grey-brown ewwwww color). I have replaced all of the drum components (wheel cylinders, springs, etc), all of the lines have been replaced with new stainless steel lines, I have replaced the calipers, had the rotors turned, replaced the master cylinder *(yes I did bench bleed it) and have a new brake booster. The first time we bled the brake system, it felt great, solid and firm for the rear brakes, but as soon as we moved to the right front, it got spongy and has not worked right since. I was pretty sure it was either the distribution block or the proportioning valve. So, I have now torn down and cleaned them, then seem to move freely. The problem I have is the top half of the brakes are weak./spongy, and the only brake that seems to be working is the right rear. Any ideas on what would make the front disc brakes not work? Is it that my proportioning valve is just toast?

Thank you in advance. I am at my wits end with this project.
 
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  #2  
Old 09-06-08, 03:23 PM
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either have air in a line still or you have a bad proportioning valve, or bad master cyl. try having a helper push on pedal and open the line for front brakes with the pressure on the pedal, see if you have fluid coming out of the master cyl at the line. if so proceed to bleed at each connection going from the master cylinder toward the wheels, that will make sure that each part is working and clear, don't let the system run low on fluid, brake fluid is cheap so step on the pedal once and then bleed, don't pump the pedal. just step and bleed.

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Old 09-06-08, 03:27 PM
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When you took off the master cylinder lines, did you have any slave cylinder bleeders open or were any of those cylinders off so that lots of brake fluid could have run out of the lines? If the master cylinder lines stay connected, and slave cylinders removed and disconnected, very little brake fluid can come out based on that principle of dumping thin bottle of fluid upside down, and it don't come out easy.

For the heck of it, have you checked the adjustment of the rear brakes, and/or tried doing a alot of backing up? You could jack up the rear of car and see if you feel any slight brake shoe drag or at least a brushing noise, where you can hear if it hits the drum once in a while when revolving the wheel. And then you could have someone gradually step on the brakes and feel if you can still turn the back wheels, and how far down the pedal has to be for that to happen.

If poor contact, I'd try to readjust. And if it then became good after adjustment and a rebleed, but then once again went bad, I'd think maybe perhaps an adjuster is backwards or on wrong wheel.

And do you know how to bleed brakes properly and in right sequence?
 
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Old 09-06-08, 03:35 PM
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Originally Posted by Speedwrench View Post
either have air in a line still or you have a bad proportioning valve, or bad master cyl. try having a helper push on pedal and open the line for front brakes with the pressure on the pedal, see if you have fluid coming out of the master cyl at the line. if so proceed to bleed at each connection going from the master cylinder toward the wheels, that will make sure that each part is working and clear, don't let the system run low on fluid, brake fluid is cheap so step on the pedal once and then bleed, don't pump the pedal. just step and bleed.

life begins when the kids leave home and the dog dies
Thanks. There is plenty of fluid (or seems to be) flowing through the front when we bleed them. I will try the procedure you mentioned. If I am correct, you mean, open the bleeder on the caliper, have a helper step on the pedal to the floor, close the bleeder, release the pedal... repeat. Is that correct? How would I know if the new MC I have is bad? I already got the incorrect one from NAPA so this will be the third time taking off the master cylinder (which requires taking off the booster too and I DESPISE that job because it is under the dash with locktite nuts... it is not a pleasant job ).
 
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Old 09-06-08, 03:47 PM
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Originally Posted by ecman51` View Post
When you took off the master cylinder lines, did you have any slave cylinder bleeders open or were any of those cylinders off so that lots of brake fluid could have run out of the lines? If the master cylinder lines stay connected, and slave cylinders removed and disconnected, very little brake fluid can come out based on that principle of dumping thin bottle of fluid upside down, and it don't come out easy.

For the heck of it, have you checked the adjustment of the rear brakes, and/or tried doing a alot of backing up? You could jack up the rear of car and see if you feel any slight brake shoe drag or at least a brushing noise, where you can hear if it hits the drum once in a while when revolving the wheel. And then you could have someone gradually step on the brakes and feel if you can still turn the back wheels, and how far down the pedal has to be for that to happen.

If poor contact, I'd try to readjust. And if it then became good after adjustment and a rebleed, but then once again went bad, I'd think maybe perhaps an adjuster is backwards or on wrong wheel.

And do you know how to bleed brakes properly and in right sequence?

Lets see, the sequence.. IIRC it should be right rear, left rear, right front, left front. Is that correct?

I have tried pulling it forward, then backing it again over and over, no change. I will try putting her back on stands and adjusting the back brakes again. Still, I worry because it seems as thought the back are working right, it is the fronts that seem to have issues. This project has taken over a month so far and I am completely running out of ideas. I am also considering the possibility of just getting an adjustable proportioning valve - any thoughts on this idea?
 
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Old 09-06-08, 04:00 PM
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Someone can correct me if I'm wrong, but I'd think the brake pedal should still be hard without the booster even in operation. At least after you pump it 3 times.

Regarding my last post: Say the OTHER rear brake was out of adjustment. Then additional travel of the shoe will result in the pedal having to be depressed longer before it gets firmer. That is why I'd certainly check the rear wheels. Both of them. Especially since of all the possible rigamarole you might be considering, this would be easy to confirm.

Regarding a theory of a bad proportioning valve: If fluid can be bled from all wheels, that means fluid is able to pass. The issue would not really be if it proportions, but rather if all the fluid in all the in and out lines there could move onto the cylinders, rather than teh issue being if balancing is correct. But if say the issue were due to airlock there, I guess someone would have to explain to me how an air lock could be trapped there, and if that is common especially in major brake overhaul work, and how one gets rid of the trap IF that truly can happen.
 
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Old 09-06-08, 04:11 PM
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Originally Posted by MsRae View Post
The first time we bled the brake system, it felt great, solid and firm for the rear brakes, but as soon as we moved to the right front, it got spongy and has not worked right since.
You didn't let the master cylinder go dry did you?, with all the bleeding. It almost sounds like maybe that is what happened, now that I concentrate on this part of your post. That really creates a problem as then your bench bleed was for naught now, and you have lots of fluid out by the wheel with air way back up the line, that can compress, that now has to all get bled out.
 
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Old 09-06-08, 04:19 PM
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Originally Posted by ecman51` View Post
You didn't let the master cylinder go dry did you?, with all the bleeding. It almost sounds like maybe that is what happened, now that I concentrate on this part of your post. That really creates a problem as then your bench bleed was for naught now, and you have lots of fluid out by the wheel with air way back up the line, that can compress, that now has to all get bled out.
You know, that is a possibility. I was not the one checking the fluid so I'm not positive. If that is the case, do I have to take the MC off to bleed it again or can I do it from where it is and use the brake pedal as the catalist for pushing the valve?
 
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Old 09-06-08, 04:27 PM
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It's too late for the bench bleed (I take that back, I'm not positive on that.)as air is now downstream if that happened. You are just in for a lot of bleeding I think. And making sure as Speedwrench said earlier, to not let it go dry (again?). Maybe Speedwrench or others will weigh in.
 
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Old 09-06-08, 04:41 PM
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Originally Posted by ecman51` View Post
It's too late for the bench bleed (I take that back, I'm not positive on that.)as air is now downstream if that happened. You are just in for a lot of bleeding I think. And making sure as Speedwrench said earlier, to not let it go dry (again?). Maybe Speedwrench or others will weigh in.
Thanks for the help so far! I am going out there now to inspect the system again. I have to wait for assistance to bleed them again. But in the meantime I am going to try readjusting the back brakes.

Tons of thanks.

Rae
 
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Old 09-06-08, 04:56 PM
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Sounds like air in the system. Do you have a friend with a hand held vacuum pump? I have a Mityvac pump with a kit for bleeding brakes, best part of all no pumping, makes bleeding a one person job. Search Mity vac on google, the electric pumps are not nessesary, mine is the hand model and works like a dream.
 
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Old 09-06-08, 05:39 PM
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MsRae,

At first I never thought of the possibility that air could have got in the system, by say running the MC dry, because you rattled off all these parts thrown into the vehicle + MC bench bleeding, that made it sound like a pro/someone very experienced would only be capable of. And then the presumption was made that SURELY they would not have let the cylinder go dry. But- it sounds like it just may have.

And I figured someone might have some bleeding trick up their sleeve.
 
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Old 09-06-08, 05:46 PM
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Originally Posted by ecman51` View Post
MsRae,

At first I never thought of the possibility that air could have got in the system, by say running the MC dry, because you rattled off all these parts thrown into the vehicle + MC bench bleeding, that made it sound like a pro/someone very experienced would only be capable of. And then the presumption was made that SURELY they would not have let the cylinder go dry. But- it sounds like it just may have.

And I figured someone might have some bleeding trick up their sleeve.

Hey, even the best of us make mistakes. And, since I was not the one filling.... not positive. Still, I have bled several systems before, this one does not necessarily feel like air, the brake just goes to the secondary (rear) brakes right away... not acting like the "spongy" air. I am not, by any means a pro - never claimed to be, so yeah, that is why I am posting for help.

Anyhow, I will try bleeding it yet more... try the system that wire twister mentioned (thanks for that tip wire twister).

Thanks again.
 
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Old 09-06-08, 06:09 PM
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Originally Posted by MsRae View Post
Still, I have bled several systems before, this one does not necessarily feel like air, the brake just goes to the secondary (rear) brakes right away... not acting like the "spongy" air.
Maybe you notice that effect because often people replace just front brakes, and if the back brakes are worn, maybe the whole system would feel spongy. But with your new back brakes and if those lines are full of fluid and able to compress, maybe that can explain why it feels like (at least one of) the back brakes are working first, but nothing in the front because that is where the air is.

Just like in my car when my back brake failed, and fluid ran out there, I only got pedal feel for the front.
 
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Old 09-06-08, 06:26 PM
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Is this the year they had the sequential rear turn signals?

If so, if you will drop it off at my house, I would be more than glad to get them brakes rock hard for you. it should only take a month or 12 to get it right.

may I suggest re-bleeding the master cylinder. Then gravity bleed each corner (one at a time). Then bleed using an assistant (in the proper order and of course, one at a time).

did you replace the rubber hoses in the system? I would do so if only as a precaution simply due to the age and the car setting for so long. You could have a hose with the inner liner collapsing. (there are 3 on the car). Since you used SS lines, may I suggest braided steel hoses. They look nice and actually allow for a better brake since they do not expand as much as a typical hose under pressure.

also, make sure the calipers slide freely (or at least as freely as they did on a 69 Cougar).
 
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Old 09-06-08, 07:22 PM
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just got back on from helping son with cycle, and had a thought, on some of the older fords when the brakes were bled the proportioning valve would move to one side or the other to push all fluid to front or to rear this was so if a wheel cylinder went out all fluid was not lost. you had to center the valve after bleeding the brakes, it has been 20 years since I had to recenter one so I can't say for sure the proper procedure for re-centering them. do you have a shop manual for this car?

what I meant was have helper step on the brake, then open the bleeder, close the bleeder then release the brake, repeat until certain all air is out of the system, it is slow but will make sure that all air is out of the system, multiple pumps can entrain minute air bubbles in the brake fluid which can then lead to poor brake pedal response,

when the master cylinder is mounted on the car with the car in the position you were bleeding it was it level? if not you will need to level the master cylinder by raising the rear or front of the vehicle when bleeding because if any air remains in the master cylinder and it is not level when bleeding it can be trapped in the cylinder and not expelled when bleeding.

if we're not supposed to eat animals why are they made out of meat?
 
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Old 09-06-08, 08:16 PM
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Originally Posted by nap View Post
Is this the year they had the sequential rear turn signals?

If so, if you will drop it off at my house, I would be more than glad to get them brakes rock hard for you. it should only take a month or 12 to get it right.

may I suggest re-bleeding the master cylinder. Then gravity bleed each corner (one at a time). Then bleed using an assistant (in the proper order and of course, one at a time).

did you replace the rubber hoses in the system? I would do so if only as a precaution simply due to the age and the car setting for so long. You could have a hose with the inner liner collapsing. (there are 3 on the car). Since you used SS lines, may I suggest braided steel hoses. They look nice and actually allow for a better brake since they do not expand as much as a typical hose under pressure.

also, make sure the calipers slide freely (or at least as freely as they did on a 69 Cougar).
hahaha - yes, it is the one with the sequential signals (just fixed those as well - I love em). It is a gorgeous car but I think it is possessed.

I did replace the rubber as well. All with the braided steel. I will do as you suggested. I will rebleed the entire system again tomorrow (perhaps getting a vacuum kit, as I have been told by a few that they are the way to go). I will let you all know what happens.

*crosses fingers*
 
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Old 09-06-08, 08:21 PM
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Originally Posted by Speedwrench View Post
just got back on from helping son with cycle, and had a thought, on some of the older fords when the brakes were bled the proportioning valve would move to one side or the other to push all fluid to front or to rear this was so if a wheel cylinder went out all fluid was not lost. you had to center the valve after bleeding the brakes, it has been 20 years since I had to recenter one so I can't say for sure the proper procedure for re-centering them. do you have a shop manual for this car?

what I meant was have helper step on the brake, then open the bleeder, close the bleeder then release the brake, repeat until certain all air is out of the system, it is slow but will make sure that all air is out of the system, multiple pumps can entrain minute air bubbles in the brake fluid which can then lead to poor brake pedal response,

when the master cylinder is mounted on the car with the car in the position you were bleeding it was it level? if not you will need to level the master cylinder by raising the rear or front of the vehicle when bleeding because if any air remains in the master cylinder and it is not level when bleeding it can be trapped in the cylinder and not expelled when bleeding.

if we're not supposed to eat animals why are they made out of meat?

Thanks Speedwrench. You are correct. The valve is actually located in the distribution block. It had gotten off center (it caused the brake light to go on) and it had frozen that way. I took out the block, and after much luck and a little help from a very nice person at NAPA I was able to get it out, and replaced all of the o-rings with new ones. I put it back together and the valve slides back and forth easily and the brake light is now off. Still having the bad braking issue. Good memory on that though!

Yes, I do have the shop manual (5 book series for this car and it is a great help but not helping much here). I am wondering if the push rod might not be the correct length??? It does say that it can be adjusted. dunno.

As for your bleeding advice - thanks. That is the procedure I followed when I first bled the system, since I knew there would be TONS of air to evacuate.

The master cylinder is level when it is in the car.

Now you can see why I am so frustrated eh? I will work more on it tomorrow with some/all of the suggestions and post an update
 
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Old 09-06-08, 09:39 PM
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just keep my offer in mind.



as to the brake push rod adjustment. I do not know the actual spec (with a library of manuals, I suspect it is available within one of them) just be sure you leave enough freeplay. Lack of freeplay could result in the MC piston not returning far enough back in it's bore to allow the MC to work properly.

the fact you had a good pedal until you bled one specific brake would tend to make me believe it is not the adjustment of the pushrod.

do you have access to plugs (real metal plugs) to seal off the MC ports?. If so, you could block off the front or rear port and see if things get better. This would also help diagnose where the problem is either front or rear, or if nothing gets better, the MC.
 
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Old 09-07-08, 01:08 PM
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Originally Posted by nap View Post
just keep my offer in mind.



as to the brake push rod adjustment. I do not know the actual spec (with a library of manuals, I suspect it is available within one of them) just be sure you leave enough freeplay. Lack of freeplay could result in the MC piston not returning far enough back in it's bore to allow the MC to work properly.

the fact you had a good pedal until you bled one specific brake would tend to make me believe it is not the adjustment of the pushrod.

do you have access to plugs (real metal plugs) to seal off the MC ports?. If so, you could block off the front or rear port and see if things get better. This would also help diagnose where the problem is either front or rear, or if nothing gets better, the MC.
The plug idea is a fantastic one. I picked up one of those vacuum bleeders. They are pretty slick. Re-bled the system again. Still no change.

I will try to block of the front and then the back with plugs and see what happens! Thanks.

And, as for the offer.... I'm almost tempted! This car is making me NUTS!
 
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Old 09-07-08, 01:28 PM
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i have used vac systems, have used pressure bleeder that use a tank and shop air and prefer bleeding with a live person on the brake pedal. that makes the most pressure on the system and seems to be the only way to get 100% of the air from some systems. some master cylinders are just hard to get all of the air out of.
when bleeding after opening each bleeder which one seems to give the least movement of the brake pedal? that is the one you need to concentrate your bleeding efforts on. did you try opening the lines at the master cylinder to check for fluid at the lines? did that seem to show good fluid flow and pedal movement?
also one other thing is the piston in your master cylinder a solid one piece piston that is separated with seals for front and rear or do you have a two piece piston, some systems that are two piece can have the front piston stick when bench bleeding and make the front hard to bleed and poor pedal feel. you might have to disassemble the master cylinder to unstick that piston. then when bench bleeding make sure that you do not press in more than 1/2 in to bleed the master cylinder.

Murphy was an optimist
 
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Old 09-07-08, 09:02 PM
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Originally Posted by Speedwrench View Post
i have used vac systems, have used pressure bleeder that use a tank and shop air and prefer bleeding with a live person on the brake pedal. that makes the most pressure on the system and seems to be the only way to get 100% of the air from some systems. some master cylinders are just hard to get all of the air out of.
when bleeding after opening each bleeder which one seems to give the least movement of the brake pedal? that is the one you need to concentrate your bleeding efforts on. did you try opening the lines at the master cylinder to check for fluid at the lines? did that seem to show good fluid flow and pedal movement?
also one other thing is the piston in your master cylinder a solid one piece piston that is separated with seals for front and rear or do you have a two piece piston, some systems that are two piece can have the front piston stick when bench bleeding and make the front hard to bleed and poor pedal feel. you might have to disassemble the master cylinder to unstick that piston. then when bench bleeding make sure that you do not press in more than 1/2 in to bleed the master cylinder.

Murphy was an optimist
Went back and inspected all the connections, made sure all the fittings were tight and adjusted the back brakes; unfortunately, the system is still messed. I think you may be on to something with the stuck piston in the MC. It is a new one but I've had new parts be bad before.

All lines seem to give good fluid movement... at least with the vacuum bleeder. The pedal seems to give good movement to the floor when I was working the pedal the last time - the weird thing is that it is only "soft" on the top half of the pedal, the bottom half seems solid. The master cylinder in this car is a double piston one. There are two things left I keep going back to.. one is the master cylinder, the other is the possibility of a bad proportioning valve. I just ordered a new proportioning valve that is adjustable and will be getting that in a few days (the proportioning valve and the distribution block on this car are actually separate).

I am going to try plugging off the master cylinder first like nap mentioned, and install the new proportioning valve (I like the idea of an adjustable one anyway) and I'll let ya know.
 
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Old 09-08-08, 02:56 PM
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I know that on the earlier ford products it was possible to put the calipers on the wrong side,I have seen this done,just check and make sure that the bleeder valve is on the top of the caliper when it is installed on the car.also there are brake line clamps that let you clamp off the lines to help diag.,if you put the clamps on all the lines and you still have a spongy pedal its the master cylinder or the valve that have the air,if the pedal is hard take off one clamp at a time and check the pedal to see if is still hard when the pedal gets spongy then that wheel is the problem.good luck
 
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Old 09-08-08, 08:28 PM
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ah man i forgot about that on the calipers. probably because i always check to see where the bleeder is.

murphy was an optimist
 
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Old 09-08-08, 09:00 PM
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Originally Posted by gregtech View Post
I know that on the earlier ford products it was possible to put the calipers on the wrong side,I have seen this done,just check and make sure that the bleeder valve is on the top of the caliper when it is installed on the car.also there are brake line clamps that let you clamp off the lines to help diag.,if you put the clamps on all the lines and you still have a spongy pedal its the master cylinder or the valve that have the air,if the pedal is hard take off one clamp at a time and check the pedal to see if is still hard when the pedal gets spongy then that wheel is the problem.good luck
she has braided steel flex lines.

Do NOT put clamps on these lines.
 
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Old 09-09-08, 11:05 AM
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Thanks for the clamp idea but as Nap said, I have braided steel lines, not going to clamp them. Yes, the calipers are on correct, the bleeder is on top and facing the back of the vehicle. I am going to try to gravity bleed the calipers this week (why not, i'm waiting for parts anyway), I have an adjustable proportioning valve on the way.

I went to Checker to get some brass or metal plugs and the guy was such a tard. He told me "that isn't what you want" you want this bleeder kit. TARD! No, I want the brass plugs (I even brought the old master cylinder with me to measure them with). Needless to say he was about as helpful as a needle in my foot. He said the only had the fittings, no plugs (strange, cause when I was in there earlier to get adapters they used plugs to measure the size). So, I don't have the plugs. I'll work on that this week as well by going to a much better auto store

Keep ya updated.
 
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Old 09-09-08, 03:19 PM
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Those female threaded ports on the master cylinder I think are a special unique thread size just so people CAN'T cap them. A guy at a parts store told me what your guy did and said, "YOU can't stop a car by plugging one of those holes !"(to get home in emergency when half the brakes failed and fluid leaking out slave cylinder.). He said you create hydraulic lock with the MC piston. He said that be dangerous and that's why they don't do it.
 
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Old 09-09-08, 07:40 PM
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they are a standard flare fitting thread and plugs for flare fittings are available. I probably have some in my toolbox that would fit. A pipe fitting is not proper and will not work. It must be a flare fitting plug. It basically looks like a flare fitting only no hole for the tubing. The end that goes into the bore has an inverted taper so the edges of the plug will seal against the seat of the female fitting just as if there were a flared tube in place.

as to making a hydraulic lock:

not happening.

think about it this way. I presume the thought is that somehow enough bypass of the MC piston would allow the piston to be pushed into the cylinder. Apparently the guy that told you this believes there is no way for the piston to now be released due to no fluid flowing back into the MC and apparently he believes that there is no mechanism for the piston to be withdrawn in this situation.

Let me present a situation that is similar and actually happens all the time.

You are bleeding the brakes. As you push the piston into its bore, it is pushing fluid out the port and to the wheel cylinder or caliper. You allow it to flow out of the bleeder. You then close the bleeder. You now have the same situation as if you plugged the MC since there is no reverse movement on the wheel cylinder or caliper to push fluid back into the master cylinder.

How does the piston return to a relaxed position?

There has to be a mechanism in place to allow fluid replacement for fluid lost on the pressure side of the piston.
The mechanism is a cupped piston seal. It is cupped so when pressure is applied, the pressure actually increases the sealing pressure as the pressure pushes the cup outward against the culinder bore. The benefit of such a seal is, in reverse action, not only does it seal poorly but the action of moving it in reverse actually causes the fluid pressure to make the seal even worse as it "closes" the cup of the seal.

Notice the cupped seal on the right end of this piston.



just as proof, I had popped a brake line before. to prevent the fluid loss and allow pressure so the other side of the mc would be more effective, I cut the line near the MC, folded it over and crimped the daylights out of it to cause a leakproof seal.

the brakes still connected to the MC worked just fine as did the MC.
 
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Old 09-10-08, 07:41 AM
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nap,

Could it be that in a *2* piston MC that you could get that hydo-lock I was talking about? if say the rear piston (whose function is to solely send fluid from rear reservoir down the rear line without any sort of a bypass) could not compress a plugged-off rear reservoir, then the front piston, since connected to the same MC rod, would not be able to move either, hence locking up the whole MC?

But if say you had a *single* piston MC that was say behind the rear and front reservoirs, then even if the rear reservoir's line hook-up got plugged off, then the piston COULD still travel?

The reason why I say all this is the guy I talked to at the parts store is not a young guy and seems to know his stuff about all kinds of automotive questions I have asked him over the years, and I was telling him the same stuff actually, like you are telling me, and he insisted it can't work, and I finally gave up arguing with him. Then thought there must be SOME good reason why they don't have such a plug, without having to rig something up like you mentioned. So -Could it be that yours worked because you had a single piston MC?
 
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Old 09-10-08, 11:15 AM
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Originally Posted by ecman51` View Post
nap,

Could it be that in a *2* piston MC that you could get that hydo-lock I was talking about? if say the rear piston (whose function is to solely send fluid from rear reservoir down the rear line without any sort of a bypass) could not compress a plugged-off rear reservoir, then the front piston, since connected to the same MC rod, would not be able to move either, hence locking up the whole MC?

But if say you had a *single* piston MC that was say behind the rear and front reservoirs, then even if the rear reservoir's line hook-up got plugged off, then the piston COULD still travel?

The reason why I say all this is the guy I talked to at the parts store is not a young guy and seems to know his stuff about all kinds of automotive questions I have asked him over the years, and I was telling him the same stuff actually, like you are telling me, and he insisted it can't work, and I finally gave up arguing with him. Then thought there must be SOME good reason why they don't have such a plug, without having to rig something up like you mentioned. So -Could it be that yours worked because you had a single piston MC?

Wow - you guys are makin my head hurt!

Seriously though, I know they had the plugs (brass plugs, and yes, they were the flared type) at this store because when I was in there with the wrong master cylinder that I had gotten and was trying to get adaptors and fittings that would work, the tech behind the counter was using these "plugs" to figure out the right size.

I would have accepted an arguement like the one the parts guy gave you - but this guy wasn't that smart, he just looked at me like I'm a little girlie that can't possibly know what I'm talking about or what I want. So, I don't think master cylinder lock up was why he tried to sell me the bleeder kit, or perhaps it was and he just figured I couldn't understand it. Regardless, I like the arguement, but I'm not certain which side I'm leaning toward. It doesn't seem to make sense that you could bleed the system and not have the same conditions as you would with plugging the front or rear port.

I do have the two pistion MC and I'm not sure who is right on this one, so perhaps I shouldn't risk it. Not sure. I'm still going with the new proportioning valve and the gravity feed of the calipers first anyhow. Then, I may just take out the MC and go from there.

Thanks again Nap and ecman. I'm doing the stuff tonight or tomorrow - so I should have an update by Thursday night or Friday.
 
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Old 09-10-08, 12:04 PM
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does it still seem that only the right rear is working?
 
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Old 09-10-08, 12:48 PM
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Originally Posted by gregtech View Post
does it still seem that only the right rear is working?
Yes, strangely. I did go back and adjust the back brakes but the right rear still seems to be locking/grabbing really hard. It was kind of funny actually because when I pulled into the garage the cardboard that I pulled onto zipped out from behind the car because the left rear tire was still trying to go They seem better after adjustment but still not quite right. I just put it up on stands so I will be pulling off the right rear drum to double check for any contamination/issue.
 
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Old 09-10-08, 01:02 PM
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Lightbulb

while you have it up and the wheels off,take the left wheel off as well and make sure that the pins that come out of the wheel cylinder are installed correctly on to the brake shoes.
Did you replace the or adjust the parking brake cables? the reason that I am asking is that the cables might be siezed in the conduit and causing your lock-up.
I know that this is basic brakes 101 but sometimes even the simpest things are overlooked when you are at wits end.
Good luck
 
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Old 09-10-08, 01:28 PM
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Originally Posted by gregtech View Post
while you have it up and the wheels off,take the left wheel off as well and make sure that the pins that come out of the wheel cylinder are installed correctly on to the brake shoes.
Did you replace the or adjust the parking brake cables? the reason that I am asking is that the cables might be siezed in the conduit and causing your lock-up.
I know that this is basic brakes 101 but sometimes even the simpest things are overlooked when you are at wits end.
Good luck

Thanks Gregtech - I agree, simple things can often be overlooked. I will do as you suggest. I did replace the parking brake cables (not the ones at the rear, those seemed ok, just from the Y point forward to the pedal itself. I will try double checking the cables at the brakes as well. Anything is a possiblity at this piont, I suppose that is why it is making me so crazy. Brakes are NOT that complicated! Or at least, I didn't think they were, until this beast continues to prove me wrong.
 
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Old 09-10-08, 02:59 PM
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When I did mine, I went, "Where are the pins?" In fact, I was looking on the floor for them, after I got the drum off. I could not find any. Then when I got the new slave cylinder it became apparent this style does not have them in the style that I had remembered from years ago.

My cylinder does not really have any, the way they used to have when they were forked and the shoe went in between the fork. Mine does not have that. Mine is wider - more like a piston, that pushes dirctly on the shoe, rather than the thinner pin style with the fork in it.
 
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Old 09-15-08, 09:55 AM
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just an update

Well, quick update.

Got the new adjustable proportioning valve, got the adapters to make it all work and put it in this weekend. Have bled the system with the “open, press pedal, close, release pedal” to the tune of three small bottles at each tire. Still no change in pedal feel. Haven’t actually put it down and taken it for a drive, but I’m almost certain it will do no good. I know how the pedal should feel and this one is definitely soft for the first half and solid for the last (first being front disc, last being what controls the rear drums). Sooooo… - since the brake lights are now off after rebuilding the proportioning valve/distribution block, and there are no visible leaks, this leads me to believe the problem is between pedal and master cylinder. I am going to be removing the master again, re-bleeding it, and double checking the push rod length just to be sure (I was told the push rod can cause some problems). Then, if I get it back together and it still doesn’t work?

I think I have a noose somewhere…. And a chair…

Kidding…….Just kidding!!!!!!

Stupid question though – the brake booster. If I am not mistaken, this only creates power to the pedal (pushing strength so to speak using vacuum) and does not really affect the braking. Is this a correct assessment or should I look into this being an issue as well? The brakes are soft with the car off, with the car on and the booster in operation, it is hard to judge pedal pressure and when I drive it there is no question the booster is operating.
 
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Old 09-15-08, 10:44 AM
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Brakes soft (as in mushy?) with the engine off? Hmmm haven't been a real motorhead in a while, but as I remember, shouldn't they be hard with no vacumn assist, and softer with the engine on? Just checked my car and thats pretty close anyway.

Should this be a clue?
 
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Old 09-15-08, 04:05 PM
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I have been reviewing posts. I guess nap said about checking the pedal adjustment. But if that was it, you would think that would just mean you would have a little free travel first, and then after that it would get hard, and all 4 brakes would work.

You make is sound like you have pedal, but it's mushy at first, then gets solid.

How about taking a pail of sand and spread it on some roadway or driveway spot, possibly spreading it strategically to test each wheel, where you apply the brakes over the sand and see if the wheel turns or locks up and skids (= good). Water would work also, but with the sand you could actually really be certain and hear it, especially with windows rolled down(if brakes locked up over the sand) also.
 
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Old 09-15-08, 05:10 PM
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softer than they should be and then firm.

Sounds like an adjustment problem or the calipers are not sliding (makes it like the fronts are not adjusting)

actually, you have the function of the brakes backwards. The first activation is the rear brakes. Not to actually provide braking but the rears have much more "freeplay" if you will so that needs to be overcome first so the front and rears will actually provide braking at the same time.



Do you have a couple C clamps handy? I would remove the calipers, leave the pads in place in the caliper or use a piece of flatstock and use the caliper to lock the inner pad against the caliper so the caliper cannot expand. Then try the brake to see how the pedal feels. If no change, I would look to the rears or prop valve.


I have had a prop valve that would not bleed out. For some reason, there was persistant air that simply would not pass.

Not sure how I finally got it out but what I would try is (two people needed); one at the prop valve. Have one person pump up the brakes as high and hard as you can. Then, crack the line going from the prop valve to the back and let it bleed. Do this several times.

I have also done this at the MC when I had persistant air in the MC that I could not get to move.


How far away from University of Notre Dame did you say you were? I do know somebody that will pick up that car for the salvage value
 
  #40  
Old 09-15-08, 05:59 PM
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It sounds to me like this post and this problem is getting way too overcomplicated. In 1969 brakes were at their simplest form. With the addition of the vacuum assist booster it made them easier to apply and much safer.
If you have a soft pedal of any kind with the engine off then you have a leaking booster. Without a doubt. If the pedal is hard and gets even harder with every application with the engine off then the booster is fine. It should be hard to the point that you are almost unable to get any action out if it.
Hope this helps ya,
Billy
 
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