1997 Cougar Master Cylinder Install; Help!

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  #1  
Old 06-17-04, 10:35 PM
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Red face 1997 Cougar Master Cylinder Install; Help!

I had a master cylinder that was leaking from the rear (towards the firewall) fitting. It (the rear supply connection) was stripped. The master cylinder body is aluminium and a previous owner probably did the bad deed. So I replaced it with a new one and tried my best to bench bleed this puppy! One problem was that the reservoir has a 3/8 line going "somwhere" that has to be plugged if you are to bench bleed this cylinder. This was tough to keep it plugged during a bench bleed. I did the best I could and tried to keep the fluid in the reservoir when I reinstalled it. I was concerned that the male fittings needed a good start so I probably lost some fluid installing this puppy.

It's in, I have installed all new pads, turned rotors, etc. Problem is that I tried to vaccuum bleed the system and one caliper (right rear) has no brake fluid coming out, even with 60 inches of mercury on a pull! The other three wheels responded nicely to the vaccuum pull. Bottom line is I have no brake pedal and I can't figure out why the one caliper has not responded to bleeding.

Any help here will be greatly appreciated!

Tony
 
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  #2  
Old 06-18-04, 11:49 AM
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first try removing the bleeder screw to make sure it isn't plugged after checking that get someone to help you bleed the brakes by applying pressure to the pedal, as sometimes the vacum pumps just dont get it done good enough to have a good pedal, start by bleeding at the master cylinder by cracking each line open just enough to leak, then continue on to each wheel starting with the furthest wheel away from the master cylinder and working your way to the left front last.
 
  #3  
Old 06-18-04, 10:44 PM
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Thanks!

Well, I got the caliper to produce fluid by just pulling more vaccuum. Unfortunately, I still have no pedal. Since I ws not happy with my bench bleed, I went and got a bleed kit from O'Rielly and length of 1/2" OD hose for the reservoir drain to ?. I removed the master cylinder and bench bled it again with a good feeling that it is primed and all the air is out of it. I reinstalled it and bled the system again using the MityVac tool. I still have no pedal! I am starting to suspect the master cylinder is no good.

Any clues or advice?

Thanks in advance,

Tony
 
  #4  
Old 06-18-04, 11:00 PM
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well there is a possibilty that you may have gotten a bad master cylinder but not that common but does happen sometimes, but i would suggest you get help bleeding the brakes as vacum pumps just doesnt cut it most of the time.
there has been numerous times I have used a vacum pump only to have to rebleed the brakes the traditional way, also this car may have a proportioning valve that could be off center usually indicated by a brake light when the engine is running it will usually recenter itself with pressure applied to the pedal and bleeding the system, but is not likely to recenter the valve using vacum to bleed the brakes.
also might add that alot of time assuming you have room you can usually bench bleed a master cylinder on the car by just installing your bleed kit and inserting the hoses into the brake fluid and very slowly actuate the brake pedal about 10 times.
 
  #5  
Old 06-18-04, 11:18 PM
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thanks Bejay!

Tomorrow we will (with a neighbor) do a traditional bleed job. We will see how that goes. My bench bleed was super today as I never lost a drop of fluid and got rid of the air. Thanks for your suggestions and I will post with an update tomorrow.

Tony
 
  #6  
Old 07-13-04, 05:47 PM
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Unhappy Strange bleeding?

Help! I just manually bled each caliper (front and rear disc brakes on this Cougar). Oddly, the passanger rear and the driver's front calipers bleed with an appreciable quantity of brake fluid exiting (volume) on each pedal depression. The driver's rear and passanger's front calipers only produce about one third the volume as the other two do with each pedal depression. My wife (helper) says the pedal "goes further" when the high volume calipers are being bled.

This is a remanufactured master cylinder that I bench bled twice. I still have no brake pedal at all. There is NO air in this system after two quarts of new brake fluid has passed through it with successful bleed jobs. Anybody have a clue? I'm ready to trash the master cylinder.

Tony
 
  #7  
Old 07-13-04, 06:27 PM
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Perhaps one of the pistons is sticking in the new MC and it will not return to its home position after being actuated in order to draw a full charge of fluid.

I'm not sure on this particular unit, but don't some MC's pressurize the lines as aja8888 has mentioned? ("the passenger rear and the driver's front calipers bleed with an appreciable quantity of brake fluid...")

I believe I saw this issue on a 98 Escort not that far back and I had to replace the MC with an OEM from the dealer.

My 2 cents.
 
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Old 07-13-04, 09:09 PM
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Wink Thanks!

Thanks for the reply, and I hope a few of the other local experts chime in. This situation is a bit foreign for me since I have done complete brake jobs on 20+ cars in my life. I am also a Mechanical Engineer and can't stand being frusterated by this dilemma! Unfortunately, I don't have a factory service manual so I can't refer to it for help.

I am sure there is no proportioning valve in the system since the car has disc's all around. With the strange bleed results, it just appears (to me) that the MC is the culprit.

Thoughts?

Tony
 
  #9  
Old 07-14-04, 05:39 AM
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I believe there are two proportioning valves that screw into the bottom of the master cylinder. One brake line will then thread into each of the proportioning valves. These valves can be dismantled and cleaned quite easily if need be.

Keep us posted.
 
  #10  
Old 07-14-04, 11:03 AM
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Exclamation The next step....

Since I have to get this car back on the road soon, this weekend I will pull the master cylinder out (again) and get another one (new, not rebuilt). I have e-mailed Cardone (supplier) to see if they will honor the one year warranty. I'll post back over the weekend.

Tony
 
  #11  
Old 07-15-04, 05:41 PM
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most front wheel drive cars use a diagonally split brake system. the LF and RR wheel are on one circuit of the master cylinder, and the RF and LR are on the other. this way you will have at least one front wheel with brakes if you have a system failure. as mentioned above, you may have a stuck piston in the master cylinder. you also should check the push rod coming out of the booster to make sure it is adjusted correctly. if it is out too far it will depress the plunger in the master cylinder partially when you tighten the mounting bolts and won't let it return in the bore fully.
 
  #12  
Old 07-15-04, 06:15 PM
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The Cougar is rear wheel drive, V8, with ABS. I'm sending the MC back to the supplier.

I'll keep the post going when I have another to install.

Tony
 
  #13  
Old 07-15-04, 06:56 PM
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do you have 2 lines coming from the master cylinder or 4?
if just 2 lines it sounds as if it is a proportioning valve problem if it has 4 then I would suspect the master cylinder.
a proportioning/combination valve on a 2 line mastercylinder is routed to apply fluid in a diagonal manner as mentioned, if a fluid leak exist it will restrict
fluid to 2 wheels thus still allowing you to have some brakes to 2 wheels slightly longer before complete failure and it also turns on the brake warning light on the dash letting the driver know there is a problem, so if you have a brake light on with the engine running and emergency brake off and your brake fluid is full the valve is likely the problem and is not centered and is blocking fluid to 2 wheels.
if your vehicle has abs you should probably get a manual to see if it requires any special procedures for bleeding the brakes.
 
  #14  
Old 07-17-04, 08:38 AM
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Thanks! I have two lines leaving the master cylinder so the problem is the proportioning valve I would suspect. A new unit is on the way. I have also ordered a shop manual on CD.

Tony
 

Last edited by aja8888; 07-17-04 at 08:39 AM. Reason: spelling
  #15  
Old 07-17-04, 09:25 AM
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I think you should take a closer look at that push rod length and the master cylinder itself for a posible sticking piston.

I would leave the proportioning valve alone for now.
 
  #16  
Old 07-17-04, 02:00 PM
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Originally Posted by aja8888
Problem is that I tried to vaccuum bleed the system and one caliper (right rear) has no brake fluid coming out, even with 60 inches of mercury on a pull!
Just wanted to let you know that's not scientifically possible.
29in is max at sea level.

If you want to take the time to test the master just go buy some plugs with a flare seat and see if you can get a hard pedal with the lines plugged. You can also pinch off the flex hoses one at a time to determine where your problem might be. My money would be on that reman master cyl. That's why I NEVER use a reman, always new and A1 Cardone makes some of the worst junk you can buy. The problem is that in most places, they're the only game in town. Like someone earlier stated, make sure there is just a touch of free play in the push rod before contacting the cylinder and that the cylinder is returning all the way. It probably is if one set is working OK.
 
  #17  
Old 07-17-04, 05:20 PM
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Wink Fixed!

The 60" was on the Mityvac gauge; probably not "real" inches of Hg. But, I got tired of looking at this car in my driveway (actually, the wife got tired of it) so I got a new MC and installed it this afternoon. Yes! Brakes are there now. The Cardone unit is curently in the trash can.

Thanks for everone's comments and advice. So much for remaufactured parts! For fun, go to Cardone's web site and review their quality claims.

http://www.cardone.com/English/Club/Products/BRAKES/default.asp

Tony

Sorry, the link doesn't get there.
 
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Old 07-17-04, 05:33 PM
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Glad to hear its stopping again.
 
  #19  
Old 07-17-04, 09:22 PM
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Ditto!! Thanks again folks! What a great place and helpful folks!

Tony
 
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