Bleeding Brakes

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  #1  
Old 01-21-04, 02:54 PM
Travman81
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Bleeding Brakes

I have a 94 Mercury Sable GS, and for some time now I have had air in the brake system. I have tried to bleed the rear brakes with a vacuum pump like the manual that I bought from Auto Zone say'd. I followed the instructions and even had my stepfather who is quite mechanically inclined and knowledgable help me, but air remains in the system and it takes extra effort when pushing the pedal to slow the car down. I have to hit my brake pedal very early and often, and some times to the floor(depending on my speed of the car) just so I can make a safe stop. My stepdad said that I need to have the breaks bled from the master cylinder, but the Chilton's manual I bought says nothing of this. There is not a leak in the system because I have replaced the calipers, and break lines since buying the vehicle so i know it is not a problem with the parts. Can anyone help me with a solution?
 
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Old 01-21-04, 02:58 PM
Travman81
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by the way, I have 4 wheel disc brakes with ABS, if that helps...
 
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Old 01-21-04, 04:14 PM
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Re: Bleeding Brakes

Originally posted by Travman81
There is not a leak in the system because I have replaced the calipers, and break lines since buying the vehicle so i know it is not a problem with the parts. Can anyone help me with a solution?
Don't be so sure

First question.....Could you have installed the calipers on the wrong side? Go back and look to see that the bleeder is at the highest point of the caliper. It doesn't appear that you are using a factory manual because the factory NEVER recommends using a vacuum bleeder, in fact some specifically say using one on ABS brakes can CAUSE a problem. I've experienced this myself on a GM car. The vacuum bleeder actually caused the system to get air locked and I had one hell of a time getting all the air back out. Manuallty bleeding with pressure is always the best way.
There is a possibility that you have a bad master cylinder. They frequently go bad during the bleeding process due to the extended pedal travel into an area of the master that may not be in good condition.
 
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Old 01-23-04, 01:58 AM
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I once fought a problem in my VW beetle like that. There was always plenty of pedal travel when trying to stop. Sometimes I had to pump the pedal a couple of times. I tried bleeding all the brakes with a vacuum tool several times but nothing worked. It turned out that the rear drum brakes needed to be adjusted. The travel was too far until the pads hit the drum so you usually needed plenty of pedal or a pump. As soon as I adjusted both rear brakes the way they should be the problem was solved. I then got good brakes with very little pedal travel. The automatic brake adjusters on that VW were all rusted and frozen and had to fixed as well.
 
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Old 01-23-04, 09:29 AM
Travman81
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jughead, thanks for your reply.
my next question is, since I have 4 wheel DISC brakes, is there an automatic brake adjuster on my car? and if so, how hard/easy is it to adjust it yourself?
 
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Old 01-23-04, 04:16 PM
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I tried the hand vacuum pump method once, it didn't work. I think air leaks in around the threads of the bleed screw. Went back to my old method of a helper pumping the pedal for me. Works everytime. Disk brakes do not need to be adjusted.
 
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Old 01-23-04, 04:27 PM
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The service brakes on your car require no adjustment,the parking brake does but would not cause your problem.If when you changed the calipers the master cylinder went dry you may have to remove and bench bleed it to remove any air.Most master cylinders are mounted at a slight angle and air gets trapped at the front.
 
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Old 01-24-04, 01:43 PM
Travman81
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are bench bleeding, hand bleeding and bleeding manually all the same ?
i am going to have my mom sit in the car and pump the brakes while I 'bleed' them, but i need to find out step by step how to do this.....can you guys tell me how to manually bleed brakes, and if I want to do it on all 4 calipers, is that a no-no or is there a certain order i should do it in?
 
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Old 01-24-04, 01:47 PM
Travman81
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Manually Bleeding-How to...?

I am going to manual bleed my breaks and I need a step by step instruction on how to do this....I do have someone to help(pump the brakes) I just need to find out what I need to do while my helper in the drivers seat.
 
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Old 01-24-04, 03:39 PM
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Just have him pump it to build as much pedal as possible, usually 3 or 4 pumps, and while he's holding pressure, open one of the bleeders to relieve the pressure then close it. Let him pump it up again and repeat. Start with the farthest wheel away from the master and move closer. Be sure to refill the master between wheels and make sure it never goes empty. Also make sure he always hold pressure while you have the bleeder open. Do this until all air is gone or fluid runs clean, depending why you are doing it in the first place.
 
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Old 01-24-04, 03:47 PM
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Originally posted by Travman81
jughead, thanks for your reply.
my next question is, since I have 4 wheel DISC brakes, is there an automatic brake adjuster on my car? and if so, how hard/easy is it to adjust it yourself?
Rear disc brakes can sometimes be a problem to get adjusted all the way. The piston tends to retract back a little every time due to the seal rolling on the piston and springing back. A little trick I use to get them tighter is to put a set of vise grips on the hand brake lever so I can apply it easily by hand. Now apply the brakes with the lever and while your holding them applied, stick a screwdriver into the caliper and grab the groove at the top of the piston and hold it against the pad while you release and apply the lever again. This will usually advance the ratchet one more tooth to get a tighter adjustment.
I answered your other thread on bleeding instructions. Have you check to make sure the calipers are on the right side of the car?
 
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Old 01-24-04, 04:20 PM
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Im merging these threads to keep things together and keep the confusion down.
Billy
 
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Old 01-25-04, 12:02 AM
Travman81
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Im not positively sure that me and my stepdad put the correct caliper to the correct wheel ( I just assumed since he knew what he was doing that all was OK), but I will remove the wheels and check..How do I check? does the caliper have writing on it that will say R or L?

and also what kind of damage could be caused by leaving air in the system for a lengthy period of time? just curious...
 
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Old 01-25-04, 04:36 AM
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Originally posted by Travman81
Im not positively sure that me and my stepdad put the correct caliper to the correct wheel ( I just assumed since he knew what he was doing that all was OK), but I will remove the wheels and check..How do I check? does the caliper have writing on it that will say R or L?

and also what kind of damage could be caused by leaving air in the system for a lengthy period of time? just curious...
It is very easy to do. The only difference is it will be upside down and the bleeder will not be at the highest point of the caliper, hence trapping air that cannot be removed. I've seen it happen often. Air in the system will eventually cause corrosion but the only immediate problem is not being able to stop....big problem.
 
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Old 01-29-04, 09:20 AM
Travman81
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Thanks for All YOur Help

I appreciate everyone's advice and help....but it turns out that the reason my brakes feel a little mushy is not due to air in the system..In fact, there is no air in the system.
I took it to a Meineke repair shop and had a free estimate performed on the entire brake system. The mechanic came in and said he couldnt find nothing wrong with the brakes, and that the pedal felt fine to him. then i told him 'my brakes havent felt the same ever since i put new calipers on the rear's.' this then prompted the mechanic to inspect the rear brakes with more detail and he noticed that the the piston in the left rear caliper was not 'in line'. so he suggested that that was the problem and told me to correct the 'brake problem' I would have to turn the piston in the rotor clockwise until it lined up with some mark on the caliper. He said the right rear caliper was fined and had the correct grooves in the piston, while the left rear did not have the same corresponding grooves. this made sense to me, so i'm going to turn the piston clockwise to the 'correct' position and see if this helps my brakes. but again the mechanic felt that the pedal was not mushy and i had good stopping power.

once again, thanks for all your advice. you've taught me a few things about brakes that I didnt know and it will come in handy im sure.
 
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Old 01-29-04, 04:43 PM
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Yes, there is a pin on the brake pad that has to sit in one of the slots. If it doesn't, you get a spongy pedal.
 
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