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Brakes... no love from them.

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Old 01-25-2007, 09:26 PM
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Default Brakes... no love from them.

Hey all. I just replaced 80% of my brake system...

But after a lot of work and money I still have low pedal which makes me sad :< Honestly, it stops a bit better now like I have to press a little less on the pedal to stop now but I can still press the pedal to the end of the master cylinder with not that much effort. Its not SOFT pedal... just LOW pedal.

This car does _NOT_ have abs. Just plain jane 4 channel master cylinder.

Newho this it what I have done, all brand new stuff, no cheap stuff either. All premium where I could afford/aquire.

Front brakes:

- 4 Wagner premium thermoquiet brake pads
- 2 Wagner premium rotors made in USA
- 2 brake lines
- 2 calipers
- 4 caliper pins
- 4 caliper bushings/insulators/slides

Rear brakes:

- 4 Wagner premium brake pads
- 2 Wagner premium brake drums
- 2 brake lines
- 2 wheel cylinders
- 2 big horseshoe shape return springs
- 2 of them small self adjuster tension springs
- 2 new self adjusters

AND. I also replaced the master cylinder.

I also lubed up the caliper bushings like a good boy. Verified by pushing them back and forth w/ out the disc installed that they were freely able to slide and not too much play. Also lubed up the self adjusters and put a tad of grease on the backplate where the pads are constantly rubbing on the backing plate.

I also checked the vacuum line coming from the booster, it was good but I replaced it anyway. I also checked the check valve, it was good but i replaced it any way with its little rubber grommet deally. They were super cheap parts so... why not.

I also checked what the booster was like, when I had the master cylinder OFF the car and the engine running. The pedal literally goes to the floor w/ no master cylinder installed with zero effort and right away comes back up to normal height when u release the pedal.

I also did the turn off the car, pump the pedal to get all the vacuum out of the booster come back in a half hour and see if it still has no vacuum and that was ok.
Then I did the turn off the car but dont pump the pedal come back in 30mins and see if there is still vacuum in the booster left and that was ok too.

I know these H-body cars the rear brake adjustment can make a huge difference in pedal slop. The rear brakes are adjusted properly as far as i can tell. With the back end up on stands both sides have just the very slightest ammount of drag. E-brake is not low either, it comes on about 1/3 way of ebrake pedal travel.

So yea... im like super stumped guys. Never had a problem like this before. With absolutely everything changed minus the steel brake lines under the car which look good, no rust and the brake booster but it really seems fine to me.

Atleast when I jam the pedal down there is no more pull to the driver side so at least I fixed one issue (the caliper slides were frozen solid). I just want my brakes to engage hard at more like 1/2 travel instead of like 3/4 travel.

Or perhaps thats just how these cars are, I have never had a 91 H-body w/no abs before to compare it to. I just seem to remember in my silverado, chyenne, two centurys, cobalt, cavalier, focus and my work van the pedal will not let me go to the end of the master cylinder nearly as easy. Every car I have ever driven has been that way... so... just makes me think the H-body might have a gremlin, or two. Brakes are important man!

That was a long one...

P.*. the wheel bearings are good too, I replaced every one of them last year with brand new ones.
Old 01-25-2007, 09:37 PM
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Default

mine is the same way. it just seems to be a weird characteristic. if your car stops normally and you can do hard stops with no problem then you should have nothing to worry about. i can do a hard stop and everything stops normally, but i can also press the pedal down pretty far... but believe me, it may seem far, but it actually isn't the brake pedal can go all the way to the floor... how much room is there between the floor and pedal. what may seem low most likely is not low at all.

Edit: mine were also that way in my '90 Electra Park Avenue....i just learned to accept it.
Old 01-25-2007, 09:41 PM
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Don't live with it. Fix it.

Did you bench-bleed the MC? How well did you bleed the 4 corners? That'* alot of work. Old fluid can do this as well. Has it flushed completely through?
Old 01-25-2007, 10:33 PM
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midas only charged me like 60 bucks to completely bleed my brakes and was well worth it!!!!
Old 01-30-2007, 02:10 PM
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Unless I missed it reading your post, like the others have said, you need to bleed the brakes. You also need to have bench bled the master cylinder before you installed it. Your low pedal is symptomatic of air trapped in the lines. Here is a procedure for bleeding the brakes if you haven't done it before. Sometimes, the pedal will remain low until the last (LF) line is bled.

These directions presume you have a good master cylinder or a new one that has been bench-bled.

You will probably need to remove the rear wheels to gain access to the wheel cylinder bleeders. You may be able to get at the front bleeders on the calipers by turning the wheels all the way left or right. I find bleeding is a lot easier with all the road wheels removed and the car up on stands. Never get under a car supported only by a jack!

Start by filling the master cylinder reservoir and replacing the cap. Don't let brake fluid be exposed to the air - it will absorb moisture from the atmosphere which can cause troubles in the brake lines. What you want is to have a helper pump the pedal a couple of times (press down - release; press down - release) then press down and hold. While he is maintaining pressure on the pedal, you open the bleeder valve on the wheel cylinder or caliper and relieve the pressure by releasing fluid from the bleeder valve. The brake pedal will suddenly go down, at first nearly all the way to the floor. The helper must not allow the pedal to come up while the bleeder valve is open or air will be sucked in through the bleeder valve. At the wheel, when the fluid flow stops, close the bleeder screw and instruct your helper to release the pedal, then "pump and hold" again. After a few times, depending on how much air is in the lines and where the air is located, you will notice as you open the bleeder valve, that the fluid flow is interuppted by escaping air. It kind of makes a "spitting" sound. That is good - that'* the air you are trying to remove. Keep repeating the procedure until the stream of fluid is solid - no air - and clean in appearance.

While you are bleeding each wheel, after about five or six squirts, check the level of fluid in the master cylinder reservoir. If you let the reservoir go empty, you will introduce air into the lines and you will have to bleed the master cylinder and all the brakes again.

I like to place a box wrench on the bleeder screw nut in a position that allows me to both open and close the valve (hopefully) without repositioning the wrench. I then attach a length of flexible vinyl tubing (maybe 3/16" inside diameter) that fits tightly over the end of the nipple on the end of the bleeder. I run the hose into a plastic pan to catch the fluid that comes out. Be careful, brake fluid removes paint. Also, don't use more than a couple of foot-pounds of torque to close these little bleeder screws - they are not solid and they can break off very easily.

There are a couple of inexpensive one-man methods. You can use a vacuum pump to suck out the air from each line, but the problem with that is that you have to open the bleeder screw to open the line and when you do, you usually end up sucking some air through the threads on the bleeder screw making it difficult to know when you have all the air out. An older method is to take the hose described above and put it into a (clean and dry) coke bottle with the end of the hose submerged under a couple of inches of brake fluid. This is not a bad idea, even with a helper, cause if your helper screws up and releases the pedal when the valve is still open, it will suck mostly fluid in from the bottle instead of air. The problem with this method is the same as with the vacuum pump. That is, on the release stroke, if the valve is open, air can be sucked into the system through the threads on the bleeder screw.

Be careful if your bleeder screws are corroded. They will break off in the cylinder or the caliper with surprisingly little force applied, and then you have a real piece of work on your hands. A good plan is to squirt around the bleeder screw (not into it) with a good penetrating oil like power blaster, kroil, or sea foam deep creep (WD-40 is not very good for this). Remove the cap from the screw and give it a couple of taps square on the end of the screw with a small ball-pein hammer, and squirt again to encourage the oil to penetrate the threads. Best if you can let it sit overnight, but give the oil at least 30 minutes to work before you try to open the bleeders.

If your bleeders don't have the little rubber caps on them, make sure the passage is clear to let the fluid out. Sometimes you have to clean them out with a small drill bit.

The traditional method is to start at the wheel farthest from the master cylinder, usually the right rear, and work to the shortest run, i.e., the left front. As you work your way around, the pedal should become firmer and progressively higher from the floor. When you are done, if you have removed all the air, the pedal should be firm, there should be no "sponginess," or softness when depressed.

Good luck!
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