# Brake Problem has me baffled... Need Help



## John222 (Oct 11, 2008)

Here are the symptoms; 

Car is a 97 Jetta GLS with rear drums. 

*Brakes don't grab like they should.* You have to stand on the pedal to lock up the brakes. Pads just don't seem to grab the disc sufficiently. But it's not a hard pedal, like insufficient vaccuum. Slight spongyness if you press hard, but that's due to slightly worn guide pins. 

*Low Pedal *- Pedal drops about 30% before any resistance at all. Just a slight squish sound. 

First of all, the car was much worst when I purchased it, so it's not something I've done. It's a pre existing condition. 

1. I replaced front brake lines at caliper. They were cracked and ballooning in several places. 
2. Front pads and disc were put on by previous owner. They are almost new. 
3. Rear rotors were also recently replaced by previous owner. 
4. One rear adjuster was on backwards. I corrected it and made sure both back brakes shoes were adjusted properly. 
5. Bled the hell out of the lines. 
6. Swapped out master brake cylinder. 
7. Checked brake booster by pumping brake to top then starting car and confirm pedal drops. Also confirmed it holds vaccuum when the car is shut off. 

Don't know what else it could be?


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## Anony00GT (Mar 6, 2002)

Hard to say without actually driving the car and feeling the pedal and brake function... 

But have you driven another A3 Jetta with rear drum that has known good brake function? You should have to really stand on the pedal to lock the brakes and skid on a dry road with good tires, the brakes shouldn't lock up with anything less (this goes for any non-ABS car), however they should be able to stop the car within a reasonable distance depending on vehicle speed, and you should have no problems during normal driving duties. 

Since you don't mention any problems with regular driving, I'm thinking you should compare this to another similar car, you may be spinning your wheels to find a problem that really isn't a problem at all...


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## John222 (Oct 11, 2008)

Actually, I also have a 98 Jetta VR6 and a 2nd 97 GLS. The brakes on the car in question are nothing like the other two. I don't believe my 105 lb daughter could get this car to stop in an emergency. Even in normal driving the brakes require much more pressure that the other two cars. 

Shouldn't there be a momentary change in vacuum change when you press the brake pedal?. I'm getting a steady 20psi. When I press the brake pedal, there is almost no variation is vacuum.


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## germancarnut51 (Mar 23, 2008)

If your pedal drops 30% before you get any braking, you still have a problem with the master cylinder. 

You may also have a problem with the vacuum booster. If the brake pedal is firm, but no braking action without applying heavy pressure to the brake pedal to get the car to stop. 

At first I considered the proportioning valve located on the rear beam, but since most braking effort comes from the front brakes, if the brake proportioning valve was defective, you would still get good braking action from the front. 

Have you checked the front calipers to make sure that they are free to slide, and the pistons are not seized or partially seized? sounds to me like the brake system has not be serviced on a regular basis, and bad/old brake fluid could have left debris in the calipers and wheel cylinders to interfere with motion, or corrode the insides. 

Is the car lowered? Have you checked to confirm that the wheel cylinders for the rear brakes are fully functional?


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## greyhare (Dec 24, 2003)

All of the above plus... 

Do you know what pads the PO put on the car? Some "life time" pads are about the same as a teflon block. No wear, no dust, no stop.


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## John222 (Oct 11, 2008)

Brake fluid was completely changed. 
Master cylinder was swapped out with know good unit - without any improvement. 
Front and rear calipers are physically functioning. 
Completely tested the booster and it's fine. 
Proportioning valve is working. 

Basically the brake pedal moves about 30% before the master cylinder does any work at all. 
And when I do brake I'm not getting the grip I should have. I suspecting cheap wheel disc may be the cause of poor performance. But the low pedal has me baffled..


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## John222 (Oct 11, 2008)

PBR Deluxe pads on the front but some cheap ass muffler shop brake disk. I'm about ready to order new pads and disc for the front. I'm also experiencing brake fade.


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## Anony00GT (Mar 6, 2002)

OK, I'm having a brain fart here, I should have picked this up before my last reply but for some reason I read "...with rear drum" and the details went over my head...You said in your first post that this car was rear drum, mentioned repairing an adjuster in the rear, then you later mentioned rear calipers. Then I re-read your first post, and saw that your first post mentioned rear rotors. Also, I'm wondering how a rear adjuster can be on backwards, as the A3 cars with rear drum don't use a screw-type rear shoe adjuster, and I think it can only fit one way. Need to know for sure if this car is rear disc or rear drum, the difference may matter. Also need to know for sure if this car is ABS-equipped or not. 

Again, it's hard to say without actually driving the car myself, but assuming it is rear drum with no ABS... 

Try this...remove the front pads, and use an angle grinder with appropriate disc to scuff up the pads and rotor surfaces, this will remove any glazing and/or rust that may have built up. Re-assemble and take for a good test drive, see how it feels. 

If it's still not fixed, since you now say that the pedal has to move 30% down before the master cylinder applies any pressure to the hydroulics (I was under the impression you had a good pedal)...re-bleed the entire system, start with the master cylinder and then bleed all 4 wheels again. Do it with a helper pumping the pedal, don't bother with the one-man bleeder things from parts stores. Pedal down, open bleeder, fluid should come out, close bleeder, pedal up...all 4 wheels in the proper order. 

Then test drive the car again and see what happens.


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## John222 (Oct 11, 2008)

No ABS, has drums in the rear. The adjuster is a wedge and it can be put in backwards. Pads and shoes are almost new. So are drums and disc. 

I'll try scuffing up the pads and front disc this week. I'm suspecting the disc are too hard and not letting the shoes bite. 

I bled the brakes again yesterday. No difference.


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## Anony00GT (Mar 6, 2002)

OK, I get what you're saying about the backward adjuster. 

Try scuffing the pads definitely. See what happens.


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## John222 (Oct 11, 2008)

Scuffing the pads made a significant improvement in braking for about a week. Also I'm finding the low pedal is a result of the adjusters not working as well as they should. Maybe I need to replace the brake springs?


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## Anony00GT (Mar 6, 2002)

John222 said:


> Scuffing the pads made a significant improvement in braking for about a week. Also I'm finding the low pedal is a result of the adjusters not working as well as they should. Maybe I need to replace the brake springs?


It would be a good idea. I know you said you didn't replace the shoes, but are the shoes relatively new, and the springs not so much?

Generally, it's a good idea to replace all the springs when changing shoes, as it's only an extra few bucks and the springs do wear out over time. I have seen people re-use the springs though.


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## germancarnut51 (Mar 23, 2008)

Since you seem to believe that the used master cylinder that you installed/swapped is good, and the problem may be due to improperly functioning rear drums brakes (due to problem with the adjusters), I suggest using a couple of pairs of vicegrips (or hose clamping pliers) on the rear brake hoses that go to the wheel cylinders.

This will isolate the rear brakes, and any fault in the wheel cylinders and brake adjusters will no longer affect front brake operation. If the brake pedal is still soft, then the problem is in fact the master cylinder that you installed, if there are no leaks in the remaining brake system, and the brake fluid was properly bled to remove all air after the master cylinder was installed.


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## John222 (Oct 11, 2008)

Rear brake lines are metal, so can't clamp. But I did put a C-Clamp across both brake cylinders and this solved the excess travel problems. So apparently I need to replace the rear brake hardware and double check that the cylinders are operating correctly.


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## John222 (Oct 11, 2008)

Replaced all rear brake springs and still the adjusters don't work as well as they should. The pads just don't get as close enough to the drum, that's why I have a low pedal. I'm going to replace the rear brake shoes next. For some reason I think the wedge must be binding against the shoe.


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## John222 (Oct 11, 2008)

Well, I ordered new rear brake shoes , parking brake cables and push bars for each side. Let see if that does the trick. Somethings got to get those shoes closer. Will put them on later this week and see what happens.


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## germancarnut51 (Mar 23, 2008)

Have you taken the time to check the diameter of the brake drums to see if they are simply worn out? 

Have you checked to make sure that there isn't a wear rdige preventing the rear brake shoes from moving properly?


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## John222 (Oct 11, 2008)

germancarnut51 said:


> Have you taken the time to check the diameter of the brake drums to see if they are simply worn out?
> 
> Have you checked to make sure that there isn't a wear rdige preventing the rear brake shoes from moving properly?


 Drums are almost new, absolutely no ridge.


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## John222 (Oct 11, 2008)

Update!! 

Big improvement in excessive pedal travel. I adjusted the brakes again but this time I completely loosened the parking brake cable before stepping on the brakes. Then I took the car for a ride and pumped the brakes several time to bed them in. This resulted in a definite improvement. Then I finished up and adjusted the parking brake. 

Now back to the poorly performing front brakes. I've come to the conclusion that the front rotor must be work hardened. So I'm going to order a new set of rotors and pads.


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## ryan56bauer (Jul 26, 2010)

Well, at least you got one thing working correctly... your best bet for the front ones is to get some new pads as you say..


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## John222 (Oct 11, 2008)

Another update - Installed new rear push bars and new brake shoes. Low pedal completely gone now. Back brakes now perfect. Just to sum up my problems turned out to be as follows; 

1. Previous owner installed lifetime brake shoes. Looked new, but had absolutely no bite. 
2. Previous owners garage must have lost some of the springs for the rear brakes and replaced them with springs that didn't even fit properly. 
3. Previous owners garage did some filing on the push bars that caused the adjuster wedges to bind up. 
4. It best to completely loosen parking brake pressure prior ro bedding in brakes. Let the wedges find their position before adjusting the parking brake cable. 

Now on to the fronts. I currently have PBR Deluxe pads on the front but the brake disc was installed by the previous owner. For some reason the pads can't bite into this metal. I use PBR Deluxe pads on all my cars and have experienced excellent results. So at this point I'm convinced it's the front brake disc. So in the next couple of weeks I'll be replacing the front brake disc with Brembo's and the pads with new PBR deluxe and that should be the end of it. 

Hope this helps someone. 
John


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