# Front breaks working to good???



## jnesbitt (Dec 24, 2009)

*Front brakes working to good???*

I have an 83 VW rabbit deluxe, 1.6 turbo diesel. I put new brake shoes on the back when the front brakes where grabbing. The old rear brakes where shot. I replaced everything, and still having the same problem. I almost seems as if all of the brake pressure is going to the front disks and nothing to the rear..is this a valve problem. I have the auto ajusting slidder type drums on the rear. Any ideas?? I replaced the fluid and bleed the system. The brakes will build pressure..I have no fluid leaks yet if i hold my foot on the pedel it will slowly go down on its own as if has a leak someplace..?? thanks for the help....










_Modified by jnesbitt at 6:10 AM 12-24-2009_


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## poonamt93 (Dec 24, 2009)

*Re: Front breaks working to good??? (jnesbitt)*

Bench bleeding does not take a lot of time. Just disconnect every thing and put it a vice and pump the hell out of it(with adapters and lines going back to the reservoir). Once installed, have another person help pressure bleed it one wheel at a time. Go in this order, Right rear, left rear, right front and last left front.


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## jnesbitt (Dec 24, 2009)

*Re: Front breaks working to good??? (poonamt93)*

Thanks..opps I meant Brakes..not breaks..


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## jnesbitt (Dec 24, 2009)

*Re: Front breaks working to good??? (jnesbitt)*

Ok..probem has gotten worse. Car brakes ok but still grabbing in the front. I drove it to the mall today and back, and the pedal was going to the floor..I got home pumped the brakes and no pressure. I check the fluid and it was empty. I added more and pumped still no pressure. I will bleed and see if that helps but I'm afraid the master cylinder is shot and ideas??


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## greyhare (Dec 24, 2003)

*Re: Front breaks working to good??? (jnesbitt)*

Did you replace the master cylinder?
Your description of a sinking peddle sounds like a failed MC. You may not see any fluid leak because it could be going in the booster.


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## jnesbitt (Dec 24, 2009)

*Re: Front breaks working to good??? (greyhare)*

I too feel its the MC and have ordered a remanned one..Thanks


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## jnesbitt (Dec 24, 2009)

*Re: Front breaks working to good??? (jnesbitt)*

Ok..I've replaced the MC and bleed the brakes..firm pedal on non running engine. When I start the engine..pedal goes to the floor..and is spongy while driving..air in the lines?? Bleed again??


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## jnesbitt (Dec 24, 2009)

*Re: Front brakes working too good...*

I'm at a dead end..I have new lines new brakes on the rears..new master and bleed the brakes 3 times. Still doing the same thing it did before I replaced anything. I pump the peddle with the engine off and the pedel is firm pumps up great..soon as I start the car pedel goes to the floor and there is a swishing sound when I pump them up..they pump up firm after 3 pumps but then slowly goes to the ground. When I drive her and hit the breaks my pedel is super spongy and goes the ground, if I put the brakes on harder than just foot presure the the front breakes grab. If I step on the brake hard the front tires lock up and slide. The rears are working if I back down my driveway and hit the brakes the catch just fine..just dont seem to work when I drive. Faulty proportioning valve?? Brake booster...I'm at a loss..next stop will be a shop..hate to spend the money on a simple fix..if it is one...


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## waabaah (Jun 24, 2006)

*Re: Front brakes working too good... (jnesbitt)*

there are alot of thigns i read that are all over the place. the thing that gets me confused reading all your troubles is that you mentioned the fluid was low before you replaced your MC. double check that you dont have any leaks..spray down the wet areas with brake cleaner or wipe them off..give the pedal a couple good pumps and recheck the dry areas.
things that could cause a spongy pedal liek you describe:
air in system
master cylinder internal leak
master cylinder external leak
rear shoes not fully adjsuted
a brake fluid leaking line/hose/caliper/wheel cylinder etc..
if i had to guess whats going on...i would say air in the system. i dont think i read that you benched bleed the master cylinder. did you?
also what method are you using to bleed the brakes?
if you are opening up the bleeder and see any delay in fluid or air bubbles then you indeed still have air. so do just that...jack up car, and crack open the bleeder screw. report back and tell us what you find when you crack open the bleeder.


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## jnesbitt (Dec 24, 2009)

*Re: Front brakes working too good... (waabaah)*

Thanks for the reply. I have uses the one man bleed tool I purchased at NAPPA..it didnt work, then I got the vacuum system and it failed,then I had my wife pump the brakes 3 times and hold while I opend the line, then had her release and i closed it. I did this 4 times per brake. I cleared all the lines except one..I found air coming in the bleeder screw. I then put grease on all the bleeder screw threads and started over. I have my wife pump all lines until there wasnt any air coming out the line, I used a liter of fluid. I see no leaks and all my lines and fittings are new.. Still the same problem..I do agree I got air in the line..just not sure where its coming from..


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## jnesbitt (Dec 24, 2009)

*Re: Front brakes working too good... (jnesbitt)*

I didnt bench bleed. I installed the MC on the car and using an old cap I installed a bleed valve on the cap itself screwed it on and pressuised my compressor to 10 psi. I used a air gun and small section of hose to add pressure to the system,via the bleed screw on the cap then i opend the back bleed screw and presurized the system unitl I got fluid to come out of the rear bleed screw.This seemed to work well to bleed the Master and add fluid to the lines, but was concerned it might add air also. After I got the fluid to run out of each port, I capped all the lines and had my wife help me bleed the traditional way...


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## waabaah (Jun 24, 2006)

*Re: Front brakes working too good... (jnesbitt)*

bleeding procedure sounds good.. another method that works well to see if you have air in the lines is to one man it by opening up the bleeder screws. no pumping pedal...no "up down" method...no tools required. just open each bleeder and let gravity do its thing.
make sure MC is always topped off and after you have all four bleeders open, grab a beer and sit back and wait until you see go flow coming out with no bubbles whatsoever.
sometimes it helps to put your finger over the bleeder screw for a second and then release yoru finger.
note that the fronts should drip like a steady stream and that the rears should drip drip drip.
note that the rears should pretty much drip the same and the fronts should drip the same when compared side to side.
tighten all bleeders and start the car..repeat the process over and over again if you still experience problems.


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## jnesbitt (Dec 24, 2009)

*Re: Front brakes working to good??? (jnesbitt) UPDATE!!!*

Ok after all this mess I read my bentley manual and decided to look at my Brake servo. I pulled the vacuum line to check to see if it was working..and it was. I then decided to bypass the brake assist servo all together by keeping the vacuum line off and test the brakes. The peddal stayed firm even with the car running, firm at all times. I took if for a spin, harder to brake but my brakes worked..just a constant hard pedal...but they worked 200 percent better than they have been. So I'm assuming the problem is the main O ring seal between the servo and Master is bad an allowing air into the system thus the vacuum isnt working, thus the assit is gone or the diaframe in the servo is shot. I'm going to replace the servo and see what happens. Just wanted to update this other having the same problem can see what to look for.







I'll repost as soon as I find out what happens...JN


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## waabaah (Jun 24, 2006)

*Re: Front brakes working to good??? (jnesbitt) UPDATE!!! (jnesbitt)*

remove the two bolts that hold down the master cylinder. dont disconnect any brake lines. pull the MC forward, away from the booster (or servo). if there is any brake fluid present, then your master cylinder is bad. (again! ugh..dang reman parts)
your booster (or servo) doenst hold fluid, it holds air.


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## A2Carat (Jan 13, 2003)

*Re: Front brakes working too good... (jnesbitt)*


_Quote, originally posted by *jnesbitt* »_I had my wife pump the brakes 3 times and hold while I opend the line,* then had her release and i closed it*. 
 
Something is wrong here. You CLOSE the bleeder BEFORE she releases the pressure. Releasing the pedal before close the bleeder sucks air BACK into the system. 
.. and if there was a vacuum leak in your booster, you will have no assist. You need vacuum in the booster in order to provide the assist. Make sure the rear shoes are adjusted properly. There should be a SLIGHTLY drag to the drums when spinning them by hand.


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## jnesbitt (Dec 24, 2009)

*Re: Front brakes working too good... (A2Carat)*

I stated that wrong..yes..your right and that what I did..


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## jnesbitt (Dec 24, 2009)

*Re: Front brakes working too good... (jnesbitt)*

The rears are working..so you too think the booster is fine and there is air in the line??


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## jnesbitt (Dec 24, 2009)

*Re: Front brakes working too good... (jnesbitt)*

Ok all good repsonces but still doing the same thing..I''m just going to take it to the shop and I'll post what I come up with..


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## A2Carat (Jan 13, 2003)

*Re: Front brakes working too good... (jnesbitt)*

If your pedal drops with the engine running when the booster is hooked up, and have a hard pedal with the vacuum disconnected, the booster is working. Check for fluid behind the master that's between the booster and master.


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## waabaah (Jun 24, 2006)

*Re: Front brakes working too good... (A2Carat)*

OP mentioned that there is no brake fluid behind the master cylinder and in front of the booster. (IM response from him).
i told him his master cylinder is bad again but OP doesnt think so. 
taking it to a shop is the best route for OP since Op doesnt understand the braking system in full detail.
spongy pedal symptomns....these are the only ones i can think of and im pretty sure these are the only things.
rear brakes not adjusted (really only applies to drum brakes)
air in system
a brake fluid leaking line or hose
leaking caliper or wheel cylinder
bad master cylinder
(does not apply since the car is a 83 rabbit) final note since you just replaced master cylinder.... there is a special procedure to bleed the abs unit using a vagcom tool. this is mentioned in the manuals and alldata along with mitchell (technician tools). im 100 percent positive on 4th generation to present. mk3 and older does not utilize this.


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## A2Carat (Jan 13, 2003)

*Re: Front brakes working too good... (waabaah)*

any news?


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## jnesbitt (Dec 24, 2009)

*Re: Front brakes working too good... (A2Carat)*

ok took her to two shops first guy VW guy couldnt figure it out..put new master clyder in her...same problems. I took it to another shop and put new pads and clipers in her..they said the master was bad and also the brake booster..leaking fluid between the two. The probem is fixed and the brakes work great now.


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