# Soft pedal after brake swap.



## veedub1991 (Mar 16, 2006)

Ok so heres the deal, I have a 91 gti 8v. I did a brake swap off of a 95 jetta 2.0. Swap everything including the master cylinder. At first the brakes worked good. Then the pedal went soft, so I figured I need to bleed them. So I did and they worked good for a day then they went back to the floor. Im not leaking fluid. What could be the problem? They still work if I pump them 4 or 5 times. But most of the time they will just go stright to the floor. Anyone have any ideas, things to check?


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## Memphis R32 (Dec 13, 2004)

probally still a bubble in the line somewhere


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## Occams_Razor (Jun 28, 2003)

*Re: Soft pedal after brake swap. (veedub1991)*

Check your master cylinder. Did you replace it or did you just swap it from the other car?


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## veedub1991 (Mar 16, 2006)

*Re: Soft pedal after brake swap. (Occams_Razor)*


_Quote, originally posted by *Occams_Razor* »_Check your master cylinder. Did you replace it or did you just swap it from the other car?

Swaped it from the other car, and it worked just fine in the other car. I was told to bleed directly from the master cylinder instead of at the brakes


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## screwedRado (Sep 20, 2004)

*Re: Soft pedal after brake swap. (veedub1991)*


_Quote, originally posted by *veedub1991* »_
Swaped it from the other car, and it worked just fine in the other car. I was told to bleed directly from the master cylinder instead of at the brakes

The bleeding from the master doesnt make sense, bleed at the caliper and then let us know how it goes


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## veedub1991 (Mar 16, 2006)

*Re: Soft pedal after brake swap. (screwedRado)*


_Quote, originally posted by *screwedRado* »_The bleeding from the master doesnt make sense, bleed at the caliper and then let us know how it goes









I have bleed at the caliper many times now. It seems to work better for a few miles, then its back to a pedal to the floor.


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## igotaprestent4u (Nov 2, 2002)

*Re: Soft pedal after brake swap. (veedub1991)*

did you try with a powerbleeder or did you pump the pedal?


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## screwedRado (Sep 20, 2004)

*Re: Soft pedal after brake swap. (veedub1991)*


_Quote, originally posted by *veedub1991* »_
I have bleed at the caliper many times now. It seems to work better for a few miles, then its back to a pedal to the floor.

Check the system, you have to have a leak somewhere, or perhaps the M/C is bad, even though it worked before, what year car is it off?


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## veedub1991 (Mar 16, 2006)

*Re: Soft pedal after brake swap. (igotaprestent4u)*


_Quote, originally posted by *igotaprestent4u* »_did you try with a powerbleeder or did you pump the pedal?

I have dont both. First was with a power bleeder than, the next time I used the pump method.


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## veedub1991 (Mar 16, 2006)

*Re: Soft pedal after brake swap. (screwedRado)*


_Quote, originally posted by *screwedRado* »_Check the system, you have to have a leak somewhere, or perhaps the M/C is bad, even though it worked before, what year car is it off?

The M/C is off a 95 jetta 2.0. My guess was I have a leak, but I can not find it. Its only leaking air in, I dont loose any fluid.


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## screwedRado (Sep 20, 2004)

*Re: Soft pedal after brake swap. (veedub1991)*


_Quote, originally posted by *veedub1991* »_
The M/C is off a 95 jetta 2.0. My guess was I have a leak, but I can not find it. Its only leaking air in, I dont loose any fluid.

I would swap out the master, because if one of your lines or calipers or brake components had a leak, it would be leaking fluid out, what you have sounds alot like a bad M/C, lmk if you have any more questions


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## veedub1991 (Mar 16, 2006)

*Re: Soft pedal after brake swap. (screwedRado)*

alright thanks


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## veedub1991 (Mar 16, 2006)

*Re: Soft pedal after brake swap. (screwedRado)*

I have new info on the brakes. So I just took a 250 mile drive and realized that the brakes will work if I pull the e-brake up and pump the brakes once. Then the brakes will work just fine.
Does this make any since? It makes me think something is wrong with the back brakes.


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## screwedRado (Sep 20, 2004)

*Re: Soft pedal after brake swap. (veedub1991)*


_Quote, originally posted by *veedub1991* »_I have new info on the brakes. So I just took a 250 mile drive and realized that the brakes will work if I pull the e-brake up and pump the brakes once. Then the brakes will work just fine.
Does this make any since? It makes me think something is wrong with the back brakes.

Do you have rear calipers or drums? If you have calipers you must remove the caliper from the carrier and turn the caliper so the bleeder valve points up and bleed the caliper this way. For some reason the rear calipers will hold a air bubble you cannot bleed out without removing them and bleeding them in this fashion. Get your hands on a power bleeder and get that thing done.


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## veedub1991 (Mar 16, 2006)

*Re: Soft pedal after brake swap. (screwedRado)*


_Quote, originally posted by *screwedRado* »_
Do you have rear calipers or drums? If you have calipers you must remove the caliper from the carrier and turn the caliper so the bleeder valve points up and bleed the caliper this way. For some reason the rear calipers will hold a air bubble you cannot bleed out without removing them and bleeding them in this fashion. Get your hands on a power bleeder and get that thing done.









I have rear drums. And I did not swap those I just swaped the front.


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## screwedRado (Sep 20, 2004)

*Re: Soft pedal after brake swap. (veedub1991)*


_Quote, originally posted by *veedub1991* »_
I have rear drums. And I did not swap those I just swaped the front.

Change your master cylinder, then go from there, I wouldnt be driving the car this way, but good luck


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## veedub1991 (Mar 16, 2006)

*Re: Soft pedal after brake swap. (screwedRado)*


_Quote, originally posted by *screwedRado* »_
Change your master cylinder, then go from there, I wouldnt be driving the car this way, but good luck
















Ya if I cant adjust the rear brakes then changing the master will be the next. I would just like to not have to buy a master, So far the cheapest I have found it 90 with a core.


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## screwedRado (Sep 20, 2004)

What size M/C do you need?


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## veedub1991 (Mar 16, 2006)

*Re: (screwedRado)*

Im not sure of the size, but its from a 95 vw jetta 2.0l no abs.
I was told that if I went backwards and hit the brakes then it would start to fix my problem. I did this and after a while of doing it, it started to work better. The only problem is the brakes only work half the time now.


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## screwedRado (Sep 20, 2004)

*Re: (veedub1991)*


_Quote, originally posted by *veedub1991* »_Im not sure of the size, but its from a 95 vw jetta 2.0l no abs.
I was told that if I went backwards and hit the brakes then it would start to fix my problem. I did this and after a while of doing it, it started to work better. The only problem is the brakes only work half the time now.

let me find out for you


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## screwedRado (Sep 20, 2004)

*Re: (screwedRado)*

Does it look like this one?








If so I can get you a used one for a couple of $$$$ SHould be a 20mm


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## Banditt007 (Oct 23, 2002)

*Re: (screwedRado)*

if everything works normal with the ebrake pulled up on a car with rear drums either your adjusting wedge is not working correctly. 
I beleive its also a symtom of a bad rear proporting valve but i could be wrong on that, but for sure i'd put $ on the adjusting wedge operation.
as for the master cylinder. buy plugs or the right thread bolts with teflon tape on them, and put them in slightly right where the brake lines normally go into the master. power bleed them until pure fluid comes out and tighten down while fluid is still comming out. hit the pedal. if it feels normal then your master is good, if it feels like crap, the master is toast.
EDIT: just re read that you swapped the master and its good, so again i refer back to the adjusting wedge operation/rear prob valve.


_Modified by Banditt007 at 12:33 AM 11-23-2006_


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## veedub1991 (Mar 16, 2006)

*Re: (Banditt007)*


_Quote, originally posted by *Banditt007* »_if everything works normal with the ebrake pulled up on a car with rear drums either your adjusting wedge is not working correctly. 
I beleive its also a symtom of a bad rear proporting valve but i could be wrong on that, but for sure i'd put $ on the adjusting wedge operation.
as for the master cylinder. buy plugs or the right thread bolts with teflon tape on them, and put them in slightly right where the brake lines normally go into the master. power bleed them until pure fluid comes out and tighten down while fluid is still comming out. hit the pedal. if it feels normal then your master is good, if it feels like crap, the master is toast.
EDIT: just re read that you swapped the master and its good, so again i refer back to the adjusting wedge operation/rear prob valve.

_Modified by Banditt007 at 12:33 AM 11-23-2006_


How would I self adjust that? I did the driving in reverse thing and it helped but its still not normal.


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## veedub1991 (Mar 16, 2006)

*Re: (screwedRado)*


_Quote, originally posted by *screwedRado* »_Does it look like this one?








If so I can get you a used one for a couple of $$$$ SHould be a 20mm

Yes that looks like it.


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## veedub1991 (Mar 16, 2006)

*Re: (veedub1991)*

Well I think I may have found the problem. Three of the back shoes are good, but one on the passenger side is completely gone on the bottom half of it. That made the adjuster move down the the point that it cant be adjusted anymore. So I will be changeing those this weekend and hopefully that will solve it.


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## screwedRado (Sep 20, 2004)

*Re: (veedub1991)*


_Quote, originally posted by *veedub1991* »_Well I think I may have found the problem. Three of the back shoes are good, but one on the passenger side is completely gone on the bottom half of it. That made the adjuster move down the the point that it cant be adjusted anymore. So I will be changeing those this weekend and hopefully that will solve it.

Good to hear you made some progress, keep us (me








) posted


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## veedub1991 (Mar 16, 2006)

*Re: (screwedRado)*

will do


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## veedub1991 (Mar 16, 2006)

*Re: (veedub1991)*

Well I changed the back shoes, along with the drums, and also I put new bearings and seals. Now the e brake is much stiffer which is good, but I still dont have brakes until the bottom of the pedal, and they dont work good down there.


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## RayzrX (Nov 20, 2006)

*Re: (veedub1991)*

Just chiming in...








You have received some great advice already; let's just get back to the basics here - you have an air leak or a possible equipment mismatch. Most air leaks come from the m/c reservoir (were it mounts into the m/c body/housing) or from the m/c rear seal (where the push-rod will attach to the brake pedal)
Pressure is maintained thru-out the system with common points-of-failure in the following areas - rubber brake lines (too soft), proportion valves (or mis-adjusted), caliper seals (not dust boots), wheel cylinders, and bleeder valves.
A few???’s…:
1. What is everything - (calipers, lines, m/c, p-valves, brake booster, rotors, etc...)?
2. Brake fluid type – before and after change?
3. Any other (non-OEM) braking mod’s…?

What you want to do/ (re)check: (paying special attention-to-detail)
1. Check entire system for any slight fluid seepage (@ caliper, wheel cylinders, brake line connections, rear m/c seal from inside the car @ pedal push rod) -you may have to pull back the carpet slightly to check the pushrod, the booster check is seen under the hood where the two mount
2. Fill & bleed the m/c - (necessary if you replaced it or not; the lines were exposed to air)
3. Have an aide/helper pump & hold the brake pedal down (ignkey off, ebrake off) - see if the pedal slowly drifts to the floor.
4. Do not apply the ebrake when bleeding
5. Have someone pump the brakes while you check the lines for expansion/leaks
6. Bleed the brakes - (starting farthest away from the master cylinder; rear pass, rear drvr's, pass frt, drvr’s frt) - Finish the bleed job before removing/checking/adjusting any components
7. Ensure that the m/c push-rod (& booster assy.) from the donor car is the same length (or spacing) as ur car - if changed. Also, check p-valve numbers
Repairs: (by the numbers)
If 1, replace leaking component(s) and re-bleed, retest
For 2, leave the m/c mounted, attach proper bleeder connections/tubes, have an aide pump brakes until no bubbles (minimum) appear. Check for leaks @ mount points and inside car @ pushrod
For 3, this is performed after bleeding the entire system and checking for leaks – if the pedal goes to the floor and no leaks; r&r the m/c
For 4, minimizes pedal travel and gives false pressure pedal feel/readings
For 5, an aide/buddy is very valuable to diagnosis of intermittent problems
For 6, best if a manual bleed procedure is performed. Ensure that a strong/constant fluid flow is present w/out bubbles (air) @ each wheel.
For 7, this physical check will determine if the parts added require adjustment or are totally incompatible

Let us know... will go to next steps after checks.
R


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## mk1g60gti (Dec 2, 2003)

*Re: (veedub1991)*


_Quote, originally posted by *veedub1991* »_ Three of the back shoes are good, but one on the passenger side is completely gone on the bottom half of it. That made the adjuster move down the the point that it cant be adjusted anymore.

i hate drums


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## veedub1991 (Mar 16, 2006)

*Re: (mk1g60gti)*


_Quote, originally posted by *mk1g60gti* »_
i hate drums









Ya me too, I thought when I found that, I had found the problem. But I guess not


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## Banditt007 (Oct 23, 2002)

*Re: (mk1g60gti)*

drums are great. they last like 100k miles trick is when you go in there replace everything and you're good to go. no brake dust on the rear wheels is a plus too. O yeah and an ebrake that works all the time unlike :cough: the rear disks. They dont look that good though..


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## veedub1991 (Mar 16, 2006)

*Re: (RayzrX)*


_Quote, originally posted by *RayzrX* »_Just chiming in...








You have received some great advice already; let's just get back to the basics here - you have an air leak or a possible equipment mismatch. Most air leaks come from the m/c reservoir (were it mounts into the m/c body/housing) or from the m/c rear seal (where the push-rod will attach to the brake pedal)
Pressure is maintained thru-out the system with common points-of-failure in the following areas - rubber brake lines (too soft), proportion valves (or mis-adjusted), caliper seals (not dust boots), wheel cylinders, and bleeder valves.
A few???’s…:
1. What is everything - (calipers, lines, m/c, p-valves, brake booster, rotors, etc...)?
2. Brake fluid type – before and after change?
3. Any other (non-OEM) braking mod’s…?

What you want to do/ (re)check: (paying special attention-to-detail)
1. Check entire system for any slight fluid seepage (@ caliper, wheel cylinders, brake line connections, rear m/c seal from inside the car @ pedal push rod) -you may have to pull back the carpet slightly to check the pushrod, the booster check is seen under the hood where the two mount
2. Fill & bleed the m/c - (necessary if you replaced it or not; the lines were exposed to air)
3. Have an aide/helper pump & hold the brake pedal down (ignkey off, ebrake off) - see if the pedal slowly drifts to the floor.
4. Do not apply the ebrake when bleeding
5. Have someone pump the brakes while you check the lines for expansion/leaks
6. Bleed the brakes - (starting farthest away from the master cylinder; rear pass, rear drvr's, pass frt, drvr’s frt) - Finish the bleed job before removing/checking/adjusting any components
7. Ensure that the m/c push-rod (& booster assy.) from the donor car is the same length (or spacing) as ur car - if changed. Also, check p-valve numbers
Repairs: (by the numbers)
If 1, replace leaking component(s) and re-bleed, retest
For 2, leave the m/c mounted, attach proper bleeder connections/tubes, have an aide pump brakes until no bubbles (minimum) appear. Check for leaks @ mount points and inside car @ pushrod
For 3, this is performed after bleeding the entire system and checking for leaks – if the pedal goes to the floor and no leaks; r&r the m/c
For 4, minimizes pedal travel and gives false pressure pedal feel/readings
For 5, an aide/buddy is very valuable to diagnosis of intermittent problems
For 6, best if a manual bleed procedure is performed. Ensure that a strong/constant fluid flow is present w/out bubbles (air) @ each wheel.
For 7, this physical check will determine if the parts added require adjustment or are totally incompatible

Let us know... will go to next steps after checks.
R











For your questions. Everything is from my car 91 gti 8v. Except the front spendials, rotors, calipers, and M/C. Those are all from a 95 jetta 8v. They all worked before the swap. Brake fluid is dot 4, and Im pretty sure it was dot 4 before, if not then it was dot 3. Other than that there is no other mods to the brakes.


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## RayzrX (Nov 20, 2006)

*Re: (veedub1991)*

Other mouthful....








My assessment is that you are having the reoccuring problem because air or vapor still exist within the brake lines and/or master cylinder (m/c). 
This would cause the exact problem ur having - "...bleeding the brakes and the car brakes fine, but shortly thereafter; the pedal is soft or spongy again..."
The reason(s) for this condition is:
1. The m/c cap 'rubber boot' (seal/cup) is distorted or swollen or damaged.
2. The m/c cap vent is plugged or restricted.
3. The brake fuild is contaminated - (due to vapor build-up, mixed brake fuild types-(racing fuild DOT5/silicone based with DOT4 or DOT3 or any other invalid combo). Vapor causes a spongy pedal.
NOTE: DOT3 absorbs more moisture than DOT4, and DOT5 doesn't absorb any moisture - DOT5 also will not harm the paint on ur car like the others will. Mixed fuilds could 'boil' @ a lower-than-specificed rate and cause/create vapor in the system, especially after continuous hard braking.
???'s:
1. Did the m/c swap include the resevior/cap/seal from the donor car OR did you swap the body only and then add ur original resevior/cap/seal?
2. What type of p-valve's do u have OR is there a combo valve installed (metering, pressure, p-valve) 
3. If combo, and the system was power bleed - was the metering valve open @ the time? It should have been...

Check:
1. Remove the m/c cap and inspect the rubber seal
2. Ensure that the cap vent (small hole) is not plugged or that one exists.
After checking and bleeding the system - be sure stop moderately for awhile - meaning try not the lockup the brakes or perform really hard stops testing the brakes until u can isolate/fix this issue. 

I believe the answer has already been stated in this thread...
R











_Modified by RayzrX at 12:59 AM 12-16-2006_


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## rccar (Jul 21, 2006)

I stronger suggest you check all brake soft pipeline especially front wheel.May be you will find some flaw on it.If soft pipeline agine,replace them.


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## veedub1991 (Mar 16, 2006)

*Re: (rccar)*

Update... Ok so I just manually bleed the entire system. I started with the rear pass side and it worked just fine. Then I went to rear driver side, that one would not bleed at all, I was able to get a little fluid out but the pedal would not go to the floor. Then moved to the front pass that too would not bleed right. So then I went to the front driver side and that bleed just fine. But there was no improvement in the brakes.

Also there was a knocking sound in the brake booster when I was pumping the brakes?


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## veedub1991 (Mar 16, 2006)

*Re: (RayzrX)*

another update... Ok so I just replaced the wheel cylinder on the drivers rear. After doing this I was still unable to bleed any fluid out. The only way I could get it out was running the car and pumping the brakes. And then it was only a drop or to.
My next thought was that there was crap in the lines so I un-hooked the line comming out of the p-valve and air was free flowing from there to the brakes. And when the brakes were pumped fluid came out of the p-valve.
Anybody have any ideas now?


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## jhayesvw (Oct 3, 2001)

*Re: (rccar)*

im actually having the same problem with the same year master cylinder and such.
my brakes have felt soft for over a year and a half. 
i put NEW calipers on and NEW lines, NEW pads, NEW rotors.
i bleed with a power bleeder (MOTIV).
the brakes work for a day or less then feel spongy again.








where is the hole in the master cylinder i should be looking for?


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