Nitroracer
Nitroracer SuperDork
7/25/14 2:53 p.m.

I am having some trouble re-building the brake system for my Volkswagen based chumpcar, and I need some help from those who may understand the VW world better than I do.

Chassis: 92' Golf GL MK2
Braking System: 94' Golf GL MK3 (equiv 90-92 Jetta GLi MK2)
Pedal set: 95' Passat (for VR6 and clutch master mount)

The chassis I am working with is a 92' Golf GL, a base model Mk2 car. At the wheels the calipers and rotors have been upgraded to 94' Golf GL spec, with 10.1" discs up from and discs upgraded from drums in the rear. This seems to be equivalent to a 90-92 Jetta GLi. The chassis side seems to have gone together without a hitch.

Booster: 92' Golf w/ Threaded adjuster

The problem is with the brake booster and master cylinder combination. We have an unknown booster that was installed in the car that always had a low pedal, the arm to the pedal is too short. So we purchased a proper MK2 VW power brake booster and now none of the brake master cylinders seem to fit properly. Correct me if I am wrong, but the brake master cylinder should slide into the booster and over the studs with no force, correct? Any master that I have been able to find needs to be pushed into place and that would effectively be engaging the master cylinder.

I noticed this difference between the boosters, but now its hard to tell what parts are right and wrong anymore. The pin on the brand new part, which no master cylinders will fit properly is flush with the mounting surface, while the used part has a pin that is recessed, and all master cylinder seem to fit as they should.

noddaz
noddaz GRM+ Memberand Dork
7/28/14 6:34 a.m.

Very interesting... Any chance that you have a local JY you could go too and find a car to pull the M/C loose and see what is correct? Although it does seem if the booster push rod is engaging the M/C while tightening it something is very wrong.. Another thought, is the booster push rod adjustable?

AngryCorvair
AngryCorvair GRM+ Memberand UltimaDork
7/28/14 8:22 a.m.

In reply to Nitroracer:

you are correct, there should be no preload on teh MC piston from the booster pushrod.

Paul_VR6
Paul_VR6 HalfDork
7/29/14 7:17 a.m.

Haven't seen this issue before, but I also have never seen a booster with the pin that far out (like your new one).

"easy" fix would be to just make a spacer/washers and see if it works. OR can you swap the pins?

Streetwiseguy
Streetwiseguy UberDork
7/29/14 7:50 a.m.
noddaz wrote: Another thought, is the booster push rod adjustable?

Yeah. Check this.

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