# MKII brake upgrade, weak pedal



## Lord_Verminaard (Apr 6, 2004)

Maybe you all can help me out here.

I have an '86 Golf Diesel, that I swapped out the stock brakes for 10.1" fronts and rear disc's. The following is a list of what I did:

I used a set of complete MKIII front knuckles and brakes from a 2.0 GTI, the rears were from the same car. I bought a new set of MKIII ball joints to replace the smaller ones that were original to the Golf so the knuckles would fit.

The calipers were all good, not seized, sliders in good shape, etc... I replaced all of the bleeders. I had the Rotors turned, the rotors and pads had about 3k miles on them before I removed them from the MKIII.

I installed stainless steel brake lines all around. I also replaced both hard lines for the front since the fittings were screwed. I also replaced the stock Golf master cylinder with a brand new parts store replacement 22mm for a 16v GLI. ATE "Super Blue" brake fluid all throughout.

Upon installation of everything, I had a real bastard of a time getting the system to bleed. I did do the "bench bleeding" procedure on the master cylinder before installation as well. What I ended up doing was applying a vacuum from my oil extractor on the bleeder screw and allowing it to suck the fluid down to the bleeder. After that, I went around the whole car bleeding it the "old fashioned way" about three times. On the 3rd pass, the pedal finally sprang back on it's own and I was getting new blue fluid out of all of the bleeders, and no air bubbles.

Driving the car, the pedal is pretty weak, you have to push it down quite a ways before brake feel gets very good. I do think it starts to slow down after the first few inches of pedal but not a whole lot, if you need to stop quickly you basically have to bury your foot in it. Is this normal? I was expecting a much firmer pedal feel and a lot less travel before anything significant happened. I know the pads and rotors need to "bed in" a bit and that will help some. Is there any adjustment to the pedal or MC pushrod?

Thanks for any information you can provide.

Brendan


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## 2.OhhhGTI (Jan 26, 2003)

I found a similar problem with my mk2 after full fluid change along with pads, calipers, rotors, & lines. Pedal went 3/4 to floor although with good feel and no air in system. For me, the fix was to take the vacuum line off of the one way valve going to the brake booster. Basically, just loosen (or cut if original) the clamp on the booster side of the valve and release the pressure that it holds by pulling the hose off a bit. Slip th hose back on and put on a new clamp. You should hear a whoosh as the vacuum pressure is released from the booster. Mine was perfect after this!


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## allintaste (Feb 5, 2011)

2.OhhhGTI said:


> I found a similar problem with my mk2 after full fluid change along with pads, calipers, rotors, & lines. Pedal went 3/4 to floor although with good feel and no air in system. For me, the fix was to take the vacuum line off of the one way valve going to the brake booster. Basically, just loosen (or cut if original) the clamp on the booster side of the valve and release the pressure that it holds by pulling the hose off a bit. Slip th hose back on and put on a new clamp. You should hear a whoosh as the vacuum pressure is released from the booster. Mine was perfect after this!


The bentley makes reference to disconnecting the check valve and such. I believe this is why you do so when you're bleeding the brakes. Can anyone verify this? 
If the vacuum line/check valve is not disconnected could it cause issues with the front brakes not bleeding after a master cylinder replacement?


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