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Wed Jun 30, 2004 9:45 pm

My master cylender decided to blow a main seal 2 weeks back and so I got a new one, intending on rebuilding the old one. So much for that idea cause my dad threw the cylender out on me. Anyway, I'm not getting the new cylender to work right. There is no air in the lines (nice firm pedal), all the brakes lock up and work just fine, but the pedal goes almost to the floor (about a quarter inch from the carpet). I've adjusted all the brake pads so they just barely rub, pumped the brakes repeatedly, no change, pads still rubbing ever so slightly. The only thing I can think of is that one of the two cylenders isn't working. Anyone got an idea? Cause other than buying another new cylender and starting over, I don't know what to do.

Wed Jun 30, 2004 9:47 pm

oh yea, I also checked/adjusted the m/c pushrod freeplay.

Fri Jul 02, 2004 12:55 pm

do you have enough fluid overall in the system?? how full is your reservoir?

Fri Jul 02, 2004 3:31 pm

Did you bench bleed the Master cyl before installing it???

Fri Jul 02, 2004 11:04 pm

bench bled, resevior nicely topped off. I'm getting another new m/c tommorow. We'll see if I got yet another bad cylender... I have the shittiest luck with brakes, though the rest of the car works great :?

Sat Jul 03, 2004 8:21 pm

so yea, new master cylender installed, still no brakes, they're behaving exactly the same: Rear brakes work fine, front brakes don't seem to bleed right, but engage and hold pressure just fine, only problem being that the pedal still goes an inch from the floor before I get any pressure. I've got no idea what to do. I've checked and double checked everything. Time to take a sledge hammer to the car.

Sun Jul 04, 2004 11:34 am

Do you know when the rubber brake hoses were last replaced? A buddy of mine at school had the same problem, excessive pedal travel, even on the third M/C. The problem went away when he replaced his hoses..

Tue Jul 06, 2004 8:27 am

superwhit wrote: oh yea, I also checked/adjusted the m/c pushrod freeplay.

Are you absolutely certain that you made this adjustment correctly? The length of this pushrod determines how fluid moves through the MC, especially how it returns once the brakes are applied and then released.

Try removing the pushrod from the brake pedal assembly, and simply using it to apply the brakes (of course at a dead standstill!). If it seems much more firm, then the adjustment is off. It's very tricky to get it right!

I also agree with the rubber hose replacement option. On any car this old, they are bound to deteriorate over time. If they are softening, they could be 'bulging' under the pressure instead of remaining 'solid' as they're intended to.

Larry

Fri Jul 16, 2004 2:00 pm

I wouldn't be able to tell if the pushrod feels more firm or not by removing it being as I don't have any brake pressure. The pedal still goes all the way to the floor with the wheels still being able to turn. As far as replacing all the rubber lines, they were all replaced last year.... So I adjusted the pushrod in quarter turn increments throughout it's entire range without any noticable difference. Any other ideas?

Fri Jul 16, 2004 3:41 pm

superwhit wrote: I wouldn't be able to tell if the pushrod feels more firm or not by removing it being as I don't have any brake pressure. The pedal still goes all the way to the floor with the wheels still being able to turn. As far as replacing all the rubber lines, they were all replaced last year.... So I adjusted the pushrod in quarter turn increments throughout it's entire range without any noticable difference. Any other ideas?

Unfortunately, it sounds like you may have to start over from the beginning:

Take the MC back out, and bench bleed it. Make certain that you're getting fluid pumping properly from both lines.

Put it back in, and bleed the brakes again ... start at right rear, then left rear (as you're sitting in the car), right front, then left front. Unless you have a power bleeder, get someone knowledgable to be the "pedal pusher". They have to push to "almost" the bottom out position, and then hold it while you re-tighten the shcraeder valve. Make certain you repeat until ALL air is out of the system.

Then, check each wheel to assure that the brakes on that wheel are properly adjusted. Since the VW stock brake system can't overcome a single cylinder failure very well, it's best to assure that all brake shoes are properly adjusted.

If you don't have brakes at that point, then I think you either have:
- one or more shot brake cylinders
- a faulty line
- a bad MC out of the box

Hope this helps?

Larry

Fri Jul 16, 2004 9:18 pm

Just had the exact problem on my bus, couldn't fix it for the life of me. I bench bled the clyinder several times, etc. Finally borrowed a hand vaccum pump from a friend to bleed the brakes with and that took care of it. It's nice when your brakes work right. With a dual cylinder m/c bleed the fronts first. :wink:

Wed Jul 21, 2004 6:55 pm

Have you adjusted the brakes at all 4 wheels? As the pads wear the pedal gets closer to the floor to get pressure.

Thu Jul 22, 2004 3:49 am

hey. i have one of those pressure bleeder things that i havn't used yet, do i still need to bench bleed a MC with that? i'd say worst come to worst buy a new MC and start over with a vaccum or pressure bleeder.