leaky brakes

Sorry, forgot the topic line. Any know if it time to replace a master cylinder when it leaks from the pushrod side? I noticed this from the pool of brake fluid under the pedal cluster. I thought it might just need a new rubber boot cuz its cracked up, but I think the boot is there to keep dust/dirt out. Here we go again!!!!!

Of course --- should be NO leakage of fluid at all. I'm very conservateive (willing to spend some $) when it comes to brakes and quality tires. You can get a master cylinder rebuild kit with new gaskets/o-rings and seals for a few $ but if old fluid has been sitting in system for awhile the innerds could have rust and brown fluid so probably just as easy to replace entire cylinder (not expensive). (Have read that Ghia ones are best for disc brake use since they don't have some residual pressure valve for the front). The long front to rear steel line (runds past gas pedal along center hump)is often rusted too - again $10-20. Plus look at the rubber connecting hoses to the drums/disk. Are they 40 years old? If so they swell when you hit brakes. Stainless steel coated ones are way to go for a positive brake petal. Rebuilding the wheel cylinders is a snap it they aren't rusted inside. If you do wheel cylinders - get the spring hardware kit too.

Hey Wolfgang,
Thx for the reply. Do the ghia masters work with 4 wheel discs? I think the current master is a dual circuit. Will be replacing resevior hoses and hoses to master, all rest look ok. Also, will the ghia masters work with the current pedal cluster or does it not make a difference.

Beetle / Ghia master cylinders are the same. About $60.00 you have a new one. The metal brake lines are available at your local auto supply store and are cheap.

You need to make sure there is no brake fluid residue on the pan, that stuff will eat through paint and steel like crazy!

Bruce: you're not alone with this problem. Gordon N. and myself had the same mess within the past year. Installed new master cyls.
Like Mike said pull up the carpet and clean the floor real good. I used brake spray to help clean it up. You'll probably have the paint peel up...I did.

~WB

Yep the pan is soaked. I'll get some cleaner today. BTW, does the pushrod need to be replaced?

Bruce, when you change master cylinders the new master may require a different length of pushrod, shorter or longer than what you have. I went from a standard dual circuit master to a dual circuit disk brake master and had to make a new push rod...it had to be about 3/8" longer to actuate the brakes. There is about 1/2" of adjustment on the rod, but even all the way out the rod was still too short..... To the point of adjusting if the rod is adjusted too long the brakes may just self actuate and lock up as they heat up....if it is adjusted too short you can't bleed the brakes and of course they don't work either.... just things I have learned the hard way....

and then, on the other hand, you may put in a new one and everything will be just fine - ya never know. Besides, a stock push rod is adjustable up to over 1/2" either way, so chances are it'll still work - just adjust the pedal as shown in any good (non-Chilton's) service manual.

I think I got my last Master Cylinder from CIP1. They offer two versions; One is an Asian knock-off for about $30 bucks, and the other is a real German one (for about $20 bucks more). After my earlier, Asian one leaked at the push rod after only a year or so, I sprung for the German one and it's been great. Pelican Parts also has German ones - get the one for a Porsche 914 or for a VW sedan.

BTW, both mine and Bill Drayer's leaked from the push rod onto/under the carpet. Good news is that it'll dry out over time, once you clean up the mess. Bad news is that it'll take off all of the paint under the rug and, maybe, on the underside of the tunnel, under the car, as well as under the master cylinder. Let it all dry out, then scrape all the bubbling areas with a wire brush, shoot them with carb cleaner, wire brush them again, let 'em dry and paint them with Rustoleum rust eater paint.

I've also found that it's good to plan on using all of a quart of brake fluid to bleed the brakes. I know it shouldn't take that much, and I thought I had them bled right last Spring when I changed the M.C., but I recently found that I didn't do a super job on the rear circuit, so just used another half quart to overkill the bleeding of that circuit. NOW they're working great! Just plan on 1/4 qt. for each wheel and that seems to work out.

Good Luck!

gn

and then, on the other hand, you may put in a new one and everything will be just fine - ya never know. Besides, a stock push rod is adjustable up to over 1/2" either way, so chances are it'll still work - just adjust the pedal as shown in any good (non-Chilton's) service manual.

I think I got my last Master Cylinder from CIP1. They offer two versions; One is an Asian knock-off for about $30 bucks, and the other is a real German one (for about $20 bucks more). After my earlier, Asian one leaked at the push rod after only a year or so, I sprung for the German one and it's been great. Pelican Parts also has German ones - get the one for a Porsche 914 or for a VW sedan.

BTW, both mine and Bill Drayer's leaked from the push rod onto/under the carpet. Good news is that it'll dry out over time, once you clean up the mess. Bad news is that it'll take off all of the paint under the rug and, maybe, on the underside of the tunnel, under the car, as well as under the master cylinder. Let it all dry out, then scrape all the bubbling areas with a wire brush, shoot them with carb cleaner, wire brush them again, let 'em dry and paint them with Rustoleum rust eater paint.

I've also found that it's good to plan on using all of a quart of brake fluid to bleed the brakes. I know it shouldn't take that much, and I thought I had them bled right last Spring when I changed the M.C., but I recently found that I didn't do a super job on the rear circuit, so just used another half quart to overkill the bleeding of that circuit. NOW they're working great! Just plan on 1/4 qt. for each wheel and that seems to work out.

Good Luck!

gn

If you get the same m/cyl, your p/rod will be ok. If the carpet is soaked you'll probably have to nix that too. Not real easy to clean all of the oil out. I'd also get new brake switches to put in. It's one of them "might as wells" to nix any trouble with them down the road and they are cheap to replace anyway.

The pushrod is not supposed to be adjusted; at least that's what the Official VW Bentley service manual expressly says. What's up with that?

Here's 2 articles that mention difference between the drum and disc brake master cylinders - something to do with a built in residual pressure valve in one and not in other. (Apparently the correct one to use is a Ghia or '73 up T1 Super Beetle one).

It says "Be aware that the master cylinder itself is different for disc brake Karmann Ghias (VW# : 113-611-015) than it is for Beetles which have four-wheel drum brakes. Make sure that you get the correct part for your car." I'll see if I can find OEM part numbers to confirm.

http://www.type2.com/bartnik/kgmastercyl.htm
http://www.vwtrendsweb.com/tech/0311vwt_beetle_super_project_part_5/


I know with 914's which have a 19mm bore - a common replacement was to use a 911 master cylinder with a 21 or 22mm bore for added braking pressure.

I don't think the disk brake (K.Ghia) master cylinder comes with the residual pressure valves.
The residual valves are a good thing because they maintain a little pressure in the brake system so the brake pads don't relax too far away from the rotors. If you don't have the valves, you end up with excessive brake pedal travel because the hydraulics have to push the pads back to the rotor. With the limited footwell space in Speedsters, excess brake pedal travel can be a problem.
CB Performance sells residual pressure valves in at least 2 pressure ranges. I think they are 2 psi and 5 psi. I used the weakest pressure one of these for the rear when I added disc brakes. It worked OK.
You can also get residual pressure valves from other sources like Summit Racing or Wilwood Engineering or any shop that sells hi performance Disc brakes.

Greg

Getting a bit confused. I thought the ghia masters were the ones with the residual ps valve. I have 4 wheel discs. I'm thinking its the one I want= ghia/ dual circuit?

you're not confused - just get the Ghia one: 113-611-015

Ricardo: Be careful what you read in Bentley's. ALL early VW MC pushrods that I've seen are adjustable so that you can make up for differences between replacement (even German) master cylinders.

If I remember right, Bentley's tells you that the pushrod is set at the factory and should not be messed with, but other service manuals tell you to adjust it whenever you change master cylinders. The procedure is to push the pedal forward until you feel the pushrod engage the recess in the center of the piston, and set your pushrod clearance such that you have about 1mm free play to the rod. This should translate to about 1/4" of free play at the top of the pedal. Be aware that this is pedal FREE PLAY, not to be confused with the distance the pedal has to travel, after the push rod engages the piston, before the piston actually moves fluid to your wheel cylinders. THAT may be an inch or two, sometimes more.

Some manuals also tell you to get this free play by changing the position of the pedal stop on the floor board, but if the pedals are lined up nicely (both clutch and brake) than I often just make the adjustment with the push rod and it works fine. You just have to be careful and set it right.

If you set it and your brakes seem to drag, then you've set it too close (let's face it.....1mm is NOT a lot of clearance).

gn

If you - just get the Ghia one: 113-611-015, it won't include the valves. They are external(separate parts) and screw into the outlet ports of the master.
Gordon,
did your replacement M/C include them? I sure couldn't find them when I was looking.

Greg

HUH? I bought 2 of them and you simply screw in the brake lines and pop in the brake hose from reservoir. These are beetle/GHIA (same thing) Master cylinder. One from Brazil (Varga) and a better one from Denmark (Dansk).

http://www.cip1.ca/ProductDetails.asp?ProductCode=VWC%2D113%2D611%2D015%2DBDGR

Greg et al:

I've received no proportioning valves on any of the master cylinders I've bought, nor did I know that there were any offered by VW to go with their master cylinders. If I did, I might have tried them out!

I've just installed them as Mike did: Pull the MC out of the box, bench prime it and then cap the outlets, install it in the car, pull the fluid through with a Miti-Vac, then finish that up with a good old fashioned pump-the-pedal-and-bleed-the-wheel-cylinders. Usually get a good pedal that way and everything works (except for the last time I did it, I guess, but that's fixed now).

I haven't noticed that I need a proportioning valve in there (disk front, drum rear), as everything stops without locking the front disks on a panic stop.

gn

Hmmmm... Could that have something to do with my brake assymmetry? It's obvious that the passenger side front brake is doing more of the work than the driver's side.

Nope...

But, come to think of it, have you ever adjusted your Rear brake shoes?

If the right rear were adjusted slightly closer, then it would seem as though the front was pulling to the right when you apply the brakes.

My response was in reference to Wolfgangs mention of "RESIDUAL" pressure valves, which is as I described.
We're talking about two different things here, Residual and Proportional.
~
Residiual pressure valves hold some pressure in the system
~
Proportional valves adjust pressure within brake system(s) to balance or imbalance pressures front brakes to rear brakes. They are ususally found in electronic controlled systems such as ABS. They can be added as a mechanical adjustable device. They are usually applied to custom applications, such as found in road racing cars.
~
Gordon, the part no you listed IS correct for a disc brake system.
Sorry if I confused the issue.

Greg

The rears have been adjusted, although that was one of my first thoughts. After paying close attention I can tell that the front right is working hareder than the left. After a lot of driving it starts to sing when you brake, as if it's gotten hot. I've bought some braided steel soft brake lines to remove the possibility of one of them ballooning on me. That'll also force me to bleed it real good again. If that doesn't help I'm open to suggestions.

You're right about that Gord; in Jjr's car we had to mess with the adjustment when we swapped the master cylinder to make it work appropriately. As I said; my commentary was meant as a word of caution, this coming from the official factory service manual.

Lane wrote: "After a lot of driving it starts to sing when you brake, as if it's gotten hot."

hmmmmmmmmm........That's interesting. It should cool off adequately in between brake applications unless something is holding the pads too close. Might bear taking a close look at that side to make sure everything is moving as it should and nothing is hanging up.

There is a totally separate brake line (no couplers) for each of the front brakes, coming from the Master Cylinder, so they are almost independent circuits (they're only common within the master cylinder).

That said, while it's possible that the flexible hoses are the problem, I doubt it. But since you've already got them, install them, then do a careful bleed job on all four wheels (you could even call me). While you're doing that, check both sides for kinks in the tubing or any potential impediments to the fluid.

I usually bleed 1/4 qt. for each wheel.....what the heck, you bought a whole quart anyway, and I always toss whatever is left as it'll probably absorb water while in the bottle over time anyway.....

If the "soft" (left?) side bleeds OK and the bubbles stop, then, fluid-wise, it's probably OK. Make sure that the bleed flow is more-or-less the same on both sides.

Then, if nothing changes (i.e., it still pulls to one side), replace the caliper on the side opposite to the direction it's pulling, since it's applying more force to the side it's pulling toward, so you know that side is at least working.

My money's on the caliper. Sometimes they don't bleed easily, or sometimes they just have too-tight pistons, or sometimes the pads are too tight in the caliper - all things to look for while you're replacing the hoses. Also, look at the rotor on the "soft" side to see if there's more wear (polishing) on one side than the other - that caliper has a piston on each side, so one may be sticking somehow.

You can't swap them side-for-side to test them, because the bleeders then end up on the bottom and bubbles don't rise downhill...... {8>(

And Ricardo: Adjusting the push rod requires very tiny increments and a deft hand. I usually only make 1/4 turn changes AT MOST, and often less. The manual is right: If you don't absolutely need to alter the push rod length, then don't mess with it!!

gn

Thanks, Gordon. I may well be giving you a call. How do you feel about a Saturday trip up to da big city?

MC is in and working fine so far! I was going for the German make but parts shop had just "ran out". Got a Brazilian instead. the one thing I was noticing was that I did see some moisture around the inlet rubbers after I installed. Later, not much. Will recheck over the next few days. If still a little wet, may need to be replaced.

"around the inlet rubbers"

??

Can you describe those inlet rubbers with a little more detail? I don't understand what you mean.

tnx.....gn

Hey Gordon,
This is where the hose from the resevoir attach to. There are 2 plastic long nipples on the top of the MC and these nipples sit in a rubber seat.

Thought that's what it was - just making sure.

Those things have almost zero pressure on them, other than the little bit from the tank down, and when you get the hoses hooked up they tend to flex just a little and sometimes weep until they settle in. After that they should be OK.

If they continue to leak, then move the hoses around a little and reposition the nipples so they seat and they should be OK.

Pretty common ailment......

gn