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Question for the group- just noticed pulling into the garage after taking the VS out for a drive, lots of fluid dripping from the front of the car. It wasn't gas but brake fluid. Checked the reservoir and it was empty. Got under the car and lots of the black paint was bubbling which it should with that nasty fluid. No fluid leakage showing at the cylinder, but guessing its coming out of the piston between the metal wall the cylinder is bolted to and the fiberglass wall- carpet is dry, thank goodness. Unfortunately, a lot of cleanup and repainting after fixing the cylinder. Here's my question- notice there are no rebuild kits but just new units. Having a front disc and rear drum, the cylinder looks of dual port type (long), not looking like a large volume type due to the cylinder diameter. I noticed from different sources, a range in prices. Any suggestions on what to look for on the replacement or even the rebuild kit, which I would like to do and hone the cylinder out. I'm surprised this happen on just 5200 miles on the car. Hope its not a piston alignment issue with the brake pedal linkage. Thank you for input.

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EMPI has a 20.6 mm big bore master cylinder for $32 ($45 other sources).  Not a fan of EMPI but worth a try. It has 5 and 4 stars at JBUGS. I'm thinking the stock is like 19 mm so bigger would move fluid faster for better braking. 

https://www.amazon.com/16-9554...linder/dp/B0046VMC3C

There is a big bore German CSP one at CIP1 for $116.

http://www2.cip1.com/ProductDe...Code=C31-611-016-000

I totally agree with Alan, too - Go German (or at least Varga/TRW from Brazil) or stay home.

The MC mounts through the "Napolean Hat" (lower bulkhead gusset) which is two pieces of sheet metal about an inch apart.  If the MC leaks and finds its' way out at the bottom of the boot, rather than at the brake pedal pushrod end, it will be inside of the Hat, and then finds its' way to the underside of the car just ahead of the floor pan and not to the carpet.

If you have a 19.5mm bore AND you have a German M/C to begin with (but if it leaked under 6,000 miles I doubt it), you could try a rebuild kit 111698183 from Bug City (they have others, too).  

To be honest, though, I have had mixed luck rebuilding master cylinders (and I have only tried it on VW MCs twice).   Much easier to just get a new one complete, bench-bleed it and install it.  Done.   The last time I used my brake cylinder hone was something like 1969, jus sayin'.

I also agree with Danny on the later (68-74) Karman Ghia MC, which is the same as the Super-Beetle 74-79 - those had the same brake set-up that you currently have and work well (I'm running one, too) and it should bolt right in and all of the brake lines should line up.   Don't forget to swap over your brake light switches or, better yet, since they are pretty poor quality these days, get some new switches (Bonus points for using German switches, too).  

Bug city has a "custom" MC for disk brake conversions, P/N 113611020BDD  but at $35 I would wonder about it (they don't say who made it, so I assume it is Asian).

The German and Varga/TRW ones are all 113611015 but then they have different suffixes for German, Varga, etc so go HERE and decide which one you want.  Just get a 113611015BH or a 113611015BHX.  Personally, I like the BH.

Happy hunting (and cleaning up...)

I disagree with Greg(Wolfgang) on the bigger bore being better. If it moves more fluid per stroke then you have LESS leverage to move the calipers and wheel cylinders. 

You gain LESS travel with a larger master cylinder bore, but with that less travel you are exerting less force on the brakes for the same force on the pedal.

Now, if you increase the M/C bore size AND change the pedal ratio you're on to something.......

It's all physics.

Everyone, thank you for all your comments. Lots of info to digest. Did finds some ads for the Varga/TRW  but had no clue where they rank. Saw the German ones for $$$ but I need to take the cylinder out and find out exactly what I have. Then buy the better version. As Gordon mentioned the leak is out of the boot and mostly draining from in between the two pieces of sheet metal and fluid dripping and moving along the bottom of the pan bubbling the black paint- another job to clean and repaint after the cylinder replacement.

Thank you again for the help.

Here's Pelican Porsche guidance I followed years ago on up grading my 914 from a 17 mm to a 19 mm master cylinder.  I replaced the 10 year old rubber lines with teflon lined stainless steel reinforced brake lines at same time.  On a 914 it was a +2 mm difference - on the bug it is a +1.6 mm so suspect the same NON "discernable change."  I'm sure if I had gone with 5 lug 911 rotors/wheels and bigger calipers, I would have reaped greater braking but that was big $$$ even back then.

"The 914 and very early 911s originally came with a 17mm master cylinder.  The 914-6 and later 911s came with a 19mm master cylinder that allowed the driver to apply more direct pressure to the brake system.  The 19mm unit is externally almost identical to the 17mm unit, and is a direct bolt-in replacement. Pedal travel is reduced a little bit, but I never really noticed any discernable change.   The more direct result is a bit more stomping power on the pedal."

You're lucky it didn't empty out into the car , soak the carpet and peel the paint on the pan, Michael.  that makes a pain in the butt job a little more of a pain.

It's another opportunity to do some automotive yoga. I used the Varga unit and it works fine with my disk front and drum rear brakes. There was a fitting on the top of the unit and I bled it in place so I didn't need to bench bleed it. Stretch first.  Good luck

Agreed, Stan. Getting under the dash sucks.

Greg/Wolfgang, I'm not buying it. Pelican Parts just want to sell you parts. It's a 15-20 percent larger master(from 19.05mm to 20.6mm). So it will be a 15-20 percent higher braking pressure from your foot, with less feeling. I'd rather have a more easily modulated pedal. These aren't power brakes, and we're not getting any younger!

If you want less mushy or less travel, just do stainless braided/teflon lines.

I've been buying a bunch of parts for my Audi from AutoHaus AZ lately. Good parts, good prices, good service. 

https://www.autohausaz.com/pn/...PEAQYASABEgIKBfD_BwE

I'll likely never get upside down under the dash again. Stan's right ...at least remove one seat. Now, I unabashedly look for help for $$$. Next door neighbour is a Cop. She's about 5' 6" and 115 in good shape. I get her to take a look, explain what I need and she sends her Son over. The Kid is not that mechanical and probably couldn't even tie a reef knot but he's keen to learn and a high school lightweight wrestler. He, and I outside passing tools and instructions turns a 2 hour job into maybe 20 minutes. 

He walks away happy making $20 for 20 minutes and I sit back happy that I can move my body tomorrow. 

I should revise that note above:   when serious things need getting done like removing an engine, I engage the help of one of my two boys who eagerly comes running to help when I advise  that the Bride and I are now making revisions to our Will. ....   :-)  

And then there's always Mike from the Marina. Catch him somewhere in between the JD the MJ and if it's not snowing there's another happy helper. 

Last edited by David Stroud IM Roadster D

I'm happy to say, spent the extra money and bought the German made MC. But, after starting the flange bolts and brake lines, then moving on to tighten down the flange bolts with lines after wards I noticed the boot was folded back- crap what happened. Turns out the pushrod has two slightly different diameters. The new boot hole diameter will not slight freely onto the next larger diameter, not even with some working it. Even if it did, the boot will fold back and forth as the brake/pushrod is activated; and assuming later will destroy the boot. I'm looking at two options, unless someone has experienced this as well with Kirk's VS cars, either take the MC back out and see how to open the boot hole, or take the MC out & remove the pushrod to turn the larger diameter down. Concern I have on the second option is weakening the strength of the pushrod.

Any other ideas?

PS. now I know why Kirk left the boot off on the Chinese MC- it didn't fit, and when the MC failed the brake fluid run between the walls and not onto the carpet how coincidental is that.

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