TheSamba.com :: View topic

Sat Jul 24, 2010 10:04 am

I put in a new single circuit master cylinder, bled the brakes good pedal etc.. I come out this morning and there is a bunch of fluid under the master cylinder and the stopper on top is all wet. Is there another washer / gasket etc that goes under the stopper? Should I have put some tape, sealer around the pipe. Its a new piece of pipe going from MC to reservoir. (Idont have the old one)

Also flange on the stopper sits above the rim on the master cylinder, in other words it looks like it should push down another step, but no matter how hard I push it wont go down anymore, and I'm afraid to damage it with a screwdriver etc.

Sat Jul 24, 2010 12:03 pm

What do you mean "stopper"? There should be a cap with a small, but important, air vent hole.

Sat Jul 24, 2010 12:13 pm

The problem may be the shape/hardness of the rubber stopper that plugs the feeder pipe to the master cylinder.

I have a 66 single circuit that had exactly the same problems that you describe and it took me months and a few MC replacements before I found out my problem was with my plug.

German made plugs are of a softer rubber and have a contour that EXACTLY fits the internal contours cast into the MC. Brazilian rubber is hard and the profile is only an approximation of the shape, hence the leak.

It's diffucult to tell what you have without a sample in hand, the differences are very subtle.

I was set on the right track by going to Wolfsburg West (I was right down the street at the time) and explained the problem to the guy behind the counter who clued me in and sold me three German stoppers.

My suggestion is call them on Monday and get their verbal assurance that they still have German stoppers on hand and order a few.

When you go to replace the old stopper, getting it out can be a problem, the top part can rip off leaving you with the bottom half jammed in the MC.

What I did was remove the gas tank (15 minute project) so I had perfect access to the top of the MC. Then I took a finishing nail and bent the tip (<1/8") at right angles to the shaft, placed it in a Vicegrip and inserted the nail point down the filling hole and lifted from the center as my free hand worked the rim to unseat the original plug. A surgical spatula is also helpful is prying the rubber, without causing it to tear.

http://wolfsburgwest.com/cart/DetailsList.cfm?ID=113611817

Sun Jul 25, 2010 4:08 pm

I too had trouble with the "stopper" until I got a German one and problem solved.

RB

Sun Jul 25, 2010 9:19 pm

I pushed the metal pipe too far in, The flared tip of the pipe needs to sit in the stopper (no leak), all the way in fluid leaks around tube

Tue Jul 27, 2010 7:48 pm

I am in the same situation. Do you have to install the plug over the metal pipe before installing the plug in the MC? My thinking here is that the flanged part of the pipe would sit flush into the MC and the rubber plug would surround it.

Did you get an answer to how flush this plug sits atop the MC? Like yours, my plug sits over the MC looking like it should sit deeper than it is.[/quote]