CMC Classic TD brake master cylinder issue

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  • #307722
    Raymond Laube
    Participant

    @raylaube

    Hi, newbie asking first question and hope this is the correct place to ask.  We have had a CMC Classic TD based on a 1963 VW bug for about 5 years.  It was assembled by someone in the 1970’s from what I can tell.  It has a plaque on firewall identifying it as number M 1040 for what that is worth.

    It appears that we have a leaking brake master cylinder and when on a lift, does not show leaks anywhere around the lines or wheels.  Inside the cabin, it leaks somewhere between the firewall when the pedals are located and down the tunnel on the inside messing the carpet.  If we fill the reservoir, it leaks out on to the ground.  I can drive it since it has some brakes but have to slow it with the engine until I have a reasonable ability to stop it.   None of the garages I have taken it to will work on it stating the body must be taken off the frame to get to the master cylinder?

    Any truth in that or is there another method to get to cylinder with this model?

    I took the battery out of the car yesterday and there is a hole cut in the bottom of that case right above the master cylinder and someone changed out the electrical connections through that hole sometime before we got it.  I can see cutting the entire back out of the battery holder to get to the master cylinder and then putting it back together with metal.  But is there a better way?  I am not a mechanic, just an old dude trying to figure this out.  There is no opening through the wheel openings in this model so I could also cut the fiberglass right behind the left wheel and access it but it seems like someone must know the secret to this repair?

    I am in Dallas, TX and would appreciate an idea of what direction to go forward in trying to do it myself, or a lead on a fellow member who can charge me to fix this?   The strange thing is that master cylinder does not seem to be leaking when you look at it through the hole in the battery box but if you fill up the reservoir it drains underneath the car through bolt holes.   I am also working on the assumption the reservoir hose may leak but cannot seem to figure out how to get to it either since it is below that shelf of fiberglass.  thanks, Raymond

    In a country where you can be anything you want, Be Kind.

    #307723
    Toller
    Participant

    @toller

    Raymond
    Have a look in the Library section of this site. You will find an assembly manual for a CMC VW based TD. On page 10 the brake assembly and master cylinder are shown. You will at least see how it was put together

    David B Dixon
    Port Perry ON CA
    Sabine

    #307725
    Raymond Laube
    Participant

    @raylaube

    thanks, David, did that a few years ago and even took it to the mechanics, but no one can figure out how to get to the assembly once the body was put on, there is no openings anywhere that we can find.  I can shine a light down the hole cut in the battery box and no light shines anywhere under the car, it is totally sealed up.  That is where the mystery arises, and the manual for the CMC is a Fiberfab manual on-line and it is not exactly the same build as the CMC version which has a different type of front section with only one section vs two as it shows in the fiberfab manual.  Strange, but I have been banging around looking for a solution for five years and the only one anyone comes up with is taking the carbody apart or cutting the holes through the body.

    but thank you, my friend, and hopefully someone else has had this same model body and issue in the past.  warmly.

    In a country where you can be anything you want, Be Kind.

    #307727
    Raymond Laube
    Participant

    @raylaube

    FOLLOW  UP:  I used an endoscope and figured out everything.  The original builder of the car, not wanting to leave the MC where it was located and use a lengthened brake push rod, put the cabin interior on the pan, moved the MC to the back of firewall behind the brake pedal to use the same setup as original on the VW.  Then he added the front of the car totally encasing the MC below the fiberglass shelf with no way to access it.  I cut the bottom out of the battery depression/box and then the side and the MC was sitting right below it, unable to be reached by anyone.  Now I can get it fixed.  Just adding this so others who may find same situation, may have a way to look for it.

    In a country where you can be anything you want, Be Kind.

    #307728
    edward ericson
    Participant

    @edsnova

    Glad you found it! Accessing the MC on these cars can be tricky and it’s also true that there as many styles of rig connecting the pedal to the MC as there are TDr manufacturers. My BCW uses a custom length pushrod. I’ve seen some that use two full set of pedals, with the one under the driver’s foot connected to the one at the original VW location with a long rod.

    No matter how those kit engineers did it, and whatever “improvements” the home builders made in the ensuing 40+ years, brake master cylinder R&R is always a challenge.

    Good luck getting it squared away, and glad you didn’t have to take the body off!

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