Brake Problem

  • I just went to start my Kar and the brake pedal went to the floor and stayed. I opened the hood to find a small puddle under the car (brake fluid) and some wet areas. The master cylinder is dry, as is all the brake lines running out of it. However, lower than the Mstr Cyl mounted to the drivers fender side of the engine bay is a small cylinder shaped device about 4-5 inches long. It has two brake lines running into the top of it. It's soaked on it's underside as is the inner fender below it. I'm not a mechanic by any stretch but know the knowledge database here is tremendous. Any idea's what it is?

    Thanks in advance!

    Damon

  • Sounds like the Disc Brake Proportioning valve, its rebuildable. If your up to it NPD and others sell the seal kit or a few people rebuild them, can't think of a name right now.

  • Hi Damon

    The cylinder below the brake master cyl is the brake proportioning valve for the rear brakes.

    These can leak if the bores get corroded.

    You can read all about it here :-http://www.stangerssite.com/brakevalve.html

    NPD sell the seal kits, there are two types as there are two different piston types.

    The bore has to be perfect to just rebuild with a seal kit, otherwise you have to get the cylinder sleeved.

    There is confusion as to which seal kit fits what piston.

    I can tell you that NPD kit 2B091-1K FITS THE PISTON WITHOUT THE BOLT IN THE END.

    But this kit does not have the rubber band in it to go round the outside of the cylinder. So you may have to get both kits to get all the pieces anyhow.

    Mark

  • Gents,

    Thanks for the quick reply! I just got off the phone with one of the F15 crew chiefs and he said the same thing. My P-valve has threads at the front but beyond that would spend quite a bit of time trying to describe it. Let me look at the link and see if I can better ID it from there!

    Thanks,

    Damon

  • original proportioning valves are very prone to having pitted bores & a rebuild kit would be of no help in stopping a leak. They need a be rebuilt by a professional. J. Cowles of shelbyparts.com restored mine several years ago, & it never gave me any trouble after that.


    Z.


    p.s. you are lucky that you weren't on a crowded highway when you lost the last bit of fluid. Have you thought about a dual chamber master cylinder?

  • Z,

    I have actually given it quite a bit of thought but haven't had the money to push that way but should shortly. I have been looking at them along with rear disc brakes (but dont' think there is an option that allows the use of SS wheels and something like Wilwood discs all around). I even went as far as to buy a product called Tank Armor (at least that's what I think it was called) due to the less than safe design of the early fuel tank / trunk / proximity to my kids / what happens if I get rear ended scenario. It's not installed yet but will go in eventually. Would like to add three point seat belts and a few other safety items (purity of car comes behind safety in some things).

    Have you installed a newer master cylinder and if so which one?

    Damon

  • I bought a nice one from cobraautomotive.com


    [Blocked Image: http://i151.photobucket.com/albums/s139/zr…-master-cyl.jpg]


    what I like about it: huge reservoirs, & better stopping power from larger piston/bore, although that does require more leg effort. They sell pre-bent lines to match up with your prop. valve and distribution block.


    what I don't like: the m/c doesn't have an internal groove to capture the clip on the rod from the brake pedal. So conceivably the rod might come out of the m/c leaving you w/o brakes. It was easy enough to make a bracket to limit the upward travel of the brake pedal, but aggravating nonetheless. My pedal assembly didn't have an integral pedal stop for the brake, but I think it is supposed to have one ?? Another thing I don't like from the cobra automotive kit is the stainless brake lines. To get them to seal against the stock prop valve & dist. block you have to tighten them way to much for my liking. I prefer the ordinary mild steel lines.


    The RAYBESTOS Part # MC36440 dual bowl master cylinder is suppose to be great replacement for the '65-'66 single bowl m/c. It was original equipment on the '74 Maverick. It might be the one CJ Pony Parts sells:

    http://www.cjponyparts.com/dual-bowl-mast…65-1966/p/DBC3/


    added: looking at the CJ Pony ad, I see they are selling a rebuilt m/c. I would rather buy a new one (The RAYBESTOS Part # MC36440) from a local auto parts store and just get the lines from CJ Pony, or make your own lines.


    Z.


    Edited by - zrayrichter on 11/29/2010 15:41:56

  • I see that VA Mustang is offering a rebuilt proportioning valve.. didn't see a price but it may be worth a look


    Edited by - sixfiveGT on 12/04/2010 19:48:04

    Can't spell


    Edited by - sixfiveGT on 12/04/2010 19:50:20

  • Damon:


    The information I have comes from the Virgina Mustang Blog if you will send me your email I will forward the email information they sent me. There are some really good photos of the rebuilding process. It seems that they used a used a company called Maple Hill Restoration to do the work; Their contact information is:


    Jeremy Turner

    13283 Timber Way

    Broadway, VA 22815

    Ph 540-896-9024

    email turnerjt63@comcast.net


    hope this helps


    Bob


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  • <BLOCKQUOTE id=quote><font size=1 face="Verdana" id=quote>quote:<hr height=1 noshade id=quote>

    Just my two cents, but Cobra Automotive makes soem really nice stuff. The parts are on the pricey side, but well worth IMO.

    Bill

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    despite my nit-picking, my thoughts exactly. If you are looking for any part more heavy-duty than stock, ask at Cobra Automotive. Also a fine source of information.


    Z.

  • I don't think such a strategy will save you any $$$. I tried rebuilding mine 8 or 9 years ago. I leaked worse. I sent it to J. Cowles. I'm pretty sure it was releeved by him. It worked, and I haven't had to think about it since.


    Z.

  • ZRay / Gents,

    I went with the Cobra Automotive's new aluminum dual bowl master cylinder. I'm also upgrading the brake lines to braided. The proportioning valve is restored and ready to go, so now all I have to do is repair the damaged paint in the engine bay. My questions are: What color paint is the bay, and where should I get it from (car is a driver). The bay has some serious brake fluid in it from the leak (below the p-valve area) and I'm curious what I should do to remove the fluid and prep the metal for painting? I'm thinking on using POR15 Marine Clean, Prep & Ready, and POR15 coating (in either black, clear or semi gloss black).

    Thanks in advance,

    Damon

  • <BLOCKQUOTE id=quote><font size=1 face="Verdana" id=quote>quote:<hr height=1 noshade id=quote>

    ZRay,

    If I can get a current match then that would be preferred, however if I'm unable how close is the Eastwoods Satin?

    Thanks,

    Biff

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    I only know it's a very durable paint, maybe someone else knows how well it duplicates the original finish.


    Z.

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