Hi , i converted my '33 to hydraulic brakes with an underfloor m/c. It's a dual chamber (looks like a '67 Mustang drum/drum one, but I'm not sure) with wilwood residual valves for front and rear. If i try to bleed the brakes the fluid goes up to the top like fountain in the reservoir.With the cap on the m/c it still doesn't work(I'don't get the air out) but fluid runs down from the top of m/c.I used the small reservoir for the front brakes, big one for rear.Are there residual valves build in the m/c?? If so how can i check? Ideas?? Thanks Michael
pull the guts out of the master. the rp valve looks like a small cup with holes in it. Ihave insomnia
If you have two different size reserviors, it dosn't sound like it's drum/drum. Suggest you check out this site for some info. http://www.kastang.net/dualmc.html
Sounds like you have it plumbed backwards. Usually the BIG reservoir goes to the fronts - extra capacity for the disc brakes. A typical drum/drum master will have equal sized reservoirs. When you get a "gyser" in your M/C it usually means you have air in your lines. AS you pump the pedal the air compresses, when you realease the pedal the air expands - pushing the fluid back into your M/C. Definitely - pull the M/C apart and check for factory Residual Pressure valves - I never pulled a Mustang M/C apart, but all the others that I have have always looked like little metal cupped discs that have a half dozen or more little holes drilled in them. After you verify this - re***emble it and then bench bleed it before installing it.
Hi, thanks for the answers. I thought mc is mounted one the firewall , you have the small reservoir towards the front of car and you need the bigger one for the longer ways(brake line) to the rear???? Does a '67 dual drum mustang has these valves build in? Thanks Michael
The larger reservoir is for the DISC brakes. The disc brake pistons are (by comparison) very LARGE as compared to drum brake wheel cylinders. As teh disc pads wear the pistons move to compensate. It's all about fluid VOLUME. A drum shoe wears and very little fluid volume is needed to compensate - as the drum brake wheel cylinder is somewhere around 1" diameter. Compare this to your disc brake piston which is probably 3 times the diameter (give or take). Add to this the fact that 3 times the diameter results in FAR more than 3 times the volume and you now see why you need WAY more fluid volume on the disc brake side of things. I don't know if the mustang cylinder has built in rpv's or not.
If you have a '67 Mustang Drum/Drum master it would look similar to this. Although the outlets may be on the opposite side.
My 67/68 drum/drum non-power M/C looks exactly like that - with the ports on the other side ;D It did not have RPVs in it though...
OK, no RPV in my M/C. I found another M/C under my workbench with 1 1/8 inch diameter(instead of the 1 inch that i had before), so i used that one. I bench bleeded it , istalled it under the car and........ viola!!!! it works. Thanks for all your help Michael
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