Mopar Performance master cylinder • The Dodge Challenger Message Board

by **LITEMUP** » 01 Dec 2003 4:05

has anyone converted to the new plastic master cylinder? im trying it. All of the instalation is fine but i am using the mopar performance proportioning valve and i cant get it to stop leaking for anything. Suggestions?

Also I am changing to DOT 5 brake fluid. Will I be condemed?

Now, I am also taking the power brakes off. My brake pedal will go very far up (towards the seat) so how do i know if i am getting enough stroke out of my pedal. I know i can use the adjustable pushrod to attach the pedal to the master cylinder but dont I still need to make sure i get the correct length of stroke? AND is it possible to over extend the master cylinder? like if the push rod was to long and i pushed all the way down (not forceably at all but...) what would happen?

by **dave-r** » 01 Dec 2003 10:20

Don't know about the MP proportioning valve. I used a Summit Racing adjustable.

I hope you have removed the bellcrank and fitted the master cylinder lower than it was with power brakes?

The two stud to 4 stud adaptor to mount the modern master cylinder had a hole in the center that was not large enough when I did mine. I had to grind it out to fit.

I also found that the pedal height was all wrong (far too high) with the MP adjustable push rod because the rod is still too long when adjusted right down. I had to cut some off the length of the screw to shorten it and tap more thread right up to the eye on the pushrod so that the pedal could sit at the right height.

You cannot push the pedal too far down so don't worry about that. It will not go very far down when filled with fluid anyway unless you have a leak.

I am not very well up on brake fluid types.

by **Christer** » 01 Dec 2003 10:36

As you surely remember, we have had a "DOT3 or 5"-discussion before, litemup (see: http://challenger.mpoli.fi/phpbb/viewto ... =9467#9467 ) I do not see why you are so eager to test DOT5 ? Is it really worth the risk of using an incompatible (with our type of cars) brake fluid ? (I have to add that I am not a brake fluid expert either, but it is fun to have a little argument once in a while)

by **LITEMUP** » 01 Dec 2003 18:16

I have almost decided that Wilwood supplies all manufactures with the same adjustable prop. valve. i have the one that has a black square housing with a round adjustable knob. 0bviously thats what theirs looks like, i ordered a mopar perf. and it says MP plus Wilwood on it, and i used a Baer valve on a friends car and it was wilwood also.

i do not know what a bellcrank but yes i did get a manual brake mounting plate. i took one off of my parts car and it was lower and stuff. i also took out the little bracket and arm and stuff that raised the pushrod for the power breaks.

my 2 to 4 hole mounting plate was correct in dimensions so nothing was needed.

The only reason i want DOT 5 is because it is non corosive. i very well may be doing more harm than good but several car builders i know dont have a problem with it. I have had so many brake problems that i am just stubborn i guess in wanting a noncorosive fluid. i have had DOT 3 eat my paint 3 different times b/c of faulty equiptment. i am just trying to take prevenative measures. here is what Wilwood brakes has to say about it...
http://www.wilwood.com/products/master_ ... efluid.asp

and so i guess i wont worry about the pedal stroke until the brakes are completely bled...

by **dave-r** » 01 Dec 2003 18:51

LITEMUP wrote:i also took out the little bracket and arm and stuff that raised the pushrod for the power breaks.

That's the bellcrank! :wink:

You are right about Wilwood making the same part for everyone. The MP version used to be bigger and more expensive though. If it is leaking from the screw it has to be faulty. If it is leaking from the in or out then I suspect the pipe is not flared correctly.

by **Christer** » 01 Dec 2003 20:05

This is a part of what they say on the Wilwood page: "DOT 5 fluid is best suited for show car applications where its anti-corrosion and paint friendly characteristics are important."
...but you want to use your car, won´t you? I would not choose DOT5 myself if I was in your clothes. Just my opinion. Go for it if you really believe in it.