Disc/ Disc Corvette MC but still bad brakes

[Brad J]

My brakes still suck even after getting another rebuilt (told it would be a new one) 67 Corvette manual disc master cylinder, bench bleeding in a vise till there was no more air bubbles, throwing it in my scout. Bleeding quarts and quarts of fluid out of each wheel cylinder. Pedal pressure is firm and does not hit the floor (about 3" away). I have a trailer brake that I crack the line open to let air out right at the trailer brake and then the leaver seems to move normally after that. There is no bleeder valve on it. I ran the front reservoir to a "T" one end going to the trailer brake the other end going to a Wilwood proportioning valve then to the rear brakes. The rear reservoir to a Line Lock (for a backup E-brake) then to a "T" that splits to the front brakes. I can get up to 30 MPH slam on the brakes w/ all my might and it is a slowed down coast that takes 3-4 times as far as it should. In reverse it seems a lot better. Could all my problems be from the trailer brake? or am I doing something really wrong? I have not adjusted the e-brake lever (rear Caddy Cailpers) all the way so could that be the whole problem? I don't understand why my front isn't at least locking up? Any ideas or suggestions would be greatly appreciated.

Thanks, Brad J.

 

[Tacoma]

Hmm.

All I think off the top of my head is that there is some kind of mismatch between the master and the wheel cylinders. are you running 4whl discs?? (havent' skimmed back through, sorry..)...

possible routing problems? I would also try the redneck fix: park it front wheels up with a 2x4 against the brakes overnight, see if there are any bubbles hiding. Worked for me on a van once.

Other than that I am unable to think clearly enough to reason any problems.

 

[Milner]

What bore is the MC? You need a pretty big MC to fill those calipers. I use a MC made for big Mopar car disk brake conversions. It is 1 1/32" bore. Jegs/Summit in the mopar sectin, made by Willwood. It will look up 38's with omly moderate pressure.

 

[OCNORB]

Have you tried an E300 MC?? When I put the caddy rear disks on my dad's Jeep I bought one because it had the right bore and stroke for the Chev front disks and Caddy rears. (It is the same bore and stroke as the stock wrangler MC, but made for 4-wheel disk brakes.) I can't remember the year, but it it fits a Ford E300 van with 4-wheel disk brakes so it must be a later model 90's-up.

Another thing you could try is to make your pedal a bit longer..... but I would try and find a MC that works first.

 

[Brad J]

Hmm.
I would also try the redneck fix: park it front wheels up with a 2x4 against the brakes overnight, see if there are any bubbles hiding. Worked for me on a van once.

I'll have to give that a try, I've bled the MC and lines over and over for months w/o any luck.

Thanks, Brad J

 

[Brad J]

What bore is the MC? You need a pretty big MC to fill those calipers. I use a MC made for big Mopar car disk brake conversions. It is 1 1/32" bore. Jegs/Summit in the mopar sectin, made by Willwood. It will look up 38's with omly moderate pressure.

I'm using a 1 1/8" Bore AutoZone M1371 for a 67 vette manual brakes nut w/ disc f/r. I'm running the same setup as mentioned in many places on Jeeps so its pretty frustrating. Here is one link I used the info from.
http://www.pirate4x4.com/forum/archive/index.php/t-50634.html

Thanks, Brad J.

 

[Brad J]

Have you tried an E300 MC?? When I put the caddy rear disks on my dad's Jeep I bought one because it had the right bore and stroke for the Chev front disks and Caddy rears. (It is the same bore and stroke as the stock wrangler MC, but made for 4-wheel disk brakes.) I can't remember the year, but it it fits a Ford E300 van with 4-wheel disk brakes so it must be a later model 90's-up.

Another thing you could try is to make your pedal a bit longer..... but I would try and find a MC that works first.

I have heard of using a Ford E300 MC when converting to disc's. Not used as often but a direct bolt on in scouts. I'll have to research what years to use. Don't they have power assist though? I'm trying to avoid putting in power brakes.

Thanks, Brad J.