What do I need to make my YJ stop. The YJ brakes go to the floor. Brakes have been blead. I was told I could go to a ford master cylinder to fix the problem. Any ideas.
F250, F350, E250, E350, all use basically the same M/C, booster, and brakes from the early 80s through 94-95. There were a couple of changes along the way, but there's nothing unique about the E350 one. It's 1-1/8", sized to push the big double piston front calipers and some large rear cylinders.
If he's using all stock Jeep brakes, a stock Jeep M/C is going to work the best. The larger Ford M/C is going to push too much fluid.
He's not using all jeep stuff. There's an disced exploder 8.8 in the back, hence the problem. The stock M/C can't provide the power the discs need. Can't he upgrade the hoses to accomodate for the fluid push with a Ford M/C and booster?
Hoses don't matter in a hydraulic system. The only question is whether or not the hose can provide the necessary volume, which in a brake system doesn't take much.
The problem with the big Ford M/C is that it has the same bias as the stock Jeep -- not much fluid to the rear, lots and lots of fluid to the front. You could use an adjustable proportioning valve to cheat the bias, but you're better off starting with the right master cylinder.
I'm not big on what fits what Jeep boosters, fittings, etc. But I'd start by looking for a f/r disc master cylinder that mates up. There's got to be something from a GM car (or maybe even the Exploder?) that would fit.
You could use an adjustable proportioning valve to cheat the bias, but you're better off starting with the right master cylinder.
I'm not big on what fits what Jeep boosters, fittings, etc. But I'd start by looking for a f/r disc master cylinder that mates up. There's got to be something from a GM car (or maybe even the Exploder?) that would fit.
True about the gm/exploder m/c. I was trying to think about the proportioning valve but that answer evaded me. It could be a possible solution, though.
There is a big write up on Brakes on Pirate on the front page of the site. Those new pistons need more fluid therefor a larger push from a larger fluid MC is needed. It's an 8.8 but he said it has an F250 Caliper on the title.
Erik has hyro assist or something. His brakes are awesome as he was my brakes coming down the hill from Kodak. I had to cut mine off and strap to him and he kept us both from going out of control.
There is a big write up on Brakes on Pirate on the front page of the site. Those new pistons need more fluid therefor a larger push from a larger fluid MC is needed. It's an 8.8 but he said it has an F250 Caliper on the title.
Erik has hyro assist or something. His brakes are awesome as he was my brakes coming down the hill from Kodak. I had to cut mine off and strap to him and he kept us both from going out of control.
Its not so much about volume of fluid as it is about pressure to the rear brakes. A bigger reservior won't make a lick of difference if the pressure going to the brakes is still 300 psi (rough drum pressure).
What about swapping the proportioning valve from a jeep that came stock with rear discs (ZJ?). If the stock YJ MC is too weak to provide the pressure needed for the rear, the 97+ XJ MC might be an option too.
Stock brakes up front? Sure there's no leaks and you've bled everything to death, INCLUDING bench bleeding the MC? Also you're sure the MC's seals are all good and there's no way its leaking into itself?
Just asking these questions because even with your rear brakes disconnected completely you should be able to come to a stop. Its not desireable or safe, but I'm just pointing it out. If you don't get this basic response from your front brakes then I'd say the problem isn't going to be solved with an upgrade in MC...
You guys rock. Looks like the Ford set up is the way to go. Here are the plans, please correct me if I'm wrong. Get a Ford 3/4 or 1 ton master and booster and bolt in, bleed and stop a YJ. Do you guys know if it will bolt right up or will I need to get the ford brake pedel and modifiy it to fit? I'll head to pull a part next week and just want to get everything the first trip.
Just to let you know, I pulled the 1/2 ton m/c and booster out of my bronco and turned them in as cores for a set of remanufactured ones for an F350 at advance auto which are now in my truck. They do not know the difference. You could probably pull a cheaper 1/2 ton set at the yard from a bronco/F150 and then do the same. Personally, I wouldn't run a set from a yard as you don't know their full history/condition. Just get a 1/2 ton setup and swap them as cores for a 1-ton.
you can swap the master cylinder but since i ran into this same problem....swap in a p. valve from a ZJ because the difference is night ans day. Also make sure your calipers are on the right side and the bleeders are above the brake lines. It sounds stupid but i had the same problem and now its fixed with my stock master cylinder.
yea i woudln't mess with the master cylinder until you get the correct biased prop. valve... as mentioned, one can be had from a ZJ......
i run a 78 grand marquid master cylinder with the stock 89 yj prop valve and somehow it works awesome.... but i'm also running huge dual piston ford calipers up front and single piston 1 ton chevy calipers out back..... i think this upgrade, or any upgrade known to work well with such huge brakes, would be a mistake for a setup consisting of stock fropnt jeep calipers....
try the porp. valve first... then IF that doesn't work, play with MC swaps.....
I have a 95 YJ with a 8.8 with discs and here is what I did. I swapped in a master cylinder from a 1985 E-350 and got rid of the stock prop valve. I put in an adjustable prop valve from Summit. However, I have the adjustable prop valve wide open. It works much better, but with 33's, I'm still not going to lock them up.
Forgot to mention, I had to take a grinder and grind just a little bit off the ears of the Ford master cylinder to get it to fit right on the brake booster.
