GC master cylinder

for my 88 with 36's I did the disc conversion rear but i feel my brake power still sucks, especially in 4-lo on deep descents. I am hopefully soon finishing the rear and will have one ton's ready to go. But i would like some better braking power since my pads and shoes are in great shape, but the jeep is not stopping how i think it should be. If i go to a Grand Cherokee master cylinder, will I get better braking and also what year GC should i get it from. Also, is it worth doing a GC master if i am going one tons eventually? I also looked into adjustable proportioning valves but came up with nothing. What can i do for bettter braking power with the 36's???? Please help anyone cause i am looking to wheel soon and need this improved. Thank you

http://www.naxja.org/forum/showthread.php?t=44506

http://www.naxja.org/forum/showthread.php?t=903934

99-04 WJ Master cylinder and brake booster - runs about $450 brand new from Napa 1/4 of that from a salvage yard
modify the the rod - flatten out side like original, and drill out the hole a little larger in diameter - just make it look exactly like original
also need two metric to SAE brake fitting adapters
then just bend up the body lip behind the booster

The GC master cylinder won't fit the '88 booster(won't seal). You could bolt in a '76 (I think--search!) Mercury Grand Marque MC intended for 4-wheel discs with hydro assist (you don't use the hydro part). It's basically direct bolt-in, requiring only one MC-to-brake-line adapter. It will give you the volume needed for your rear discs. You didn't state what brakes you're running front and rear. If your going to run larger brakes (like Chevy, or early full-size Jeep), you'll probably benefit from a larger MC, like the Mercury mentioned above. If you're going to use stock GC brakes, then the GC MC, along with the GC booster would work. In either case, your stock XJ proportioning valve needs modded, or replaced, to run rear discs.

xjbubba said:

The GC master cylinder won't fit the '88 booster(won't seal). You could bolt in a '76 (I think--search!) Mercury Grand Marque MC intended for 4-wheel discs with hydro assist (you don't use the hydro part). It's basically direct bolt-in, requiring only one MC-to-brake-line adapter. It will give you the volume needed for your rear discs. You didn't state what brakes you're running front and rear. If your going to run larger brakes (like Chevy, or early full-size Jeep), you'll probably benefit from a larger MC, like the Mercury mentioned above. If you're going to use stock GC brakes, then the GC MC, along with the GC booster would work. In either case, your stock XJ proportioning valve needs modded, or replaced, to run rear discs.

Click to expand...

im thinking of having the stock prop valve plumbed out to allow more fluid to the rear, what do u think????

jackdes said:

http://www.naxja.org/forum/showthread.php?t=44506

http://www.naxja.org/forum/showthread.php?t=903934

99-04 WJ Master cylinder and brake booster - runs about $450 brand new from Napa 1/4 of that from a salvage yard
modify the the rod - flatten out side like original, and drill out the hole a little larger in diameter - just make it look exactly like original
also need two metric to SAE brake fitting adapters
then just bend up the body lip behind the booster

Click to expand...

im starting to lean toward this conversion, but first i think i might plumb the proportioning valve

xjrugger said:

im starting to lean toward this conversion, but first i think i might plumb the proportioning valve

Click to expand...

Just swap in GC 4 wheel disc prop valve internals. It's a bolt in, just did this with my 95 booster and master.

That's what I did--works fine.

Will this be enough for big 8-lug d44 front discs and 3/4 ton chevy disks out back running 37s? This is for a 99.