bad brakes

Start here, you need the booster to "boost".

JoBo

Why try and make some unsafe bastardized brake system?

The Cherokee's have been stopping fine since 1984 with their 'stock' setup....

The best you can expect with stock is to lock up the front wheels. The rear wheel will not lock up unless you are almost stopped. The combination valve does that to prevent rear wheel lock so you don't do

360's down the road anytime you jam on the brakes.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Erik Litchy wrote:

I am thinking the '89 only had a single diaphram booster. If you could get a double diaphram booster, from like a '95, then it should be a double diaphram. This will add about 400PSI to your brake system. The easy way to check for single diaphram/double diaphram is: single diaphram is about 4.25" from MC mounting surface to the back where the brakets are, double diaphram are about 6".

--James

why? the pedal can hit the floor with enough effort without stopping that quickly. wouldnt a smaller bore master push less fluid into the system, making longer stopping distances?

or am i confused?

it does have a single diaphram booster.

Ahh....

Maybe the MC doesn't have enough stroke? or the bore? or more likely the proportioning valve isn't right for dual disks.

I would be trying to find out what the bore and stroke are for the rears.

Also drum and disks have different MC's. There is a backflow valve or something in the one of them. The Jeep drum brake MC will not work on a disk brake setup.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Erik Litchy wrote:

well it takes a LOT of force to make it hit the floor.

You have air or maybe dead wheel hoses that are ballooning. My bet is air.

Did you bench bleed the MC?

Was the proportioning valve ever empty of fluid? If so there is likely a pin in the end of it that needs to be held or pushed depending on version to lock the guts so you can bleed the air out. If you don't do this, that valve will never get the air out and work and you can compress the pedal down if you really push on her.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

My Jeeps brake booster died with only 700km on her. Was heading out on my first camping trip (mountains in BC near Hope...awesome). Luckily I was stuck in a traffic jam on the highway and wasn't going faster than 15kph.

First thing I noticed was my RPM's kickin up when I hit the brakes and found I was having trouble stopping. I actually had to pull myself down with the steering wheel and couldn't stop. Had to downshift and use the E-brake. Anyhow, I was close to a dealership and luckily the salesmen were still around (was 8pm or so). they were cool enough to give me the loner car for the w/e (damned frickin NEON car...got teased bad about that!).

anyhow, they fixed it and it was covered, of course. the guy told me that it reverted to manual brakes....I kinda laughed. I've driven some manual brakes before and that wasn't what they reverted to....could've stopped better sticking my foot out the door!

Have a look at the MPI brakes site, some good info under thier Tech Info section, lots more in thier catalog, you can download it as a PDF.

Howard.