Brakes???!!!

[GTsenre]

I helped a friend put a 4.5" RE kit this past weekend on an 1988 XJ w/o abs. The problem that we're having is the brakes aren't working. We bled them 4 or 5 times I even had the new fluid we were puting in come out of the rear brakes. It builds up pressure fine with the engine off, but as soon as we start the engine all pedal pressure goes away. The brakes worked fine before the lift. Also we can pump the brakes with the engine on and build up pressure, but as soon as we leave off the presure goes away. Can someone please help???!!!

[JeepFreak21]

Originally posted by GTsenre
I helped a friend put a 4.5" RE kit this past weekend on an 1988 XJ w/o abs. The problem that we're having is the brakes aren't working. We bled them 4 or 5 times I even had the new fluid we were puting in come out of the rear brakes. It builds up pressure fine with the engine off, but as soon as we start the engine all pedal pressure goes away. The brakes worked fine before the lift. Also we can pump the brakes with the engine on and build up pressure, but as soon as we leave off the presure goes away. Can someone please help???!!!

Maybe a leak in the power brake booster?

[old_man]

Sounds like a vacuum booster problem or a vacuum leak problem. Did you have the MC or booster disconnected?

You mention bleeding the rear brakes, did you bleed the fronts as well? Did you replace the front brake lines with longer units?

Where are you located? I have a spare booster as well as MC you can have if you need them. I upgraded to dual diaphram booster and E-350 MC.

Tom Houston
Loveland, Colorado

[GTsenre]

Yes I bled the front brakes also and replaced the front lines, and no I didn't unhook anything from the mc or booster

[old_man]

Start the engine, let it idle for a few seconds or so. Turn off the engine. Wait a minute or so then pull the vacuum hose with the checkvave from the booster. Did you hear a vacuum whoosh? If the MC is good, you should still have vacuum in the booster for a long time after turning off the engine. This is a quick and dirty check for booster failure.

Like I said, if you need one, call me. If you pay for the shipping you can have the one I pulled.

Tom Houston
970-690-6270

[JeepFreak21]

I don't know how this translates to fuel injected... but to check for vacuum leaks on my carbureted 340 you can just take the air cleaner off the carb and cover the hole with a piece of cardboard. If the engine dies then there's no leak, if it keeps on running, then you have a leak.

[vintagespeed]

Might be a toasted M/C or the pedal rod needs to be adjusted. If you have good pressure with the engine off and you let it sit & check it again, if the pressure is gone then you've got air in the lines (if there's no leaks). If you come back & the pressure is good then it's a booster problem.

[RCP Phx]

Although its not uncommon to lose a MC or Booster after doing brake work,Id bet on air in the system!Make sure the rears are adjusted up properly first(very important).Then re-bleed both the front and the rear.

[XJJPR]

Re bleed the system.

Make sure your doing it enough to get all the air out.

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