jub

I found this '95 gc laredo sitting in a field by a barn. 230,000 miles and sat well over a year but the body is amazing and the engine is strong and quiet. 4wd works good enough to pull out of the ditch/snowbank it sat in with 4 flat tires. So far I'm just trying to give it life again, new tires, battery, trans filter and fluid. Now the problem, I put new calipers on front and rear and only the front will bleed. There is no fluid getting to the rear. I have fluid from the mc to the proportioning valve and out to the abs pump. Don't know if the abs pump is putting out fluid but there is none at the distribution block on the rear axle. And no abs light unless i pull the fuse. I could bypass the abs with a non-abs prop but I want to do it proper. If I do that the Jeep outsmarted be and I can't let it win. And yes, I tried peeing on the tire so it knows who's boss.

dave1123

Have you tried opening the rear bleeders and standing on the brake with both feet? It might be the ABS unit is froze up from lack of fluid. IDK about jeep systems that much, but I know GM systems have a shuttle valve that if you lose pressure in one side of the system, it shuts that side off and it needs to be reset by pushing a rubber plunger button on it's end. That's probably what you're calling the proportioning valve. It's right up by the MC.

ZJMAX

Try undoing the line before the rubber hose to the rear diff. The hoses can sometimes come apart inside and act like a 1 way valve.

Max

jub

I've seen that rubber line come apart on my brothers '00 gc on the inlet to the rear caliper, like a one way valve. I think the problem is between the abs pump and the distribution block on the rear axle. Fluid comes out of the prop valve into the abs pump but I have to remove the abs pump to reach the outlet to the rear in order to check if flow is coming out of the abs pump. If I open up anything else I'll have air in the system so I'm thinking I should get a vacuum bleeder and start over. I think trying to reset the valve in the prop won't matter if I already have fluid coming out of it to the abs pump, if there's fluid coming out of it to the abs pump why should I try to reset it dave1123?

dave1123

You don't have to in that case. I'll bet it's the ABS unit.

jub

I'm going to try the abs pump tomorrow, hope that does it.

dave1123

Are you bleeding the brakes with the engine running or not. On my 2000, there is no proportioning valve and that function is done by the HCU or hydraulic control unit. When you hit the brakes, the unit closes the valve to the rear brakes with a solenoid, then pulses it until pressure builds in the rear system. This allows the front brakes to take the initial load and keeps the rear brakes from locking. The HCU is part of the ABS unit and is controlled by a microprocessor. As I said before, can they make this any more difficult? Your 95 may be totally different, or at least I hope so.

jub

Bleeding with engine running, tried with just key power on and the pedal feels same as with key off.

jub

Good news I hope! Before I left to buy parts I decided to try a gravity bleed on the right rear, just for fun. For the first time I actually have fluid (dirty) coming out so I'm doing a vacuum bleed and replacing the cap for the mc.

jub

I just finished trying to bleed with the vacuum bleeder, I did all 4 in order. I had a **** ton of air in the lines at all 4 wheels. I have all clear fluid coming through but there's still bubbles. All of the old dirty fluid has been removed. Brakes are still squishy and I have to pump a little to get good pressure. At this point I'm not sure if I just need to bench bleed the mc or keep trying to work the air out of the lines.

dave1123

If you can find someone with a pressure bleeder, they work a lot better. There's a cap and hose that clamps over the mc cap and you pump the bleeder tank up with a hand pump built into the tank. You can let each bleeder valve run continuously until no air comes out. The tank holds over a quart of fluid. It's about the only way to bleed an ABS pump if that gets air in it.

peep

I've done a vacuum bleed with my vac pump, one time had a poor fit of the hose to the bleeder stem, was getting a lot of air bubbles. Was bleedin and bleedin and still air bubbles. Fixed with a fresh hose line, my bleed was already good.
How is your brake pedal now that you have the old junk out of the lines and fresh fluid coming thru?

jub

I fitted each bleeder valve with it's own clear hose so all I have to do is connect the vacuum pump to the hose not the bleeder. It worked better and saved time bleeding all 4 tires. Pedal is much better. Took it on it's first drive this morning and got stranded on the way to my friends wedding tho. The brakes weren't the problem, I drove 25 miles and it stalled

jub

I probably need to make a new post for that issue tho.