brake issues?? help

[insufficient funds]

So I was climbing up a gravel (not. Too steep) I was in 2 wheel drive and started to BOG down. When I stopped to throw it in 4 the Jeep slid backwards down the hill the front tires where locked up and the rear was not. The rear brakes are not working or have very low pressure. I have a 8.8 in the rear discs with new pads and roters all around. Fluids good no air in lines. Any thoughts??

 

[insufficient funds]

It's a 95 2.5 Wrangler.

 

[Utah_jeepster]

Its your proportioning valve most likely. Did your jeep come with discs up front and drums rear? if its the factory valve its was set at 70/30 with a reduced flow to the rear for dual piston drum brake. My 2001 came with that set-up, when I changed to discs in the rear I had to change the braking bias with a manual valve I got from summit. I plumed it in, then went and did hard braking tests in the parking lot till I got my front end to stop diving down in front then gave it a 1/4 turn more. I waited till winter to fine tune it on ice. That is when I got the rear to lock up just about the same time my front did. (Have that funky ABS type of system on the front only)

 

[PoliceMonkey161]

I would start with Utah_Jeepster thoughts.... I have never done this conversion personnally, but have read several articles about it. Also, if you have the orginial Master Cylinder, there is a check valve for the rear lines (it is underneath or between the flare nut and cylinder threads) that must be removed after or during the conversion.

 

[TerryMason]

I've got the same setup (8.8 with discs) in my 2005 (originally with drums in the back) and haven't addressed this. Is there an easy way to test the function of the rear brakes other than high speed parking lot maneuvers (maybe put the front wheels on car movers)?

I don't know if there is a difference between YJ and TJ proportioning valves, but in my reading I've heard that alot of people remove the O Ring from the proportion valve (it is on the plunger rod). They say that this provides more fluid to the rear brakes. I have not done this, so your mileage may vary.

 

[TerryMason]

One quick question - are your bleeder screws (on the rear 8.8) above the brake lines going into them. It's not hard to install the calipers on the wrong side, and if that happens you won't be able to correctly bleed them.

I would start by re-bleeding the brakes. Even with the wrong proportioning valve, you should get some level of stopping.

 

[insufficient funds]

Thanks guys. The bleeders are on the bottom of the calibers. Is that wrong? I might try removing the o ring in the valve. Has anyone else.done this with any luck?

 

[808CJ7]

The bleeders should be on the top of the calipers as terry mentioned. You'll have to swap them over to the other side

 

[TerryMason]

Thanks guys. The bleeders are on the bottom of the calibers. Is that wrong? I might try removing the o ring in the valve. Has anyone else.done this with any luck?

Yep, the calipers are on the wrong sides (take both off and put the driver side one on the pass side, etc). Essentially the air stays trapped in the lines and doesn't go down and out of the bleeders. When you swap sides, the bleeders will be located at the top (as they are intended to be), and the air will have an easier time getting out.

You probably won't have to do anything with the valve (I didn't on mine). Be sure to bleed them well, as you probably have a good bit of air trapped in the rear lines (and will have more after swapping the calipers).

 

[insufficient funds]

Will do. thanx