Waning brake problem

I got a 90 cherokee in February with the 4.0 & I've noticed the brakes getting wierd ever since, I can push the pedal almost to the floor(firewall) without much resistance even at a dead stop(the most resistance is when the pedal is pushed the furthest down) and the brakes don't really do a good job, I can slam on them and the pedal hits the firewall &I will slow down but I can't lock the wheels up...it just feels like the brakes should be "tighter" and more responsive.

I was told by the dude I bought it off of that the pads are all new and there's a new E-brake cable, a mechanic who looked the truck over for me when I first got it says that the pads were brand new and I took it to a dealer to get something else looked at and they said the pads are good but the rotors are "blued"(and presumably warped) from heat so they need to be replaced.

I checked the brake fluid level in the square box thingy and it was good and I checked the round thing next to it and it was good as well (is that the clutch resevoir?) so what is most likely my problem here? I don't wanna not be able to stop one day so I thought I'd ask...

Thanks

Bleed your brakes.

1. Start from the right rear, then left rear, then right front, and finally left front.

2. get a one man pump or have a friend pump the pedal until it gets as hard as it can. Usually about 6-8 times. release the bleeder valve until NOTHING but fluid comes out.

3. Check level in master Cyl. Fill if necessary.

4. repeat step 2 in the order list in step 1.

5. Don't come anywhere near me and test drive your rig. If that doesn't make it better...my guess is the power booster, behind the master cyl.

6. if it is the booster...upgrade to later model and get the master cyl with it.

7. GOOD LUCK.

A couple of questions for you:
After I bleed the brakes, about how much fluid does the system hold?
If the booster is gone about how much should a new one cost for a 90 xj and how much more should the kit for the newer one be?
By any chance could this be a vacuum problem?

A couple of questions for you:
After I bleed the brakes, about how much fluid does the system hold?

If you get the BIG bottle of fluid you'll have more than enough.

If the booster is gone about how much should a new one cost for a 90 xj and how much more should the kit for the newer one be?

unsure on cost but the 96 up I believe is a DUAL diaprham. You could probably pick one up used, cheap. Then get a MC for the same year as the booster.


By any chance could this be a vacuum problem?

yes it could, but I forget how to check vacuum. I know Yucca-Man knows. You could PM him. Nice Guy. Alwasy glad to help.

After and during bleeding keep fluid reservior between the lines... call a junk yard and try to get one from a 96 and up I believe, i think they give you a lot more boost than a brand new stock one of your year through 95. There are def. articles on swapping a newer one on the web somewhere. Expect it to be A LOT from the stealership.

guys here have done it. It's a little hard on the back lying down on your floor with your seat in the way. I'd take mine out if at all possible.

The MC, is it the square thing in front of the cylinder shaped thing on the fire wall or is it both because I can get the square thingy for about $10

Get the roters turned (resurfaced) then bleed everything. There are very few ways for the booster to cause mushy brakes. Also ask the previous owner if/when the master cylindar (squarish fluid thingy) was replaced. It may need bench bleeding.

-r0

STOP!


If you don't know anything about brakes, don't touch them.
Especially if you call brake parts "thingys".
Brakes are like algebra, it's easy if you know how...otherwise x=y and you can't stop your XJ.

As far as resurfacing (turning) brake rotors goes, you can usually get a new OEM style rotor for the same price or $10.00 more (locally). Just get the new ones.

red91inWA said:

unsure on cost but the 96 up I believe is a DUAL diaprham. You could probably pick one up used, cheap. Then get a MC for the same year as the booster.

Click to expand...

My '95 has the dual diaphram model, I believe it was the first year.

I would start here by bleeding the brakes (or having someone do it), and making sure that the rear brakes are adjusted properly. Don't trust anybody's word on this, especially if an amateur did the rears. The adjusters are iffy even when they're right, and it's easy to get them wrong. If you haven't had someone look at the insides, you can't even guarantee that the previous owner put in all the right parts, or didn't put the adjusters on backwards. If after all that the pedal doesn't firm up suspect the master cylinder. A bad booster will cause a hard pedal with high braking effort, not a low soft pedal.

I would definitely not bother to deal with the rotors if the pedal is soft or low when you are standing still. If you have seriously bad rotors, which is to say bad enough to cause shaking and pedal pulsating and the like when you stop, they MIGHT be bad enough to cause a slightly soft pedal when you first apply the brakes, but this is unlikely, and I would never trust a dealer who says the rotors are "blued" and likely to be warped. They either are or they aren't, so don't replace or reface them on the suspicion of a person who stands to make a big profit by selling you new rotors.