Stiff Brakes

[revolver]

Citizens!

I just bought a '96 Cherokee Classic to replace my trusty rusty '90 Laredo, and I'm just now noticing that the brake pedal on this Jeep is pretty stiff. It'll stop and all, but it takes more effort than it should.

I was searching around the forums while I'm stuck here at work to see if I could get a clue and ran across several horror stories about ABS brakes. I checked the dash at lunch and when the ignition is turned on I don't see an ABS light come on, but I'm not convinced. Before I tear into this, I'd like to have an idea what I'm tearing into if you know what I mean. So what's the most fool-proof way (and I do mean fool-proof :wierd: ) to tell if I have ABS brakes in this vehicle?


:Revolver

 

[bajacalal]

I just bought a '96 Cherokee Classic to replace my trusty rusty '90 Laredo, and I'm just now noticing that the brake pedal on this Jeep is pretty stiff. It'll stop and all, but it takes more effort than it should.

-snip-
to tell if I have ABS brakes in this vehicle?

Open up the hood and look for the brake master cylinder where the brake fluid goes. Follow the tubes coming out of it and they go to the proportioning valve which is like a little brass rectangle bolted to the body and the lines then go to the brakes. This is if you have normal brakes. If theres a bunch of other junk that the brakes lines connect to like a electrical pump, a pressure resivoir (a small can, like a fire extinguisher) and possibly another larger proportining valve all together that you've got ABS. If you don't have abs this problem is probably a siezed cylinder / caliper or pinched / clogged line.

 

[revolver]

Outstanding bajacalal, thank you. I'm all over it. And thanks for the heads-up on the stiffness. It's weird, I've dealt with all manner of non-ABS brake failures on many different kinds of vehicles, but this is different. Instead of fading out, they kind of fade in, for lack of a better description. As soon as I figure it out I'll post the solution for future forum searchers.

:revolver

 

[bajacalal]

Outstanding bajacalal, thank you. I'm all over it. And thanks for the heads-up on the stiffness. It's weird, I've dealt with all manner of non-ABS brake failures on many different kinds of vehicles, but this is different. Instead of fading out, they kind of fade in, for lack of a better description.

Thank you. That sounds like a problem w/ the wheel cylinders or caliper. Cold, they are released but after breaking they heat up and jam w/ the piston extended b/c they are worn out of round. It seems common w/ xj's as my 95 needs cylinders. Now, after they become stiff drive on a road that doesn't require much breaking & stop w/o braking much. Go to the wheels, feel the drums, are they burning hot? Is one hotter than the other? It could also be the fron caliper but they are harder to check. A temporary is to pull on the brake w/ your foot like pumping the brake in reverse.

 

[RyanWM1239]

Revolver - Your problem is probably more in line with the responses above, but... Had my XJ for about 3 months when the brakes got very stiff. Set a day aside, and began to troubleshoot. After a while poked my head under the pedal. Damn aftermarket floormat had worked its way up and became wedged behind the pedal. Felt like such a dumba$$! I'm sure no on else could work right by the obvious, but there it is.

 

[revolver]

Hey Ryan,
I had the same thing happen to me with the clutch pedal of my wife's old Sportage. Every now and then, like maybe once a month, a tiny fold in the carpet kept the damn car from starting by keeping the pedal from depressing the plunger on the clutch sensor that last friggin' millimeter it needed to complete the start circuit. And yes, although I was happy when I finally figured it out after three years of thinking it was a short in the alarm system, it left me with a very sub-genius feeling for a long time. So I'll be sure and check .

Well bajacalal, I'm happy to report that I do NOT have ABS brakes, and you may be onto something with the calipers; because of your suggestion I did notice that the brakes seem to be more effective cold. Unfortunately I'm on 12-hour days until Tuesday and therefore can't pull the wheels off until then.

God I love this car! The engine compartment still has all of the factory stickers all over it, nothing leaks, and all of the nuts and bolt heads have sharp corners. I know it sounds kind of silly, but at nine years old this is the "youngest" Cherokee I've owned, so I'm just not used to everything being so shiny. Hell, I was startled to find rubber plugs in all of the inspection and adjustment ports in the rear backing plates. Until now I didn't know Cherokees had come with those!

:revolver

 

[jerrywagner]

Does not sound like a ABS problem, my guess is that the front pads and rotors are glazed from heat and it's taking much too much pressure to stop and this is glazing the pads, if it was my Jeep I would pull the front pads, inspect the rotors, look for heat marks and especially hair line cracks from the heat, DO NOT DRIVE if there are cracks, replace the rotors and pads if there are cracks, if no cracks I would sand the pads to remove any glaze and do the same to the rotors and be on my way. let us know the outcome

 

[revolver]

Re: Stiff Brakes RESOLVED

Front brake pads appear relatively new, obviously less than 10k miles. Rotor surface could be better, but no evidence of uneven wear nor any defects or glazing.

Rear brake linings show considerable wear but still have enough meat on them to be effective. Rear right-hand side wheel cylinder on the other hand has a coating of hydraulic fluid and brake dust, although there isn't enough hydraulic fluid present to have contaminated the brake shoes.

Verdict: rear hydraulic system mildly compromised to the point that there is a loss of rear braking power, but not to the point that it produces a tell-tale increase in pedal travel.

Remedy: replace rear wheel cylinders and brake shoes, machine rear brake drums. I will also be using the opportunity of opening the hydraulic system to replace as much of the fluid in the system that I can.

Grateful thanks to all who took the time to provide input for this thread; wheel on with your bad selves! :sunshine:

:revolver