'94 Jeep With Rubbing Brakes

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  #1  
Old 01-08-05, 10:11 AM
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'94 Jeep With Rubbing Brakes

I have a '94 Jeep Grand Cherokee, 4.0 L and 104,000 miles. At 63,000, the left front brake was completely worn out and had grooved the rotor so deeply, I had to replace it. The right front was only slightly worn and I had it turned and replaced the discs.

Again 30,000 miles later, the right front rotor is grooved on the outside only and the bottom side of the outside disc is completely worn down (the right side rotor and discs look almost new). I again replaced the right rotor because it could not be turned and it sounds like the brake is rubbing all the time. What would cause this?

Thanks.
 
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  #2  
Old 01-08-05, 04:20 PM
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Originally Posted by ellersk
Again 30,000 miles later, the right front rotor is grooved on the outside only and the bottom side of the outside disc is completely worn down (the right side rotor and discs look almost new). I again replaced the right rotor because it could not be turned and it sounds like the brake is rubbing all the time. What would cause this?

Thanks.
Please review your post. It looks like at least one time you mentioned the right rotor when you meant to say the left rotor so it's somewhat confusing. Brake rotors are the same as brake discs. I believe you meant the brake pads when you said discs.

Look for a stuck caliper or piston, make sure the calipers slide back and forth easily, plenty of grease on the sliding parts. Check that calipers are releasing properly when the brakes are disengaged. Possible brake hose failure on one side.

Did you install new brake pads on both the right and left sides(4 pads total) the 1st time you changed the rotors? Is the Jeep pulling to one side when braking?
 

Last edited by jeff67; 01-08-05 at 04:34 PM.
  #3  
Old 01-08-05, 07:56 PM
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It could also be a flexible brake hose that has bulged (pinched) on the inside preventing the piston from unloading when the brake pedal is released.

You'll be able to bleed a caliper that has a pinched flexible brake line, but it will be difficult to retract the piston. Brake fluid can pass through the blockage under pressure, but not release under normal return pressure.

Check it out, I've seen this many times.
 
  #4  
Old 01-09-05, 09:02 AM
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Thanks for the messages and sorry for the confusion. Yes, the left side is wearing fast and I have now gone through two brake disc's on the left side. When I did change them out, I changed all four brake pads (both front wheels). And no, the car does not pull to one side when braking.

The caliper seems to be moving freely but both of you mentioned brake hose failure that I did not even think of. Other than just replacing the hose, is there a way to tell if the hose is pinched? Is replacing the hose a difficult repair?
 
  #5  
Old 01-09-05, 12:09 PM
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Sorry, yes Jeff suggested a brake hose first. My proof reading is shot.

To test for a blocked hose, first see if the piston can be pushed back in its bore fairly easily. Most of the time, I remove the caliper and let it hang by a zip tie or piece of wire so as not to damage the flexible brake hose while I see if I can push the piston back into its bore using my hands - specifically my thumbs. Usually, the piston will begin to slide back into its bore. If my thumbs wont set the piston back, I'll try a c-clamp and see how much effort it takes to accomplish this.

You can usually tell right off the bat. It will be very stubborn to move if the line is blocked.

Another test is to remove the banjo bolt from the caliper (where the brake hose attaches) and see if the line dribbles for a while once the bolt has been removed. If the line is blocked only a small amount of fluid will leak out.

A word of caution here: you probably have ABS brakes and you do not want to introduce air into the ABS system as you will need special equipment to remove any trapped air from the ABS control unit. To prevent this, get a helper to top off the reservoir with fluid while you perform the above test. Remember to seal off any fitting while you have that component removed so as not to drain the reservoir.

A third way is to completely remove the brake line and see if air will easily pass through both ends of the line. Don't swallow any fluid, it's toxic. A small drinking straw may come in handy here.

Post back with your results.
 
  #6  
Old 01-11-05, 06:24 AM
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Thanks for your advice and the brake line was it. I pulled the old hose off and blew air through it and it seemed okay to me, but I changed the hose anyway. No rubbing or burning smell anymore. Nice job.

Is this something I should consider normal maintenance and also change the right hose even though I am not having any problems with it?
 
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