JeepForum.com

JeepForum.com (http://www.jeepforum.com/forum/)
-   WK2 Grand Cherokee Forum (http://www.jeepforum.com/forum/f309/)
-   -   Rear brakes wearing out faster than front (http://www.jeepforum.com/forum/f309/rear-brakes-wearing-out-faster-than-front-1563048/)

rmac427 08-16-2013 11:12 AM

Rear brakes wearing out faster than front
 
Just took my 2012 Grand Cherokee V6 4x4 in for an oil change, and was told that my rear brakes are almost worn out, but my fronts still have plenty of life left on them.

The Jeep only has 16,000 mi. on it and the rear brake pads only have 3mm left while the front pads have 7mm per the technician.

There were no signs of the calipers sticking or getting hung up.

Shouldn't the front and rear brakes wear evenly, or at least the fronts should wear out faster than the rears because they do most of the braking?

Is there a proportioning valve on this system that maybe isn't set properly?

Any ideas what might be causing this?

tjkj2002 08-16-2013 06:40 PM

Your Jeep in normally in RWD and with ESP and traction control the rear brakes will wearout faster then the fronts with those driving aids.Even if you don't know it or feel it those rear brakes are engaging more often then you think.

loveracing1988 08-16-2013 08:00 PM

No matter what though, unless you are constantly spinning the tires brake pads should not wear out in 16,000 miles.

tjkj2002 08-16-2013 08:27 PM

Quote:

Originally Posted by loveracing1988 (Post 15803078)
No matter what though, unless you are constantly spinning the tires brake pads should not wear out in 16,000 miles.

Tell that to Chrysler minivan owners,lucky to get 20k out of the front brakes before there metal to metal.Same problem from '96-'13 models.

Jackal01 08-16-2013 09:10 PM

I checked mine earlier today and mine are still about half way through the original pads. Fronts are worn less than rears; normal.

NDSU_Bison 08-17-2013 10:17 PM

My 2008 WK does the same thing. I do a lot of highway driving and had the rear pads replaced at about 110,000 miles. The fronts are still OK at 128,000 miles.

ColdCase 08-17-2013 10:26 PM

Quote:

Originally Posted by tjkj2002 (Post 15803167)
Tell that to Chrysler minivan owners,lucky to get 20k out of the front brakes before there metal to metal.Same problem from '96-'13 models.

We always got 80,000 + miles on the three minivans we had during that period....

ColdCase 08-17-2013 10:51 PM

Quote:

Originally Posted by rmac427 (Post 15801334)

Is there a proportioning valve on this system that maybe isn't set properly?

Any ideas what might be causing this?

Well the parking brake uses the drum, not the pads... so someone hasn't been driving with the parking brake on.

The service manual says they use a Electronic Variable Brake Proportioning designed into the combined hydraulic control unit and ABS module which eliminates the typical combination/proportioning valve. Its a four channels sytem with each caliper directly connected to the HCU. As far as I can tell there are no manual adjustments, although the dealer's scanner may have some kind of capability.

I would suspect something amiss in the HCU/ABS module or perhaps sensors. Perhaps the control system thinks the rear tires are spinning faster than the fronts, and are routinely applying the rear brakes.

Unless you have someone riding the brakes, 16,000 miles is a bit short.

Rears brakes use smaller pads and are lighter duty than the fronts, so they could wear faster than the fronts. Our WJs alway wore fronts twice as fast as the rears, however.

There are a number of things that will cause brakes to be applied automatically, yaw, stability, wipers, along with traction.

ColdCase 08-21-2013 10:37 AM

1 Attachment(s)
Did you get this sorted out?

While perusing for another issue I ran across the reminder that the master cylinder has two pistons, one for fronts, one for rears and this proportioning description. Both my front and rear pads have plenty left after 36,000 miles mostly highway. Hard to tell if one set is wearing faster than the other.

Dave2002ti 08-21-2013 03:19 PM

????
 
Quote:

Originally Posted by tjkj2002 (Post 15802816)
Your Jeep in normally in RWD and with ESP and traction control the rear brakes will wearout faster then the fronts with those driving aids.Even if you don't know it or feel it those rear brakes are engaging more often then you think.

My 2012 Grand Cherokee Laredo X AWD with the ORAI package is in RWD normally??? Really? And you are a mechanic.

If OP's rear brakes are wearing out there is a problem. Either with driving style or more likely a failure of some component.

The front brakes of most vehicles do approx 70% of the braking. You do not want the rear brakes doing much more than 30% because then you run into all kinds of balance and handling issues. Race cars have an adjustable proportioning valve you use this compensate for wear, weather, and track conditions.

Jpiwonski 08-21-2013 05:51 PM

Was it the outside or inside pad or both that was down that far?

ColdCase 08-21-2013 06:13 PM

Quote:

Originally Posted by Dave2002ti (Post 15820865)

The front brakes of most vehicles do approx 70% of the braking. You do not want the rear brakes doing much more than 30% because then you run into all kinds of balance and handling issues.

True, but many manufactures now skimp on rear shoe material (a lot smaller pad), so they can wear out faster than the front even at 30% load.

In any case, worn pads at 16K miles is not right regardless.

Dave2002ti 08-22-2013 04:21 AM

Back in 1970
 
Quote:

Originally Posted by ColdCase (Post 15821481)
True, but many manufactures now skimp on rear shoe material (a lot smaller pad), so they can wear out faster than the front even at 30% load.

In any case, worn pads at 16K miles is not right regardless.

Porsche 1970 911S had a smaller rear pad for the rear disc brakes. I cant remember if it was thinner. 1974 Lotus Europa was similar. My 87 GTI 16v with read discs the rear pads were smaller and thinner. Same with 90 325i.
A M3 from the same year also had smaller rear pads and the pad was thinner.

ColdCase 08-22-2013 07:10 AM

Quote:

Originally Posted by Dave2002ti (Post 15822846)
Porsche 1970 911S had a smaller rear pad for the rear disc brakes. I cant remember if it was thinner. 1974 Lotus Europa was similar. My 87 GTI 16v with read discs the rear pads were smaller and thinner. Same with 90 325i.
A M3 from the same year also had smaller rear pads and the pad was thinner.

Yes, as do all my cars as you don't need as much pad material and don't want extra unsprung weight by design. I'm just saying that it seems like, for some models, a bean counter saw extra rear pad material for the a car's design life and found way to save a few $$ per car by skimping. So the rears wear out before or near the same time as the fronts.

tjkj2002 08-22-2013 07:50 AM

Quote:

Originally Posted by Dave2002ti (Post 15820865)
My 2012 Grand Cherokee Laredo X AWD with the ORAI package is in RWD normally??? Really? And you are a mechanic.

.

With a selectable 4wd system it is moron,even AWD's are not always AWD(50/50 split).In your case it's more power to the rear then front.With more power going to the rear with a front engine design your going to to have more slippage.


The time now is 05:55 AM.

Powered by vBulletin Version 3.8.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.