Uneven front brake pad wear!

[msanta]

I just noticed today while I was rotating the tires on my 03' 4runner that the right front pads are worn more than the left front. What would this be an indication of? I am taking it to the dealer on Monday fearful that they will charge me for new brakes. I have a V8 and I hit morning & afternoon traffic every day to work. I am concerned that there is a big problem brewing here...any advice?

 

[Jeff Kleb]

Hard braking during left turns? Shux.....I can hardly guess what it might be. I know that front pads wear faster than rears (for obvious reasons), but I have never heard of differences in left versus right brake pad wear.

Someone on this forum will know, however, you can rest assured of that! The T4R.ORG Brain Trust will always come through for you.

 

[Fourty-four]

The first thing I would check is that the calipers are not sticking/binding. That's probably the most likely cause for uneven brake pad wear.

 

[Mr. Lambdebois]

Your front pads should be pretty close in the front on both sides.

On each side there is an inner pad and an outter pad.

If the pad that is touching the piston on your caliper is noticabley more worn than the other pad on the same side then your piston is sticking and you need a new caliper. If the other pad is more worn your sliding pins are sticking and should be replaced and relubed.

If no problem is found I would then look at how the master cylinder distributes the fluid.

No matter what the front pads should be doing 70-80 percent of the braking and should be wearing pretty much even imo.The left and right side and the iner and outer pads on each side should be fairly even wearing as well.

A thought just came to mind. Could the pad wear be a result of Atrac pulsating that side more than the other?

Measurements for the pad wear would be helpfull

 

[msanta]

Thanks very much for the information. I compared the left and right front pads, and the right pads seem to have worn down considerably more than the left. Both right pads, inner and outer pads are worn about the same. It was quite interesting what you said about the pins. I didn't know you have to lubricate them?

 

[Mr. Lambdebois]

If the inner and outer pads on each caliper are worn about the same so it sounds like your caliper pistons and sliding pins are not sticking. For example - You should see the Left inner and left outer pad should have about the same amout of wear and right inner and right outer pad should have the same amout of wear. That is good cause it sound like your calipers are not sticking.

Is the vehicle pulling during a hard good brake from say a 60mph speed? (disclaimer-Please don't slam on your brake sin the middle of the highway to check. Use cation and make sure it is a safe place to do this and no one is behind you)

Does anyone have access to alldata and can get a scematic of the fluid flow from the 4runner master cylinder and proportioning valve to its calipers?

What it sounds like to me is that one side is considerably doing more braking but by the destription of the pad wear it does not sound like a caliper is sticking. I'd have to see it to make sure.

It is possible that there is a restriction in the master cylinder or the line on the side that has less wear causing that pad not to recieve full pressure untill the pads on the right side are at full pressure and applying first. I'd to a brake flush and make sure I can get some clean fluid out of all the calipers.

How many miles do you have on the pads in question?

It would be interesting to see if other owner are experiancing the same type of wear you are.

 

[msanta]

To keep everyone updated on this issue, today I took the 4runner to the dealer and they found that the right caliper was "frozen", I forgot to ask them what that meant,possibly like sticking, and the left one was starting to freeze, therefore they will put two new calipers tomorrow(parts were not available). I have never heard of this term before. The rep couldn't explain why this was happening on a three year old truck, thank God I am still under warranty so at least I won't have to pay for the calipers which are around $400 each. I am sure they'll hit me with new brakes, cutting rotors and flushing the fluid. But why would I pay for all this if it was caused by this problem?I only have 55,000 on my truck and I already have change my brakes three times. He mentioned a few things that 4runner owners in general may want to look into, rust around the pistons can cause sticking, broken down brake fuid can cause issues. Last summer a posted a message related to a lot of squeaking from the front brakes at very slow speeds when brakes were warm. That may have been an indication of problems with brakes. I never thought I was going to need to replace both calipers, it is kind of disheartening to have this kind of problems, I love my truck, and I am glad I was able to find out the problem now before it became a bigger problem.

 

[Mr. Lambdebois]

So the caliper was sticking after all


Glad they are taking care of it for you. You should not have to buy new pads if they worn prematurely due to a faulty caliper. They should at least prorate you for the pad on a 30k mile scale if they are your front and 80-90k for the back since not all the wear was from your normal driving. Pads are relitively cheap so I bet they will take care of it. They are already paying for the labor to fix the calipers uderwarrenty so my bet is they will give you new pads as well.

I am suprised that the other one is failing also? I bet they are just replacing them in a set.

 

[msanta]

That's an excellent point about the life of the pads, I'll tell them tomorrow and hopefully I won't have to pay for them. What puzzles me is how and why did the calipers go bad?