Distorted Caliper Dust Boot--repair or not?

[The Critic]

I did a brake job on a 06 Corolla with 37,501 miles over the weekend. I noticed that the left front brake caliper's dust boot was slightly distorted. By that I mean a 2-3mm section of the dust boot was sticking out very slightly once the piston was fully retracted. The dust boot wasn't cracked, but a slight edge of it was sticking out and covering the lip of the piston. It appeared as though once the piston was pushed out, the dust boot would pop back into place.
The pads that I removed from that caliper looked like this:

2mm

1.5mm

The pads from the right front caliper, which did not have any piston seal problems, the pads looked like this:

3.5mm

2.5mm

Not as bad, but still worn out. The difference in pad wear is no more than 2mm. However, BOTH rotors were badly grooved, even on the right front caliper for some reason. The rotors looked like this:

When you run your fingernails across the rotor surface, you can definitely feel the grooves.

I went ahead and installed new pads and rotors. I'm guessing that while the piston seal may not be in great shape on the left front caliper, it isn't bad enough to warrant replacement. There's only about a 2mm difference in pad wear over 37.5k. The driver of this vehicle is on track to wear out pads every 20-25k (she bought this car used).

What do you guys think? What should I do? Should I just tell her to not worry about it in the meantime and just replace both calipers at the next brake job? Or is it not a concern at all?

 

[Shannow]

I missed the pic of the seal.

If you can see part of the pressure seal ring, I don't think that's a good thing.

If it's only the dust seal, then prolly not that bad.

 

[The Critic]

Originally Posted By: Shannow
I missed the pic of the seal.

If you can see part of the pressure seal ring, I don't think that's a good thing.

If it's only the dust seal, then prolly not that bad.

Sorry, I didn't bring a camera with me.

It's the dust boot. The dust boot is contacting part of the piston. I think once the piston extends outward, the boot will pop back into the proper place. However, this doesn't explain why there's a difference in pad wear between the LF and RF calipers.

 

[The Critic]

I tried to make a drawing of the problem:

The black ring is your dust boot. The black shaded part is how the dust boot is contacting the piston "lip." Nothing is torn. It appears to me as though once the piston is pushed out, the dust boot will be normal again. However, this doesn't explain the strange pad wear. Perhaps that's a completely separate issue altogether?

 

[tom slick]

If it isn't torn I wouldn't worry about it.

I don't think I've ever done a brake job where the pads wore exactly the same, even though in theory they should.

 

[punisher]

Something I have noticed in the shop is that the left front pads tend to wear more vs the right side. I always figured it had something to do with the left bias weight distribution on most cars.

 

[The Critic]

Originally Posted By: punisher
Something I have noticed in the shop is that the left front pads tend to wear more vs the right side. I always figured it had something to do with the left bias weight distribution on most cars.

Thanks, you were right.

I called the local dealership and spoke with a technician. He told me that the distorted dust boot was a the result of an air pocket. He told me to poke a hole in it and tuck it back in. I told him that I just pushed it back the best I could and reassembled it, he said that was fine.

As for the pad wear, he said some difference between the LF and RF caliper is normal. Unless one caliper was at 10mm and the other was at 3mm, there's nothing to be concerned about. He also told me resurface the old rotors and reuse them next time.

 

[RH+G]

The boot is not flush because their is an air pocket behind it. Not a big deal. I normally use a screwdriver to gently lift the boot a little bit so that the air comes out and the boot sits flush. More of a personal thing with me.

 

[doitmyself]

Critic,

What I want to know is how you managed to talk to a real mechanic at a Toyota dealership, on the telephone,no less, and get him to share some practical DIY info.

That is outstanding. In my area, it is next to impossible to get past the dreaded service advisers at the front desk.

You must have magical powers of persuasion.

 

[The Critic]

Originally Posted By: doitmyself
Critic,

What I want to know is how you managed to talk to a real mechanic at a Toyota dealership, on the telephone,no less, and get him to share some practical DIY info.

That is outstanding. In my area, it is next to impossible to get past the dreaded service advisers at the front desk.

You must have magical powers of persuasion.

Here's what I did.

I called the local dealership and told the operator that I wanted to speak with the service department. The lady at the service department answered, and I told her that I had a question about brake wear and I would like to speak with a technician. She put me on hold for several minutes, then returned to tell me that the available technician must be out on a test drive. She told me to leave my name, phone number and a brief description of the problem. The technician then called me back about 30 minutes later to answer my questions.

 

[bdcardinal]

you sure it was a tech? wasnt a service writer jsut relaying a message? we have strict rules that techs are to not give out repair info at our work.

 

[RH+G]

Not knocking the tech but why would he tell you to poke a hole in the rubber dust boot? All that is needed is a gentle lift and push to let the air out, not a hole in the dust boot so water and dirt can get in and contaminate the piston.

I assume that is what he meant though

 

[mechtech2]

the piston is not normally seated - this can happen. Just set it right.
Make sure it is fine when in it's running position.