Help me diagnose my odd brake wear!

[mbakken]

Hi all, Im normally able to solve my own automotive issues, but this one has got me stumped.

I have a 2002 Tahoe and I recently replaced all the rotors and pads. When I removed the pads I found that all the inside pads were worn irregularly, some worse than others. The fronts had chunks missing on the inside pads causing a zebra-like pattern on the rotor and they looked like they had not been wearing at all recently. I lubed all pins and the backs of pads prior to reassembly and replaced the stainless trays that the pads slide in on the caliper bracket.

Now after about a month of driving, I noticed that the insides of the front rotors are very "dry" feeling. Almost like a chalkboard. But, there is contact because I can feel a ridge at the inside and outside edges of the rotor from normal corrosion. I also have an annoying squeal that comes at certain low speed, low pressure applications - i can make it go away by pressing harder.

I plan to bleed out the whole system, but havent done so yet. Can anyone help diagnose why the insides are wearing so weird so that I dont end up chewing through more pads? The assembly seems to move freely as it should...could there be something in the caliper? It doesnt make sense!

 

[Astro14]

First - that vintage Chevy truck chassis jsut eats brakes. Every 20 - 30K for some folks...

what you describe sounds like sticking calipers - even though you lubed them, that doesn't always work...depends on the condition of the pins and the calipers and what kid of grease you used (non-silicone grease can cause rubber parts to swell and stick). I would consider upgarding your brakes to Hawk pads with new calipers and new rotors (shop around, www.tirerack.com is usually pretty competitive...). The higher temperature and wear resistance of the Hawks will help your next brake job to survive. They'll fix the squeal as well...

 

[mbakken]

Thats what I thought because if the caliper was sticking I would either get NO wear or excessive wear on both or inside only. The fact that its minimal/no wear on the inside is the converse of what I usually see which is sticking pads.

The guide pins were dry, but didnt look corroded so I lubed with Syl-Glide and reinstalled. Is it possible that they can look good and just not work? The rears seem to be doing OK

 

[EricF]

usually the caliper is sticking, or the piston didn't get pushed in squarely.. but at a slight angle. It happens.

 

[mechtech2]

I'd take the time to yank the parts off and start again.
Really clean everything well, then lube it. Special brake lubes are preferred. Some normal chassis grease can swell rubber, and make things stick.
You can check for the sticking caliper problem or pads that need to be dressed a bit to fit better. An application of anti squeal sauce [$6 at auto parts store] will stop the noise.

 

[mbakken]

I'm less concerned about the noise, although annoying, than I am about the wear. I plan to bleed the system and get good pressure going through there first, but when I do that I was thinking of adding some anti-squeal sauce on the components. Nothins ever easy

 

[spasm3]

I just replace my calipers when my vehicle hits 100k miles or whenever the next brake job is after 100k or 6 years. +1 on the hawk pads.

 

[RH+G]

So the inside pad was worn more than the outside bad or less?
WHat pads and rotors did u use?
WHen u lubricate the slide pins did the slide in and out easily?
Do u have a brake pull and are the pads wearing eaven on the driver side and pass

 

[mbakken]

I took all the wheels off last night to have a look and I also bled the system out. The fluid was quite dark and looked to have some very fine gas bubbles in it. The pedal feels a little better, but it still has some softness to it which Ive had in every chevy ive owned. I had a [censored] of a time bleeding the drivers side rear though. I dont know if the bleeder screw is bad or what, but when I pull a vacuum on it close it holds, but when I open it the pressure drops quick and no fluid comes out. If I sit and pump and pump for a while to maintain vacuum I can get a little to dribble out. I managed to get about 3-4oz out that bleeder and moved on.

After looking at the rotors again, they seem to be OK. I dont know why the insides of the front looked and felt chalky the other day, but I feel better about them now. Calipers and slides move freely. I dont think I got enough lube on the backs of two of the pads when I put them in and I suspect thats where the squeal is coming from. Ill dress it in the next day or two.