DannyG

So, I bought an 07 Z06 a week ago and, from an outward appearance standpoint, it's practically flawless. On the day I bought it - a Sunday - I asked if I could get the car up in the air to see the undercarriage. The dealer told me I could but the shop was closed that day; however, he'd seen the undercarriage and said everything looked great. The car was from New Jersey/Alabama but only has 14k miles on it, so I told him I trusted him.

Well, got the car into the shop this last Saturday to fix a slight wheel balance issue and, the guy told me this was my chance to see under the car, so I got under there and checked it out. What I found was quite a bit of surface corrosion on all of the bare metal parts... At the same time, I noticed rusty brake components (pad locator pins and hard brake lines). Photos attached.

The guy told me he didn't remember seeing so much corrosion so he would have a corrosion removal and protectant application service performed and would cover half the cost... I don't plan to pay anything for this service, but that's another issue all together. Still waiting to find out what he plans to do about the brake parts.

My question for you is - Is this an acceptable/repairable amount of corrosion/rust? Should it be considered normal since the parts are bare metal? Or should I pursue this dealer to take the car back and unwind the deal?

I never deal with this kind of problem as I live on the west coast and don't see corrosion on vehicles that often. I love the car aside from the issues I've found so, if it's easily repairable with no long term damage, I'd love to have them fix it and just move on. However, if there's any long term effects to this level of corrosion on these parts, I don't to deal with that.

Any insights/advice would be greatly appreciated.

DannyG

Brake photo

DannyG

Additional undercarriage photo

mjoacim

I wouldn't worry so much at all about that little bit of corrosion as much as I would be losing my mind about how they have that car on the lift like that. Why aren'y the lift pads under the jack points?

DannyG

Oh, yeah... They got an earful about that! Didn't hurt anything though.

Bill Dearborn

First, the picture shows aluminum oxide on the aluminum control arm. This isn't a problem as it actually makes the aluminum corrosion resistant. From the web:
Aluminium corrosion resistance

Aluminium corrosion resistance is very good in untreated aluminium. Untreated aluminium has very good corrosion resistance in most environments. This is primarily because aluminium spontaneously forms a thin but effective oxide layer that prevents further oxidation.
Aluminium oxide is impermeable and, unlike the oxide layers on many other metals, it adheres strongly to the parent metal. If damaged mechanically, aluminium’s oxide layer repairs itself immediately.


This oxide layer is one of the main reasons for aluminium’s good corrosion properties. The layer is stable in the general pH range 4 – 9.


The brake pad guide pin bolts do get rusty when exposed to rain. The brake lines on the caliper can get rusty but usually don't.


I don't see anything that would make you take the car back to the dealer. The brake stuff could be seen by anybody walking around the car and the undercarriage looks damn good. It is much cleaner than many other street driven cars. Is it show quality? No, but you don't buy show quality cars at dealers. You get show quality cars by spending long hours of cleaning, polishing and using lots of elbow grease.

Bill

DannyG

Very informative and educational - Thank you, Bill! I feel somewhat ignorant not having known any of this but, hey, now I know.

Bill Dearborn

One thing you should check if you have a chance to pull the wheels is if you can loosen the pad guide pin bolts. GM had the caliper designed so the pads could be replaced by just pulling a couple of guide pin bolts and then pulling the pad from the outside of the caliper. It is a nice idea in theory but the bolts freeze in the calipers over time or if they get hot like when running on a track. If you can get the bolts out one at a time put a little antiseize on each and reinstall. While you have them out you can replace them (not cheap as they cost about $12/each from a discount GM parts supplier).

If you are handy doing brake work and bleeding brakes you could remove the corroded pipe on the caliper and buff off the rust and hit the it with some clear coat and reinstall. That would keep it from rusting again but you would have to bleed the brakes after getting things back together again.

Bill

DannyG

Thanks, yet again, Bill - I actually plan on attempting to get those pins out and replacing them with the "racing" style M10 pins as I will be tracking the car and, thus, likely replacing the pads somewhat frequently. If successful, I will definitely put anti-seize on the new bolts prior to installing!

As for the caliper pipe, I was actually going to tape off the caliper, get as much of the rust/corrosion off as possible with a sanding pad, then hit them with a high heat silver caliper paint.

AimHigh

HOLY CRAP!!!!

DannyG

Ludedude

I'm sure he's referring to the way the car is on the lift

DannyG

Ah... Yes. I'll definitely be standing there when they lift my car next time, if there is a next time, to ensure they use pucks. They're just lucky they didn't damage anything.

Bill Dearborn

If you are going to track the car there are other issues with those pins. My car had 13K miles on it when I took it to the track the first time using stock brake pads. At the end of the first day I had to change pads and couldn't get the pins out. Just two days earlier they had come out very easily when I was doing my pre track tech inspection. When frozen into place they were in hard enough that my heavy duty Torx bit broke off in one of the pins. However, on track some time later one of the pins came loose and worked its way out far enough that it hit the backside of the wheel. Others have had them work out on the inside so that when it came out the brake pad came along with it. Obviously, a lot of heat loosens them.

After almost ruining a wheel I really considered installing aluminized duct tape over the pins to keep them from backing out. Then I went with a BBK front and rear and didn't worry about those issues anymore.

Bill

DannyG

Very good to know. I won't be tracking the car extremely hard or often - Probably 7-8 autocross days and 3-4 HPDE events per year. However, if I can, I'd like to avoid any possible issues like the ones you've described... Isn't there a solid single pad replacement made for our stock calipers, which don't even allow the use of the pins?

mjoacim

Yeah, please be there when they lift it again. They almost picked it up by the damn gas tanks that time. That's original. And listen to whatever Bill tells you. He's forgotten more about these cars in particular than some of us will ever learn.

Adam@Amp'dAutosport.com

No, there is not to my knowledge but, if you are interested in the Carbotech 1 piece pad I will be happy to help you. The Carbotech 1 piece pad allows you to just take the 2 caliper bolts off and leave the pins in. No need to even touch them.