pontiacstogo

Noticed this on my front rotors today - guessing they are done;



I think I'm just going to replace them with a good quality solid (not drilled or slotted) rotor unless anyone has any other suggestions.

JakeRobb

Yep, drilled rotors are prone to stress fracturing, which is illustrated very nicely by your photo. This is the right time to replace them.

You don’t want solid rotors, nor are you likely to find such a thing for your car. What you want are plain, vented rotors. Plain means no slots or drilling; vents are the interior channels, visible from the edges.

Slotted-only is also good, if the vehicle sees extended track use with elevated pad or rotor temps. It accelerates pad wear a bit, but allows hot pads to offgas a little without disrupting the friction surfaces.

JakeRobb

Here’s a visual on solid vs vented, in case I wasn’t clear.

pontiacstogo

Sorry - when I wrote 'solid' I was simply meaning not drilled or slotted - I realize the OEM's were vented.

PO also put drilled and slotted rotors on the rear - I don't see any cracking on those yet, but I plan to replace those as well.

Injuneer

A real old WS6.com post about cryogenically treating drilled rotors to reduce cracking..... not really a successful approach.

Cryo Treatment

JakeRobb

The rear brakes on our cars do VERY little of the work. I’d be surprised if you saw them cracking unless they were very old and had seen some track days.

pontiacstogo

This car has definitely had it's share of track days, but I do not know if the rotors that are on the car now were fitted during that part of it's life. The PO never raced it, so he may have fitted them purely as an 'appearance' item. I'm going to replace them just to be sure;

pontiacstogo

Did ARP studs in new Timken hubs along with new rotors and pads today. I cannot believe how much quieter the car is - I was aware of some drive train noise it seemed to me like it was coming from the rear end. Boy was I wrong.

Next on my list is new rotors and pads for the rear along with ARP studs and a rear end fluid change.

pontiacstogo

Just popped a rotor and caliper off of the rear - no way to get the ARP studs to go in without removing the axles. Not a big deal I guess as I plan to change the fluid anyway so I'll just pull the axles and press the studs in. As I mentioned above 95% of the noise I was hearing has been cured by the front bearings - but should I be doing bearings and seals in the rear while I have the axles out? All bearings or just axle bearings? Any opinions or thoughts?