Ray Calvo

Agree with others; junky rotors. Doubt that cracks alone cause the out-of-balance problem; have had several front rotors that showed cracks after lots of service but didn't vibrate. Then again, had one el-cheapo set (Vertex) that cracked and vibrated after one 20 minute session on the track.

I installed an aftermarket brake cooling kit; under A-arm style. Was made by Alan Johnson and has metal ducts unlike the plastic ducts offered by others (that can shatter if you hit them with something; the Alan Johnson ones can be hammered back into shape). Don't really know if they help, but figure they can't hurt. Pads are from Performance Friction.

And YES, stay off the brakes after car comes in off the track and brakes are hotter than h*ll.

slapshot

Ok, another "while we are on rotors" question. Mine have a lip and wear that the shop says is just a hair above (30.75mm) the "recommended" 30 mm replace mark. The pads need to be replaced as does the fluid. I have a set of pads that I want to put on, ATE Blue and my Motive Power Bleeder, is it mandatory that I replace the rotors with the lip or can I get some more miles with them? Currently the brakes work wonderfully, have not pulled a light yet, and no spider veins/cracks, etc. Any thoughts? Mr. Calvo?

1999Porsche911

I would keep the rotors. They still have plenty of meat left on them and your driving experience tells you that they are true.

Flying Finn

I've hear only bad things about Zimmermans...

Ray Calvo

To slappyshot: I have replaced rotors without changing pads and have changed pads without changing rotors; haven't noticed a problem either way. I generally don't replace the rotors till the radial cracks start getting greater than about 2 hole diameters.

Motive Power Bleeder works great. Gave up on Stupid Blue; it stains everything it contacts. I use ATE Type 200 which is Stupid Blue without the blue dye.

slapshot

Awesome. Thanks for the feedback! BTW, RC I am using your 1 hour DIY method when I change the pads and flush! Thanks for providing it.

jford

Vibration update. Well I had thought the vibratoin went away by putting the old rotors back on. So, I had attributed it to the small cracks in the rotors. Well after logging a few more miles the vibration is coming back. It must be buildup from the padgid oranges as they are the one constant in this whole scenario. They will be tossed tonight in favor of some padgid blues I have.

Ray, Eric, Greg and Mark were right on the money regarding the buildup. Ray, I am ging to install some brake cooling ducts as well....as you say, it can't hurt. Thanks all.

Jamie

TheOtherEric

I don't know if anyone mentioned it, but keep in mind that cracks in the rotor holes are both normal and acceptable. AFAIK Porsche recommends replacing the rotor when a) the thickness falls below spec, or b) the cracks are over 7mm long (or are touching hole-to-hole?). I don't think the cracks would cause a balance problem.

Greg Fishman

Jamie,
Are you doing any track events with the car? If not just stay with the stock pads.

If you want to borrow some old Hawk Blues to clean up the pads let me know and I can let you have a set I keep just for back up.

jford

Greg,
Thanks for the offer. I had a set of pagid blues in reserve and I just put them in. I am loaded on the trailer and off to Summit Point in an hour. Looks like a possible 2 days of rain....let's hope not. I will hopefully be doing about 16 track days this year, time permitting so I will definately be looking for the best pad/rotor set up for the car.

Eric,
A few people chimmed in about the cracks not being that big a deal. Glad I didnt' chuck the offending rotors. I'll most likely put them back on after this event. Thanks.

Jamie