72 911T Brake Question

[GirtAllerton 72-911T]

Ok guys I'm going to throw my first newbie question out there.

I have a 72 911T with S front brakes, M rear. Planning on a full brake job as the rear pads are getting close to replacement. No issues at present, stops well.  I purchased new hawk street/perf pads for front and rear, also a brake bleeder and ase 200 gold.

My question is: I'm planning to replace the front rotors since thay are at 18.30mm. The rears are 19.78 - min is 18mm. 

1. Should I purchase zimmerman crossdrilled rotors for both? This car will see auto-x  this year and maybe DE next. Has anyone had problems with cracking? I understand from other forums this may be a problem on older cars due to how thin the rotors are.

2. If I purchase regular vented rotors would you suggest "turning" the rears or just starting with new?

Thx guys...

Girt

[AMoore]

There are others more informed than me, but here is my two cents.

Cross drilled do often crack, but that doesn't necessarily mean that they are ruined, unless the cracks extend to the edge of the rotor, or if cracks extend from one hole to another. 

That being said, I use slotted, not drilled rotors, with Hawk Blue track pads for DE.  I think they hold up better and dissipate heat well enough. 

[Brian Minkin]

I agree that slotted wear longer and do not generally have the cracking issues of cross drilled.  I had Power Slots on my car for years and had no issues.

Hawk HP+ is a high performance street pad and should serve you well for Ax and as a DE student. There are other similar pads from other manufacturers.

[GirtAllerton 72-911T]

Thanks guys,

     I read that there were issues with slotted rotors and difficulty stopping in the rain. Not that this car will see alot of bad weather but better safe than sorry. Have you heard this or is it just one of those forum rumors? I can't think why there would be any problem.

     What do you think about "turning" the rear rotors before new pads? I stopped by the local porsche dealer service center and he felt it was better not to, unless the rotors are pitted or scored. He felt it would only create potential problems; wobble etc... 

[Brian Minkin]

I never had a problem with slotted in the rain.  I would not turn the rear rotors if they are in good shape.  If not they are not that expensive to replace.

[Larry Herman]

All good advise here.

[michael lang]

Girt, I would not suggest having the rotors "turned" either. German brake components are made of a much softer metal than what you will find on a Japanese or American car therefore are easier to damage by the brake lathe. If they are "pitted" or "scored" and they were mine I'd just get a new set of rotors. As far as solid, crossdrilled, or slotted I think it's really a matter of personal preference. Any of us in the lower run groups really aren't generating enough heat for an extended period of time to do any kind of real damage anyway. Atleast I know I'm not.

 

[GirtAllerton 72-911T]

Thx for the info guys. I went with new vented zimmerman stock rotors all the around.

They just arrived today so  looks like I'm doing brakes weds or thurs. Thanks for the help, Great as always.

Girt