250 Turbo Zimmerman Discs 30k miles?

[dlknight]

Hi Guys,

I recently noticed my front brakes have started to squeal, I replaced discs and pads in 2007 at about 130k miles (zimmerman discs and textar pads). On the weekend I removed the pads and cleaned up the calipers. The pads are almost worn through to the wear sensors but not quite and the outside face of the discs are fine. Problem is the inside face and inner circumference of each disc has a raised lip about 8mm in width coming in from the edge of the disc. Is this normal wear for 250 turbo discs? I managed to knock some of this "lip" off on the one disc by tapping it with a screwdriver.

Be interested to hear other peoples experiences with discs and how many miles they expect to get out of them on a road car with not much (if any) track driving.

I'm going to get some Sebro's next time as I don't like the rusty zimmerman bells

EDIT: Forgot to mention the car has done about 30k miles on those discs and pads

Cheers

Dave

 

[barks944]

What did you scrape off? Was it rusted metal or brake dust build up or something. Did you check if the discs were warped?

 

[dlknight]

ORIGINAL: barks944

What did you scrape off? Was it rusted metal or brake dust build up or something. Did you check if the discs were warped?

Some of the lip came away to make the level uniform with the rest of the disc, it looked rusty but not all of it came off. Don't think the discs are warped, no juddering etc and brake performance is brilliant and even more so since I removed the pads and reseated them on the weekend.

 

[barks944]

If the discs have plenty of thickness left in them I wouldn't worry about it. I guess there must be a difference in the inner and outer faces in where the brake pads are located relative to the inner circumference of the disc, my brakes are the same with a lip on the inside but smooth on the outside.

 

[dlknight]

ORIGINAL: barks944

If the discs have plenty of thickness left in them I wouldn't worry about it. I guess there must be a difference in the inner and outer faces in where the brake pads are located relative to the inner circumference of the disc, my brakes are the same with a lip on the inside but smooth on the outside.

The existing inner pads have worn with a mirror of the lip on them so are not flat. Only problem is I'm going to be replacing the pads soon as they are close to the limit. With the discs like they are the inner pad will not be making full contact with the disc. How many miles have you got out of your discs?

 

[DivineE]

8mm that's nearly the total thickness of each face! It can't have been metal surely or you'd have about 2mm left!

 

[barks944]

I think he mean't 8mm wide not deep!

My discs are massive and I can't see them needing to be replaced any time soon.

Your new pads will wear pretty quickly to the lip profile of the disk. You could always get the discs skimmed, although I'm not sure what the general consensus on skimming is.

 

[will87r]

This lip, is this built up where there is no pad disc contact? or has this lip built up, eating into the pads? discs do this sometimes if the havent been cooled properly. It shows up more under hard use, a good reccomendation would be cyrogenically frozen discs, Have had a few sets, they are far more resistant to abrasian and far harder. www.nitrac.co.uk i think, good reading, and reasonably priced, often cheaper than ordinary mainstream "high perfromance" discs like red dot etc. The Supplier is excellent to talk to and supplies to a few 911 race car owners, and i think supplies some Le Man Teams as well.

 

[dlknight]

ORIGINAL: barks944

I think he mean't 8mm wide not deep!

My discs are massive and I can't see them needing to be replaced any time soon.

Your new pads will wear pretty quickly to the lip profile of the disk. You could always get the discs skimmed, although I'm not sure what the general consensus on skimming is.

Yep 8mm wide [][] I thought about skimming but it means the car is unusable while the discs are being skimmed, maybe just change them for now and see about getting them skimmed and keep them as a spare set?

ORIGINAL: will87r

This lip, is this built up where there is no pad disc contact? or has this lip built up, eating into the pads? discs do this sometimes if the havent been cooled properly. It shows up more under hard use, a good reccomendation would be cyrogenically frozen discs, Have had a few sets, they are far more resistant to abrasian and far harder. www.nitrac.co.uk i think, good reading, and reasonably priced, often cheaper than ordinary mainstream "high perfromance" discs like red dot etc. The Supplier is excellent to talk to and supplies to a few 911 race car owners, and i think supplies some Le Man Teams as well.

Yep lip has built up where there is pad contact and so has eaten into the edge of the pad making a mirror indentation in the pad. I always cool them properly and never stand on the footbrake when in traffic.... Is this why Zimmermans get such a bad rep? Car is only a daily driver and not tracked, although I give it some spirited driving sometimes its nowhere near what people get up to on track []

 

[will87r]

By cooled properly, i meant when they were manufactured. If they are not cooled evenly there will be a layering which beaks up as you described, like the surface being cooled more quickly than the inner part of the disc. the outside of the disc is most suceptable to this sort of break down as it is furthest out near the vents etc so will exchange heat faster when driving, heating up when braking and cooling faster than the inner (nearest the hub centre) when driving so it breaks down first, the layers seperate. Theres not really alot to be done, other than try a different brand the next time you change like nitrac. If the brake force is still ok, i wouldnt worry untill you feel they need replaced.

 

[DivineE]

Ahh that makes more sense of course! I had visions of you running some lethal brakes on your car for a moment there.[]