How important is the stoneguard behind the front discs (M030)? - Pic
 

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Here is why i ask......

I've got a 944S2 that I have upgraded to M030 front brakes (also known as S4 brakes). I've kept the old steel stone guard behind the disc. They weren't rubbing with the standard M030 discs (the 928S4 undrilled but vented 304 x 32mm) but when I put the new cross drilled discs on tonight (968 clubsport brakes crossdrilled 304 x 32mm) the disc rubs on the steel backing plate!?!. Its close - the difference between rubbing and not rubbing is about 1mm (1/16''?). The backing plate has never been buckled. I tried bending it out of the way but its a kind of springy steel.

I've checked the PET and it seems the same "Cover Plate" is used for both standard and M030 brakes.

Anyone out there with S4 brakes want to chime in?


http://forums.pelicanparts.com/uploa...1288859578.jpg

The advantage to running them is they keep heat off the tie rod end and the ball joint. Downside is it makes the rotor harder to cool which is really only important for a track car.

I have had them removed on my '88 since i put on the M030 calipers and had them removed on my '87 which saw many street miles. No problems to report.

i don't remove them any more we take brake temps at the track every run session . with out them temps were about 200 degrees higher running about 1000 to 1100 degrees were its the max for the brake pads i use ( Hawk DTC-60 and 70 .) with them and still using cooling ducts we now have temps in average about 800 degrees . if you only plan on street driving its ok to remove them you would never see temps like you do on a track .

Ok - I managed to keep the dust shield based on the comments above. Just required a bit of careful manipulation (aka bending) Here is the finished result....

http://forums.pelicanparts.com/uploa...1289176893.jpg
http://forums.pelicanparts.com/uploa...1289176928.jpg

I removed my shields on my 951S street car a few years ago with no ill effects.

looks good . what most people don't realize is that brakes cool kind of like a turbine sucking the air in from the inside center of a rotor and exiting out the out side top of the rotor . removing the backing plate takes away from the ducting in coming air . if you look at all GT ,GTP, LMP , F1 and so on you will see they all have and use backing plates of some kind .

I took off mine because they were kind of mangled on the one side anyways from when my caliper fell off.

No problems thus far.

:)