UFO caliper questions

[Brett Dikeman]

On Sep 20, 2005, at 4:30 PM, Rbade12 at aol.com wrote:

> Are rebuild kits available for UFO calipers?

Nope- nothing except the piston boot and seal.

> What purpose does the thin steel rod a couple inches long with the  
> small puck on the end, on the  back of the
> caliper serve?

Anti-vibration.  Yes, I'm serious, and yes, it's Very German :-)

> I've got an extra set of calipers that I cleaned today. The 2  
> halves of the
> caliper seem to be prevented from coming apart by the rubber boot  
> over the
> thicker of the 2 slider pins.

Correct. The boots are held in place with metal rings that snaps into  
place sandwiching the boot between the ring and the bracket (or  
caliper).  One ring on each end.  If you are very careful, with a  
soft plastic implement, you can pry the rings open.

> I don't want to tear that boot [which seems to be
> a distinct possibility if I try to free it up] unless I can replace  
> it.

I nicked mine and repaired it with some glue I found that claimed to  
be able to handle rubber.

Given the condition I found the grease, pins, etc in- I recommend  
getting in there if you can.  Use high temperature synthetic brake  
grease to thoroughly lubricate the jumbo guide pin.  Make sure to  
clean out the inside of the rubber bit where the mini guide pin goes,  
and it gets grease too.

> A good source of UFO rotors? Anyone cyro treated UFO rotors?

I've considered it after seeing the difference between a cryo treated  
944 turbo rotor and a non-treated rotor after a few races each.  It  
was astounding how much better the cryo unit held up.  The only  
question I've had is whether the funky shape and construction of the  
UFO (ie the weld, for example) poses any problems.

As for Bernie's comments about wear- rotors are thick and heavy for a  
reason.  Thermal mass, and strength.  As you erode the rotors,  
stopping the car (from say 60-0) heats the rotor more because you're  
putting the same amount of energy into less mass.  The rotor also  
needs thickness for strength- there is a tremendous amount of torque  
involved in stopping a 3600lb car from 80mph in 250 feet.

Brett
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