I had a caliper lock up last night effectively killing one of my center caps, but any way called my local auto zone for a new one and they told me there are two diffrent piston options. One is the stock metle piston the other was a steel piston. any one know any thing about this

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85 fiero GT stock FOR NOW!
94 bonniville ssei stock
85 S-10 turbocharged 3800
83 Citation x-11 turbocharged 3.1 with AWD 6000 running gear

I believe that the options are metal or fiber caliper pistons. I prefer metal as they work and they are stronger

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87GT 3.4 Turbo- 0-60 5.2 seconds -Best
Engine Controls, ECM goodies, Chip
re-programming & odd electronics stuff

Raybestos® gives you three choices on the 88 piston:

Some of us believe the phenolic pistons are the best choice. They don't transmit as much heat from the pads to the brake fluid, and they're lighter, reducing unsprung weight and improving handling a bit.

awsome thanks for the information guys i might just go with the grand am set up but i like seeing the alloy calipers in there

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85 fiero GT stock FOR NOW!
94 bonniville ssei stock
85 S-10 turbocharged 3800
83 Citation x-11 turbocharged 3.1 with AWD 6000 running gear

quote Originally posted by Whuffo: Some of us believe the phenolic pistons are the best choice.

I have heard that the phenolic pistons will swell up if the car sits for a long time, and cause the calipers to lock.
I don't know for sure though. Might be interesting to research this.

I'm not disputing your point regarding heat transfer, though. Makes good sense.

Basicly, phenalic pistons are far supperior in stopping brake fade. They act as an insulating layer to protect the brake fluid from heat. They also have a shorter life span than the steel pistons.

Kind of a trade off, safer driving and the pistons will need to be replaced every 5 years or so, or loss of stopping ability and the pistons will last 10 years plus.

I would not want the phenolic piston's in the rear because of the e-brake actuator. It will strip quicker.
Don

quote Originally posted by ka4nkf: I would not want the phenolic piston's in the rear because of the e-brake actuator. It will strip quicker. Don

The threads where the actuator goes into the piston are not phenalic, there is an insert in it. Remember, the inside of the piston ratchets, on both style pistons. Both pistons have inserts.

quote Originally posted by Electrathon: The threads where the actuator goes into the piston are not phenalic, there is an insert in it. Remember, the inside of the piston ratchets, on both style pistons. Both pistons have inserts.

Thanks for that info. I have the new re-call kit but have not installed it yet. It has the metal piston's and they are heavy.
Don

Personally, I prefer the metal pistons because I am very frugal and want things to last forever. If I was racing or driving in an agressive manor, I would go for the phenalic ones.