My son’s 2000 Cherokee has a stuck caliper. Looking at remanufactured calipers I see the OEM has a phenolic piston, and then there is a metal piston version available. (Price difference is minimal $16 v. $19) What recommendations are there between the two? I’ve seen some comments about phenolic pistons having more tendancy to overheat, and seize. Any truth to it? (He regularly does mountain driving but knows to gear down and use engine braking vs. the brake pedal.)
A phenolic is a thermoset polymer (plastic). A good plastic for sure, but why use plastic when for $3 more you can have metal?
Get the cheapest one. The one that seized on my car was phenolic and I replaced it with the metal one.
Choose the metal piston. Phenolic pistons tend to sieze up more than the metal pistons.
Replace BOTH calipers with metal piston units. Since the one rotor is also probably toast, replace both of those also, along with the pads.
lets see… 8 years. in this age a caliper has been full stroke probably 3 or 4 times. it would be highly unlikely for ANY caliper to NOT stick.
whether this is plastic or steel is irrelevant. at this age, any caliper can or will get bound up. this is not rocket science. these items are routinely replaced.
Phenolic is supposed to transfer less heat to the fluid. It is only a factor in very heavy brake use. Crown Victorias and even limos based on the same platform have steel pistons, but the Police interceptor versions have phenolic pistons.