Caliper pistons.

[robertodonnell]

A quick one:

Am I correct in saying that the caliper pistons on the GC / Commander are essentially plastic?

Cheers,

Robert

Sent from my D6653 using Aussie Jeep Offroad mobile app

[JamesLaugesen]

Yep, well sort-of, they're a phenolic resin-based engineering plastic. Think snooker balls.
Conspiracists say they're an evil ploy to save money, but they have real advantages, and lower manufacturer/machining cost would be one of them.

IMO they're fine if you don't heat the brakes enough to fade (they transfer less heat than steel, which is good if you're slack with fluid changes like me, but bad if you work the brakes hard.), and the best option if you're in salt water often. Otherwise stainless steel is the go.
Plain steel is a downgrade from phenolic IMO since the plating eventually wears off and accelerates wear on the seals and bore.

Phenolic also tend to be quieter/smoother (since they're lighter, they don't 'shudder' with as much energy.), but probably not a factor for us.

[robertodonnell]

Yeah, phenolic is what I had been reading. The pistons on mine are a bit damaged from what I expect was some idiot ramming the caliper down over the top of new pads, without pressing them back in.

I agree that they are better from a corrosion/electrolysis point of view, but the point you make that they aren't as durable if heavily heated is an interesting point.

At any rate, 4 pistons from rockauto for $22.50 AUD isn't bad, and I can afford to stock a set for the impending rebuild.

Cheers,

Robert