Plastic plugs in brake pistons.

[Eckhard Grohe]

I recently bought a rebuild kit for my brake caliper and the pistons in the kit have plastic plugs in them. The original pistons don't. What might the plugs be for???

[T__]

I recently bought a rebuild kit for my brake caliper and the pistons in the kit have plastic plugs in them. The original pistons don't. What might the plugs be for???

 

Eckhard, that is a very good question.. Seeing as brake temperatures at the back of the brake pad piston interface area gets pretty darn hot it seems unusual place to put plastic parts doesn’t it?.

 

Do those plastic inserts look like they positively belong in the pistons? Or could they be a plastic cover for a caliper bolt or other area?

 

I don’t know, but if it were me I would track those plastic parts back to the supplier & ask what there function is.. Maybe they were mistakenly left in the pistons after a plating process or other manufacturing process.. Then again maybe they do have a function (I don’t know what function they would provide though other than keeping dirt or mud out of the piston cavity)

 

Twisty

[Ken H.]

Yes, I've seen a couple that way. Not sure of the reason for the change but they seem to work just fine.

[Davis]

My guess is that the spacers are to provide some thermal isolation between the pads and the fluid so less of the heat is transfered to the brake fluid.

[T__]

Eckhard, well I had a chance to talk with our advanced brake group this morning & their consensus is those plastic inserts are for noise control (brake squeal control)… It seems a lot of motor companies are looking at plastic brake caliper pistons with metal inserts or plastic piston insert type devices for noise control..

 

Their suggestion is to take a hot soldering iron to the inserts & if no apparent heat related melting then just go with them.. On the other hand if they melt easily they are probably thermo plastic & should be removed..

 

Twisty

[Eckhard Grohe]

Thanks for all of the input.