Toyota Avensis 2.0 D-4D Brake Caliper Rebuild - Piston question

[arvind.d]

Hello,

I'm new here and this is my first post. I am rebuilding a brake caliper and after removing the pistons and cleaning them, I could see scuff marks on part of the surface. However, the inside bore of the caliper seems to be clean and I suspect that the marks were caused by gunk between the seal and the piston. Running my finger tip and even my fingernail over the surface I cannot feel any scratches or grooves at all. So my question is, can I use the pistons safely like this or should I get brand new ones (not cheap!)? I'm attaching several pictures so that you can get an idea of what I'm talking about.

Thanks in advance for your kind help!

- Arvind

[Brian R.]

As long as there were no leaks in the cylinder before you disassembled them, you can reuse the pistons. Even then, you only need to be concerned if the marks were in the seal surface. The piston walls are not a critical finish.

Be sure to apply lithium soap base glycol grease to the pistons and boot for assembly.

[arvind.d]

Thanks for the tips Brian. I didn't notice any leaks while disassembling but then the calipers had been sitting for about a year. They still had full brake fluid inside though, as the brake was removed with the hose still attached to the metal pipe that was pinched and cut off.

I suppose I could reassemble them and test with a new seal to check for leaks, would that work?

[Brian R.]

It seems that checking after assembly would only tell if there was a really bad leak. You can tell if there is a deep scratch or gouge in the seal area. I think you would have noticed if there were fluid getting past the seal when you took it apart initially. I don't think you have to worry about it.