TR2/3/3A Front Brake Calipers TR3 Late

[Tinkerman]

I just purchased two front brake calipers as reserve items. I suspect that one or both of mine may belly up when I start putting the pressure to them. I got them today and the cylinder areas have surface rust on them. Can this be honed out? assuming it is not pitted. Haven't taken them to my machine shop friend, thats next. Just thought I would find out if there is any experience out there.
Thanks, Tinkerman

 

[Banjo]

Shoulden't need to be machined. The critical surface is on the piston (new ones available through Moss) You can bead blast the calipers and they will be fine. Pay close attention to the groove where the seal sits. that's the most important part of the caliper body.
Good luck.

 

[martx-5]

Are these calipers disassembled?? Are you looking at an assembled caliper and seeing rust on the inside of the piston?? If there is rust on the outside surface of the piston (the part that you would see after you pop the piston out of the bore), then you would have to replace the piston. It is plated on that surface so there is no way to economically redo them. If the rust is on the interior section as you see the piston in it's assembled state, that is nothing to be concerned about. It is just cosmetic, and will not affect how the caliper works.

 

[Tinkerman]

Great, thanks for the info felows.

Cheers, Tinkerman

 

[Don Elliott]

If you want to remove the surface rust on the bores where the pistons will go, rub it off with 600 grit emery cloth. Then wipe them clean with a solvent. This might prevent the rust coming off later and staying in your brake fluid just behind the pistons.

 

[Geo Hahn]

[ QUOTE ]
...If there is rust on the outside surface of the piston (the part that you would see after you pop the piston out of the bore), then you would have to replace the piston. It is plated on that surface...

[/ QUOTE ]

If you do get new pistons, in my opinion the stainless steel versions are well worth the slightly greater cost.

 

[Don Elliott]

My original pistons were a bit rust when I last looked in 1989. I smoothed it off with 600 grit paper and reused them. I use silicone brake fluid and I assume that the lubricating properties of silicone have not produced any new rust. I've driven 94,000 miles since I did mine in 1989.