After doing extensive research I have found recommendations and warnings about using any sort of grease to lube the brake caliper pistons and seals. I have been warned about contaminating the brake fluid, and that only brake fluid should be used to lubricated the seals. I just thought there might be something appropriate for some sticky pistons prior to a full rebuild. It looks like Brembo makes a grease for this purpose, so it must be acceptable on some level, but I just wasn't to get some more opinions. Thanks guys...
I sure would think Brembo grease would be good. Having said that, I've never used it. I just clean the pistons up, coat them in brake fluid and reinstall.
I've never found any purpose in greasing up the seals. As the service manual will always tell you, don't put anything on the pistons and/or seals on reinstall except for fresh brake fluid, and that's served me quite well throughout the years. The only thing grease is going to do down there is act as a magnet to attract dirt and brake dust (which by its very nature is designed to create friction, exactly what you don't want on those piston sliding surfaces). I also can't see any reason why it would help to smear grease onto the outside of a piston that is already stuck from crud and you're trying to get pulled apart.
As something as important as brakes I wouldn't be using it unless is says specifically its compatible with said system. I wouldn't be using anything like wheel bearing greases etc on a brake system that's using glycol based brake fluids. I wouldn't be too concerned about excess grease as that can be cleaned after the fact, its the compatibility that would be my highest concern.
http://www.ebay.com/itm/2-oz-100-PU...105549?hash=item3f6c313bcd:g:5Y4AAOSwYIxX8Ev8 I got a tube of this years ago and have used it on a few different brake caliper seals with no issues.
whats wild is you see street bikes with zillions of miles and 3" of crud on the front brake pistons & too much mocha colored fluid in the reservoir... yet the brakes still work (if not down to the backing plates). I dont mind it attracts dirt or debris on a racebike.
Pretty sure it's Yamaha that includes a small tube of grease with each package of new piston seals. I've used it with all new seal installations. Use just enough on the seal to cover all surfaces and make the seal look "wet" - don't try to slather it on like cake icing. No blobs of grease anywhere and no grease at all on the pistons, just a little on the seals. Makes it easier to install the pistons. I don't know if it helps any more than that though.
when i clean them at the track, after drying a little silicon spray and let them dry. 5+ years like this and no issues.
If I might ask, what functional purpose does spraying silicone lube all over the pistons or smearing grease on the seals provide (that coating them in clean brake fluid on reassembly per the manual does not).
I feel like the brake fluid may help with the seals but doesn't really do anything for how smooth the piston runs in and out. Also anything wet will attract dirt and dust so something that dries should (in theory) be better.
Brake fluid or nothing. The fluid in the system will take care of lubrication. If it isn't working smoothly it's dirty, not a lube issue.
Also with respect to the above comment about spraying silicon spray on the pistons. Isn't DOT 5 brake fluid silicon based, and the DOT 3, 4, 5.1 we use on our motorcycles all glycol based.....and aren't you NEVER to mix the two? Seems to me spraying silicone onto the piston that is going to come in contact with glycol based brake fluid a bad idea.
You can put the Yamaha grease of Brembo grease on them safely - but it's all gone once the brakes get really hot anyway. If they're kept clean, they won't stick.
The silicone spray, keeps the dust from dc pads from building up quickly and sticking,( which when hot, thats what dc pads do best). i let the silicone dry before pushing the pistons back in.
I ride Honda's. The manual says brake fluid on the inner seal and silicon grease on the outer seal. I just get them wet looking with the grease, not cake them in it. Not sure why Honda does it this way but their engineers are probably smarter than me. This is with both Tokico and nissin calipers. Coated and uncoated pistons. I also just moisten all sliding parts with silicon grease including the backing plate where the Piston rubs, the brake pad edges where they rub the caliper, and the pins.
Apparently looking into it silicone base greases are ok for the braking systems, that's what the Yamaha stuff is. Don't be using petroleum based stuff. Need to be mindful when you say "grease" as it applies to a lot of different things.
