Should i lube the pistons in my brake calipers?

I cleaned the calipers real good with the pistons pushed way out and put in new gold fren pads and now the brakes are reeaaaaallllllyyyyy dragging. It is to the point where the wheel will only make about 1/3rd of a revolution when spun. Are you supposed to spray a bit of lube or anything on those pistons or anything? They were ok before that and now they are sticking. I gotta get them sorted this afternoon cause i am heading to beaverun tonight.

I have a brembo mc, goodridge lines, gold fren pads and motul rbf600 fliud.

any ideas? Thanks.

 

No. Anything you put on the bores or seals will attack the seals and maybe even contaminate the brake fluid.

With new race pads, some incidental friction is normal. You don't have the spin of the rotors which usually pushes the pistons out of the way and reduces this drag. Until you do a test ride and check the spin resistance afterwards, you won't really know if you have a problem.

If its still doing it and you are positive that you have the brakes assembled correctly without any binds. About all I can suggest is to work the pistons back and forth several times to see if they loosen up.

 

If you used a harsh soap to clean them and did not get all the residue off before retracting, you may have "dryed up" the pistons.
+1 on extending and gently retracting the pistons to free them...

 

to answer the question, yes, lube them with the same brake fluid that's going into the system.

 

i used mineral spirits and a toothbrush to clean them. generally mineral spirits will not damage seals or orings and that was my reasoning for it. I also need to check to make sure the fluid level is not too high (and maybe a couple other obviousnesses).

 

I've been told the same thing by two knowledgeable racedads. One is a motorcycle mechanic and the other's son is a Rookie's cup rider so I believe them.

Just take the calipers off and remove the pucks and wash everything with dishwashing soap and water. Do not use brake cleaner it will damage the seals. Dry everything off and reassemble. As mentioned above, you want to coat the sliding surface of the piston with new brake fluid you will be using.

The first bike worked perfect. On the second bike my son said the brakes weren't grabbing. So I had to remove the pads and lightly scuff with sandpaper and sanded the rotor by hand to remove any glaze. Then they worked good too.

After putting it back together, the brakes were still dragging. After a session on the track the dragging was noticeably reduced. Maybe it would be better if I had new seals, but they weren't readily available to me at the track.

rob

 

good stuff. thanks guys. my main thing is that they just function this weekend. a little dragging isn't going to kill me but being a slow ass i need all the help i can get.

 

Are you sure the rotor isnt warped?

 

nah, they worked fine untill i replaced the pads the other night. they didn't get tight untill i pumped and bled the brakes.

 

Find some new seals, cause the ones in there are now ruined.

I don't know what caliper seals are made of, but kerosene, naptha (like what's in Safety-Kleen solvent), mineral spirits, ect. cause them to swell.

The only thing I let touch the seals is brake fluid, or the specialty grease that is sold just for that purpose. If you're going to clean the calipers without taking them apart, just use some kind of soap and rinse well. (I've had good luck with Simple Green.)

 

that doesnt make sense, why would everyone recommend to use kerosene to clean an o-ring chain if it will fuck up the o-rings? i could see the mineral spirits maybe drying out the seals but i dont think it would ruin them would it?

 

The o-rings in brake calipers are different critters than the ones in chains, or engines, or whatever else because they have a specific composition to resist the nasty effects of brake (hydralic) fluid.

 

O-rings in chains and seals in calipers are made out of different materials.

What the difference is, I don't know. I have seen caliper seals so swollen, that they wouldn't fit in the calipers anymore though.

 

Damn, this guy has the answer... that acai berry availabel now ! will really flush that brake system of toxins.

 

lube the piston seal with brake fluid liberally, and the piston too. use a high temp grease on the dust seal only. do not use sandpaper to scuff the surface of the piston! this will damage the piston. it needs to be smooth, polished (that is why they come that way from the factory. scuffing will just help the piston stick to the seal and/or dust seal, causing you to lose your braking as the pad wears. if you already put something on your seals, buy some new ones and rebuild your calipers. dont forget to get new crush washers when you put your calipers back on your bike.

just realized this is really about a half year old.

 

bump a year old thread for that?

 

nah, the dude before me, he bumped it...i guess. and i just read it.

 

I use silicone spray when I push the pistons back in, won't swell or damage rubber and doesn't damage the seal due to dry pistons.

 

Hate to reply to an old thread but there is a silicone paste (in a tube) that's made for lubing the o-rings and seals during caliper rebuilds.
I used to have a tube that was many years old, got it at Napa, don't know if they still sell it.
Warning, do NOT use the caliper slide lube sold at auto stores, that's for external use only.

 

We stock this grease for lubing pistons.

http://www.yoyodyneti.com/ProductInfo.aspx?productid=04.2954.10