Caliper slider rubber boots -- grease?

rat_race

Hey...

What grease have you had success with on caliper rubber boots? Last time I serviced my calipers, I gave the boots and and the sliders a clean. Silicon-based grease is recommended, presumably because it is better for rubber, but I had none -- only silcone lube (made by WD-40), which I sprayed generously, but knowing that it probably wouldn't last too long.

Today (year later, maybe), I went to give them a clean, as I do now and again, and noticed the rubber boots have swollen, and one slider was seized because of corrosion. They no long perform a seal or fit snuggly (too big)...

The only other greases I have are all oil or lithium based...guessing they're not rubber friendly, so I didn't use them.

What do YOU use to grease these? Maybe I'm being too pedantic and should have just used regular grease...

I know that red grease you get with rebuild kits is rubber friendly, but a) I have none and b) seems to be hard to get, and c) don'tk now if it would be heavy enough for the job.

CRC part 5351

Richard tea

I think red rubber grease is best. If your not in a hurry order a tub off eBay. The one I got will last year's

Just put copper grease on the sliders . People say it damages the boots, I've never seen it and i would prefer to replace a 20 cent boot than have a pin sieze in the caliper

rat_race

Dustin Dirty Orate wrote: »

Just put copper grease on the sliders . People say it damages the boots, I've never seen it and i would prefer to replace a 20 cent boot than have a pin sieze in the caliper

Good to know. I think (and I've read this elsewhere) that my putting silicon lube on it may have reacted with existing grease on it, creating something the rubber DOESN'T like.

CJhaughey

I wouldn't use copper grease. I got some on a piston boot when rebuilding a caliper and by the time I realised it the boot was very baggy and no longer sealed the piston any longer. Rubber parts aren't cheap and if the rubber swells it can jam the slider in the caliper.
A lot depends on the type of rubber used to make the slider boots but my experience with copper grease and rubber is poor.
If you have red rubber grease use it failing that use a silicone grease that is rubber safe.

I dunno, fair enough using it on piston seals etc fine thats what it's made for but it has no anti sieze properties whatsoever.

I had to have my calipers taken by my mate to his engineering shop to remove the slide pins from the calipers when i was rebuilding them because some clown either didn't put grease on them at all or else used something other than copper grease.l and they were essentially welded . If he wasn't able to do that your talking hundreds for one used caliper and the bike has 2 on the front

When putting them back together i copper greased the pins , but mainly the threads.

i liberally coated the threads, put barely a lick on the pins and that was it. Nothing near the boots, absolutely no need imo.

There's actually really no need to grease the pins at all tbh, just make sure you use copper on the threads don't put rubber grease near the threads.

I went on a rant before about not needing red rubber grease on the seals, whatever about that everyone has opinions make sure to use copper on the threads. Don't want anyone to have to go through what i did rebuilding those calipers, broke my heart.

CJhaughey

Dustin Dirty Orate wrote: »

I dunno, fair enough using it on piston seals etc fine thats what it's made for but it has no anti sieze properties whatsoever.

I had to have my calipers taken by my mate to his engineering shop to remove the slide pins from the calipers when i was rebuilding them because some clown either didn't put grease on them at all or else used something other than copper grease.l and they were essentially welded . If he wasn't able to do that your talking hundreds for one used caliper and the bike has 2 on the front

When putting them back together i copper greased the pins , but mainly the threads.

i liberally coated the threads, put barely a lick on the pins and that was it. Nothing near the boots, absolutely no need imo.

There's actually really no need to grease the pins at all tbh, just make sure you use copper on the threads don't put rubber grease near the threads.

I went on a rant before about not needing red rubber grease on the seals, whatever about that everyone has opinions make sure to use copper on the threads. Don't want anyone to have to go through what i did rebuilding those calipers, broke my heart.

I am in complete agreement with you as regards metal to metal contact and the use of anti-seize but when it comes to metal to rubber then I am very careful with what I use.
Mitsubishi and Subaru both sell brake pin grease for use on the slider pins, but Lidl also sell silicone grease from time to time in small white tubes.
I find the metal pin can corrode inside the rubber if a lubricant isn't used and then the caliper doesn't float and wears one pad down to the metal while the other pad gets next to no wear.

landmarkjohn

Dustin Dirty Orate wrote: »

Just put copper grease on the sliders . People say it damages the boots, I've never seen it and i would prefer to replace a 20 cent boot than have a pin sieze in the caliper

Copper grease is not the correct application on slider pins on brakes. It is discussed much on the internet and a very common mistake. Copper grease is an anti-seize compound and a dab is often used on the back of a pad that contacts the piston to prevent brake squeal. If you come across slider pins that have had copper grease applied you will find them sticky and not slidey!

Silicone grease is recommended on the slider pins (although I use a tin of Castrol LM High Melting Point that I have had for 30 years). Use sparingly I put a tiny bit on the lugs where the pad contacts the caliper as well.

And red rubber grease for the seals and boots.

Wonda-Boy

From what I read online in numerous articles copper grease should only be used where there is "HEAT" present....so if there is no possibility of heat generating its not advised to use it.

CJhaughey

Copper grease is an anti-seize agent that works well for high temps, I used to use it when I worked in industrial machines for plastic extrusion to prevent corrosion and simplify disassembly of large bolts.
It is good stuff for what its designed to do which is resist high temps and aid disassembly.
So where the pins screw into the caliper carrier is an excellent use, be careful with getting it on ABS sensors as it can cause them to malfunction.

The grease that Japanese brake systems use is usually Niglube RM, which is a high temp resistant grease that is safe to use on rubber as well, not easily got though.
Its Orange in colour, failing that Silicone dielectric grease would work but I'd check that it is compatible with rubber first, not all silicones are rubber safe but most are OK.

Richard tea

CJhaughey wrote: »

I am in complete agreement with you as regards metal to metal contact and the use of anti-seize but when it comes to metal to rubber then I am very careful with what I use.
Mitsubishi and Subaru both sell brake pin grease for use on the slider pins, but Lidl also sell silicone grease from time to time in small white tubes.
I find the metal pin can corrode inside the rubber if a lubricant isn't used and then the caliper doesn't float and wears one pad down to the metal while the other pad gets next to no wear.

This actually happened me. One pad wore quicker and scored that side of the disc. This reminds me to service the rear caliper soon

rat_race

CJhaughey wrote: »

I find the metal pin can corrode inside the rubber if a lubricant isn't used and then the caliper doesn't float

This is exactly what has happened to me...and the slider got stuck inside the caliper. Wouldn't budge. I had to get a clamp and actually compress the slider just to loosen it, then had to beat it the other way with a rubber hammer (while off the disc, of course).

However, I only noticed this as I was giving them a clean / check as I do every 6 months or so.

Oddly enough, the brakes seemed fine before that, and there was very little brake rub.

After my fix/service (cleaned pistons, retaining pins & pads, etc.), there's quite bad brake rub, and even brake judder when braking to a stop. Typical!