brake caliper/ pad lube

[another Todd]

Originally Posted By: E150GT
I use superlube silicone dielectric grease


Seems to me Superlube is not compatible with the rubber parts.

I only use "Motorcraft Silicone Brake Caliper Grease and Dielectric Compound" on anything brakes related. Part number XG-3-A. Excellent for disc brakes, drum brakes, and spark plug wires (not to be used on primary wiring electrical connectors or bulbs).

 

[nthach]

If the grease will touch rubber, silicone or glycol grease is best - just make sure there isn't any petroleum component like mineral oil or PAO/ester in it. That copper grease is anti-seize and while it might work fine for the pad ledges and any metal-on-metal slides, it will swell up EPDM/natural rubber in brakes used on slide pin bushings and piston boots.

I think SuperLube does make a rubber-safe silicone dielectric grease, I've seen it listed on their website.

 

[bonjo]

What I know about lubricants is that they do not stay in one place when applied to moving parts even less so when the parts are subject to movement & vibration.

I am really looking for one solution that I can apply to the whole brake assembly: calliper and pad both metal and rubber parts hence my original question about silicon grease. ON paper it looks that it has a better performance than grease (maybe not the same pressure strength?)

BTW are the rubber parts these days not made of synthetic material resistance to petroleum based products?

 

[Ducked]

Originally Posted By: bonjo


BTW are the rubber parts these days not made of synthetic material resistance to petroleum based products?


This is a VERY GOOD QUESTION, to which I've never seen a good answer, though I've asked similar questions a few times.

It seems to be generally recognised that you shouldn't use oil-based greases on rubber brake components, and I wouldn't choose to do so, especially on the old cars that I usually drive.

However, I SUSPECT that, since you can't apparently get any brake greases here in Taiwan, mechanics just use ordinary lithium general purpose petroleum-base grease, and I have personal experience of British mechanics doing this on a sticky piston of my 4 ton Renault Dodge truck wheel cylinder, which I found a bit alarming.

This might suggest that you can get away with it, at least for a while, and that while might be long enough, especially here, and especially if it wasn't your car.

I recently asked a related question about the rubber compatibility of greases used on other components like CV and track rod end boots. This was completely ignored, which I find a bit odd considering the endless and largely pointless "what oil should I use" discussions on here.

I don't know rubber incompatability is a problem in those applications, but I can't see why it wouldn't be unless they use more oil resistant rubber than is used for brakes.

I've never seen this discussed, AT ALL, ANYWHERE, apart from by me. I am the rubber duck in the room.

If it is a problem, it still may not matter as much as the lubricant performance, which might be why it is generally ignored and people go for a molybdenum grease.

I suppose the optimum might be a silicone grease with molybdenum in it. I dunno if this exists but if it does its a fair bet I couldn't get it here.

 

[bonjo]

I have finally settelrd on silicon grease as the best product I can get over here.

I tried searching for permatex (which looks ideal for me) but the costs are very high. A 25$ container costs £42 + duties if any!!!!

thanks for all your informative input

 

[R18Civic]

NAPA Sylglide