Greasing calliper slide pins?

In message , Redwood writes

Opinions vary but I always clean them up and fit them without any grease.

I use PTFE/Silicone grease. Never had a problem. Just don't use mineral based grease as you stated.

JB

Whilst for the last 30 years I've always used Copaslip sparingly applied!

I think that the most important thing to use in these situations is common sense.

Chris

Which isn't so "common" when you get three different opinions from 3 different posts. I would say do what it is says in the f manual.

They're stainless so don't rust and they tend to come dry from the makers as installed, so I just make sure they're clean, and the seals in good condition.

I have taken to using 'CERATEC' grease on this sort of stuff, although copaslip gets used on exposed steel pins. The advice against copaslip is usually about getting it near abs sensors.

Which says use silicone grease.

If they're stainless they'll make the inside of the bores go rusty instead.

Ditto that, always used copper slip after giving them a good cleaning up never had a problem. Always a doddle to take them out come change time.

My last three BMWs have all had the same idea and I've done all the pad changes. Not had a problem yet. If the seals are good they shouldn't rust.

Methinks that that's probably the important bit, and copaslip isn't particularly good for seals, wheras silicone grease is.

I'd have thought if lubricant of some sort was essential they'd supply a sachet of it with the pads.

Copperslip can be used on pad retaining pins, but should not be used on caliper slides.

The slides should have a light coating of a grease that won't dry out (normal greases tends to dry out, and can cause binding brakes), and won't attack rubber (mineral oil based grease can cause the guide seals to swell, leading to binding brakes), which makes silicon grease the ideal choice.

They normally do supply a sachet with aftermarket pins.

Any reason for that, moray?

Chris

Retaining pins are normally steel, and are a pretty loose fit on the pads, and biggest issue is them rusting so they don't come out easy. If they rust where they pass through the pad, it's not a big deal, as for the rust to get thick enough for the pads to seize onto them, chances are the pads themselves have badly rusted and the linings most likely about to fall off. Only thing the copper grease does, is (hopefully) make them come out a bit easier next time you want to take the pads out.

Caliper slides on the other hand, are highly polished items, and can be made from chromed steel, stainless steel, or just blackened steel, and have relatively tight tolerances (compared with retaining pins) on the bore they pass through. A seized or sticky caliper slide can cause a whole host of problems (binding brakes, excess pedal travel, uneven pad wear), which is why using the right grease (or no grease as the case may be), is more critical.

The message from "moray" contains these words:

That's the pin sort. For them I'd stick with the proper grease, which all the instructions I've seem specify silicone grease. The cruder sort where the pad grinds along a barely machined ledge on the caliper seem to work better for longer with copper grease, in my experience.

It depends on if they're sealed or not. Sealed ones, are generally not as corrosion resistant as the unsealed ones, so silcon grease is a must to help ward of corrosion. Unsealed ones, are normally chromed or stainless, and grease doesn't make much difference to them. Giving them a good clean when you've got them stripped is the best bet, although a smear of grease in the caliper housing does help.

They're not what get's classed as caliper slides. That's just where the brake pads sit on/in the caliper. Best option is to strip and clean the brakes periodically. A coating of grease on the contact points will help prevent the rust from swelling for a short period, but given the exposed nature of most calipers, any grease will get washed of pretty quickly in the wet.

Thanks for the replies. Finally had a dry day to fit new pads & rotors and jobs a good 'un. Yes it was the shiny chrome steel calliper slides that I wasn't sure which grease to use. I used a smear of silicone grease on them and copper slip on the back of the pads and where they slide on the calliper bracket. When pushing the piston back in I found it much easier to crack open the bleed nip and it goes back very easy with thumb pressure.