Brake pad - stainless shim greasing

[DIYspanner]

Really just want opinion on whether folk apply grease between pad and shims when the brake pad lugs are mounted in stainless shims.

I use ceramic grease. The car is a 2023 Corsa and I noticed when inspecting the front pads for the first time today that they were running dry in the shims, still nice and free.

 

[Belle427]

No real need, probably attracts dust too. I grease underneath the shims to try and stop rust jacking though.
Priority is that they move nicely in the carrier.

 

[Burnerman]

For me, it's shims out, and file where they sit if necessary - rust can be a huge issue here, and it doesn't seem to matter what quality of car you have - rather the metal that the pad carrier bracket is made of.
Then, all contact areas are plastered with ceramic grease and reassembled.
John

 

[JohnD]

I believe that with these high-temperature "greases" any mineral oil content burns away, but the other content (presumably ceramic particles) remains and prevents the parts seizing together.

I first saw it on hot iron components that had been assembled with Copaslip. There was no trace of grease remaining, but the threads unscrewed dry with a coating of copper dust.

Ceramic grease has the advantage that, unlike copper, it does not accelerate corrosion of aluminium.

 

[Avocet]

I really don't know why manufacturers do that! Stainless is just about the worst bearing material known to man! As if that wasn't bad enough, it's viciously corrosive to iron and mild steel when in electrical contact with them. After a while, the groove that they sit in just corrodes like crazy and the extra rusty material has nowhere to go, so it pinches the stainless which, in turn, makes the ears on the pad stick. I generally use ceramic grease on them, but it won't stop the underlying problem.

 

[Stivino]

I really don't know why manufacturers do that! Stainless is just about the worst bearing material known to man! As if that wasn't bad enough, it's viciously corrosive to iron and mild steel when in electrical contact with them. After a while, the groove that they sit in just corrodes like crazy and the extra rusty material has nowhere to go, so it pinches the stainless which, in turn, makes the ears on the pad stick. I generally use ceramic grease on them, but it won't stop the underlying problem.

On the contrary, stainless steel is an excellent material to use for that application. It has high corrosion resistance, which is important to survive in that environment, and it can also sustain high temperatures. As proof of its longevity, I recently got rid of a 16 year old car, and the original shims that were on it were like new.
I never use any "grease" ceramic or otherwise on any part of front brakes, neither do the manufacturers, I'm sure they know what they are doing. If everything is cleaned up properly there will be no problems.

 

[Burnerman]

I don't think manufacturers give a chuff about their vehicles - just so long as they don't have to pay out on warranty claims and they can screw you big time for service.
Here's an example........Honda HRV, 19 plate, bought new costing around £35K (I think) so hardly a bargain basement vehicle.
5 years service included - naturally any wearing bits would be down to me, fair enough.
It went back to Honda on a yearly basis, and I got a nice video of the tyre condition and the vehicle underside, etc etc.
Oil and filters change sir? That'll be £350 but of course you get a free wash. Would you like your air conditioning checked for extra?
At 30k miles I noticed the front pads were maybe 60% worn, so rather than be billed by Honda I put new ones in. The old ones were so seized in place I had to hammer them out! One of the pads was just in the process of delaminating from the metal backplate, but that had a long time to go.
Stainless shims perfect, carrier bracket rusted to hell and back. Filed up, ceramic greased and reassembled.
At 60k miles new discs were needed - slight judder on braking, the usual. New Febi discs fitted, the previous set of pads slid out perfectly and I fitted new pads too, of course. No filing of the caliper bracket was needed, just the usual brake dust removal. The stainless shims were still perfect.
I'll continue to do things my way!
John

 

[Avocet]

On the contrary, stainless steel is an excellent material to use for that application. It has high corrosion resistance, which is important to survive in that environment, and it can also sustain high temperatures. As proof of its longevity, I recently got rid of a 16 year old car, and the original shims that were on it were like new.
I never use any "grease" ceramic or otherwise on any part of front brakes, neither do the manufacturers, I'm sure they know what they are doing. If everything is cleaned up properly there will be no problems.

Yes, the stainless will be fine! It's anything ferrous that it's in electrical contact with that suffers! It's galvanic corrosion. Surely you've tried putting a stainless self-tapper into a piece of thin mild steel and leaving it out in the rain for a few months? The stainless will absolutely destroy the mild! Put a zinc passivated screw into the same bit of mild and see the difference. Car manufacturers aren't in the least bit interested in the car by the time it gets old enough for this to be a problem. They only make their money out of the first couple of owners. After that, hardly anyone gets it main-dealer serviced and uses genuine parts.

 

[Stivino]

Stainless steel is a ferrous material. And, having studied engineering components and materials, I know about the workings of Luigi Galvani, galvanic cells, galvanisation etc.

 

[Avocet]

Stainless steel is a ferrous material. And, having studied engineering components and materials, I know about the workings of Luigi Galvani, galvanic cells, galvanisation etc.

It's ferrous insofar as it has iron in it - all stainless does, but metal merchants would sell it as non-ferrous. If you know about galvanic corrosion, you should know what happens when you put stainless in contact with mild or cast iron...

 

[Stivino]

I'm not here to have a game of oneupmanship.

 

[Avocet]

I'm not here to have a game of oneupmanship.

As you wish. I'll keep scraping the corroded iron out from under them whenever the pads start sticking...

 

[DIYspanner]

Interesting and informative commentary.
Thanks All!