206 brake caliper guide pin grease

[alexfisher]

Hi, my local Peugeot parts department can't identify a suitable product. They can only sell me a schet of grease with an unnecessary replacement guide pin set.
Does anyone know of a suitable product? Alex.

[Michel]

Silicon grease or red rubber grease NOT copper grease.

[lexi]

https://www.ebay.co.uk/itm/Dow-Corning- ... SwkLhaCCu3

[CitroJim]

Excellent and well-timed... I need to get some for my Saxo

Also useful on my bikes

[white exec]

Maybe useful, Rothenberger do a 500g tub of clear Silicone Lubricant Grease (ref 6.7051).
Got mine from a branch of Plumb Center.

OK for O-ring and tubing use, harmless to rubber, compatible with mineral oil. A stiff grease which clings well to applied surfaces.

[Mandrake]

Silicon grease or red rubber grease NOT copper grease.

Can someone explain why copper grease is not suitable for guide pins when I have just used exactly that on the guide pins on my Ion with no apparent issue ? (In fact the brakes are working great now and no longer rattle...) I've never even heard of red rubber grease... Silicon grease on something as hot as a brake caliper assembly doesn't seem right either ?

Is there any science behind this advise or is it just opinion ?

If there is a good reason it shouldn't be used is it likely to do any harm if it's left in there ?

[Gibbo2286]

Red rubber grease was a Lockheed product for lubricating wheel cylinders and the like where the grease came into contact with the seals.
If there's no contact with rubber parts there's no reason why copper grease can't be used, personally I use the stuff they supply for drive shaft cv joints.

[Mandrake]

Red rubber grease was a Lockheed product for lubricating wheel cylinders and the like where the grease came into contact with the seals.
If there's no contact with rubber parts there's no reason why copper grease can't be used, personally I use the stuff they supply for drive shaft cv joints.

The pins are within a rubber boot.... but without knowing what the boot is made of there's no way to be sure whether it would be harmed by copper grease or not.

I would find it strange if modern cars were still using old fashioned "rubber" boots that are easily damaged by mineral based grease - it's far too easy for someone to use the "wrong" grease if that was the case, as mineral grease is ubiquitous in so many parts of a car.

Not to mention copper grease is used on the back of brake pads and as such must surely come into contact with the rubber boot on the piston which is likely made of the same stuff...

[Gibbo2286]

The instructions that came with my last set of pads were quite specific "Do not use copper grease on the back of pads."

[Michel]

The instructions that came with my last set of pads were quite specific "Do not use copper grease on the back of pads."

Yes. Mine too. I definitely don't use it on slider pins. It dries out and can cause more problems than it solves. It also attacks rubber boots. It can also cause electrolytic corrosion between static parts (Xantia rear caliper issue anyone?) which is why I never use it on wheel hub faces to stop alloy wheels sticking either.

Google will throw up a whole load of scientific reasons why it's a no-no.

[Mandrake]

Yes. Mine too. I definitely don't use it on slider pins. It dries out and can cause more problems than it solves. It also attacks rubber boots. It can also cause electrolytic corrosion between static parts (Xantia rear caliper issue anyone?) which is why I never use it on wheel hub faces to stop alloy wheels sticking either.

Uh, I thought the copper content of copper grease was specifically recommended to minimise electrolytic corrosion between dissimilar metals, like Xantia rear calipers ? Almost every single person on this forum who has had to scrape the corrosion out and sort this problem out has recommended applying copper grease to prevent it reoccurring. Were they all wrong ? (Just asking, not passing judgement)

And the tyre fitter that fitted new tyres for me recently copper greased both the wheel studs and the faces between the wheel and the hub.

Google will throw up a whole load of scientific reasons why it's a no-no.

I've already searched, and all I could find was loads of contradictory opinions, no concrete scientific recommendations. In fact I even found some contradictory information from a Toyota bulletin which specified "Lithium Soap" based grease for the slider pins on some of their cars. "Lithium Soap" grease is bog standard mineral oil based lithium grease...which is basically mineral oil suspended in a Lithium soap with some added emulsifying agents.

The only thing I can see that might be an issue is if the mineral oil content of copper grease attacks the rubber boot - but I'm not convinced that any modern rubber boots used in cars these are so susceptible to mineral oils that misplaced grease will destroy them... 30 years ago yeah, today, there are so many much better oil resistant synthetic rubbers available that it seems unlikely to me and sounds more like wives tales handed down from times when it was true.

Look at just how much more durable drive shaft joint boots are today compared to those in the 80's and before.

So I remain skeptical.

[white exec]

Must say, have often used a smear of copper grease on the slider pins when applying the same stuff to the backs of brake pads (to acoustically couple them, to prevent squeal). First I've heard of potential issues here.

Copper grease does appear to dry out on the backs of pads, but there it is operating at both very high temperature and in a highly dusty location.

[Pug_XUD_KeenAmateur]

Also useful on my bikes

just a mention re Bike Grease, if you're using it plenty, consider HM [High Melting Point] Grease.

Back in the 1990's and early noughties when I was doing big mileages on a pusher (100+miles a week, every week - I had no car at all back then), I had issues with rear wheel bearings and bottom bracket bearings going south as much as every couple of months.

I changed from Castrol LM or 'Bike Shop Grease' [white stuff in tubes - utter cr*p] to Castrol HM / aka 'Marine Grease' and the problem ceased. I haven't yet finished the pot and still use it for most grease jobs.

Also use proper loose bearings if you do a Hub or BB rebuild, not the 'Race' type, as the 'Races' tend to break up

Frame technology has moved on from the Raleighs and Peugeots I had back in those days [and still have, gathering rust], but I doubt Bearings & Hubs have changed.

[CitroJim]

Frame technology has moved on from the Raleighs and Peugeots I had back in those days [and still have, gathering rust], but I doubt Bearings & Hubs have changed.

They have, immensely! Bearings are no longer rebuilt on modern bikes now - they're sealed and replaced as a whole... That applies to the BB, hubs, freehub and steering gear...

The days of the old traditional cup and cone is over - at least on my sort of bikes...

The upside is they last a lot longer now... The downside is that special tools and skills are required to service them, especially pressed-in bottom brackets in carbon frames...