Lubricating the calliper pistons

[Balky001]

I regularly clean the calliper pistons but a mechanic I was speaking with mentioned that the pistons should be greased. Another said if I grease them then sometimes you get more brake lever travel (I'm assuming this is because when pressure is taken off the lever the pistons receed slightly and if greased they slide in more than normal?)

Well, my question is does anyone lube their pistons and if so, if red racing grease the same as red rubber grease (as I have been told, but only by the guy selling red racing grease!)

[jonboy]

As far as I'm aware pistons shouldn't be greased as they'll soon trap dirt and dust which will form a paste that will foul everything up, though I stand to be corrected.


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[Fuzz]

An article in TWO (or Ride, can't remember) this month suggests greasing the pistons with red rubber grease, or copaslip, aswell as on the back of the pads. Never done it myself, but I probably wouldn't use copaslip as it can be abrasive. Really wouldn't like the seals to fail.

Even though greasing them up will trap dirt and gunk, cleaning them should be easier, as the grease will be easier to remove and reapply than baked on brake dust that takes half a can of cleaner to remove.

[Well Oiled]

Seem to be two schools of thought. I use grease around the seals. IMO it forms a barrier to help keep the salty crud from getting at the outer dust seals and into the groove. The problem I've seen is that the cruddy deposits in the seal groove tend to push out the dust seal and can cause it to pinch in the gap between piston and bore. Others say keep em clean and just use brake fluid as the grease will trap dirt.

Choice is yours I guess.

Oh - and I agree - I wouldn't put coppaslip on the pistons themselves.

[rictus01]

suggests greasing the pistons with red rubber grease, or copaslip, aswell as on the back of the pads. Never done it myself, but I probably wouldn't use copaslip as it can be abrasive. Really wouldn't like the seals to fail.


Don't copaslip, has (yes you guessed it) copper in it, it will destory you seals( you'll be forcing the bits of copper passed the seals back & forth, on the back of the pads is fine, but keep it away from the seals. generally just keep them clean, but if you feel the need you can indeed use the red rubber grease.

Cheers Mark

[Balky001]

Thanks for the comments - I wouldn't use copaslip except on the back of the pads. I'm guessing not greasing the pistons isn't going to damage them so may keep them dry for now and see how it goes.

[Cloggsy]

I've never lube'd mine with anything...

[jambo]

Copaslip on the back of the pads, red rubber grease on the pistons and seals... It's the way to go. :wink:

[northwind]

I've never greased mine... But I keep them pretty clean. I'm not even going to hazard a guess which way's better.

[andy]

I used to use BNS grease on the pistons, but since I have stopped doing it I have not really noticed any difference apart from a little more corrosion on the ungreased ones.

[chazzyb]

...The problem I've seen is that the cruddy deposits in the seal groove tend to push out the dust seal and can cause it to pinch in the gap between piston and bore.

I concur - I had a partially seized piston recently. As I pumped it out a bit to clean it, the dust seal popped out on a great wodge of aluminium salts. I used red rubber grease all round the dust seal, and brake fluid on the main seal when putting the piston back in.

[Sid Squid]

Red rubber grease only, never anything else.

Whilst it may say in manuals that brake fluid can be used as a lubricant for brake seals/pistons etc, if you want to have brakes that stand a chance of not crudding up in no time don't use brake fluid, far too corrosive for Japanese metal.

[embee]

The trouble with brake fluid is that it absorbs moisture from the atmosphere.

That's no big problem while it's inside the system and only gets a small amount of exposure at the master cylinder, just change it every year or 2.

If however you put it round the seals it will take in a lot of water and hold it in contact with the metal components, just right for corrosion. It's fine for assembly purposes if you wish, but not recommended for adding external to the hydraulic system.

Me, I'm a red rubbery man :oops:

PS - before anyone suggests silicone based DOT5 fluid, it's not generally recommended for road use by any brake manufacturer. It doesn't absorb moisture, true, but because of that any moisture that gets into the system can collect in one spot and cause corrosion, or it can boil, or it can freeze.

It's intended for competition use where it's changed frequently.

It's recommended that only the ester based fluids are used for the road, that's DOT3, 4, or 5.1 (not silicone DOT5)

[Sid Squid]

Me, I'm a red rubbery man :oops:

Oooooeeeerrrr missus, :lol:

[northwind]

I suppose one of the things that's always made me not use red rubber grease would be the fact that I've never seen it for sale ;)

[chazzyb]

I suppose one of the things that's always made me not use red rubber grease would be the fact that I've never seen it for sale ;)

I asked for it (the rubber grease, that is) in my local motor factor. I was presented with a white, unmarked grease can, with a paper label stuck on it, saying 'rubber grease'. They told me a) it was made by Morris Lubricants (on Sythree's patch) and b) it would last me the rest of my life. Looks like raspberry jam, though I've not tried it for that purpose (yet). Knowing the jokers there, it's always possible it *is* raspberry jam. :oops:

[northwind]

I don't even know what a motor factors looks like :roll: I'm from the Halfords generation. (I bought a tyre pen there today- bling!)

[embee]

I suppose one of the things that's always made me not use red rubber grease would be the fact that I've never seen it for sale ;)

I asked for it (the rubber grease, that is) in my local motor factor. I was presented with a white, unmarked grease can, with a paper label stuck on it, saying 'rubber grease'...............

that sounds quite familiar, the tin I've got came from a bearing stockists (actually Bearing Man in Shrewsbury as I was passing) so it's very probably Morris's :wink: . It's always a little disconcerting when no-one seems to want to own up to making it, but I think Morris's are like that! :lol:

[Balky001]

I've never seen red rubber grease for sale either - does anyone know whether the red racing grease is the same (as told by the man in the garage I mentioned) - it does also look like raspberry jam but without the real piece of fruit in it

[mysteryjimbo]

Pretty sure they may mean the Castrol Super high temperature grease or something similar. Its the stuff Spanner Man uses on brakes.


Castrol Pyroplex Red
High temperature, EP, lithium complex grease that meets the highest performance standards of automotive, fleet, industrial, farm and off-highway applications.

[mysteryjimbo]

suggests greasing the pistons with red rubber grease, or copaslip, aswell as on the back of the pads. Never done it myself, but I probably wouldn't use copaslip as it can be abrasive. Really wouldn't like the seals to fail.


Don't copaslip, has (yes you guessed it) copper in it, it will destory you seals( you'll be forcing the bits of copper passed the seals back & forth, on the back of the pads is fine, but keep it away from the seals. generally just keep them clean, but if you feel the need you can indeed use the red rubber grease.

Cheers Mark

Quite right. Copaslip is an Abrasive and should never be used on materials which wont stand up to the abrasion. That includes engine bolts on an alu or mag engine!

[Fuzz]

Is copper grease only to be used on the backs of brake pads and retention pins then? I really can't think of anywhere else it would be useful that multi purpose grease cant be used.

[mysteryjimbo]

Is copper grease only to be used on the backs of brake pads and retention pins then? I really can't think of anywhere else it would be useful that multi purpose grease cant be used.

Most of the bolts on the SV are fine to use Copaslip on. Avoid the engine area though. I cant say lubricating bolts with a grease is a good idea. You'll probably find the bike start to unscrew itself! Copaslip itself isnt that good of a lubricant, it's primary function is to stop things seizing up as its a soft metal.

[Fuzz]

I forgot about the bolts themselves - mine never seize (yet.) There was a debate recently though on whether to use copaslip or locktite on caliper mounting bolts?

[mysteryjimbo]

I forgot about the bolts themselves - mine never seize (yet.) There was a debate recently though on whether to use copaslip or locktite on caliper mounting bolts?

Famous last words when it comes to the Suzuki "cheese" bolts! :lol:

I've no qualms over using copaslip on brake calipers. So long as they've a good amount of torque they wont go anywhere. I cant remember if they've got a torque setting in the manual, I'm sure they must do. I just do em tight!

[northwind]

Frost's sell red rubber grease, it turns out. So I've just bought a 500g tub that'll probably last for a century :)