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View Full Version : Don't use copper grease on caliper sliding pins


TamSV
04-03-11, 10:00 PM
I've stripped the front calipers on my Dad's Mk1 Bandit which were badly siezed after a long period off the road. The Nissin calipers are two pots with sliding pins, much the same as the SV calipers.

The pistons were OK - the piston recess/dust seal looks to be a better design than the Tokicos. The problem was the caliper wasn't moving on the sliders - they took some separating.

Once I got them apart I could see the cavities where the pins go were rammed full of copper grease which had dried into a solid lump. The rubber boots that protect the pins had swelled up and were no longer sealing the dirt and water out so there was all kinds of corrosion to deal with.

Here's the new boots I got from the Suzuki dealer today along with the swelled up items I took off the calipers. You can see there's a big difference in size. I'll reassemble with rubber grease but wondered if it was likely the copper grease that caused the rubber boots to swell?

http://i918.photobucket.com/albums/ad23/tomSV/SV650/Picture.jpg

barwel1992
04-03-11, 10:54 PM
copper grease reacts to rubber same happen'd on my rear calliper

beabert
04-03-11, 10:56 PM
I received a set with larger ones on, i had assumed they were just aftermarket, they worked fine though.

barwel1992
04-03-11, 10:59 PM
the new boot i got direct from suzuki, was smaller than the original ones

beabert
04-03-11, 11:05 PM
How do you know they were original? same markings on the rubber?

barwel1992
04-03-11, 11:12 PM
yup, and was a fair bit smaller

beabert
04-03-11, 11:26 PM
Naa, i meant the fat ones. How odd though.

barwel1992
04-03-11, 11:29 PM
the fat one was very soft and wasn't like that to start with only went like that after using copper grease so now use rubber grease

mikerj
04-03-11, 11:30 PM
Don't use red rubber grease on the sliders, it dries out quite quickly and almost completely seizes the pins. My old man rebuild the calipers on his SV just before Christmas, but in a fit of optimism used the original and slightly scabby pistons and use RRG (Castrol brand) on the sliders when he reassembled them. One piston was leaking, so I bought a complete set of pistons and rebuilt them again a couple of weeks ago and I had a hell of a job to get the carriers to part company with the caliper they were so tight.

Silicon grease is the stuff to go for IMO, doesn't dry out and doesn't rot rubber.

Lozzo
04-03-11, 11:31 PM
Red rubber grease is the only thing I'll use in that location. Seen too many rubber boots swell up and jam the sliding mechanism. I bought a tub of RRG a few years ago and have hardly made a dent in the stuff despite rebuilding loads of brakes since. Same as my pot of copper grease, must have had that 5 years and use it every weekend.

I'm sure there are grease fairies who come and top them both up when I'm asleep

Lozzo
04-03-11, 11:36 PM
Don't use red rubber grease on the sliders, it dries out quite quickly and almost completely seizes the pins. My old man rebuild the calipers on his SV just before Christmas, but in a fit of optimism used the original and slightly scabby pistons and use RRG (Castrol brand) on the sliders when he reassembled them. One piston was leaking, so I bought a complete set of pistons and rebuilt them again a couple of weeks ago and I had a hell of a job to get the carriers to part company with the caliper they were so tight.



I rrg'd my Versys calipers 2 years ago on the day the dealer delivered the bike (they were dry from factory, as were the steering head races, gearchange and rear brake pedal pivots and just about everywhere you'd expect to find grease). When I fitted new pads all round just before I went to Malta, the calipers were sliding fine and the grease hadn't dried out - that was Castrol stuff too.

barwel1992
05-03-11, 12:00 AM
I rrg'd my Versys calipers 2 years ago on the day the dealer delivered the bike (they were dry from factory, as were the steering head races, gearchange and rear brake pedal pivots and just about everywhere you'd expect to find grease). When I fitted new pads all round just before I went to Malta, the calipers were sliding fine and the grease hadn't dried out - that was Castrol stuff too.

never had a problem with castrol RRg drying out ether

yorkie_chris
05-03-11, 12:05 AM
Yes those boots look swollen and yes copper slip can cause that. Cheap stuff seems more oily and worse for causing that but it's the wrong stuff for the job anyway.

I use silicon grease in that location but only because I've got a tub. RRG seems perfectly fine and I've used that on lots of them too.

embee
05-03-11, 12:18 AM
FWIW the manual says silicone grease

http://i258.photobucket.com/albums/hh268/Hi-vis/Bikes/SVcalipergrease.jpg

Some vehicles do specify RRG (e.g. my Suzuki Cappuccino rears do), but most I've come across have been silicone. Copperslip definitely isn't the right stuff.

Lozzo
05-03-11, 12:24 AM
FWIW the manual says silicone grease



FWIW, the manual also says you should replace the tyres with another set of Dunlop's famous bakelite compound D220s

embee
05-03-11, 12:28 AM
FWIW, the manual also says you should replace the tyres with another set of Dunlop's famous bakelite compound D220s

Yes, but a liberal coating of copperslip soon softens them up.

timwilky
05-03-11, 09:53 AM
I cannot understand why one would even think of using copperslip there.

My view and therefore not gospel is it is a slide and therefore should be lubricated. I tend to think of copperslip as too abrasive for mated components. You wouldn't put it in a bearing so why put it on any other "bearing" surface.

barwel1992
05-03-11, 01:11 PM
I cannot understand why one would even think of using copperslip there.

My view and therefore not gospel is it is a slide and therefore should be lubricated. I tend to think of copperslip as too abrasive for mated components. You wouldn't put it in a bearing so why put it on any other "bearing" surface.

some might think the "slip" in the name is a good thing :rolleyes:

punyXpress
05-03-11, 01:22 PM
Jim Slips FTW

beabert
05-03-11, 04:20 PM
Same checked my rebuilt brakes after 10k and 1 year, the red rubber grease look as new as when i put it on.

The copper grease on pad retaining pins was dry.