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Very quick grease questions
Slimy38 - 2/7/13 at 11:43 AM

My poly bushes for the wishbones have just arrived, they look quite good. The top hats for both sides don't meet in the middle which I assume is correct, would it be a good thing to pack that void with a suitable grease or would that be too much? I'd put the top hats in the wishbone tubes dry, pack the inside of the bushes with grease, then use the crush tube to push the excess back out.

I seem to remember seeing on here that the crush tube rotates inside the bush, and the bushes stay fixed relative to the wishbone? Is that right?

mookaloid - 2/7/13 at 11:49 AM

I'd say you have that spot on.

I have even considered fitting grease nipples to the wishbones to fill the void but I am concerned about weakening them.

Mr Whippy - 2/7/13 at 11:50 AM

They'll squeak if you don't will also feel smoother

AdrianH - 2/7/13 at 11:57 AM

Just got to get the correct grease in there, is it silicon grease that people use? I know I did.

Adrian

HowardB - 2/7/13 at 11:58 AM

many of the cars at the race meet had grease nipples on the bushes,...

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[Edited on 2/7/13 by HowardB]

rusty nuts - 2/7/13 at 12:34 PM

Make sure that the crush tubes aren't too short , do a dummy build of the bush assembly and nip the crush tube in a vice then check that the wishbone can rotate freely around the crush tube , if it doesn't then it won't matter how much grease you use , it will still bind. The crush tube does not rotate ,it should be clamped solidly between the mounting bracket, the bush and wishbone rotate around the crush tube

Slimy38 - 2/7/13 at 01:02 PM

quote:
Originally posted by rusty nuts
Make sure that the crush tubes aren't too short , do a dummy build of the bush assembly and nip the crush tube in a vice then check that the wishbone can rotate freely around the crush tube , if it doesn't then it won't matter how much grease you use , it will still bind. The crush tube does not rotate ,it should be clamped solidly between the mounting bracket, the bush and wishbone rotate around the crush tube


Thanks for the tip. I've already had a go with the crush tube and the brackets. The brackets I have were ever so slightly open, so I wanted to see what would happen when they were bolted up against the crush tubes. They closed up a little as I tightened the bolt, so I'm happy the tubes and the brackets both meet the requirements. Now I just need to ensure the wishbone tubes are similarly in spec.

big-vee-twin - 2/7/13 at 03:09 PM

You need to use a moly based grease i.e. a grease that is not a petroleum product to prevent it eating the poly bush.

PhillipM - 2/7/13 at 03:14 PM

'moly' grease is actually lithium based in most cases, the moly is just an additive, so 95% of the time it is petroleum thickened with lithium and fortified with moly for high loads.

Having said that, most poly bush compounds are quite tolerant of petroleum greases anyway.


[Edited on 2/7/13 by PhillipM]

Slimy38 - 2/7/13 at 03:29 PM

quote:
Originally posted by PhillipM
'moly' grease is actually lithium based in most cases, the moly is just an additive, so 95% of the time it is petroleum thickened with lithium and fortified with moly for high loads.

Having said that, most poly bush compounds are quite tolerant of petroleum greases anyway.


[Edited on 2/7/13 by PhillipM]


It's a tub of lithium grease that I was planning to use, it's served me well when I fitted poly bushes to my tin top.

PhillipM - 2/7/13 at 03:43 PM

Can't say I've had any issues with lithium on most polybushes - I usually use Hi-Mol 20 - but the 'failsafe' option is a silicone based grease.