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Grease for polyurethane bushes
https://ausmini.com/forums/viewtopic.php?f=2&t=95025		 Page 1 of 1
Author:  Mearcat [ Sun Mar 12, 2017 8:54 pm ]
Post subject:  Grease for polyurethane bushes
I purchased a set of polyurethane mounts for subframe, engine steady and also have a sway bar with poly bushes and none of them (including sway bar) were supplied with grease. I have been advised that I can't use a grease that has a petroleum base and the local Super Cheap, Repco and AutoPro surprisingy didn't know what to use. Can anyone recommend a brand/Product which I can use and is suitable for poly bushes?
Author:  drmini in aust [ Sun Mar 12, 2017 9:24 pm ]
Post subject:  Re: Grease for polyurethane bushes
I have bought poly bushes in the past that all came with good old lithium EP2 grease.
And Nolathane bushes in Mini racks are fine with either grease or gear oil.
So I see no problem using regular greases. Who said you cannot?
Author:  Mearcat [ Sun Mar 12, 2017 11:42 pm ]
Post subject:  Re: Grease for polyurethane bushes
drmini in aust wrote:
So I see no problem using regular greases. Who said you cannot?

The advice was from a suspension place.
Author:  drmini in aust [ Mon Mar 13, 2017 5:11 am ]
Post subject:  Re: Grease for polyurethane bushes
Don't be tempted to run them dry. They tear up and crumble.
Author:  KLAS [ Tue Mar 14, 2017 5:20 am ]
Post subject:  Re: Grease for polyurethane bushes
lithium based grease should be ok, they say https://www.suspensionconnection.com/bl ... e-bushing/
Author:  peterb [ Tue Mar 14, 2017 5:50 am ]
Post subject:  Re: Grease for polyurethane bushes
Just be wary of some of the no name bushes, they're rubbish and drop to bits in a few months. I think they're made of old Cheddar cheese.
Author:  drmini in aust [ Tue Mar 14, 2017 6:25 am ]
Post subject:  Re: Grease for polyurethane bushes
peterb wrote:
Just be wary of some of the no name bushes, they're rubbish and drop to bits in a few months. I think they're made of old Cheddar cheese.

I've been down that road. I went back to stock suspension bushes for my road car, they last. Poly doesn't.
Author:  peterb [ Tue Mar 14, 2017 4:59 pm ]
Post subject:  Re: Grease for polyurethane bushes
+1 on that, rubbers the go.
Author:  Phil 850 [ Tue Mar 14, 2017 7:55 pm ]
Post subject:  Re: Grease for polyurethane bushes
Poly Bushes are not meant to be a bearing surface, so I'm not sure why you would lubricate them.
Poly Bushes do not have the same compression capacity that rubber does, so unless you have very little suspension travel, I would not use them.
When rubber bushes are used, they are designed to have a lot of static compression. The reason for this is so that as the bush "twists" the rubber never goes into tension.
To explain that a little further. Look at a simple round tubular suspension bush. Imagine a dot on the outer surface and a corresponding dot on the inner surface.
When the bush is Pressed into its housing with a shaft through the centre of it, the dots will be a lot closer to each other. The rubber is under compression.
When the suspension moves the inner of the bush rotates relative to the outer, and the two dots rotate away from each other, but as long as the distance between the two dots does not exceed the distance between the dots with the bush in the free (uninstalled) state, the rubber has not gone into tension. Therefore the life of the bush will be almost infinite.
Yes eventually the plasticisers will evaporate out and the bush will harden, but it will last a lot longer that many sets of Poly Bushes.
Author:  FNQ [ Wed Mar 15, 2017 2:01 pm ]
Post subject:  Re: Grease for polyurethane bushes
Good info phil 850, could you comment on the twisting forces, this potential for stict ion / excuse the probable mis naming, would appear where lubricant maybe advantageous ... No idea really, just fishing for comments from others more clever than me
Author:  Phil 850 [ Wed Mar 15, 2017 7:58 pm ]
Post subject:  Re: Grease for polyurethane bushes
If you need lubricant to overcome stiction, you have a problem of the bush holding the housing and the shaft until the limits of press fit are exceeded, and it then slips.
In a proper design this should not happen.
However, poly bushes rarely have a significant amount of compression when installed, and therefore have little grip on the housing or shaft. Therefore with a little torsional movement you soon exceed the grip and it slips.
Some people lube them up which just masks poor design.
Author:  Mearcat [ Thu Mar 16, 2017 1:18 pm ]
Post subject:  Re: Grease for polyurethane bushes
Referring to the original post, I recently spoke to KMAC Suspensions (sway bar supplier) as well as a specialist lubricants manufacturer and both recommended silicone grease - a "methylphenyl silicone fluid thickened product". It is suitable for rubber and also for use with polyurethane.
Author:  pfmmini [ Thu Mar 16, 2017 8:36 pm ]
Post subject:  Re: Grease for polyurethane bushes
Supercheap sell Herschells Silicon Grease 100g,2 tubes for $13.50
Author:  Mearcat [ Fri Mar 17, 2017 11:05 am ]
Post subject:  Re: Grease for polyurethane bushes
pfmmini wrote:
Supercheap sell Herschells Silicon Grease 100g,2 tubes for $13.50

That's exactly what I bought :)
Author:  Morbo28 [ Sat Mar 18, 2017 2:47 pm ]
Post subject:  Re: Grease for polyurethane bushes
The lubrication is only to stop the annoying squeak of poly bushes.

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