Spring bushes.......

Submitted: Wednesday, Feb 22, 2006 at 09:42
ThreadID: 31033 Views:4089 Replies:7 FollowUps:1
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This might be a real stupid question but it wouldn't be my forst one........
I see a lot of ads selling greasable spring hangers and same people sell neoprene bushes. I thought Neoprene bushes don't need grease.
Or do they?

Reiner
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Reply By: Hero - Wednesday, Feb 22, 2006 at 10:52

Wednesday, Feb 22, 2006 at 10:52
The correct term is polyurethane, this material is much tougher than rubber and can be greased to extend the life of the bush. As rubber cannot be greased, it is normal practise to install Polyurethane bushes when fitting greasable shackles.
AnswerID: 156444

Reply By: Philip A - Wednesday, Feb 22, 2006 at 11:12

Wednesday, Feb 22, 2006 at 11:12
Polyurethane bushes act by rotating on the central steel tube in an application like a spring shackle. This rotation will quickly cause wear between the tube and the bush. the greasable bolts usually have holes in the sleeve to let grease between the centre tube and bush. Also as part of the deal unless they are greased they can squeak annoyingly.
I had poly bushes in my Range rover panhard rod. One trip to the Simpson and there was about 1MM play between the inner sleeve and bush.
I changed back to rubber as in that application all the movement of the type of bonded bush is within the rubber in shear, so there is no rubbing wear, but they might be OK in leaf spring shackles where even the rubber has a rubbing rotation wear.
regards Philip A.
AnswerID: 156447

Reply By: Member - Phil G (SA) - Wednesday, Feb 22, 2006 at 11:18

Wednesday, Feb 22, 2006 at 11:18
Polyurethane bushes can be quite squeaky which is a PITA. Greasable shackles stop the squeak and they also allow the leaf springs to move easily, so are supposed to improve the ride.

Rubber bushes have changed a bit. Many of the ones on later leaf spring vehicles (eg 78/79series) have a steel sleeve, so move pretty freely.

I'm running poly bushes and greasable shackles on my vehicle, but given my time over again, I'd stick with factory bushes.
AnswerID: 156448

Reply By: Member - Reiner G (QLD) 4124 - Wednesday, Feb 22, 2006 at 11:44

Wednesday, Feb 22, 2006 at 11:44
Thanks for your replies, I had a broken spring hanger in the front and was wondering what to replace it with. I might go with the factory rubber bushes after reading your replies.
Thanks again
cheers
Reiner
AnswerID: 156454

Reply By: Member - Stephen M (NSW) - Wednesday, Feb 22, 2006 at 13:29

Wednesday, Feb 22, 2006 at 13:29
I have just replaced the front springs on my hilux all OME and have put in greaseable shacklespins etc and have used rubber bushes as the other ones wear the pins away and eventually when you need to replace the rubber bushes you will have to do the pins as well.The other ones squeak and also do not have the flexibility that the rubber ones do, and yes the rubber can be greased without the grease damaging the rubbers. Regards Steve M
AnswerID: 156471

Reply By: Member - Collyn R (WA) - Wednesday, Feb 22, 2006 at 15:09

Wednesday, Feb 22, 2006 at 15:09
Reiner
Have never been totally convinced re non-rubber shackle bushes for anything except extreme off-road use. Not even 100% convinced then.

A colleague has a 4WD converted Coaster with greatly increased spring travel and axle articulation and the original rubber shackle bushes have survived any number of cross-Australia trips.

Rubber bushes confer useful torsional and other flexibilty, and this reduces suspension component stresses.

As typical life of a rubber bush is at least 100,000 km - what advantage is the claimed added longevity? Greased bushes need regular greasing - this adds to maintenance costs.

I'll buy arguments about more precise axle location - but this can be contradictory to the torsional and other stresses then passed on to other bits.

I vaguely recollect (from my research engineer days) telling a designer that 'an ounce of rubber can be worth a ton of theory'.
Collyn Rivers

AnswerID: 156486

Follow Up By: Member - Reiner G (QLD) 4124 - Thursday, Feb 23, 2006 at 10:00

Thursday, Feb 23, 2006 at 10:00
Thanks for your reply Collyn, that makes a lot of sense. I will replace my bushes with rubber ones.
Rubber would take out a lot of the fine vibrations too which the hard bushes wont.
Cheers
Reiner
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FollowupID: 410697

Reply By: Member - Collyn R (WA) - Thursday, Feb 23, 2006 at 12:03

Thursday, Feb 23, 2006 at 12:03
Reiner
Should add to my response re rubber bushes - that my comments do not apply to racing cars nor serious sports cars, where rubber can introduce unpredictable steering effects.
Collyn
AnswerID: 156650

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