Polyurethane Bushes

[testrider]

Are these type of bushings supposed to pivot around the inner steel shaft like a rose joint does or are they meant to flex torsionally with the inner part staying static and the material flexing to give the movement?

I'm trying to get to the bottom of why the rear suspension on my 2000TC is both harsh and too high so I've disassembled it all. With the De Dion elbows and springs removed the trailing arms were stiff to move (accompained by a loud creaking sound) and would stay at whatever angle they were left at. So, I think the yellow polyurethane bushings fitted are the problme, either because they're not working right or they're just not suitable for road use. Any thoughts?

 

[DaveHerns]

Isn't that the drawback with polybushes ? You can grease the sleeve so it moves quietly but the effect soon wears off

 

[ewokracing]

Here in Aus, we don't have the different colour for grades/types of bushes that you UK guys do, so it might be slightly different. The different colours of bushes you can buy here in Aus corresponds to different brands such as Whiteline, Superpro, Pedders and so on.

As Dave said, I always thought that the plastic/poly material wasn't meant to compress like a normal rubber bush and is also meant to slide around the inner metal sleeve (where fitted) or the mounting point where you fit it, which is why you always get grease to use. I know that a few brands in Australia - Noltec, Nolathane and one more whose name I forget, used poly material which wasn't strong enough and the bushes would tear as they rotated around. The Noltec bushes I used on one car crumbled to pieces in less than a year as the outer part (or brim if you think of a top hat shaped bush) ripped away from the smaller shaft of the bush.

I have also seen poly bushes have indentations in them where obviously the bush has not moved at all and the suspension movement has caused the poly material to start to compress in one area, I forget what bushes they were (I suspect pedders as they looked like they were a faded red colour).

 

[testrider]

Hmm, that confirms my suspicions then. I'll try to knock out the pin and grease it to see if that frees up the movement, if not I'll fit a proper metalastik one on the front pivot of the trailing arm.

Will normal bearing grease (Castrol LM) be OK?

 

[billoddie]

I know that a few brands in Australia

...

I agree.
Of the poly bushes I have used in the Rove, the have all been Superflex, and (touch wood), have had no problem with them.
The suspension is not harsh, nor does it squeak.
My understanding is they are properly engineered and used stainless inserts as opposed to zinc plated steel on inferior brands...and affordable to boot.
Mind you, I have been judicious where I have used them...and have used genuine Metalastik elsewhere.

 

[testrider]

I've got Superflex ones in some of the pivots in the V8 which are all purple, as are some of the pivots on the TC, but these yellow ones on the trailing arm don't seem to move.

 

[testrider]

Here is the offending item.

And with the pin removed.

It's definitely stainless as it doesn't stick to the fridge door, but it was stuck in very tightly. I'll clean this and the other ones up and refit them with plenty of grease.

On the left of this photo you can see where it's been rubbing on the mount as it rotates and I'm not convinced that's a good thing long term.

Any idea what the random steel pipe on the diff nose mount is for?

 

[Dave3066]

It's definitely stainless as it doesn't stick to the fridge door,

Is your fridge door magnetic then Paul?

Any idea what the random steel pipe on the diff nose mount is for?

It seems your missing an exhaust clamp as there should be rubber bush with an exhaust clamp attached to that.

Dave

 

[DaveHerns]

There's an advert by one of the polybush manufacturers saying they use stainless sleeves as plated ones rust , wear away the bush and squeak.

 

[testrider]

It's definitely stainless as it doesn't stick to the fridge door,

Is your fridge door magnetic then Paul?

No, but the seal inside is

Any idea what the random steel pipe on the diff nose mount is for?

It seems your missing an exhaust clamp as there should be rubber bush with an exhaust clamp attached to that.

Dave

That makes sense, I've always though the exhaust looked like it should have more holding it on.

 

[ewokracing]

timely arrival last night, got some SuperPro bushes for the front end, in the instructions it states that grease must be applied between any metal and plastic contact surfaces.

With that wear mark on the suspension, I would put a smear of grease on the bush and the suspension point so that it can rotate smoothly. I've got photos somewhere of the rebuild I did on one of my Mazdas and there was literally grease everywhere by the end, but the bushes are still like new 4 years later.

 

[OrganDoctor]

I would guess that silicon grease would be preferable on those materials.

 

[ghce]

or molykote grease?

Graeme

 

[billoddie]

The grease normally comes supplied in small satchels, and is white in colour.
Those yellow bushes appear to have none at all, so I'm not surprised they are problematic.

 

[ewokracing]

I edited my post to include a picture but it seems the forum was playing funny buggers.

Anyway, here's a shot of how I fitted some superpro bushes into the lower control arm on one of my Mazdas. This joint pivots the LCA on the engine crossmember. I smeared grease in there literally everywhere.