Front wishbone bushes GT6

[Dave the tram]

Rebuilt the suspension with yellow polybushes and gaz shocks about 6 years ago (I think). The nearside has squeaked ever since and tried all sorts to remedy it, inclding oil or spray with PTFE in it - probably not a good idea as I suspect from other threads that oils might harm the bushes.

Decided to check everything again and surprised to find the lower inner ones looked very off- centre so took everything apart and found this - bit surprised after about 15k miles.

 

So, will dismantle both sides, clean and paint the wishbones, rebush plus fit new drop links for antiroll bar. Everything else ok I think. 2 problems, can't fully undo the nut from the drop link where it attaches to lower wishbone. The threaded part just turns and can't get at the nut that I think is supposed to be held captive by the wishbone - so will saw it off. Secondly, can't get one of the bolts out of the yellew bush. It just rotates so must be siezed inside the metal sleave. Again, I'll just cut the bush apart and force it all out, then make sure I use silicone grease or equivalent when rebuilding.

Question is, what bushes? At one end I could try and get better polybushes, perhaps superflex medium firmness - quite expensive. At the other end, might cheap black ones from rimmers actually be better. I guess the original type were probably best.

I was intrigued by the debate in an earlier thread about what actually moves. I was convinced that the sleeve moved on the bolt and that the bush only absorbed radial shocks, rather than twisting. If in fact everything is rigid and the wishbone moves by twisting the bush, that must be millions of twists over a few thousand miles!

As ever, any advice welcome

Dave

[Pete Lewis]

poly are not always what they are cracked up to be 

then oriental rubber of the std bushes is also deemed poor stuff these days 

but compare cost per 1k miles your  yellow have not been good , 

superflex appear the best for quality and getting the actual hardness specification quoted 

pete

[johny]

5 hours ago, Dave the tram said:

I was intrigued by the debate in an earlier thread about what actually moves. I was convinced that the sleeve moved on the bolt and that the bush only absorbed radial shocks, rather than twisting. If in fact everything is rigid and the wishbone moves by twisting the bush, that must be millions of twists over a few thousand miles!

As ever, any advice welcome

Dave

Certainly in the original bushes the metal tube was bonded to the rubber hence the recommendation not to finally tighten the bolts until the wheels are supporting the cars weight. Doing this the rubber has to twist less for the full movement of the suspension.....

[Nick Jones]

Standard rubber bushes work entirely by flex. The inner tube is clamped in position by the bolt and the outer is fixed in the housing. This is why it’s important to tighten the bolt when the suspension is in its normal running position so the rubber is not continuously under tension.

Poly bushes are designed to slide on the inner tube which should be clamped solid by the bolt. They should be lubricated with silicone grease when assembled and if they squeak a lot it probably means they need dismantling and lubing so they don’t wear through too quick.

if proper Metalastik bushes were availed I’d use them. However, as they aren’t I use Superflex.

[johny]

yes my originals are 50 years old and still going strong - no fancy colours and dont look very pretty but doing the job!

[Dave the tram]

Thanks all - Superflex it is then, with silicone lube. I remember being carefull to only tighten when off the jacks when I did this previously. As I had the tracking set up recently after fitting new rack and track rod ends, I'd best get it done again in case going from such worn bushes to new ones affects it.

Cheers

Dave

[johny]

It sounds like with polybushes its not necessary to tighten the bolts on the ground cos, as has been indicated, the bushes rotate on the metal sleeves anyway..... 

[Badwolf]

Interesting... I was told my a member of the polybush team on the stand at the NEC Restoration show, that on no account should you use grease/lube of any kind when fitting. If fitting was difficult use a smear of washing up liquid as this was water soluable. Anything else mixed with grit/dust etc and formed a grinding paste which knackered the bushes!! This came up as I mentioned that R*mmers had tried to sell me 'polybush' grease when I ordered my bushes.

[Nick Jones]

All Superflex kits come with sachets of silicone grease.  As I understand it the bushes should be fitted dry into their housings but lubricated in the central hole before fitting the crush tube.....  They were pretty much the first in the business and still around.

Nick

[Dave the tram]

Hmmm! Just fitted Superflex polybushes to inner wishbones, which came with silicone grease. The technical section of their website says clean all old stuff, grease etc from parts, then coat all contact surfaces of the bush with silicone grease. I took that to mean coat the bush all over, as pretty much all surfaces contact something. 

I'm halfway through reassembling front suspension, wishbones back on the car but not fully tightened. At the moment the bushes move with the wishbone against the mounting bracket - I'll see what changes when fully tightened.

I guess if I'd pushed the bushes into the wishbone without grease, but greased the tubes before pushing them into the bushes, then :

a - it would be easier to get the tubes in without the bushes popping out of the wishbone (I sqeezed them with a clamp untill fully in to overcome this)

b - the bush is more likely to stay static in the wishbone but turn on the tube. But this would mean the bush end turning against the bracket, so needing grease there.

If the thinking is that the bush is static against everything and simply twists and flexes, then you would grease nothing other than the bolt to prevent corrosion and siezing.

I'm going to get it all back minus the spring and shocker so that I can move it up and down and observe, fully tightened - then retighten once finished and on the ground.

Dave