Polybushes went lose

[Jas]

Hi

I have just fitted new polybushes to the front and rear suspension.
When I came in to retighten the suspension after the first drive, the front wishbones had slid halfway out over the polybushes. I?m glad the drive wasn?t longer.

No I haven?t lubed the bushes before installing them in the wishbones.
Is there supposed to be some large washers on either side of the bushes to keep them from sliding out? There weren?t supplied any, just the locknut and normal washer for each bushing.

Have I missed something?
How have you fitted them?

[TeeJay]

Hi Jannik. Yes, large dia. washers are fitted, see my post in the plus 2 section, "Restoration Update" last post was March 11. See photo, sorry away from home so cannot give a link from my mobile.

[alexblack13]

Hi Jannik,
I could be wrong here but I am sure the wishbones are not supposed to be kept in place with the large dia washers and indeed they should not in fact be touching these. They are a final defence in the event of bush failure.Wishbones touching the washers are in turn touching the pivot pins and all road harshness / noise will be transmitted directly to the chassis.

I would refer back to the manufacturer for advice, as the bushes are not supposed to rotate in the wishbone boss.They rotate (like a bearing, which they are) around the stainless steel crush/spacer tubes and should be a tight fit in the boss. If the polybush is staying still whilst your suspension rises and falls then something is up and needs further checking out.. Some of these Polybushes are not the be all and end all. I had to send back bushes that were just hopeless and should not have been supplied as they were not fit for purpose and just did not work, or indeed fit!

Who supplied these?



Careful mate...

Alex B....

[Jas]

Hi Alex and others

I didn't think that a large washer should be stopping the bushing, as the wishbone would rub against the washer, steel against steel doesn?t seem right.

They are Power Flex and supplied by TTR, and Tony usually sell quality items.

Cheers

[gerrym]

Jas, I bought polybushes from one of the major Lotus specialists and had exactly the same symptoms as you. Chassis and wishbones were in good condition. Bearing in mind that the original bushes are press fitted into the wishbones, in hindsight I'm not surprised. I ended up putting additional washers on the inner side of the wishbone pins, to stop the wishbones sliding fore and aft over the polybushes. These located against the inner stainless bush and so did not interfere with the moving wishbones themselves. I remember being pretty concerned and talking to Pat Thomas. He seemed to think my solution should work.

Regards

Gerry

[TeeJay]

The inner steel bush is slightly wider than the bush. The large steel washer locks on the steel inner bush when the suspension is set and then the nut tightened to the correct torque. I purchased a chassis kit of fasteners and the large washers were part of the kit. The kit parts list stated that they went on the wishbones.
But as Alex suggests, always wize to check with the bush supplier.

[alexblack13]

Hi Guys,

Yes the large retaining washers go on the wishbone pivots and tighten against the bush inner tubes but the wishbones should not contact against them or rely on them to stay in position. I went to the trouble of making some small spacers to keep the washers away from the wishbones and prevent metal to metal contact. Made a difference in the car's running 'smoothness'

Gerry's solution sounds like a worker, But.. I would still ask TTR for advice etc..

Let us know how you go... and be carefull....

Alex B....

[ceejay]

Why is it that the suppliers of polyurethane bushes get it so wrong?

The photo's below show how to install urethane bushes.
Yes, the side thrust washers (Inner & outer) are extremely important.

Each bush also requires that a thin flange (Hat shape) is provided on
the outer edge to act as a bearing surface for the thrust washers.

Installing urethane bushes is not just a simple matter of pushing
them into the wishbone ferrule, you need to spend some time fine
tuning the amount crush imposed on the bush set.

The internal sleeve or crush tube is machined from stainless
steel, it is imperative to make sure that when the pivot pin
holding nuts are tightened that the crush on the bushes are neither
too tight nor too loose, and yes it is OK to install the bushes with
some graphite based lube.

The crush tube sleeve controls the amount of crush applied and
generally requires small amounts of metal to be machined from one
end then re-assembled with the bush into the wishbone, then
tension the nuts up, you may need to trial fit several times before
you get it right.

You might think they are not worth the trouble, but believe me they are,
once you get the fit right you wont need to touch them for decades.

Our S2 elan has employed urethane bushes since 1984 and on a recent
pull down only two required replacement. How good is that!

Did you also know that there are different grades and hardness of urethane
available. Out here in Australia the best material to use for suspension
bushes is coloured red (As shown in the photos here), the black material
is far too hard, and yellow is far to soft... it is important that the correct
grade is chosen. If you want to get more technical they are also graded
in Shore hardness or quoted as a certain durometer hardness figure... be
guided by what ever you wish.


Most bushes supplied are of the moulded type, but far better results can
be had by machining (Lathe) the hat shaped bushes from solid rod, urethane
purchased in this manner is quite cheap and it is easy to work with.
The rest of the components... i.e. crush tube or sleeve... the steel thrust
washers and the thin lock nuts can all be machined from readily
available materials.

Just a note on the lock nuts... normal nyloc nuts wont work because
the chassis pivot or fulcrum pin is just a shade too short, so twin
lock nuts offer the safer option.

So there you have it... a general run down on urethane or poly bushes
as some like to call them... In my opinion urethane bushes are far
superior to the original type of bushes... every old bush in the elan
can be replaced (but not lotocones & engine mounts) with urethane.
If the correct material is chosen and the bushes are set up correctly
difference between the old and the new would not be noticeable.

Having said all of this you may wonder if we supply kits, the answer
is no, because there are far to many variables between different cars,
fitting urethane bushes should be done on an individual case after
careful examination and measurement of the wishbone components.
Hope this is of some help to you.
Col.

[Jas]

Thanks Col

That looks like a good fitment you have there.
None of the kit I have seen has top-hat bushes for the front wishbones.
Seems like you have to make them yourself, just a pity spring arrived today
What shore hardness are you red polyurethane?

[ceejay]

Jas.

I suggest you download the following pdf document (See below)... it
provides a huge amount of info on this product. The shore hardness
can vary from about 45 to 85 depending on the material, from memory
the red material is around 75-80. As I said I have it my elan and I don't
consider it harsh at all.
Download Link:
http://tinyurl.com/ygzuplo
Also it appears that the company "Dotmar" are unique to Australia & NZ.
They bought out "Ludowici" the company that used to make all this stuff.

Another great advantage is that 1KG two part pouring packs are also
available should you have the need to pour your own new bushes, providing
you have the correct moulds (molds) etc
Cheers.
Col.
PS.
I would imagine that there would be several Co's in USA - Canada- UK etc
who would be also manufacturing/supplying this material.

[GEORDIE]

Jas
I fitted poly bushes supplied by Sue Miller afew years ago, they are the 'top hat' design and held in place by large diam. steel washers, but the washer is separated from the wishbone by brim of the top hat.

[Jas]

Thanks, I will have a look.

I heard from Stuart at TTR that they are selling Sue's / Super Flex bushes at the moment because Power Flex had a fire and their moulds got damaged.

[Lincoln62]

I can understand the value of poly bushes for a competition car but any road car I have driven with poly bushes (not Lotus) has a really harsh ride.

Can the Elan suspension handle poly without losing that beautiful supple ride?

I replaced my rubber bushes 20 years and 25000 miles ago and they are still fine. They are bound to need replacing sooner or later.

Pete
66S2

[ceejay]

Pete.
I have had the correct grade of urethane bushes in my S2 (More than 20yrs)
and can say that the ride has been fine... in fact people have often
commented on the "beaut" ride, especially for a sports car... even non sports
car people comment, so when elan owners say the bushes are harsh maybe they
have been supplied with the wrong material?
There is a little more work involved in fitting and "fine tuning" them, but once
that is done you wont touch them for a long, long time.
Col.

[rocket]

If it is of interest to anyone i can supply polyurethane in rod form at any hardness from 60a to 80d(110a) I have looked at producing kits but cant really be bothered producing moulds etc..

Ian.