Superflex Bushes ESM

[philthehill]

In the light of what you are saying I would suggest that you go back to having rubber bushes to the front and rear of the tie bar bracket to prove or disprove whether the Super Pro bushes are the cause of the problem.

[PhilAllen]

Thanks Phil. I originally had poly at the front and a rubber one at the back which had perished in 4 years from fitting so I could go back to that (with a new rubber bush obviously!) to see how things are, that’s a good idea. A job for next weekend!

[svenedin]

I fitted Superflex bushes in 2023 (I had to check my records that they were definitely Superflex).

Superflex in front and rubber behind. The firm bush for braking and the more flexible rubber for articulation.

I didn't have any of your difficulties at that time. I wonder whether they have changed them recently? The Superflex bushes I used were rather hard.

I also replaced the tie bars at the same time because mine were corroded and worn.

I did have problems with juddering on braking earlier this year. I thought it was loose tie bars because I had swapped the castle nuts and split pins for nylocks and they seemed too slack (just not tightened enough, they had not worked loose). In fact the problem was loose brake backplate fixings (also my error).

Stephen

IMG_8850.jpeg (1.55 MiB) Viewed 4834 times

[mowogg]

Is the brake force not on the bush at the back when travelling foewards? When the brakes are applied the force would be in the opposite direction to the travel.- resulting in pressure to the back bush.

Am I missing something?

[svenedin]

Is the brake force not on the bush at the back when travelling foewards? When the brakes are applied the force would be in the opposite direction to the travel.- resulting in pressure to the back bush.

Am I missing something?

Maybe I am wrong! I thought the brakes are trying to stop the wheel but the car is trying to carry on moving forward so the force when braking is on the front bush?

Stephen

[ndevans]

I agree. When the brakes are applied, the wheels are trying to stop but the body of the car is trying to carry on, so the tie bar is pulling back and compressing the front bush.

[ndevans]

Maybe what is needed is a composite semi-rubber, semi -poly bush that can be fitted either side.

[PhilAllen]

I reverted back to the more normal poly at the front, rubber at the back setup yesterday afternoon and we’ve been out to the local club meet today. I still feel a slight shimmer in the steering wheel when braking from above 50mph, but the best it’s been so far. I might try tightening the nut a bit more, or putting a washer back, to see if that will make it go away altogether. Failing that I might do a more thorough dismantling and investigation over the winter to see if there is something else that I’ve not spotted so far.

I did check the brake backplates just in case, but they’re solid.

One thing I noticed is that the Superflex bushes I had from ESM are stamped 2755S where the pack in Stephen’s photo are 2755SK. I thought I’d been provided with the correct ones, but now wonder what the difference is.

Thanks everyone for your help so far.

[philthehill]

The correct SuperFlex part number for the tie bar bushes is SF268-2755 SK.
The tail end letters = 'S' denoted - shell only. The 'K' denotes a kit.
Therefore the variation in the part numbers can be ignored as the base part number is the same.
So my advice is to fit the SuperFlex bush to the front of the tie bar mount bracket and a rubber bush to the rear of the tie bar mount bracket and see how you get on.
This combination of bushes and location has been used many times without problems so it is worth looking elsewhere around the suspension for wear or loose parts.

[ndevans]

A thought - if the hole in the chassis for the eye bolt that the lower wishbones attach to is ovalled, or the eye bolt shaft itself is worn, you might get a bit of movement and a clunk when braking. Might also explain why the tie bar is not fully up against the bushes and nut.
Also worth checking the torsion bar mounts on the cross member for tightness.