Wishbone Pin Bushes

[prutland]

I am in the process of replacing the wishbone pin bushes on my BN4. Whilst I am having the oft quoted difficulty in removing the pins from the bushes / brackets on the frame (one removed three to go), however, that is not my query:

The old bushes (not clear if they are original) have a large metal washer bonded to the outer end which bears against the bracket on the frame whereas the new bushes do not have the washer. (see accompanying photo)

Has anybody seen the older style bushes previously? It seems that they are a far better solution than the new ones and would reduce the friction between the bush and the brackets on the frame (if kept lubricated anyway) and possibly provide a more rigid connection between the wishbone and frame. I am assuming that the new bushes are all that is available these days?

A second related query is when I reassemble the wishbones onto the pins, what would people recommend as the lubricant to keep the bushes free on the pins for as long as possible.

Options would appear to be:

• Molybdenum disulphide grease. (Molybdenum disulphide should at least provide some ongoing slip when the grease dries out). Petroleum grease however not kind to rubber
• Silicone grease that shouldn't harm the rubber. Unsure of its long term lubricating qualities however
• Copper-eze . (Similar pros and cons to molybdenum disulphide grease)
• Anything else

Any thoughts on the above would be greatly appreciated.


Thanks in anticipation.


Paul R

 

[red57]

Hi Paul,
If you are using the rubber stock type bushes, there should be no lubrication (other than plain water to help assembly). They are designed to be locked into position and not are not supposed to slide in the control arm or over the pin. The rubber is intended to simply flex as the arm goes up & down. That is why it's important to follow the direction in the manual when installing them and have the assembly at normal ride height before tightening the nuts on the pins. If you have the suspension in full drop when you tighten the nuts, you will over-stretch the rubber when it goes over a bump and the rubber bushings will fail prematurely. Pictures from Bentley Book, Section L.5. There should be no additional washer like shown in your picture - that may be aftermarket urethane or ???
Dave

 

[BobHaskell]

I wondered if the steel washer on the bushing was actually from item 2 (special washer) in IMG_7249.JPG.

 

[Randy Forbes]

OMG, heck just froze over (Dave said something I didn't agree with__must be first time ever)!

Actually, I HAVE seen those bushes with the washer as part of the assembly, so I surmise that it had only been part of the earliest 6-cylinder cars (and possibly the 100s, but I don't have any memories_remaining_of working on one). I suppose the bonded washer bushes were phased out sometime early in the production, but I can't say if it was pre-post around the time assembly moved to Abingdon.

Any historians here have more specific data?

 

[John Turney]

On my BN4, it seems that the Special Washer, #2, is like the Bentley manual.

Also, as Dave said, the rubber bushes get no lubrication, but flex to allow movement. The bushes should have a metal sleeve in the center. This sleeve is held tight by the two washers. You might consider putting some anti-seize on the new pins to make them easier to remove next time.

 

[prutland]

Thanks all for your responses. It does seem surprising that you can generate sufficient compression in the bushes that they will shear rather than slip where they are clamped at each end. Notwithstanding that I will set them up as per the manual and keep my fingers crossed.

The new pins are zinc-plated so I suspect a smear of Copper Eze will suffice to help prevent the bushes from seizing onto the pins. Given that the bushes are likely to have been in place for the best part of 40 years (or possibly longer), they will likely outlast me.

Paul R