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Norton plunger suspension seized.

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iansoady:
I had a feeling this would happen.....

I'm starting to get down to some work on my 1952 Norton ES2. I did have a feeling the rear suspension wasn't working and have discovered that the alloy slider on at least one side (all I've looked at so far) is seized onto the bearer rod. After slackening the pinch bolt and freeing the taper the bearer rod is free in the frame but the slider just moves with it.

I've run penetrating oil down the join as much as I can but suspect large amounts of heat (which I don't have) will be needed, I don't really want to get down to the bare frame at this stage as I was hoping to get the bike up and running to discover what was needed. Seems I've got to this point already.

This is the arrangement:



Any helpful suggestions welcome.

john.k:
A bit of heat applied to the ally will free the seizure.Be rust inside too,I would imagine.Be careful not to overheat,as the ally will certainly be heat treated,and you may weaken it...Usually,the sliders are flogged out.I always use molygrease with 30% MoS2 on mine.

R:
There is a grease nipple dead smack in the middle of that beautifully done alloy casting.
Replace the silly original type with a modern one, attach a good grease gun to it, and pump away.
Grease guns can apply serious pressure, so with any luck grease may be forced through to where its needed.  Of course, if the seizure is above the nipple and the grease all goes downwards, or vice versa, then it may be no help - but it has to be worth a try. It must have been a lazy PO that let the grease dwindle to the point of allowing rust, plunger suspension is totally reliant on those alloy sliders being free to move.

P.S. Have you tried a good sharp WAP with a heavy hammer down on the rod, any initial movement may free it off ?  Probably with the wheel still fitted to restrain it all, and the frame jacked up a bit

mini-me:
Diesel is a better penetrant in these cases than oil, patience is needed.

As for heat, a  Black and Decker hot air gun should provide enough encouragement to  the alloy to get the diesel seeping through. It is best to have some kind of baffle behind to direct heat back.

33d6:
Are the sliders bushed or being alloy do they run direct on the central rod? I'm trying to attach a photo of the last plunger rear suspension I did. It shows both the clamp I used to fit the refurbished units plus the extra grease nipple I installed on the top.

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