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ewyasrover

Damper rod jammed

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Recently bought a model 27 as a resto project and have removed the front forks for a strip and rebuild. The bike has been stood for 30 odd years and the the one fork leg stripped out fairly easily but the other one is a bigger problem. The damper rod is jammed in the stanchion and refuses to budge, even after giving it a good soak in Plusgas for the last 3 days.  It's got to come out as I'm fitting new stanchions, the old ones are round and true, but the chrome is tatty. I have removed the ciclip but rod won't move either way.  Any ideas as to the best way to remove the damper rod?  

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That is a pity and I hope it is not the lower stanchion as it was at a pair of forks I bought believibg it where "just" the inner stanchions. 

There is no other clue then pulling and may be putting one end into a vice and using an oil filter wrench to turn or move the rod until it comes out. 

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To get a bit of movement started you could heat the outside of the fork tube at the position where the damper rod piston is stuck while gently tapping opposing ends of the damper rod in turn

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You may want to try putting the damper rod bolt back in but nowhere near tight and giving the centre of the allen head bolt a whack with a pin punch to try and get the damper rod to start moving. A bit of heat as Feetupfun has said.

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Tried all suggestions and it still won't budge, it appears that the alloy collar has fused to the steel stanchion. Careful use of the angle grinder seems to be the only option.

Unless someone has a damper rod assembly (or a pair) they could sell me? Bike is 1968 model 27 with the taper top 35mm fork stanchions.

Edited by ewyasrover
more info

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The damper rod itself is a loose fit in the alloy spacer that sits inside the bottom of the chrome stanchion, so even if the spacer has fused to the stanchion the damper rod should still move being a loose fit inside that spacer. However, the piston on the top of the rod is steel and although the entire rod assembly is not a tight fit inside the stanchion, maybe there is corrosion around the piston?. If the cone shaped bump stop is removed from the bottom  of the damper rod, the rod can be removed by sliding up and out of the top of the stanchion ( in ordinary circumstances) leaving the alloy spacer in the bottom as that part will only come out of the bottom. As you seem to have nothing to lose now I'd remove the bump stop, screw a bolt into the damper rod and give it a whack with a hide mallet and see if it will force it loose and up through the stanchion. The spacer can then be tapped out through the bottom taking care not to break the shuttle valve which may still be in there and which are very brittle as I can't remember if that can be removed through the top of the stanchion or only the bottom

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All excellent suggestions here. I've done the same, beginning with what Woody suggested:

" If the cone shaped bump stop is removed from the bottom  of the damper rod, the rod can be removed by sliding up and out of the top of the stanchion ( in ordinary circumstances) leaving the alloy spacer in the bottom as that part will only come out of the bottom.

To accomplish this, I use a vise, a relatively long 8mm hex bolt, a rawhide mallet and a propane torch.

1. Thread the long-ish 8mm bolt into the end of your damper rod.

2. Open the jaws of your vise and clamp tightly with the aluminum bump stop to one side of the jaws and the stanchion end to the other.  Hopefully your vise is of the size that will allow you to do so.  If not, you can likely rotate it or the fork assembly into a position that will help you to accomplish the same task.

3. While self-supporting, apply some heat to the bump stop with your torch to expand the aluminum a bit (not too much, as there's a small rubber gasket within that you don't want to burn.).

4. Once heated, SLIGHTLY LOOSEN the jaws of your vice just wide enough for the damper rod to slide between but NOT wide enough for the bump stop to pass through.  The idea is to use the vise as support for the bump stop as you drive the threaded bolt through (and damper rod OUT of) the bump stop.  If the jaws of your vise are too tight, you could mar the surface of the damper rod - too loose and there'll be insufficient surface area to properly support the thin aluminum end of the bump stop you'll be hammering against, potentially causing surface damage to the leading edge of the aluminum.

5. Supporting the fork assembly within the loosened vise in one hand, with the other use your mallet to hit the bolt you've threaded into the bottom of the damper rod hard enough to drive the damper rod through and out of the bump stop.  It may take several whacks but she'll eventually come out.  

I've found this to be the easiest method for difficult-to-remove damper assemblies.  Good luck!

Edited by vintagenut
Typo
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Have followed all excellent advice, thanks guys! Damper rod is now out all except alloy collar and shuttle valve, but problem is now solved thanks to Richard Allen supplying a replacement damper rod, slightly different but I was able to make one as original rod out of the two.

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