F15a shock absorbers

[Jacques Reed]

Hi Dave,

You are most welcome. Always glad to help.

Had a look at the shock absorber that I pulled apart and I have another thought about the gasket between the reservoir cover and the lower ring.

Looking at the sealing area between them, there is a very distinct taper and not a square mating surface as shown in the photos.

I am thinking maybe an O-ring would do the job there instead of laboriously cutting a gasket. The V groove formed by it would squish the ring tight against the threads and against the edges of the tapered surface.
Those kits to make your own O-rings might do the job. Perhaps 2-3mm diameter O-ring material would work there.

Just a thought anyway. Gluing a length of O-ring material is a lot easier than cutting out a thin rubber gasket and may be worth a try.

Cheers,

[Dave Schindel]

Hi Jacques, now I think I see what I did wrong. I was not aware of the O ring gasket. When I took the cover off the ring came off with it, in one piece. How does the ring separate from the cover?

[Jacques Reed]

Hi Dave,

The ring should just come apart from the cover but after 7 decades it probably is well stuck. Rubber becomes a great glue with age. Just look at trying to break the tyre bead on these old trucks.

If the ring stays on the body of the shock absorber, and you want to remove it, it can be screwed off after a good wire brushing of the exposed threads and application of lots of penetrating oil. There is a tiny hole visible on the lower ring so it would not be to difficult to fabricate a special wrench if needed but I just got mine off by wire brushing, lots of oil, and working it back and forth.

Besides sealing the unit I believe the lower ring is to also used to allow the cover to be positioned with the filling plug uppermost. By adjusting the position of the ring when the cover is screwed down tightly it will allow the plug to be on top.

Cheers,

[Dave Schindel]

Jacques, thanks for the explanation . Mine was indeed stuck together enough that I thought it was one piece ! Great pics . Thanks so much.
Dave

[Jacques Reed]

Hi Dave,

Good news.

I am just curious if you could confirm if it is an O-ring seal at the cover when you take the lower ring off?

The reason I ask this is that I am having second thoughts if that is an original seal or if the rebuilder just gave that O-ring to me. It could have been something he tried and which didn't work. Would account for all the silicon sealant he used. Memory is a bit hazy from all those years ago. I seem to remember digging out black gunk from between the cover and the ring on the one I took apart.

If it is not an O-ring used there then perhaps its back to cutting out a bit of neoprene to make a flat gasket for that area or trying smaller diameter O-ring material. The parts manual does show a flat gasket there and it is speckled which could be representing rubberized cork material. That would compress into the "V" quite nicely.

Cheers,

[Dave Schindel]

Jacques, I took one of mine apart and there was a white fiber gasket in between. When I re-assembled it I made one large oring out of two smaller ones by cutting and super-gluing the ends together. I didn't think the oring would seal against the threads,so I used a wee bit of silicone gasket maker where the oring sits and screwed the reservoir down onto the ring.I will find out tomorrow if it is holding or not.It seemed to fit real nice and I got good compression on the oring.

[Dave Schindel]

Jacques, when I unscrewed the reservoir the gasket seemed like some kind of a packing similar to what would be used on a pump shaft.it was well embedded in the threads and came out with a wire brush quite easily. I think packing in the form of a heavy string would be ideal but no idea if such a thing even exists.