Avon A4 valve repair/replacement

[martini]

I've been tasked with fixing up someone's leaky old Avon tender, it's got the old A4 valve (neoprene glued on ones with the plug that pushes in)

I assumed I was going to end up cutting them both out and fitting C7's but I've just found you can still buy new diaphragm's for the A4.

Has anyone got experience of replacing an A4 diaphragm in situ? Does anyone know how or if they can be replaced once the valve's fitted to a tube?

Thanks for any advice

[ribraff]

It might be best to buy the whole valve and just screw it in to the old frame inside the tube. It'll be nice and shiny then too!!
Speak to Mr Tilley, I think he sells them.

[martini]

The A4 doesn't work like that unfortunately, it's just a big rubber thing that glued to the tube then a doubler patch with a hole in the middle glued over the top.

The sensible thing is probably to just cut it orf and glue a new patch on with a modern valve, I'm just being lazy.

Although you can buy a new diaphragm I can't see a way of replacing in in situ

[ribraff]

Leafield

[martini]

No that's an A7, this is the A4:

[ribraff]

Sorry.. it's been a long day! I would say rip it out and bang in a C7!

[Nos4r2]

Originally Posted by ribraff

Sorry.. it's been a long day! I would say rip it out and bang in a C7!

Ditto.

The A4 valves can be a bugger to get off though-they tend to leave big black lumps behind.

[ribraff]

Yes, it can be a pain, I usually sand the black rubber down with an 80 Grit disc on a mini grinder, then you can cover it with a circular patch before putting the valve in.

[martini]

I'm going to just fit 2 new C7 valves in I think, no point in doing one and leaving the other. Rib-shop do a kit with a doubler and all the glue, thinners etc so I'll probably get that