Topeak Track Pump Woes

[Cranky]

I've had a Joe Blow Sprint track pump for about four years. Recently the piston occasionally started flying up to the top from back pressure in between pump strokes. Then it would be ok again. Needless to say the problem got rapidly worse until it wouldn't actually put any air into the tyres.

I took the piston out and there's a plastic end with a rubber 'O' ring. The ring looked in good condition so i just greased it and put it back. This didn't fix the fault.

Then I bought the Topeak pump repair kit (£2.00) for the Twinhead but this didn't work either. Today I received the complete replacement hose and Twinhead kit (£14.00), attached it, and it still hasn't cured the problem.

I can hear the presta valve opening on downstrokes but the tyre is just going flat. The pump doesn't work on schraeders either. However, there's plenty of pressure when I put my palm over the outlet and push the piston.

Does anyone know if this can be fixed or do I just write off the expense of attempting to repair it and buy another?

 

[Llama]

I would give Topeak a quick e-mail to ask explain that you spent a bit trying to remedy the situation and see if they can offer any help

 

[Cranky]

Thanks Llama. I might try that.

 

[Globalti]

If the pump is pressurising but air is returning from the valve and the tube is not inflating, the fault is with your valves not the pump. The pump doesn't have any mechanism for preventing air from flowing back; it relies on the valve to do that.

Have you tried another pump on the same valves?

 

[Cranky]

If the pump is pressurising but air is returning from the valve and the tube is not inflating, the fault is with your valves not the pump. The pump doesn't have any mechanism for preventing air from flowing back; it relies on the valve to do that.

Have you tried another pump on the same valves?

That's what's so puzzling, RR. The pump now doesn't work on the valves of any of the bikes - presta or scraeder - but my frame pump works fine on them all. Yet there is quite a lot of pressure from the Twinhead which registers up to about 20psi when I cover it with my palm.

 

[Globalti]

Bizzarre indeed. Does the pump have the same effect on other people's tyres?

Maybe give Topeak a call and ask to speak to their technical manager?

 

[Cranky]

Bizzarre indeed. Does the pump have the same effect on other people's tyres?

Maybe give Topeak a call and ask to speak to their technical manager?

I contacted Extra (UK) who, I discovered, are the UK distrubutors for Topeak and had a reply, and subsequent advice with diagram, from a very helpful James Moloney.

It seems that the problem lies with a non-return valve in the base of the pump which, he says, is a fairly simple problem to fix by dismantling and cleaning out. I did take the base of the pump off during my earlier attempts to find the problem and didn't notice this valve but am going to have another look tomorrow. I'll let you know how I get on.

 

[Cranky]

Final update on the pump. On taking out the non-return valve, the spring had completely corroded away, hence the air rushing back into the pump from the tyre.

James from Extra (UK) sent me a new spring and valve which have completely cured the problem, much to my relief.

Great customer service.

 

[Globalti]

Very useful post. Is there a technical archive?

 

[Cranky]

Very useful post. Is there a technical archive?

No technical archive as far as I'm aware. I was sent a file showing all the parts for the Joe Blow Sprint. I tried to attach it here but in reducing the size the quality is too poor to be of any use.

However, from my experience it seems that Extra (UK) are willing to help with technical enquiries.