What's wrong with my pump?

[roubaixtuesday]

Lezyne flex house pump

Failed when I needed it. Doesn't produce any pressure whatever.

Here assembled

And here unscrewed, which revealed a loose o ring, which I guess is the most likely issue.

No idea how to fix it, any pump experts able to help?

 

[si_c]

Take a look online - Lezyne do seal kits so you can disassemble and rebuild the pump from scratch.

I've done it with one of my pumps a couple of years ago when it got water logged. Works fine now.

Edit: Not sure if this is a suitable kit, but I think so.

 

[roubaixtuesday]

Take a look online - Lezyne do seal kits so you can disassemble and rebuild the pump from scratch.

I've done it with one of my pumps a couple of years ago when it got water logged. Works fine now.

Edit: Not sure if this is a suitable kit, but I think so.

Thanks! But I've taken it apart, and no idea why it's not working or where the seal should be.

 

[ColinJ]

No idea how to fix it, any pump experts able to help?

How about the Lezyne experts?

 

[wafter]

I think the floating seal might just be there to act as a buffer, although tbh I'm also struggling to see what's going on.

Is it a multi-stage pump or just single stage? My gut suggets it might need further disassembly, if possible..

EDIT: Actually, it would make sense if there was a propriatory piston seal (or really fat O-ring) on the end of the inner bit - have you checked to see that nothing like this has become detached and stuck inside the end of the outer piece?

 

[briantrumpet]

I really shouldn't giggle at the thread title.

Sorry.

 

[chriswoody]

My Lezyne track pump was recently the same, it had been getting progressively worse and failing to gain pressure. A quick look at the Lezyne rebuild videos and alongside the replacement O-Rings they also talked about greasing the O ring lightly. So I decided to try it prior to buying or finding some suitable O-Rings and was pleasantly surprised to find all the pressure returned to the pump and it was working good as new.

 

[roubaixtuesday]

My Lezyne track pump was recently the same, it had been getting progressively worse and failing to gain pressure. A quick look at the Lezyne rebuild videos and alongside the replacement O-Rings they also talked about greasing the O ring lightly. So I decided to try it prior to buying or finding some suitable O-Rings and was pleasantly surprised to find all the pressure returned to the pump and it was working good as new.

So leave the o ring floating and add grease?

Worth a try!

 

[chriswoody]

So leave the o ring floating and add grease?

Worth a try!

Yep ,exactly that. My track pump has a floating O-Ring as well. Here's the youtube video I followed and you can clearly see the floating O-Ring.



If it doesn't work, you should be able to easily source a replacement O-Ring, but I'd give a splash of grease a try first, they do warn in the video not to add too much though because that can be detrimental.

 

[si_c]

Edit: Ignore me, that video is better.

I've got a similar pump though so I'll dissassemble tomorrow.

 

[roubaixtuesday]

Thanks all, much appreciated.

So, it turns out the main seal o ring is completely detached and stuck at the bottom of the barrel.

No idea how to get it out, a poke with a kitchen skewer won't shift it.

 

[wafter]

Thanks all, much appreciated.

So, it turns out the main seal o ring is completely detached and stuck at the bottom of the barrel.

No idea how to get it out, a poke with a kitchen skewer won't shift it.

Do I get a biscuit?

Sounds like you need a long hooked pick... could make one out of a bit of wire although you want to be careful not to scratch the bore of the barrel...

 

[mickle]

Dont use regular grease, use silicone lube from the plumbing department of B&Q. It comes in a tub (looks like vaseline) - or a aerosol spray.

 

[roubaixtuesday]

Dont use regular grease, use silicone lube from the plumbing department of B&Q. It comes in a tub (looks like vaseline) - or a aerosol spray.

Thanks, but just a tad too late. Managed to free the o ring, refitted, and smeared a little grease on it per the video posted above. All now working.

Thanks all for the advice!

It is, however, the third time a pump has failed on me since covid; previous to that they invariably lasted many years. But if a mystery.

 

[roubaixtuesday]

Well, thanks again all, definitely saved my bacon - punctured on the way in this morning! Pump worked perfectly.