Repairing a pump seal

[Hugh2]

My Naish pump started sticking. This is the modern kind that is a little taller than the original size, but not the monster kind. I like it a lot as it has a gauge built into the handle, and is the right height for me, plus the handles are more comfortable. Anyway, the seal in the twist off/on cap around the shaft failed and started sticking. This pump design is used by many companies today, so this failure is surely nothing unusual. Local Naish shop said a pump is a "consumable", just buy a new one. No way to replace the seal even if you could buy one, which has a complicated shape, anyway, as the handle and the main seal unit at the other end are glued on tight. But fortunately the seal is held in place by a white plastic ring held down with two small Phillips screws. So, I removed the seal and replaced with two O-rings, cut once each and with the cuts on opposite sides from each other, kind of how rings on pistons work. Now the pump works well on the downstroke, and about half well on the upstroke, but at least it works.

[unclebill]

Great job. Like you I hate this idea of scrapping something that is still 99% good just because one small cheap part is worn out and broken. And you have got me thinking to look inside my pumps with the idea of maybe modding them to pump on the down strokes only. I find the push down is very little effort compared to the up pull and would be happy to have them or maybe one work that way.

[cglazier]

You can extend the life of any pump greatly by occasionally lubricating the shaft. Avoid petroleum based lubricants like oil because they may react with the O ring. You can buy silicon spray lubricant at automotive or hardware stores.

CG

[BillyGoatGruff]

give all pumps an occasional clean and relube with silicone grease, it does not react with rubber and will make the pump last much longer. My latest blade pump has sponge in the inlet valve to stop sand getting in the shaft, which is a good design.

[dylan*]

but for real you can get those pumps for $7 on amazon right now

[unclebill]

but for real you can get those pumps for $7 on amazon right now

Got a link to those? I searched amazon but could only find regular prices

[WMFG]

My Naish pump started sticking. This is the modern kind that is a little taller than the original size, but not the monster kind. I like it a lot as it has a gauge built into the handle, and is the right height for me, plus the handles are more comfortable. Anyway, the seal in the twist off/on cap around the shaft failed and started sticking. This pump design is used by many companies today, so this failure is surely nothing unusual. Local Naish shop said a pump is a "consumable", just buy a new one. No way to replace the seal even if you could buy one, which has a complicated shape, anyway, as the handle and the main seal unit at the other end are glued on tight. But fortunately the seal is held in place by a white plastic ring held down with two small Phillips screws. So, I removed the seal and replaced with two O-rings, cut once each and with the cuts on opposite sides from each other, kind of how rings on pistons work. Now the pump works well on the downstroke, and about half well on the upstroke, but at least it works.

I have the part in stock in USA.

email info@wmfg.co

[Hugh2]

Thanks WMFG! But how does one replace it without slicing that seal. Does the handle or the main pump seal at the other end come off the shaft somehow?

[WMFG]

Thanks WMFG! But how does one replace it without slicing that seal. Does the handle or the main pump seal at the other end come off the shaft somehow?

Remove the lid of the pump and pull the plunger out. Unscrew the handle and you'll have access to the top seal.

You need to be a bit careful not to damage the main seal on the plunger (inside the pump canister). If you're taking the pump apart and it's apparently a well used pump you can clean and re-lubricate the pump. Lithium grease is the lubricant used by the manufacturer.

[Hugh2]

Thanks again, if I had known the handle unscrewed I would not have had to slice my O-rings. They were cheap anyway.