Joe Blow Track Pump inflation problem

ded

OK, so I've had the pump a year, always worked fine. The other day, however, it decides to throw a wobbly. Basically it seems to push the air out into the tyre properly, but then it "self inflates" i.e. the air seems to come back out of the tyre into the pump, pushing the pump handle upwards. I'm presuming some washer/seal has broken/come loose and I had a quick look but didn't see anything obvious. Anyone else had/solved this issue and got any tips before I harass the bike shop and/or manufacturer????

Scrumple

I have a sport one, and the push to deflate button lets air out... but the gauge goes to zero!
Hardly a way to accurately get to the exact pressure, Sorry to hijack, but it is another fault to consider....
Should I return?

To the OP - I'd return or ring/email Topeak.

ColinJ

Something is catching on the end of the valve and pressing the little knurled bit in and letting the air back out. I kept doing that with my Blackburn Airstik when I was tired and it did my head in!

oldwelshman

Nothing to do with the valves Colin, I have the same issue with mine and it is the same on several wheels I use it on, just have to get the air in, watch the gauge before it drops to zero, stop the handle going up and release the valve!!
I have checked everything on the pump, tightened screws on the base, lead etc, even tried a new head.
It only went like this after some one borrowed it at a track meeting

ded

Oldwelshman - I'll try your method tonight - you're right, mine isn't the valves either because it happens on any bike and using both the presta and schraeder sides of the head. It went wobbly when I was using the schraeder side, but the misbehaviour is now on both

Bit disappointed tho' - it's not the most expensive pump out there but it's not the cheapest either and 1 year's worth of use isn't much. Even if I get a workaround I might moan at the manufacturer.... :x

Captain Fagor

My Joe Blow also sometimes takes a bit of persuading to prevent the tyre pressure from pushing up the handle.

My guess is that the non-return valve at the bottom of the smaller of the two tubes has life expired. The ball floats in mid-air as you plunge the handle, as the pressure in the bottom of the main cylinder exceeds the pressure in the tyre & small cylinder & flexible tube + adapter valve. When you lift the handle, the pressure in the main cylinder drops and the ball should then fall into its housing, creating a seal. This seal should prevent the tyre pressure pushing the handle upwards.

I've never tried to take one apart, but if it is a serviceable unit and spares are available, then it should be an easy fix. I wouldn't be surprised if it's a sealed (i.e. disposable) unit though.

ketsbaia

I've an issue with mine too on both schraeder and presta sides. Essentially, it appears to lock and not allow me to pump any air in at all. I have to physically jump on it before the handle will go down and it doesn't appear to be putting any air into the chamber at all. It either carries on like that until I get frustrated and give up or suddenly starts working. Oddly enough, it only seems to do it on certain tubes as I can often move to pumping up the other on the bike and it works fine. A real head-scratcher.

torrens

I have the Joe Blow turbo. Really pleased with it for ages until about a year ago when it, most disconcertingly, started to attack me in the manner descibed by others above- the handle would propel itself violently upwards towards me at the end of a pump stroke!

So.... stripped it all down - yuk- loads of brown sludge at bottom of barrel (this is normal I suppose after years of use - condensate always present when you're pumping non dry air).

I cleaned everything up and found that the spring which holds the black rubber non return valve in place at the base of the barrel had snapped in two due to being heavily rusted. So I then spent about half an hour trying to find a replacement by turning my garage up side down. When that failed I took a length of (approx. from memory) 22swg piano wire and wound a new spring around a suitable mandrel (a piece of dowel).

Put it all back together and it's been working fine ever since. Hope this helps

oldwelshman

Aha, mine is now working again
I thought I would check the spring as suggested above.
Took the plastic cap off, spring was ok, removed non return valve, looked ok, put back together inserted o ring, it now works !!
Guess something was stuck.

starboard135

Thanks for this. At the base there is a little plastic screw cap covering a non return valve and spring. I just pushed the valve with a small screwdriver and flexed the spring a few times and it works as before once more. Just got stuck I guess - hence the design to give access to it.

Mike67

ketsbaia wrote:

I've an issue with mine too on both schraeder and presta sides. Essentially, it appears to lock and not allow me to pump any air in at all. I have to physically jump on it before the handle will go down and it doesn't appear to be putting any air into the chamber at all. It either carries on like that until I get frustrated and give up or suddenly starts working. Oddly enough, it only seems to do it on certain tubes as I can often move to pumping up the other on the bike and it works fine. A real head-scratcher.

Which model do you have.?
I have the Joe Blow Sport and as far as I can tell it's designed to work like that.
You need to get more pressure in the pump than is already in the tyre to overcome the tyre valve and let air in.
So for example a tyre that only has 40psi in it will let air in quite easily, whereas a tyre with 120psi in needs a good bit of pressure on the pump before any air will pass into it.

paulwillis

I had exactly the same problem as described above with my Joe Blow Sport. It worked one minute on one tyre and then suddenly the handle wouldn't push down. It was as if the tyre valve was locked.

Following the tips given here I unscrewed the valve cap on the front just above the footrest and removed the spring and little black point bit on the inside end of the spring.

I stretched the spring bit, blew into the hole, wiped clean the area and the bits and screwed everything back and the pump now works again. Brilliant. Thanks to all.

Bar Shaker

paulwillis wrote:

I had exactly the same problem as described above with my Joe Blow Sport. It worked one minute on one tyre and then suddenly the handle wouldn't push down. It was as if the tyre valve was locked.

Every time I have had this it has been the pump nozzle catching the inner tube valve. Remove from the valve and re-fit... all perfect.

eastendoflondon

Thanks for above information about the spring issue on this track pump. I've been scratching my head about this until I found this thread. I would attach it to the presta valve only to find the pump would completely deflate the air in the tube. Such a simple fix! Nice one.