Joe Blow Max HP failure.

Pat "5mph"

A kilogrammicaly challenged woman
Moderator
Location
Glasgow
Hi all!
My Joe Blow Max HP is broken: it might have been my fault because I didn't open a Presta valve properly, the pump is now deflating instead of inflating.
Don't know if this is relevant, but it does the same on the Schrader side of the head too.
Thinking it might have been the rubber seals, I purchased a rebuilt kit.
After changing the rubber seal, that looked worn, matters stayed the same.
So I did a search, found a You Tube video that suggests the check valve is defective.
I removed it, there seems to be nothing wrong with it, although now I can't seem to manage to tighten it properly again :rolleyes:
Anyhow, questions:
can someone tell me what the largest o ring in the rebuilt kit is for?
If I manage to purchase that check valve (seems to be out of stock in most outlets) would that solve the issue, or could it be something else?
It would be a shame to have to bin the pump, it is only 2 years old, used about twice a week: is this an acceptable lifespan for a middle of the range pump?
Thanks very much for your help!
Pat.
 

I like Skol

Hold my beer and watch this....
Not acceptable IMO. My joe blow sport has been going strong for approx 7 yrs with regular use looking after around 6-10 bikes. Is the check valve goosed or could a clean and reassemble be the answer? It must be one of those things that has a knack to it. Persevere and it should go back together.
 
OP
Pat "5mph"

Pat "5mph"

A kilogrammicaly challenged woman
Moderator
Location
Glasgow
Thank you @I like Skol, the check valve seems fine to me: I will try reassembly again tomorrow.
Do you know what the big seal in the first link is for?
Maybe that's the one I need to change.
 
OP
Pat "5mph"

Pat "5mph"

A kilogrammicaly challenged woman
Moderator
Location
Glasgow
OP
Pat "5mph"

Pat "5mph"

A kilogrammicaly challenged woman
Moderator
Location
Glasgow
Stupid point.. You have screwed the hose back on the correct side near the gauge haven’t you? Mine can be connected on the left or the right.
Uhmm, not sure, I will check.
Anyhow, if I put it back together like before, it still will be broken, as a new seal in the Presta head (before dismantling the check valve) did not make a difference.
I'll chance the Schrader seal too, just in case.
 

Yellow Saddle

Veteran
Location
Loch side.
Pat, the large O-ring is probably for the pump plunger/piston.

You should be able to see if the check valve works by blowing into it. In one direction the air will go through, the other direction it will not. It is a one-way valve. If you can visualise which way you want the air to flow (i.e. from the pump barrel into the tyre) and which way not (i.e. from the tyre into the pump barrel), then you will be able to install it correct way round.

It is almost certainly not the head.
 
OP
Pat "5mph"

Pat "5mph"

A kilogrammicaly challenged woman
Moderator
Location
Glasgow
Update!
I have done the test on the valve like suggested by @Yellow Saddle: all good, air going in in only one direction, the right one.
Then I have changed both the seals on the pump head.
Finally, I have tries to pump up several different tubes (to exclude valve defect) in their tyres+wheels, both Presta and Schrader.
Am I not a lucky woman in having several bikes with several inners in my bike room? :wacko: :laugh:
Results: across all tubes, the pump will inflate but will immediately loose air from the pressure gauge, deflating the tyre as fast as it is inflating it.
In the interest of, ... erm ... science, I have also inflated a tube without the tyre, as much as I dared: in this case, the tube held the air, without deflating again.
This makes me think it's something to do with the check valve, it looks ok, but maybe the wee ball inside is somehow damaged?
What next? :smile:

I think also there is an air release valve near the base-is that fully closed?
Hope this helps.
Can't find that valve, but there's no air coming out from the base or the hose.

Pat, the large O-ring is probably for the pump plunger/piston.
How do you dismantle the plunger piston to renew the O-ring?
I think by screwing the two bits apart? Don't want to cause more damage.
 
OP
Pat "5mph"

Pat "5mph"

A kilogrammicaly challenged woman
Moderator
Location
Glasgow
@numbnuts I did see that video a few days ago, but he problem the guy in the video had with his pump is not the same as mine.
Will try it anyway, as a last resort, cheers for that.
 

Yellow Saddle

Veteran
Location
Loch side.
Pat, if you can, remove the check valve and attach the pump head to the wrong end and pump to see if it resists at high pressure. They are simple devices so if it is clean in there and the little ball is smooth, it MUST work. But check.

Many pumps don't have check valves and we rely only in the tube valve to do it's job, but then the pump head must not keep it open, it must only attach around it and let the pump's air open it.
 
Top Bottom