A note on rebuilding a leaky Topeak Twinhead
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A note on rebuilding a leaky Topeak Twinhead
I recently rebuilt my Topeak Joe Blow Sport Twinhead pump head. It was leaking badly and needed new o-rings. The reason for this post is to document the exact o-rings used. I know you can buy a replacement head (for $30+), but what fun is that? I like to repair stuff, and it is very satisfying to have my Twinhead now working like it was brand new.
The important thing to note is that Topeak used not one or two sizes of o-rings in this head, they used THREE DIFFERENT sizes of o-ring. Clearly this is a case of engineering with no intent to repair. But luckily, o-rings come in standard sizes and with a little detective work, I was able to deduce the correct sizes.
To rebuild, one has to remove both nipple adapters with rubber inserts, unscrew a slotted nut on one side of the head, remove the (yellow) lever, and push out a sliding plunger which enables the head to do its thing. The nut, the lever and the slider all have different size o-rings, to wit (note that all the o-ring designations below are per AS568B, an SAE aerospace standard):
Reassembly is the reverse of disassembly, with lots of silicone grease and care reinserting the slider so that its o-rings are not pinched in the lever holes. If there is any interest in this, let me know below and I'll re-repair my Twinhead and take pictures. I simply wanted to document the o-ring sizes for the Greater Interweb.
Willie
The important thing to note is that Topeak used not one or two sizes of o-rings in this head, they used THREE DIFFERENT sizes of o-ring. Clearly this is a case of engineering with no intent to repair. But luckily, o-rings come in standard sizes and with a little detective work, I was able to deduce the correct sizes.
To rebuild, one has to remove both nipple adapters with rubber inserts, unscrew a slotted nut on one side of the head, remove the (yellow) lever, and push out a sliding plunger which enables the head to do its thing. The nut, the lever and the slider all have different size o-rings, to wit (note that all the o-ring designations below are per AS568B, an SAE aerospace standard):
- the nut uses a 011 o-ring (available from Danco as their #6 package, confusing, I know)
- the lever uses a 012 o-ring (Danco #7)
- the slider uses two 013 o-rings (Danco #41)
Reassembly is the reverse of disassembly, with lots of silicone grease and care reinserting the slider so that its o-rings are not pinched in the lever holes. If there is any interest in this, let me know below and I'll re-repair my Twinhead and take pictures. I simply wanted to document the o-ring sizes for the Greater Interweb.
Willie
Last edited by WillieA; 01-28-23 at 09:27 PM. Reason: Additional retailer information
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Thanks
Thank you for doing the research on that. I was able to rebuild my twinhead with some o-rings I keep in a plumbing spare parts box but I honestly don't know what sizes they are. I just eyeballed it. Put it all back together and no more leaks. So my trusty floor pump has a new lease on life. Good to know that if I ever have to do it again the correct parts are readily available. Keep the shiny side up and the rubber on the road. Thanks again!
I recently rebuilt my Topeak Joe Blow Sport Twinhead pump head. It was leaking badly and needed new o-rings. The reason for this post is to document the exact o-rings used. I know you can buy a replacement head (for $30+), but what fun is that? I like to repair stuff, and it is very satisfying to have my Twinhead now working like it was brand new.
The important thing to note is that Topeak used not one or two sizes of o-rings in this head, they used THREE DIFFERENT sizes of o-ring. Clearly this is a case of engineering with no intent to repair. But luckily, o-rings come in standard sizes and with a little detective work, I was able to deduce the correct sizes.
To rebuild, one has to remove both nipple adapters with rubber inserts, unscrew a slotted nut on one side of the head, remove the (yellow) lever, and push out a sliding plunger which enables the head to do its thing. The nut, the lever and the slider all have different size o-rings, to wit (note that all the o-ring designations below are per AS568B, an SAE aerospace standard):
Reassembly is the reverse of disassembly, with lots of silicone grease and care reinserting the slider so that its o-rings are not pinched in the lever holes. If there is any interest in this, let me know below and I'll re-repair my Twinhead and take pictures. I simply wanted to document the o-ring sizes for the Greater Interweb.
Willie
The important thing to note is that Topeak used not one or two sizes of o-rings in this head, they used THREE DIFFERENT sizes of o-ring. Clearly this is a case of engineering with no intent to repair. But luckily, o-rings come in standard sizes and with a little detective work, I was able to deduce the correct sizes.
To rebuild, one has to remove both nipple adapters with rubber inserts, unscrew a slotted nut on one side of the head, remove the (yellow) lever, and push out a sliding plunger which enables the head to do its thing. The nut, the lever and the slider all have different size o-rings, to wit (note that all the o-ring designations below are per AS568B, an SAE aerospace standard):
- the nut uses a 011 o-ring (available from Danco as their #6 package, confusing, I know)
- the lever uses a 012 o-ring (Danco #7)
- the slider uses two 013 o-rings (Danco #41)
Reassembly is the reverse of disassembly, with lots of silicone grease and care reinserting the slider so that its o-rings are not pinched in the lever holes. If there is any interest in this, let me know below and I'll re-repair my Twinhead and take pictures. I simply wanted to document the o-ring sizes for the Greater Interweb.
Willie
#3
Rhapsodic Laviathan
Joe Blows are garbage, take $20 and buy another, or simply a better pump.
#4
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Learned Friends:
I have a Joe Blow Sport and in an ill-advised move -- yeah, that's it! It wasn't stoopid, it was ill-advised... -- I opened the valve at the very bottom of the pump to let out some air after pumping up a new tire.
That's kosher in and of itself, but I was having trouble getting the air to come out, so I opened it too wide, then pumped a little more to maybe get the valve stem to move, and blew off the cap I had loosened. It appears that underneath that cap is a check valve, which went on an explosive journey and hasn't been seen since. At the time, of course, I didn't know a part had gone missing. It's apparently available as a part in the U.K. but not in the U.S., at least not from reputable sources.
I would consider it a favor if someone would undo the cap circled in the picture on their pump and look in there and tell me I'm not crazy. I'll bet you'll find the check valve shown in the inset.
Extra credit if someone knows where to get these.
Thanks in advance!
cheers -mathias
I have a Joe Blow Sport and in an ill-advised move -- yeah, that's it! It wasn't stoopid, it was ill-advised... -- I opened the valve at the very bottom of the pump to let out some air after pumping up a new tire.
That's kosher in and of itself, but I was having trouble getting the air to come out, so I opened it too wide, then pumped a little more to maybe get the valve stem to move, and blew off the cap I had loosened. It appears that underneath that cap is a check valve, which went on an explosive journey and hasn't been seen since. At the time, of course, I didn't know a part had gone missing. It's apparently available as a part in the U.K. but not in the U.S., at least not from reputable sources.
I would consider it a favor if someone would undo the cap circled in the picture on their pump and look in there and tell me I'm not crazy. I'll bet you'll find the check valve shown in the inset.
Extra credit if someone knows where to get these.
Thanks in advance!
cheers -mathias

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Clark W. Griswold
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Curious if you have actual thoughts and reasons why they are garbage? Also curious what pump you would actually suggest to replace the Joe Blow?
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It's a good pump.
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#7
Rhapsodic Laviathan
We have been using one in the shop for a while and had one at my old shop as well and have sold quite a few of them over the years and years and years and more years. Don't think I have had more than a couple problems in that decade of selling them and using them.
Curious if you have actual thoughts and reasons why they are garbage? Also curious what pump you would actually suggest to replace the Joe Blow?
Curious if you have actual thoughts and reasons why they are garbage? Also curious what pump you would actually suggest to replace the Joe Blow?
#8
Clark W. Griswold
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If you had bought it from a Topeak dealer they would have replaced it for you or at least taken a look at it and tried to fix it.
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Regarding the Topeak Joe Blow pump purchased at WM that was less than satisfactory, that is surprising that WM would carry that item. The pumps I've seen from WM are typically sold under the Bell brand. Regardless, if WM sells, or sold, a Topeak Joe Blow pump, it would be interesting to know if it's actually the same product that is sold at bike shops under the same brand and model.
#10
Rhapsodic Laviathan
https://www.walmart.com/ip/Topeak-Jo...9?from=/search
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it wase 2010-11 back when you had an instore choice of Topeak, Zefal, cheapo and Schwinn. I remember they were green and about $15/20. They still carry them.
https://www.walmart.com/ip/Topeak-Jo...9?from=/search
https://www.walmart.com/ip/Topeak-Jo...9?from=/search

Topeak, in my NSHO, has the pump thing down, both with their Morph-series portables, and the Joe Blow floor pump series.
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it wase 2010-11 back when you had an instore choice of Topeak, Zefal, cheapo and Schwinn. I remember they were green and about $15/20. They still carry them.
https://www.walmart.com/ip/Topeak-Jo...9?from=/search
https://www.walmart.com/ip/Topeak-Jo...9?from=/search
You could have gotten some bad stuff at wally-mart but that is wally-mart but at the shop it is unlikely you will come across a bad Topeak product that they wouldn't warranty if you got unlucky enough to get one. I am staring at my bikes right now and have 7 of their products visible and most of that stuff I have had for many years and use regularly.