What to do with this air pump?
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What to do with this air pump?
So I have Serfas tcpg tire pump which I very much like. The head works on both Presta and Schrader stems without having to change anything.
The other week, I was helping my neighbor's Girl Scout troop get ready for a group ride. After inflating a couple of really low tires, the resistance in the handle was increasing and each down stroke was making a squeaking / squealing noise. It's as the cylinder heated up that it got harder and harder to use. It got to the point where I gave up on it and starting using a Ryobi battery-powered pump.
Simple tool, right? What can go wrong? Before I start taking it a part, I was wondering if anyone had any suggestions on a fix? Does it need oil or lubricant on the end of the piston? THe thing is making me feel stupid.
Altair 4
The other week, I was helping my neighbor's Girl Scout troop get ready for a group ride. After inflating a couple of really low tires, the resistance in the handle was increasing and each down stroke was making a squeaking / squealing noise. It's as the cylinder heated up that it got harder and harder to use. It got to the point where I gave up on it and starting using a Ryobi battery-powered pump.
Simple tool, right? What can go wrong? Before I start taking it a part, I was wondering if anyone had any suggestions on a fix? Does it need oil or lubricant on the end of the piston? THe thing is making me feel stupid.
Altair 4
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Is it working now, that it has cooled off?
Boyles law specifies that compressing a gas will cause it to heat up. It could be that you did this so many times you just exceeded the design limits of that little pump at the time.
Boyles law specifies that compressing a gas will cause it to heat up. It could be that you did this so many times you just exceeded the design limits of that little pump at the time.
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Yes, it works okay after it cools down - but it starts the noise and resistance after, say, bringing two 700 x 35's up by 20 PSI. This wasn't an issue when the pump was new - you could pump up tires from zero PSI without this happening. I sorta thinking about opening it up and see what's what inside.
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There may be a replaceable piston head or ring. At the very least, try a little grease on it.
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Yes, it works okay after it cools down - but it starts the noise and resistance after, say, bringing two 700 x 35's up by 20 PSI. This wasn't an issue when the pump was new - you could pump up tires from zero PSI without this happening. I sorta thinking about opening it up and see what's what inside.
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I've taken pumps apart before to grease the little flap that seals around the piston. You could give it a try if its not too difficult to take apart.
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I've used silcone lube on mine before I got the Ryobi pump.
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Last time I took apart my 1970s frame pump to fix it I found it used leather for the piston seal. To my surprise leather is still used today and I was able to get a replacement.
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if it's unreliable compared to when it used to be, I'd chuck it.
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This marketing bit explains why leather: https://blog.silca.cc/uniquely-silca-the-leather-washer
It may give insight into why Altair's pump is heating and binding - some lube should help no matter what the washer material. Alternately you could build a water cooling system for it.
Hmmm, so there are such a thing as vegan floor pumps...
It may give insight into why Altair's pump is heating and binding - some lube should help no matter what the washer material. Alternately you could build a water cooling system for it.
Hmmm, so there are such a thing as vegan floor pumps...
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So I have Serfas tcpg tire pump which I very much like. The head works on both Presta and Schrader stems without having to change anything.
The other week, I was helping my neighbor's Girl Scout troop get ready for a group ride. After inflating a couple of really low tires, the resistance in the handle was increasing and each down stroke was making a squeaking / squealing noise. It's as the cylinder heated up that it got harder and harder to use. It got to the point where I gave up on it and starting using a Ryobi battery-powered pump.
Simple tool, right? What can go wrong? Before I start taking it a part, I was wondering if anyone had any suggestions on a fix? Does it need oil or lubricant on the end of the piston? THe thing is making me feel stupid.
Altair 4
The other week, I was helping my neighbor's Girl Scout troop get ready for a group ride. After inflating a couple of really low tires, the resistance in the handle was increasing and each down stroke was making a squeaking / squealing noise. It's as the cylinder heated up that it got harder and harder to use. It got to the point where I gave up on it and starting using a Ryobi battery-powered pump.
Simple tool, right? What can go wrong? Before I start taking it a part, I was wondering if anyone had any suggestions on a fix? Does it need oil or lubricant on the end of the piston? THe thing is making me feel stupid.
Altair 4
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My $8 Harbor Freight floor pump did that after six years. Rubber seal. I put some silicone spray in there. If it eats the rubber, I get a new pump,
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Air has particles in it that accumulate. I have taken apart pumps and cleaned them. I have also replaced a rubber o-ring in a frame-type pump with a stock part from the hardware store.
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A seal fail on the plunger also wouldn’t result in the problem Altair 4* describes. Plunger seal failures would result in no resistance at the handle during pumping because the air column being compressed would leak past the seal. The squeal he describes is probably air being forced past the seal as the pressure increases in the tube due to the failed (or failing) check valve but the seal isn’t the problem.
*Now I get it. Do you want to be Captain Adams, Morbius, or Robby?
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Oh, it works on more levels than that. Star Trek, Stephen King's "The Tommyknockers," and others. Actually, I'm into backyard astronomy, so it covers all my bases.
If I get a few minutes over the weekend, I'm going to try and take the pump apart and see what's going on in there.
If I get a few minutes over the weekend, I'm going to try and take the pump apart and see what's going on in there.
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If a couple drops of oil down into the cylinder doesn't fix things, replace the pump.
Note: wax is not recommended for this application.
Note: wax is not recommended for this application.
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all else fails & you're determined to keep trying to save the pump, pour in some tubeless tire sealant above the plunger area if you have it around. It may or may not be effective & could cause some snot at the feeding valve. I've used Slime* in a cheap 12v car pump by backfilling it & it worked. Sold the vehicle with it in stored in the trunk.
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Oh, it works on more levels than that. Star Trek, Stephen King's "The Tommyknockers," and others. Actually, I'm into backyard astronomy, so it covers all my bases.
If I get a few minutes over the weekend, I'm going to try and take the pump apart and see what's going on in there.
If I get a few minutes over the weekend, I'm going to try and take the pump apart and see what's going on in there.
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Pokin' around the Poconos A cold ride around Lake Erie
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A seal fail on the plunger also wouldn’t result in the problem Altair 4* describes. Plunger seal failures would result in no resistance at the handle during pumping because the air column being compressed would leak past the seal. The squeal he describes is probably air being forced past the seal as the pressure increases in the tube due to the failed (or failing) check valve but the seal isn’t the problem.
The increasng pressure/resistance at the pump handle is a sign of 'air with nowhere to go' - so check valve or a problem at the head at the end of the hose, or a Presta valve not loosened, or ???
If it's a simple thing to do, removing the head at the end of the hose, or removing the hose from the pump will help to localize the problem.
Squeaking during pumping by itself and/or decreasing resistance at the pump handle would be (IMO) signs that lubrication of the piston seal was required.
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The Serfas TCPG is a pretty cheap pump, so I expect the components are of mediocre quality. I just checked the Serfas replacement parts page, and they don't offer a check valve.
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It may have been cheap, but I got 10 years out of it. I really can't complain. Not being one to simply replace something, I thought I'd give it a try to fix. No complaints if it's dead - I got my money's worth out of it.
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Potential conflicting evidence to that model:
Of course it is possible check valve fails as it warms.
Or the seal increases resistance as it warms due to lack of lube.
Or the seal increases resistance as it warms due to lack of lube.
Last edited by noisebeam; 06-24-21 at 06:08 PM.
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Seals wouldn’t really cause an increase in resistance. Worn seals just let air blow by when pressure is applied…think old leather pumps
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Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
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Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!