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Pump Repair and Maintenance

PostPosted: Sat May 25, 2013 11:28 pm
by Salmonslayer
I had a few pumps to give away that were good enough for a spare because they would fill a kite with air. However, they were far from optimal. It seems as if most kite boarders just buy a new pump instead of repair their tired used pump. I wanted to figured out how to effectively repair a pump with reasonable efficiency.

In my experience, most pumps lose their effectiveness on the upstroke.There is an o-ring in the pump cap that keeps air from escaping on the upstroke. This o-ring takes a beating from sand and any other debris that sticks to the pump shaft. In order to replace the o-ring you need to remove the handle which is screwed and glued to the pump shaft. you can use a pipe wrench or an oil filter wrench. I used an oil filter wrench as you will see in the pics below. You can use a pipe wrench by grabbing the small collar that is on the "piston head" where it connects to the shaft.

You can see where the o-ring is placed in the cap in the picture below. it can easily be removed and replaced. Note the damage on the inside of the pump cap. It is no wonder why the o-ring is damaged and not performing well on the upstroke.
gasket in cap.jpg
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pulling gasket in cap out.jpg
pulling gasket in cap out.jpg (86.99 KiB) Viewed 12772 times



This is what you will need to fix your pump
New o-ring part # 727-2215 at Napa 80 cents each
White Lithium Grease $4.00
Oil filter wrench or pipe wrench
oil filter wrench.jpg
oil filter wrench.jpg (101.69 KiB) Viewed 12792 times

oil filter wrench 1.jpg
oil filter wrench 1.jpg (91.26 KiB) Viewed 12792 times


Look at how much sand I found in one of the pumps. Before reassembling the pump, clean it out and spray some white lithium grease in the pump casing and on the pump shaft. Even it your pump is working decently now, it is still important to open it up to clean and re-grease it so it will last longer.

Sand from pump.jpg
Sand from pump.jpg (136.56 KiB) Viewed 12792 times


I definitely felt improvement in the pump performance after I installed a new o-ring and reassembled the pump.

Good luck with your repairs.

Re: Pump Repair and Maintenance

PostPosted: Sun May 26, 2013 10:07 am
by C.J.
Great post! Finally someone did this!

Thanks for posting the o-ring part number too! Do u know whatbthe od and id of the ring is? Id like to order some through mcmaster

Re: Pump Repair and Maintenance

PostPosted: Sun May 26, 2013 10:16 am
by Salmonslayer
C.J. wrote: Do u know what the od and id of the ring is? Id like to order some through mcmaster


I dont remember the dimensions. You could call Napa and ask for the ID/OD using the part #

Re: Pump Repair and Maintenance

PostPosted: Sun May 26, 2013 11:57 am
by Chriswhitcomb
Great right up Paul! This will come in handy

Re: Pump Repair and Maintenance

PostPosted: Mon May 27, 2013 12:59 pm
by Loki
Woohoo! Thanks for figuring this out for us.

Re: Pump Repair and Maintenance

PostPosted: Sun Aug 18, 2013 2:45 pm
by CC_Kiter
Paul, thanks for the "how to". I just repaired three pumps, all just like new now. :-)

PS: I picked up the grease and o-rings at NAPA.

Re: Pump Repair and Maintenance

PostPosted: Mon Aug 19, 2013 8:42 am
by HotLaunch
Great write-up! Thank you.

Re: Pump Repair and Maintenance

PostPosted: Thu Sep 12, 2013 9:33 pm
by Salmonslayer
I found this interesting piece of info elsewhere.

========================

If your poor performing pump is one of the tall ones and you store it with the handle all the way down, then the seals on the piston are at their maximum compression from the pump cylinder. To injection mold the pump cyclinder there is about a 1-degree draft angle on the bore, making the diameter at the top bigger than at the bottom. Storing your pump with the handle all the way down compresses the seals on the pistons, so they barely seal at the top of the cylinder.

Store your pump with the handle fully out and the seals will come back, you'll get more air flow when the piston is at the top of the cylinder.


Re: Pump Repair and Maintenance

PostPosted: Fri Sep 13, 2013 8:22 am
by CC_Kiter
Thanks Paul, I had no idea the bore was different between the top and bottom, I always thought it was just straight plastic tube.

From now on I will store my new, old and repaired pumps with the handle up :-)

Re: Pump Repair and Maintenance

PostPosted: Fri Sep 20, 2013 9:26 am
by RebelRyder
Paul,
Thanks So Much for posting this topic...very instructional indeed.
I like to hear your viewpoints on the various threads posted on PSKite.
Also really like how you try to re-invent and re-purpose equipment and share your insight with us so that we can learn from your efforts.

WRT Pump Repair and Maintenance, I have had the large o-ring seals on the piston deform with us, and also get damaged from sand & grit in the cylinder.
==>> Would you know where to obtain new piston o-ring seals, or know where I could investigate further to dig out that information as well ??

Thanks, --Michael