I have purchased and used 4 or 5 of the famous red cast iron HF barrel pumps, like so:

http://www.harborfreightusa.co...me=&SubCategoryName=

I use them for pumping wvo out of my storage barrels, and for pumping methanol out of my 55 gallon barrels.

After 2-3 years of use, two of them started to leak. So far as I know, you can't buy replacement seals, and I looked pretty hard at various vendors. If I'm wrong, let me know.

So, hating to throw out a pump and buy a new one, I found a work-around.

The pump is a short cylinder, with two end plates. Both end plates have lousy inaccurate paper gaskets to form the seal to the main pump body. One of the plates has a hole for the drive shaft that connects to the handle. There is a shaft seal of mystery polymer. So, here's the fix:

1. Make new paper gaskets that actually fit. I used plain old 20# bond, the stuff you run through photocopiers and printers. If you don't know how to make an accurate gasket, ask, it's easy. When I did final assembly, I used a very thin coating/film of wheel bearing grease on both sides of the paper.

2. The shaft seal itself was not damaged in the sense that, it had no chewed up edges where the shaft goes through. It did look like it had shrunk a little, maybe because of its exposure to methanol, maybe because it's made of mystery polymer. The seal fits in a snug pocket on the end plate. The problem is, since it had shrunk, it was now a loose fit. So, I wrapped it on the outside of the rubber seal with 5-6 wraps of the thick (yellow) teflon tape, the kind that is rated for natural gas. This made it a nice snug fit in the cast iron side plate.

3. Once you have your (2) new paper gaskets made, the rubber shaft seal wrapped with teflon and stuffed back into the side plate, everything greased up and ready to assemble, I wrapped the drive shaft with 5-6 wraps of the same teflon tape. NOTE: You must wrap the tefon tape in the correct direction, so that turning the pump handle will tend to keep the tape wrapped tight. If you wrap it the other direction, cranking the pump handle with unwind the tape and you end up with a balled up shredded mess of teflon. That also means, you can only turn the pump handle the normal clockwise direction. If you turn it backwards, you'll mess up your tape on the shaft.

4. I removed the suction pipe from the pump body, and the discharge pipe, and put new deluxe teflon on there as well.

Conclusion. All leaks in both pumps are gone. I didn't need special replacement parts imported from china, just paper and grease and teflon tape. Of course, if your rubber shaft seal is torn up, this won't work for you. The original paper gaskets for the side plates were crap. I made the first replacement gaskets by copying the original paper gaskets. They fit like crap, the holes didn't line up, etc. I should have known to just make it to fit the actual pump in the first place.

I noticed that the pump primes almost instantly now, whereas before, I often had to crank and crank and crank to get it to prime. Cost to rebuild each pump was about 0.25 worth of teflon tape. I was somewhat surprised to see that the vanes were in excellent shape, suggesting that the polymer may be robust enough to withstand long term exposure to methanol.


Finest regards,

troy

quote:

I noticed that the pump primes almost instantly now, whereas before, I often had to crank and crank and crank to get it to prime

The nicer pump (not a HF item: I think I bought it at Utah Biodiesel Supply) that I have in my methanol barrel is at that pump & pump & pump & pump to prime stage: maybe it time for me to look it over for some new seals. The handle shaft seal weeps as it is now.

quote:

Originally posted by Ryan P.:

quote:

I noticed that the pump primes almost instantly now, whereas before, I often had to crank and crank and crank to get it to prime

The nicer pump (not a HF item: I think I bought it at Utah Biodiesel Supply) that I have in my methanol barrel is at that pump & pump & pump & pump to prime stage: maybe it time for me to look it over for some new seals. The handle shaft seal weeps as it is now.

Same thing here with the leaking shaft seal on the same item

On the red Harbor Freight barrel pumps...
I bought some out of China once that had Viton seals specially made for them & that's what these photos are. The construction is almost identical to the Harbor Freight ones though.
I tore one completely apart once to see what they looked like.
Basically big massive steel components. Cheap paper seal and a shaft seal.
Here's a link to the pictures I took. Hope it can help some of you as you tear into them.
http://www.utahbiodieselsupply...leries/barrelpumpred


On the poly viton sealed hand crank pumps...
They do sell a seal kit for the nicer pumps (the Black ones I carry). I've torn them apart before and for the life of me I still am baffled as to why they lose the prime the way they do. The only think I can make heads or tales of is that the teflon vanes either wear out or the tubes that stick down in the methanol barrels develop an air leak.

Here's a tip that a Biodieseler passed on to me though.
Take your pump out of your methanol barrel and store it upside down.
This keeps the seals in the pump saturated with methanol and the next time you go to use it, it'll prime much faster and you won't get as much weeping at the shaft.

I was told once by a pump rep that Teflon is somewhat porous and that it has to saturate the methanol somewhat before it seals properly. I don't know if that's true or not, but do know that if you keep the seals wet with methanol (ie. upside down pump) the pumps do much better.

Hope that helps.
-Graydon

For those that have pumps that don't leak, but are difficult to prime, here's an easy fix.

Get a pump/squirt oil can. Fill it with used motor oil (which, in trivial amounts, won't hurt a thing if it ends up in your processor.) When you need to pump your methanol, shove the spout of the oil can up the discharge pipe of the barrel pump. Squirt 6-8 shots of used motor oil in there. Now, pump away, it will prime in just a couple turns of the handle because the motor oil seals all the little imperfections and allows it to develop good vacuum.

HTH,

troy

Troy,
This is a great post! Loved it! Nicely done!
-Graydon