Tokheim Transfer Pump

Tim in Montana · Jan 4, 2010

I have a Tokheim Model 702 transfer pump on a transfer tank in the bed of my pickup. It has always pumped good until about a month ago. I tried to use it, and it sounded differnet and would not pump. To make a long stoy short I wound up swapping the gears around in the pump and lubed them up with petrolem jelly, turned it on and it pumped like it always had before.
Now I go to use it today and it did like it done before, sounds different and will not pump. Any ideas what is wrong?
Thanks,
Tim in Montana

Anonymous-0 · Jan 4, 2010

Still might have ice in it. Just a little ice will mess it up.

Jon Hagen · Jan 4, 2010

I believe those pumps have a check valve in the base of the pump that will allow the pump to lose prime if the valve is defective or has a bit of crud holding it open.
Also the pump dip pipe will lose the pump prime if there is an air leak where it threads into the pump base.

It is not unknown for sloshing and vibration in a mobil tank, causing the dip tube to crack in the threads just below the pump and leak air.

ArleninOr · Jan 4, 2010

Tim, make sure your connections are right. Mine did the same thing and when I looked I had hooked it up wrong. CRS I guess

Tim in Montana · Jan 4, 2010

The pump motor runs when I tuen on the switch, so that rules out a bad connection. The truck is parked inside my garage, which is at 61 degree, so that rules out ice. The dip pipe threads don't appear to be a problem and I see no check valve in the pipe.
Could the gears be worn out?

Tim in Montana

Jon Hagen · Jan 4, 2010

The check valve, if it has one, will be in the base of the pump, not the pipe.

Any chance you swapped the feed wires to that pump ? Most have a permenant magnet field motor on them, which will run backwards and not pump if the polarity is reversed.

A couple years ago during crop spraying season, I came home with the sprayer to find my totally frustrated brother in the final stages if disassembling the 12V herbicide pump.
I asked what the problem was ? He said, the durn thing runs good, but will not pump a drop of liquid. I helped him finish disassembling the last of the pump and found nothing wrong.
About then, the little light bulb went on in my head. I asked, did you watch the battery polarity when you hooked the pump clips on ? His only reply was a deer in the headlights look. I looked at the battery, and sure enough, red clip on neg and black on pos.
We reassembled the pump, correctly connected the battery and the pump worked great ;-)

Tim in Montana · Jan 4, 2010

I pulled the motor off and put some more petrolem jelly on the gears and it started pumping. My guess is the gears are worn out.

Tim in Montana

Jon Hagen · Jan 4, 2010

Might be worn out gears as you suspect.
When you pull the cover off the pump, is the housing full of fuel ?
The pump check valve should keep fuel in the pump housing to 'prime" it for the next use.

If the pump has no check valve , and worn gears refuse to prime, you may be able to fix it by installing a brass well "foot valve" on the bottom of the stand pipe to prevent loss of prime.

Tokheim Transfer Pump

Tim in Montana

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Anonymous-0

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Jon Hagen

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ArleninOr

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Tim in Montana

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Jon Hagen

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Tim in Montana

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Jon Hagen

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