Testing for leaks

I think my pump may be leaking, is there any way to check this?

I have to keep re-pumping to keep the same vacuum level, it is the same with all my cylinders. I am well trimmed and use plenty of lube.
This has only just started happening.

I use a mityvac metal pump.

Pump and hop in a bathtub full of water?

gprent knows about this, I think - either using a bathtub full of water or not. TPS, you are always thinking. :)

Surely it is not a good idea to get the metal pump wet, or is it?

He was kidding, bluenun.

Somewhere here in the Pumper’s Forum is a thread that talks about detecting pump leaks. One involved water, but not up through the tubing and into the gauge and brass pump. The gauge especially is susceptible to moisture damage.

Just hang on. Somebody who has this in his head will respond.

I’m no expert, but you might try making up a soap and water solution and squirting it on connections as you pump up. If there is a leak, the soapy water will bubble at the leak. Use a little dish washing liquid and water.

If you have a threaded female connector in the top of your vacuum cylinder, you may want to try wrapping the threads of this connector with plumbers Teflon tape and then screwing it in, in addition to the O-ring seal.

This is what you do, take the pump apart. There is a rubber valve in the cylinder. If this valve gets wet it wont seal. Take it out dry it off, and try to keep the pump from getting in the water. You will have to do this because the thing will never dry on it’s own. I think it will rot away before it dried.

As with any issue, first thing I’d do is to isolate the problem. Bend the tubing over right out of the pump and give it a squeeze. If it holds pressure, the problem is cylinder side, probably a fitting. If it bleeds down, it’s pump side. Start narrowing down which fitting might be leaking on the pump. The eaiest might be the bleed valve. You should be able to build up pressure (bend over tubing and squeeze handle) and press the bleed valve in quickly and seal the exit with your finger. You will lose some pressure but once your finger has made the seal against the pump body, it should hold steady. From here on out you’ll have to be mechanical. Remove the fitting that comes out of the pump into the tubing. Hold your finger over the end up the pump and squeeze. If it still loses pressure, you’re down to the guage or pump seals. Put the fitting you just removed back in (preferrably with new teflon tape or whatever the manufacturer used to seal the threads) and remove the guage. You can put your finger over that hole and try pumping the pressure up again. If it still leaks, its the seals inside the pump. Some pumps can be pulled apart and cleaned, rebuilt, etc etc. Of course its extremely important you always make a perfect seal with your finger. Good luck. :)

I think the soapy water idea would work since the tube is clear.

By the way, I had a NASA “engineer” tell me to look for VERY TINY vacuum leaks by watching for the soapy water “disappear” into the leak! He also told me “vacuum pumps aren’t designed to pump air only vacuum”. So much for “rocket scientists”. Real rocket scientists excepted.

He asked about his pump leaking. He knows thats where the leak is because it happens with all his cylinders. Why you guys keep giving advice about finding the leak in the tube is beyond me.

You’re pump screws apart in the middle. (or at least mine does) Look for a rubber seal, it’s likely a wet one that needs to be dried. Good luck and hopefully your pump comes apart as easy as mine.

When you pump with water in the cylinder. If any gets up into the pump itself, it will get to that seal. And once it does it leaks. After you dry that thing, it’s like a brand new pump.

If you’re not shaved, then it takes more lube.

Even if the tube had a leak, it would be negligible compared to lost suction

on the pubic pad.

Thanks to all that took the time to answer.

After taking off the trigger I undid a screw and removed a washer, spring and plunger. Although it looked perfectly dry in there I cleaned all the parts and re-fitted.
Problem solved, thanks deadeye3200.

You’re welcome