Tricks for finding suction-side air leak?

lhfarm · Jan 12, 2016

I've been looking a method to test for an suction-side air leak. This is on one of my farm jeeps. I'm "foaming" the fluid. I've read about putting oil on the fitting and listening for a change in pump sound. The pump is driven off the crankshaft, so heard to hear the sound of the pump separately from the motor. Anyone have a trick/technique to identify leakings in this situation?

Thanks,

oldnslo · Jan 12, 2016

If you can get saran wrap to suck into a joint but there has to be enough of a leak to create the vacuum to make this visible.

Jnf · Jan 12, 2016

oldnslo said:
If you can get saran wrap to suck into a joint but there has to be enough of a leak to create the vacuum to make this visible.

We used shaving cream placed around fitting, it will pull it in where the leak is.

zzvyb6 · Jan 12, 2016

Smoke or steam or spray with WD40 and watch the hose dry. I would expect the leak to be there under pressure, too. Can you seal the pump cap and use a spare cap with a Shraeder valve in it to precharge the reservoir ?

J_J · Jan 13, 2016

Just use thick grease on all suction parts.

SPYDERLK · Jan 13, 2016

zzvyb6 said:
Smoke or steam or spray with WD40 and watch the hose dry. I would expect the leak to be there under pressure, too. Can you seal the pump cap and use a spare cap with a Shraeder valve in it to precharge the reservoir ?

This is a good one, BUT pressure must be limited to just a few psi in a foolproof fashion. Suction leaks can be very small - so small as to not be observed leaking outward at 0 pressure -- and slow to appear at low positive pressure.

wdchyd · Jan 13, 2016

J_J said:
Just use thick grease on all suction parts.

X2.....

Don't forget to pack grease around the pump shaft seal......an exposed failed pump shaft seal can
suck in air too making foamy oil

lhfarm · Jan 13, 2016

wdchyd said:
X2.....

Don't forget to pack grease around the pump shaft seal......an exposed failed pump shaft seal can
suck in air too making foamy oil

So is the grease a "fix" vs a means of founding the leak? That would be fine with me. I only have 3 fittings (pulse the shaft). My guess is the leak is at the manifold where I have an elbow. It has to be at the correct angle so I can attach the hose. I suspect that I don't have it screwed in tight enough. Perhaps I could find a swivel elbow?

Thanks

SPYDERLK · Jan 13, 2016

lhfarm said:
So is the grease a "fix" vs a means of founding the leak? That would be fine with me. I only have 3 fittings (pulse the shaft). My guess is the leak is at the manifold where I have an elbow. It has to be at the correct angle so I can attach the hose. I suspect that I don't have it screwed in tight enough. Perhaps I could find a swivel elbow?

Thanks

Then put a drop of loctite all the way around the fitting and then start up momentarily. It will suck into the leak path. Cut off and allow about a day to harden in the confined path.