Tricks for finding suction-side air leak?

/ Tricks for finding suction-side air leak? #1  

lhfarm

Veteran Member
Joined
May 17, 2002
Messages
1,370
Location
Central Indiana
Tractor
NH TC40DA
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,
 
/ Tricks for finding suction-side air leak? #2  
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.
 
/ Tricks for finding suction-side air leak? #3  
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.
 
/ Tricks for finding suction-side air leak? #4  
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 ?
 
/ Tricks for finding suction-side air leak? #5  
Just use thick grease on all suction parts.
 
/ Tricks for finding suction-side air leak? #6  
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.
 
/ Tricks for finding suction-side air leak? #7  
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
 
/ Tricks for finding suction-side air leak?
  • Thread Starter
#8  
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
 
/ Tricks for finding suction-side air leak? #9  
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.
 
/ Tricks for finding suction-side air leak? #10  
Not a fix, only a path to finding the culprit.......then a direction to the fix
 
/ Tricks for finding suction-side air leak?
  • Thread Starter
#11  
I finally got around to working on the pump. I purchased some LockTite hydraulic thread lock and that seems to have solved the leak. Thanks for all the help.
 

Marketplace Items

Towable Generator (A60352)
Towable Generator...
2023 New Holland CR10.90 Combine - 332 Engine Hours - 244 Separator Hours (A63118)
2023 New Holland...
2011 Freightliner B2 School Bus (A61568)
2011 Freightliner...
iDrive TDS-2010H ProJack M2 Electric Trailer Dolly (A59228)
iDrive TDS-2010H...
SET OF UNVERFERTH LIFT ASSIST WHEELS & REACH ARMS (A63291)
SET OF UNVERFERTH...
2019 CHEVROLET EXPRESS 3500 PASSENGER VAN (A59912)
2019 CHEVROLET...
 
Top