Thomas 243 HDS Auxiliary pump oring leak

[jim743]

I have replaced the O-rings on the Auxiliary and charge pump due to an oil leak at the rear of the Aux pump where aluminum center meets cast iron housing. 1st replaced with std oring, but leaked as it pinched, as was .010" too big. Polished all mounting surfaces and installed metric O-rings. Dripping from rear after filling, not run. Disassembled, inspected, and reassembled with Loctite 518 as advised by HD mechanic. Good until machine was run, now dripping while sitting. What could I be missing? Cannot see any cracks or pitting, casting flaws.

 

[Tazza]

You have done everything i'd do... Still sounds like a crack to me. Orings should be pretty good at sealing.

 

[jim743]

You have done everything i'd do... Still sounds like a crack to me. Orings should be pretty good at sealing.

It's driving me nuts. I was hoping that someone else out there had run across the same problem. Are these pumps prone to cracking? Might have to get it magnafluxed.

 

[Tazza]

It's driving me nuts. I was hoping that someone else out there had run across the same problem. Are these pumps prone to cracking? Might have to get it magnafluxed.

Sadly you may have no choice but to.
Generally cracks appear on the high pressure outlets where the port is threaded into the housing. You mention it's where it joins to the cast iron housing on the other pump (i assume it is the drive pump). That area has only los pressure and shouldn't crack

 

[Thomas1]

Sadly you may have no choice but to.
Generally cracks appear on the high pressure outlets where the port is threaded into the housing. You mention it's where it joins to the cast iron housing on the other pump (i assume it is the drive pump). That area has only los pressure and shouldn't crack

Looking at the breakdown it shows a gasket between the gear and tandem pumps.