L60 rear remove valve body leak

[Jchonline]

Hello Everyone, I have let this go since the dealer installed the remotes last year as it is a slow drip. It looks the be the valve body for the rear remotes, nearest the hydraulic pump connections. Any thoughts on what I should check (easiest to hardest please).

 

[mcmxi]

The first thing I would check for is oil leaking at the hydraulic fittings and running down the valve stack. I seem to have that issue on my M6060. It's not uncommon to have leaking Pioneer type fittings it seems, either at the interface between the male and female couplers, or where the fitting threads into the valve body.

 

[TheOldHokie]

The first thing I would check for is oil leaking at the hydraulic fittings and running down the valve stack. I seem to have that issue on my M6060. It's not uncommon to have leaking Pioneer type fittings it seems, either at the interface between the male and female couplers, or where the fitting threads into the valve body.

Pretty simple.

Make sure the bolts holding the sections together are tight. Typical value 12-13 lb-ft.

If that's not the issue the valve needs to be separated, mating surfaces inspected, and any damaged orings replaced.

Dan

 

[Jchonline]

The first thing I would check for is oil leaking at the hydraulic fittings and running down the valve stack. I seem to have that issue on my M6060. It's not uncommon to have leaking Pioneer type fittings it seems, either at the interface between the male and female couplers, or where the fitting threads into the valve body.

Good thought I did check those and no oil on the hoses from the hydraulic fitting assembly down to the valve body.

 

[Jchonline]

Pretty simple.

Make sure the bolts holding the sections together are tight. Typical value 12-13 lb-ft.

If that's not the issue the valve needs to be separated, mating surfaces inspected, and any damaged orings replaced.

Dan

I saw those 4 bolts…so they run all they way from the 3rd remote valve body to through the 1st? Those are some long bolts! I’ll check tomorrow Thanks.

 

[TheOldHokie]

I saw those 4 bolts…so they run all they way from the 3rd remote valve body to through the 1st? Those are some long bolts! I’ll check tomorrow Thanks.

 

[TheOldHokie]

Yes - the valve is a sandwich held together by tie rods. Example below. Orings in counterbores seal the passages.

Dan

 

[Jchonline]

Torqued them down they were pretty loose. Put a fresh piece of cardboard under the drip spot...will report back.

 

[kubotafreak]

The orings flatten over time. I can say it was more than likely the proper torque at instal. Not uncommon, better to have to tighten them up, then them be stripped out.

 

[whitetiger]

It is far better to have it assembled and torqued to the specified 20 ft lbs the first time.

 

[Jchonline]

No dice still leaking when I checked this AM. I am going to pull the remotes fitting interface down to make room to re-tighten all of the hoses going into the valve body. I cant actually tell where the leak is coming from yet...I just know it is not from the remote fittings assembly you plug the couplers on implements into.

Unless anyone has something else to check first.

 

[Jchonline]

The orings flatten over time. I can say it was more than likely the proper torque at instal. Not uncommon, better to have to tighten them up, then them be stripped out.

These would only be 2 years old...if they flatten that fast we have a problem lol.

 

[kubotafreak]

These would only be 2 years old...if they flatten that fast we have a problem lol.

They do, from initial install at the specified torque. The seals are generally still good, and the fix is to retorque them. I have noticed this from the Kubota backhoe valve blocks, remote valves, and other oem kits installed over the years. The ones that don't weep after a year or two were probably over torqued from the dealer/factory, since they know the seals will relax with time. As you indicated the bolts felt loose, which is a good indication the seals relaxed tension, and the joint got loose. Now in your case, you may just not have the right joint identified yet.
As far as the jic fittings, they don't take much torque. I have found the ones that got over torqued from the start can get deformed and leak. I like to initially install them on the lower end of spec torque. That way you have a little wiggle room to tighten them more if they weep without distorting the sealing face.

 

[TheOldHokie]

They do, from initial install at the specified torque. The seals are generally still good, and the fix is to retorque them. I have noticed this from the Kubota backhoe valve blocks, remote valves, and other oem kits installed over the years. The ones that don't weep after a year or two were probably over torqued from the dealer/factory, since they know the seals will relax with time. As you indicated the bolts felt loose, which is a good indication the seals relaxed tension, and the joint got loose. Now in your case, you may just not have the right joint identified yet.
As far as the jic fittings, they don't take much torque. I have found the ones that got over torqued from the start can get deformed and leak. I like to initially install them on the lower end of spec torque. That way you have a little wiggle room to tighten them more if they weep without distorting the sealing face.

I have trouble with this theory. The orings are a static face seal and are compressed in a precisely machined counterbore on the face of one section. Once the machined faces of the adjoining sections come into full metal to metal contact the orings are fully compressed and further tightening will not compress them further.

Both Bucher and Prince specify 12-13 lb-ft torque for the tie rod nuts on their HDS and SV sectional valves.. That's screwdriver tight

Dan

 

[Jchonline]

I have trouble with this theory. The orings are a static facecseal and are compressed in a precisely machined counterbore on the face of one section. Once the machined faces of the adjoining sections come into full metal to metal contact the orings are fully compressed and further tightening will not compress them further.

Both Bucher and Prince specify 12-13 lb-ft torque for the tie rod nuts on their HDS ans SV sectional valves.. That's screwdriver tight

Dan

Should I loosen then retorque them down? I just tightened them last time.

 

[TheOldHokie]

Should I loosen then retorque them down? I just tightened them last time.

I think you need to positively ID the location of the leak.

Dan

 

[whitetiger]

Both Bucher and Prince specify 12-13 lb-ft torque for the tie rod nuts on their HDS and SV sectional valves.. That's screwdriver tight

The Kubota installation instructions spec the 10mm tierod nuts to be torqued to 20 ft-lbs.

 

[TheOldHokie]

The Kubota installation instructions spec the 10mm tierod nuts to be torqued to 20 ft-lbs.

I am not debating the exact torque value - that varies by OEM. If Kubota says 20 lb-ft on those valves so be it.

My point is all the torque is doing is tensioning the fastener to prevent the nuts from loosening. It is not altering the amount of "squeeze" on the orings.

In a static face seal design "squeeze" is controlled by the depth of the counterbore. General design practice is 70-80% of oring cross section or if you prefer 20-30% squeeze. On a 2mm oring that's only .015-.020 inches of compression.

Dan

 

[kubotafreak]

The oem gland seems to be less than 70%, but I didn't measure it. All I am concluding is the oem torque is not enough to hold the joint on new installs for 1-2 years without seals weeping. Kubota seals are some of the higher quality ones I have come across, so I blame the torque spec or the hardware. The indicator they "get loose" says it all...

 

[Jchonline]

Spent an hour pinpointing the leak...it was exactly where my original picture showed it. I took the rear remote coupler bodies off, then got a good look at everything with the machine running.
While looking I found a small shard of metal (maybe 1/8" x 1/4") that was sandwiched in the bottom portion of the 1st rem block...hoping that was the issue. Removed it with magnetic screwdriver, re torqued all bolts. I should have an implement on it in the next few days, but without one right now no leaking.