BX23S Hydraulic Pressure to High

[motorhead3]

Bought one of those hydraulic pressure gauges with a shim kit. My less than 100 hr BX23S was reading 1750PSIG so I was going to add the 0.2 mm shim to bring it up 80PSI more. Took off the cap, installed it and retest showed 2500PSIG. Tried it with the stock shims and still 2500PSIG. Took out all shims and got it to go down to 2300PSIG so the relief is functioning. Checked the gauge, its good. Everything inside the relief moves easily,spring ,poppet, except the relief valve seat. Won't budge. I ordered a new one to see what I'm up against. Didn't get it yet. The original must of moved when I first disassembled it and I drove it in to far or cocked when re tightening it, their are holes on the side of the seat cage that don't exactly alien with the drain hole in the casting. First is 2300PSIG to much for this tractor? Maybe the spring is to tight and the cap just wasn't that tight from the factory. File the spring? I have no clue how to get the seat out other then try to thread a bolt into it and pull, or carefully drilling it out, thus destroying it. I'd appreciate any advise because I'm very meticulous they way I take care of my equipment,boats, cars, etc, and this is kind of embarrassing.

 

[Dave M7040]

It is a little late now but for the future owners who think getting an 80 psi increase is going to be magical........ leave things alone.

Also, recognize that all gauges have errors. Cheaper ones usually 5% of full scale which could be 150+ psi.

The WSM I have access to says 1780 to 1840 psi with warm oil and full rpm.

Are you working from a factory Workshop Manual using the recommended Tee adapter fitting?

I have attached the specific WSM page.

Dave M7040

 

[Tractor Seabee]

I raised the pressure on my BX25 to 2000 PSI using Kubota OEM shims. Worked exactly as the WSM said. Actually had it apart 3 times checking progress. Seems very simple to me. You must have done something wrong. Did you actually measure the shim thickness? The OEM ones come in envelopes with the MM on each one. Made a big difference in FEL operation. Prior I could not lift 50 GL diesel, after I could.

Ron

 

[dragoneggs]

Time to check mine again... been quite awhile and it seems a little weak but I do push my BX to limits when it comes to FEL lifting. Mainly moving big stumps, cement blocks, or pavers.

 

[Tractor Seabee]

Time to check mine again... been quite awhile and it seems a little weak but I do push my BX to limits when it comes to FEL lifting. Mainly moving big stumps, cement blocks, or pavers.

Mark, what does your FEL Bucket look like? Fish mouth like mine?

Ron

 

[dragoneggs]

Mark, what does your FEL Bucket look like? Fish mouth like mine?

Ron

Ha... no actually looking great. I put a piranha tooth bar on which saved the lip... and also have a quick attach and dedicated forks for the heavy lifting. I remember you have the bolt on forks and I know if I went that way, I would be in the same boat as you.

Here is me unloading my new 450lb wood lathe, maybe close to 500lb including the crate. Love my QA and adjustable forks. Never dreamed I would use my forks so much and probably wouldn't if I didn't splurge for Jery's QA and forks.

 

[motorhead3]

It is a little late now but for the future owners who think getting an 80 psi increase is going to be magical........ leave things alone.

Also, recognize that all gauges have errors. Cheaper ones usually 5% of full scale which could be 150+ psi.

The WSM I have access to says 1780 to 1840 psi with warm oil and full rpm.

Are you working from a factory Workshop Manual using the recommended Tee adapter fitting?

I have attached the specific WSM page.

Dave M7040

Dave, thanks for the copy of the manual page. I did order a copy of the manual after I screwed up. Once I get the new seat I'll have to get that one out. I know about positive displacement pumps, hydraulics and gauge error. Just thought maybe I'm overlooking something obvious in removing this seat.

 

[motorhead3]

Seat is in there tight. Tried everything , can't get it out. Took 1.016MM/.040 in off the spring. I have 1850 psig hot now. Wasn't worth the hassle for a hundred pounds.

 

[Tractor Seabee]

Seat is in there tight. Tried everything , can't get it out. Took 1.016MM/.040 in off the spring. I have 1850 psig hot now. Wasn't worth the hassle for a hundred pounds.

Weird situation, thinking there was probably no design change with the new model I checked my BX25 manuals. Everything looks the same. I assume you are reading pressures on the implement circuit.

The seat piece should not be tight, per the Parts Manual (PM) it slides in and out, maybe like you said, it is cocked and jammed short of the bottom. If all of a sudden you have no pressure you will know. Taking .040 from the spring is a lot of pressure change, you must have been desperate. Per the (PM) the original assembly has two thick shims and 2 washers on top of the spring. Those shims are listed as .10, .20, and .40 mm. You would need to mic them to know which. I put the adjusting shims on top the two washers.

Do not give up, get a new spring, check shim thicknesses, and start over. That seat has to be gotten loose though; if cocked it should show up easily by measuring. Don't give up, you will be glad; see my earlier post.

Back in my industrial machinery overhaul days we ran into a lot of weird happenings but there was always a reason and a solution, we just had to keep at it.

Ron

 

[motorhead3]

I'd love to see that sudden pressure drop. I have a new seat and enough shims to make up the difference until I can get a new spring.