Educate me on adjusting hydraulic system pressure

[JWR]

I am puzzled by your post. The very thing that is being discussed is setting the max pressure by setting the pressure relief valve (PRV) and how to test it with a gauge. No??

OK, exposing my ignorance further, no one said they were tweeking a setting on the relief valve (and I have never messed with mine.) There was discussion about making adjustments but I didn't know where.

Post #17 by Seabee provides excellent clarification.

 

[Tractor Seabee]

My WSM for the B3200 has brake repair specifications on page 5-S4. Hydraulics are in section 8. I'll take a closer look and see if I can find the info.

Sorry, I was using my BX WSM. It states 1 mm=39 PSI. Yours may be different

 

[Tractor Seabee]

I thought the PSV was the final step in protection of the system from overpressure. Is the working pressure not controlled by another device that regulates pressure (below the PSV setting)??? Wouldn't the working pressure be increased by shimming this device and not the PSV?
Confused and confounded in the Sunny South ...........(also puzzled)

The thread is about the working pressure for operating implements/attachments. This PRV is down stream from the HST system and is the one we are discussing. Tractors w/o a HST are radically different. The HST relief valve at the pump discharge is not considered field adjustable; so, WSM does not detail it except in the transmission section; it is a technician shop job. With a WSM you can trace out the fluid flow and see all the components. I have tried to keep this simple for us barn mechanics, not the experts.

Ron

 

[Downeaster2024]

I've read several threads about how Kubota routinely sets hydraulic pressure lower than what's claimed in the literature. I've always felt that my loader wasn't lifting what it was really capable of. Last fall I loaded my 5' brushhog onto a flatbed trailer. The cutter weighs about 500lbs. I couldn't lift it any more than about 30" from the ground so it was a struggle to get it over the sides of my landscape trailer. I've got a B3200 with a LA504 loader. From what I've read I need a pressure gauge which can be inserted in one of the front loader hose ports to check the pressure on the system. Once the pressure is determined there are shims or washers that can be inserted to raise the pressure on the system.

My questions are these -

When installing the pressure gauge (with the hydraulic system quick connect) I'm assuming the tractor must be shut down and all the pressure relieved on the system - correct?

Once the gauge is in the loader hydraulic block, I fire up the tractor to operating RPMs and read the gauge as I cycle the loader control handle. If the pressure is lower than what the literature claims it is how do I determine which shim/washer is needed to raise the pressure? Are multiple shims/washers added or are there different size shims/washers?

The shop manual doesn't have a really clear photo of where the shims/washers are added so any info on that would be helpful.

Thanks

This video will show you how. He is doing his backhoe, but it is all the same. Watch the video and you are in there.

 

[big bubba]

interesting thread. this is basically a sub compact forum. i look with interest as sub compact owners frequently try to inch up their machine performance to accommodate different utility tasks that should have probably been considered before purchasing.

make no mistake, i've been there several times in choosing a machine to fit the task. good luck to OP. & with the increased hyd psi, keep an eye on the hoses/connections. wear safety glasses at all times. best of luck

 

[ultrarunner]

interesting thread. this is basically a sub compact forum. i look with interest as sub compact owners frequently try to inch up their machine performance to accommodate different utility tasks that should have probably been considered before purchasing.

make no mistake, i've been there several times in choosing a machine to fit the task. good luck to OP. & with the increased hyd psi, keep an eye on the hoses/connections. wear safety glasses at all times. best of luck

For some of us the pressure produced is found below spec...

Mine was 12% under and one shim brought me up to spec...

Maybe why Kubota sells shim packs?

 

[big bubba]

makes perfect sense if testing equip is at hand. probably more of a liability issue w/K, regards