BX 23 Relief Valve location

[radioman]

From the illistration of the hydraulic circuit, I would agree that there is no direct connection between the relief pressure and the operation of the HST. My tractor also stops abruptly when I take my foot of the pedal, but this only happens in low range. I think this has more to do with the spring that controls how fast the pedal returns to neutral. There is a brief description of its operation along with an illustration in the BX23 operatorｴs manual

Yesterday I purchased a glycerin-filled gage and connected it to an extra female quick-disconnect fitting I had lying around. I was a little surprised at only seeing a mximum 1625 PSI, and plan on boosting the pressure when I have more time this weekend. I will also verify if there is a change to the way the tractor comes to a stop.

funny you have mentioned that today. This thread is exactly why i went out and checked the pressure on mine yesterday. I used the quick coupler from the backhoe lower hose. I found that my pressure was about 1600 psi as well. I didnt have any shims so i used a brand new washer that was .8mm thick and my pressure shot up to 2020 psi !! I did a test run with the front lift and reverse driving. There was a impressive performance increase on the FEL. The reverse felt more "responsive" and "snappy". Remember I had a thread awhile back when I thought I was able to lessen the abrupt stop after I tighten the HST pedal spring pressure. I ended up taking the washer back out and will head to my dealer to see if he has those shims in stock. I want to get the pressure close to the recommended PSI at 1850 .
The only thing I noticed difference is that the spring looked like it was ground flat on the ends possibly from the factory. I wonder if they ground it .2mm to .4mm too far ? Darn it!! I just realized I should have measured the spring length before putting back in . I wonder what the shop manual says what the length of the spring should be before adding the shims ?

 

[schrand]

I don't see a spec for the spring length in the WSM, only the pressure limits.
It does state that for every 0.1mm (.0039") of shim, there will be an increase of 39 psi.

 

[radioman]

Ok- thanks for the spring info from WSM.

 

[ibnxe]

funny you have mentioned that today. This thread is exactly why i went out and checked the pressure on mine yesterday. I used the quick coupler from the backhoe lower hose. I found that my pressure was about 1600 psi as well. I didnt have any shims so i used a brand new washer that was .8mm thick and my pressure shot up to 2020 psi !! I did a test run with the front lift and reverse driving. There was a impressive performance increase on the FEL. The reverse felt more "responsive" and "snappy". Remember I had a thread awhile back when I thought I was able to lessen the abrupt stop after I tighten the HST pedal spring pressure. I ended up taking the washer back out and will head to my dealer to see if he has those shims in stock. I want to get the pressure close to the recommended PSI at 1850 .
The only thing I noticed difference is that the spring looked like it was ground flat on the ends possibly from the factory. I wonder if they ground it .2mm to .4mm too far ? Darn it!! I just realized I should have measured the spring length before putting back in . I wonder what the shop manual says what the length of the spring should be before adding the shims ?

These springs are ground slightly short of needed length and the shims fine tune the final pressure. If the spring were too long, there would be no way to adjust the pressure any lower. Also if they weren't ground flat, the ends would dig into the shim or the relief plunger and the pressure would fall off quickly.
Over the 300 hours that I have owned my tractor, the hydraulic performance has slowly dropped off, most likely the result of spring fatigue. Now that I have the gage/coupler, I plan on checking this pressure on a regular basis.
I hope the weather is going to cooperate, as I plan on changing the trans fluid and filter, cleaning the strainer and then digging into the relief valve. Question... does a bunch of fluid come running out when the releif valve is removed?

 

[radioman]

nope, at firsts its kinda like a small dribble and then nothing . nothing a rag can't cure. the amount lost is hardly anything to fuss over.

 

[Zick]

Please do....if you get it up near 2000 PSI....let me know if you hear anymore hydraulic noise and if the abrupt stop in reverse gets worse....I get it worse in high range.

I do have a BX24 and the extra noise I am hearing may be in the power beyond loop or BH....it just seems noisier.

I have my BX2350 bumped up to about 2000psi (can't remember exact number) and I have not noticed any extra noise or any increase in the abrupt reverse stopping either.

 

[ibnxe]

This morning I pulled my relief spring out and checked it out. There were two 0.4mm shims under the spring, at the bottom of the threaded housing. When I took it apart, only about a teaspoon of oil drained out. In case anyone is interested, the free length of the spring measured 43.65mm. I removed the two shims and replaced them with a washer that measured 1.2mm thick. After it was all back together, the system pressure came up to just over 1850 PSI... just right.

I went down to the gravel pile and had no trouble lifting a heaping loader full. The backhoe operation feels like new again as well. I could tell no difference in the operation of the HST. It feels just like it did before.

Tomorrow, I am planning on digging about a 50-foot ditch for a French drain, so I am looking forward to putting the backhoe through its paces.