Komatsu dozer D37 blade control

[Mtnviewsw]

The float position of the joystick doesn’t stay without physically holding it there. I suspect it is the pilot valve that’s bad. A new pilot valve is $3000 from Komatsu, so I can’t afford a mistake! Any words of advice for me? My dozer is a D37EX-21A. It is 19 years old but new to me.

 

[Welder Dave]

Check to make sure it's not a linkage problem or a problem at the valve. On my tractor the bracket that holds the control lever to the valve has come loose and prevented the spool from detenting in the float position.

 

[chidog]

How come when something breaks everyone automatically wants to replace it? No I'm not picking on or belittling anyone.

I just take things like that apart and come up with a plan to fix it.

Especially when its not on the bosses machine they need fixed yesterday.

 

[HarleyHappy]

Slow your roll, lol.
Not everyone, I hate being a parts replacer. I may have been that in my teens but for the last 40+ years, my job has been to fix things right and sometimes that means a part replacement. Part of my job has always been, to know whether it’s better to buy a new part or better to fix the old part.
All of us that fix things for a living, have had to deal with the fact that some new parts are not equal to or have longevity of the old parts that we are replacing.
Sometimes, it’s more work and may cost a bit more to refurbish or rebuild an older but more sound part than buy some of this new crap.
Then, sometimes, you are completely surprised when you open the box, to find a nice, new and well built part.

 

[John V]

Slow your roll, lol.
Not everyone, I hate being a parts replacer. I may have been that in my teens but for the last 40+ years, my job has been to fix things right and sometimes that means a part replacement. Part of my job has always been, to know whether it’s better to buy a new part or better to fix the old part.
All of us that fix things for a living, have had to deal with the fact that some new parts are not equal to or have longevity of the old parts that we are replacing.
Sometimes, it’s more work and may cost a bit more to refurbish or rebuild an older but more sound part than buy some of this new crap.
Then, sometimes, you are completely surprised when you open the box, to find a nice, new and well built part.

Hey @Mtnviewsw did you ever resolve this? I'm experiencing the same thing on my d37px-21a.

 

[John V]

Circling back on this. I took my pilot valve off, and I was about to start disassembling it. Just before I did, I saw a section in the service manaual "Adjusting Play of Work Equipment PPC Valve." Sure enough, that fixed the issue. I guess the push rods in the valve wear down over time, creating play in the joystick so that it eventually doesn't actuate the float valve enough for the detent ball to latch. I'm not sure why the service manual says to remove the PPC valve from the machine first. I feel like you can just do the adjustment on the machine after you get the covers off and pop the bellows up.