TCV relief setting

[Harry]

I have had a dumpster in my driveway for a few weeks and as I was driving the 644 lbh by it I decided to check the hydraulic pressure in the drive and loader circuit. I have a gauge installed in the dash so that makes it easy. I drove up to the dumpster and opened up the throttle. Pushed down on the drive pedal and checked the gauge. Then pushed the blade under the edge of the dumpster and tried to lift it. The drive circuit maxed out at 2500 psi and the lift circuit maxed out at 2000 psi. I never heard any relief squeal for either circuit. This is an old tractor that had engine problems and set for who knows how many years in a barn in Pennsylvania. The seller told me he had found it at his Fathers farm after he had passed. I’m glad I purchased this machine because I use it a lot. Harry

[ssmewing]

I have a 648 that is after the original settings, and I suspect the pumps used. The visual tells are in the parts manual. I have a full hex nut on the cover for adjusting the TCV pressure.

I have mine all torn apart and have not been doing so well, and it has been sitting. I did buy an extra-long screw driver for the job, and I did have to drop the 3-point to access the hole fully. I hit the same issue as Harry? You cannot get to the nut. I have the add-on version of the retard that I cannot remember the name of. I did not want to be that guy who cuts holes for access after barating people who cut sections of their tower out instead of unbolting the engine and moving it forward for access. Then, recently, I found out that starting with the 6018, the factory created an access hole for adjusting the pressure relief. Now, I will cut an access hole. I will drill two holes, cut out the center, and then put a cover on it, similar to the 6018.

I, too, found I was at 1,500 psi. I followed the hydraulics manual and performed the bench test using the grease gun filled with oil method, turning it up to 2,400 psi, as per the setup I used, which required a much higher-rated check valve, but I was still able to see how far the needle would swing and never go past that, so the needle did not hold after each pump. I just had to pump faster.

It seems that way back when the other forum had Tom and Gator around, they both agreed that pump specs are arbitrary and meaningful. So, even though the pump says it is only as high as 3,000 rpm's was never a hard limit, but it was more a decision by the engineers using factors that we do not know.

[Harry]

I have a 648 that is after the original settings, and I suspect the pumps used. The visual tells are in the parts manual. I have a full hex nut on the cover for adjusting the TCV pressure.

I have mine all torn apart and have not been doing so well, and it has been sitting. I did buy an extra-long screw driver for the job, and I did have to drop the 3-point to access the hole fully. I hit the same issue as Harry? You cannot get to the nut. I have the add-on version of the retard that I cannot remember the name of. I did not want to be that guy who cuts holes for access after barating people who cut sections of their tower out instead of unbolting the engine and moving it forward for access. Then, recently, I found out that starting with the 6018, the factory created an access hole for adjusting the pressure relief. Now, I will cut an access hole. I will drill two holes, cut out the center, and then put a cover on it, similar to the 6018.

I, too, found I was at 1,500 psi. I followed the hydraulics manual and performed the bench test using the grease gun filled with oil method, turning it up to 2,400 psi, as per the setup I used, which required a much higher-rated check valve, but I was still able to see how far the needle would swing and never go past that, so the needle did not hold after each pump. I just had to pump faster.

It seems that way back when the other forum had Tom and Gator around, they both agreed that pump specs are arbitrary and meaningful. So, even though the pump says it is only as high as 3,000 rpm's was never a hard limit, but it was more a decision by the engineers using factors that we do not know.

I feel that adding an access area and cover it will a plate to access is what the engineers should have done originally. Some people do hack jobs which I have seen on GT’s that I have purchased. The worst was the shroud on an Onan hacked up to replace the starter. Harry