Dale in Prospect
New User
Hi All, helping my dad with his 601. TPH wont lift (all the time). I've spent hours looking at archives here and watching videos on pump rebuilds, etc, but they have only helped so much. TPH started lifting intermittently after it sat a while. Once it started working, it worked fine and was "strong". Ultimately, it wouldn't lift at all despite manually lifting TPH, cycling control lever, etc. Dad drained oil (it was pretty bad shape), flushed everything clean and added new oil. He removed cover plate and cleaned up the easy-to-get-to items. Main cylinder is tight - no leaks. O-rings where vertical tubes meet cover are good. Control valve, and check valves removed and cleaned and reinstalled - work freely. Primed pump and restarted with no luck. TPH wont lift - doesn't even budge. Pulled PTO lever cover off and watched inside for leaks when attempting to lift TPH - no leaks. Could see some minor movement of fluid down toward front right corner of bottom. Pulled cover back off. Removed control valve / spring. Looked well and moved free. Removed check valve and pilot/spring and ball. Seemed clean - moved freely. Did NOT pull the backpressure valve out as nothing handy to pull the bushing. Did move the valve back and forth with screwdriver. Moved freely. Valve would push in and spring back freely on its own. I know there is an o-ring back in there also. Unsure of its exact function. Could see the ID of it all the way around and looked ok, but unsure of its actual condition. Pulled the unloader valve and it looked decent, but seemed to stick somewhat at extreme travel positions. Moved very freely in between. Polished bore and valve some and reassembled with similar sticking at extremes. Unsure if this is an issue. Was able to put air to cover ports and use control valve to cycled unloader back / forth. With cover off, started tractor and got nice fountain of flow up out of vertical supply tube. Put back together and nothing. TPH never budged. Looking through side hole, no leaks, just minor movement of fluid in bottom. Played with control level and lifted TPH up/ down manually and banged things around a bit and saw TPH budge a little. Then, on next control lever cycle, TPH worked perfect. Very strong and smooth. This lasts about half dozen cycles and then just quit in the down position. Never got it to budge again despite more "mechanical agitation" / cycling, etc. Shut tractor off and checked pump prime - fluid was at very top when took plug out, so don't think any issues with pump. Prior to this, the TPH was always very strong and smooth with no issues. Also, when it worked those few times, it lifted me on hitch effortlessly. So, don't think any pump issues. The fact that it lifted me those few time, don't believe and issues with pressure RV or with piping holes in tranny. Think I have a valve sticking. ?.. Which one would do that? Can I test pump pressure with port under seat if valves are not working? Thanks for any insight - this should be enough to get us started. Dale