786 3 point won't go down

MARK ROBKE

Well-known Member
I'm working on a 786.The 3 point lift stays up,and will only creep down after a week of not running.The fluid was nasty dirty and has been drained.We have the valve on top of the rockshaft housing off,and disassembled.None of the valves were stuck,but are very lightly scored.Reading the manual,three of the possible causes for the 3pt not lowering involves the drop poppet valve,(and it's cage). We are unclear if this valve is below the rockshaft cover,but believe it is. Can anyone help point me in the right direction? I appreciate any help,thanks.Mark.
 
The draft control linkage inside the rear end could be messed up making it want to raise all the time it's a fairly simple fix after taking the top link bracket off. Shoot me an email and I will give you a phone number and talk you through the process if you want. Here's the condensed version park on level ground or with the front wheels lower and you don't have to drain any oil and take the bolts out holding the top link mount. Inside towards the right side of the hole there will be 2 levers one coming down from the top and one up from the bottom and it is supposed to be the bottom one pushes the top one to signal the valve to move as the draft or pull gets stronger and most likely what has happened it the levers flexed too much and got on the wrong side of each other just carefully pry one around the other and get it on the proper side again. BE CAREFUL the lever can be sharp from years of rubbing each other. You can run it with the cover off and see if this helped before you close it up.
 
I might add that the top lever goes on the back side of the bottom one and this top lever is under heavy spring pressure . I have a home made hooky tool for this job like said things in there can be sharp and even slice thru welding cloves . what has happened is that there was a heavy pull on the three point and all of a sudden the load was released fast and caused the jump. Ths happens usually while plowing and hitting a rock or while pulling something stuck out and the chain breaks . This may or may not be a one time thing , if it happens again then you can weld a washer on the arm coming up from the bottom on the side colest to the rear end housing , i have done this . The linkage always jumps off towards the right side . As to placement of the tractor it don't matter as i have done them in the shop , out in the fields facing up hill or down hill leaning to the right or left . If it has something hooked to the three point it is wise to block it up since your working right there . Next it helps to pull the draft sensing lever all the way back while doing this and and extra set of hands holding it back is a help.
 
THANK YOU- tractor vet and tjv ! You were correct about the linkage being the problem. The levers were reversed; we were able to reposition them,but we pulled the lower lever pivot pin because we were afraid to pry too hard on them. We have the tractor split apart for another problem,and wanted to fix the 3 point too, so we won't get to try it til next week.
Your solution goes to show that the 'book' does not always have all the answers! And things wear and become problems after 38 years! I kept thinking something was wrong linkage wise; I had thought once possibly linkage had fallen off,but had not considered it had reversed itself. Thanks again,Mark.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top