817 dump truck question

[cubdriver55]

I just picked up a dump truck with a winch. It starts and drives good but the pto seeems to work fine to the front for the winch but I can not get it to work to the back for the dump bed. Anyone got any ideas?

 

[derby]

The lever to your left behind the parking brake lever is how you control the dump. If that is not working check the linkage to the pto/valve body. Also read the TM's about proper operation.

 

[dozer1]

The lever to your left behind the parking brake lever is how you control the dump. If that is not working check the linkage to the pto/valve body. Also read the TM's about proper operation.

Yep, that lever runs the dump box hydraulic valve and the rear pto output as well. If it is not working right, there could be some frozen up or improperly adjusted linkage. Let us know how it works out.

 

[BKubu]

Make sure the hydraulic fluid is topped off, too. Still, it is probably a linkage issue as others have stated.

 

[cubdriver55]

Thanks for the help. I did get it to work by adjusting the linkage. Even with new pins there is a lot of play so the adjustment is minimal. The difference in the PTO going in and out and not going in at all or not coming out at all is 3 threads.

 

[masalser]

I'm having a similar problem with my M817 - I can adjust the linkage from the control box so that I can engage the PTO to the dump hydraulic pump, or I can adjust it so that I can disengage the PTO. However, there doesn't seem to be enough travel so that I can have it adjusted so that I can both engage and disengage the PTO. I've looked through the various TMs available on this site for information on adjusting the linkage, but I haven't found anything helpful there. I have two thoughts about cause of the problem.

The first is that I have noticed that the linkage arm coming out of the control box and going to the transmission power takeoff is made up of two linkage arms connected by a pivoting arm that basically shifts the linkage over to be inline with where it needs to be on the transmission power takeoff. There is some play in where the linkage arms connect to that pivoting arm - Should those connections be absolutely rigid?

The second idea I have is that perhaps the parts in the control box are worn such that the control box doesn't move the linkage arm over the full range that it is supposed to. Is that likely?

The linkage arm whose length I have tried adjusting is the long one that connects directly to the transmission power takeoff.

Any help would be greatly appreciated.

 

[m816]

Check the free play in the plunger that controlls the hydraulics to the hoist. I found mine was sticking and badly out of adjustment I had to crawl under the truck and manually push it up to get the oil flowing and then pull it down toe get the body down

 

[masalser]

m816, the problem isn't with the hydraulics. It is with getting the pro shaft that powers the hydraulic pump to properly engage and disengage in the transmission. By adjusting the linkage length I can get it to either engage the pto with the transmission or to disengage the pto with the transmission, but I can't get it to be able to do both. It's like the range of travel for the linkage just isn't long enough.

When the pto is engaged the hydraulics work fine - I can dump and power down the dump bed and put it in the neutral position just fine.

Anybody out there have any more suggestions on what to look at?

 

[sidel2426]

I'm having a similar problem with my M817 - I can adjust the linkage from the control box so that I can engage the PTO to the dump hydraulic pump, or I can adjust it so that I can disengage the PTO. However, there doesn't seem to be enough travel so that I can have it adjusted so that I can both engage and disengage the PTO. I've looked through the various TMs available on this site for information on adjusting the linkage, but I haven't found anything helpful there. I have two thoughts about cause of the problem.

The first is that I have noticed that the linkage arm coming out of the control box and going to the transmission power takeoff is made up of two linkage arms connected by a pivoting arm that basically shifts the linkage over to be inline with where it needs to be on the transmission power takeoff. There is some play in where the linkage arms connect to that pivoting arm - Should those connections be absolutely rigid?

The second idea I have is that perhaps the parts in the control box are worn such that the control box doesn't move the linkage arm over the full range that it is supposed to. Is that likely?

The linkage arm whose length I have tried adjusting is the long one that connects directly to the transmission power takeoff.

Any help would be greatly appreciated.

masalser, did you ever determine what the problem was with your linkages. I'm dealing with a similar problem right now. I pulled apart the control box and everything seems fine. I did find that the "linkage arms connected by a pivoting arm that shifts the linkages over" will not move while this assembly is bolted to the frame. Once I loosened the bolts it moved freely. After I removed it I found that the two arms have been welded in place even though the pins are still in place. I'm going to try and grind the welds back off and knock out the pins and see if the arms are aligned properly with the pinned holes. I will replace the pins and bolt it back up and see if it will move freely. I will try to post some pics tonight.

 

[masalser]

masalser, did you ever determine what the problem was with your linkages. I'm dealing with a similar problem right now. I pulled apart the control box and everything seems fine. I did find that the "linkage arms connected by a pivoting arm that shifts the linkages over" will not move while this assembly is bolted to the frame. Once I loosened the bolts it moved freely. After I removed it I found that the two arms have been welded in place even though the pins are still in place. I'm going to try and grind the welds back off and knock out the pins and see if the arms are aligned properly with the pinned holes. I will replace the pins and bolt it back up and see if it will move freely. I will try to post some pics tonight.

sidel2426,I still haven't bothered to get it figured out. We use the dump truck sporadically on our farm and so it hasn't been a high priority. I've basically been operating the truck with the pto shaft to the dump hydraulic pump running continuously which in the long run is probably not good, but we don't put many hours on it in a year so I'm not too concerned. I believe the problem at least on my truck stems from excessive play in the numerous linkages that go from the lever in the cab to the control box. I'm guessing that the person who owned your truck maybe had the same problem and their solution to try to eliminate slop was to weld those arms in place. I've thought about doing the same thing. Please let me know if you find a solution. If I manage to make time to tinker with mine I will let you know if I have any success.

 

[autoshopteacher]

I don't remember all the combinations of linkage adjustments I went through to get my 817 dump to engage and disengage, but it took a lot of tinkering. There is not a lot of motion needed in the pump to get it to work correctly. Before I got it fixed, I drove it 20-some miles with the pump running and it got really hot. Probably not a good idea.

 

[masalser]

I don't remember all the combinations of linkage adjustments I went through to get my 817 dump to engage and disengage, but it took a lot of tinkering. There is not a lot of motion needed in the pump to get it to work correctly. Before I got it fixed, I drove it 20-some miles with the pump running and it got really hot. Probably not a good idea.

Autoshopteacher, thank you for the info about the heat. I guess I better make time to get this figured out

 

[sidel2426]

When I got my truck the PTO was engaged. There is no telling how long it was like that and no way to know how much driving was done or how fast it was driven. What I do know is that my pump is covered in oil and dirt probably because it is leaking from being run at high speed. It still works but I plan on rebuilding it later on at some point.

This is a picture of the control box when I opened it up. Full of nasty rusty grease.
View attachment 559050

This is one of the shafts with control arm inside the control box. The shaft is bent a little but I don't think it is part of the problem I am having although I could be wrong.

View attachment 559054

Below is the transfer shaft (that's what I will call it) that was welded.

 

[sidel2426]

Not sure why my pictures didn't show up. hopefully it works this time.

 

[sidel2426]

These are some pictures of the linkages, pump, and pto. Notice the linkage to the pto is unpainted. I believe this was replaced at some point for some reason. Also, the pins that were installed at the ends of it were bolts that had holes drilled in the for the hitch pins. I have since replaced those bolts with the correct size pins which eliminates the slack they had in them. Also, you can see the oil dripping from my pump. If anyone sees something that doesn't look right by all means let me know.