I broke my three point hitch.!!!

[vtsnowedin]

O ring part #21 was flattened. I changed both O Rings and the piston rings and the relief valve. No way to tell if the relief valve was working properly so changed it out to be sure considering how far into the tractor it is.

 

[vtsnowedin]

Are we having fun yet? Went down to my dealer today to get the right bolts. I took the scv valve block with me to show them. They looked it up and said that those were the bolts that come with the kit. My BS meter went off but I just had them order some that are 10 mm longer as that was all they could find in the parts list. When I got home I looked up the kits myself and confirmed that they were not pulling my leg. I do have the cap screws part NO 19m9249 that are M10x100. The problem is that a single scv calls for screws that are M10x80 and the second valve body is 38mm thick. So I think the right part would be M10x 117 to 119 long.
Any thoughts/ Or experience out there. With all the double rear remotes out there I'd have thought that this would have come up by now. Of course other tractors with double or triple remotes as standard equipment have entirely different valve blocks.

 

[CobyRupert]

O ring part #21 was flattened. I changed both O Rings and the piston rings and the relief valve. No way to tell if the relief valve was working properly so changed it out to be sure considering how far into the tractor it is.

How did it get flattened? I understand you hooked onto a frozen log and asked the hitch to do more than it should, but isn't that the point of the relief valve? (i.e. how do you prevent it from happening again if you don't know the weight of the log or if it's frozen?)

 

[CobyRupert]

What is the green part on the table with the rings?

 

[vtsnowedin]

What is the green part on the table with the rings?
View attachment 378638

That is the rockshaft cylinder that the piston beside it moves inside of.

 

[vtsnowedin]

How did it get flattened? I understand you hooked onto a frozen log and asked the hitch to do more than it should, but isn't that the point of the relief valve? (i.e. how do you prevent it from happening again if you don't know the weight of the log or if it's frozen?)

Well for starters if you think something might not come along peaceable you should hitch to the drawbar not the 3PH. When I came to the end of the chain I must have brought the pressure inside the cylinder well above the relief valve setting and the pressure is what flattened the o ring and let oil escape past it afterwards. Also the pressure relief valve may have failed or it's o ring but I could see nothing wrong with them and don't have a test block to check it. I changed both O rings and the PR valve out as well as the piston packing to give myself the best chance of having it right when all finished. Noway to besure until you get the whole thing back together.
It was about ten below zero F when I did this and even though I was a half mile from the house the rear end and it's fluids may not have been all that warm so that might have had something to do with it.

 

[JCByrd24]

The relief valve may not have been able to relieve the pressure fast enough. It it designed to pass the flow of the tractors hydraulic pump with a certain amount of pressure accumulation across it. The force of the tractor moving and the sudden stop may have forced the fluid to move fast enough through the relief that even more pressure accumulated behind it, as the OP said. A relief valve designed to pass 2 gpm won't do much to help components if the pump is several times larger.

 

[vtsnowedin]

The relief valve may not have been able to relieve the pressure fast enough. It it designed to pass the flow of the tractors hydraulic pump with a certain amount of pressure accumulation across it. The force of the tractor moving and the sudden stop may have forced the fluid to move fast enough through the relief that even more pressure accumulated behind it, as the OP said. A relief valve designed to pass 2 gpm won't do much to help components if the pump is several times larger.

Yes but I'm unclear as to why it would then pass fluid all the time. What keeps it from closing after the pressure spike is gone?

 

[Zebrafive]

Yes but I'm unclear as to why it would then pass fluid all the time. What keeps it from closing after the pressure spike is gone?

Take it apart and see what you can find. Maybe dirt in the seat. Maybe it was moved beyond it's design range and became stuck. Maybe a metal shaving from machining inside that never got cleaned out jammed it when it opened.

Are you back together and working OK?

 

[vtsnowedin]

Take it apart and see what you can find. Maybe dirt in the seat. Maybe it was moved beyond it's design range and became stuck. Maybe a metal shaving from machining inside that never got cleaned out jammed it when it opened.

Are you back together and working OK?

Waiting on the 110 mm bolts.