3 point control B7100HST (newer version)

[EdF]

B7100HST 3 point hitch

I took the 3 point hitch control valve apart to fix a leak. Found an O ring in the Relief Valve was missing (see pictures) according to the WSM. There was nothing to indicate an O ring was ever in the Relief Valve. I suspect the O ring was missed from new or the WSM is wrong about the need for an O ring in the relief valve?????

I am going to replace all O rings and gaskets on the rebuild to include a new O ring in the relief valve. Does that make sense? If the WSM is wrong and I put an O ring in the relief valve what could possibly be damaged???

 

[cviola2005]

Re: B7100HST 3 point hitch

Hard to tell from here, but to me, it looks like a few things are different. According to the manual picture, after the spring holder and ball should be a valve seat and then the o-ring. I don't see the valve seat in the second picture, so maybe it's still in the valve body? If so, that would be why you don't see an o-ring.

 

[North Idaho Wolfman]

Like cviola2005 said, you don't have all the parts out of the valve.

You had a leak in the relief valve assembly?

 

[EdF]

Like cviola2005 said, you don't have all the parts out of the valve.

You had a leak in the relief valve assembly?

You guys are correct the valve seat w/O ring is still in the assembly. How do I get it out? I have picks but none to go through the hole in the valve seat. Possibly blow it out with compressed air?

The leak was coming out where the control valve mounts to the lift cover. I suspect the O ring(s) failed (see picture).

 

[cviola2005]

You guys are correct the valve seat w/O ring is still in the assembly. How do I get it out? I have picks but none to go through the hole in the valve seat. Possibly blow it out with compressed air?

The leak was coming out where the control valve mounts to the lift cover. I suspect the O ring(s) failed (see picture).

Yes, you should able to blow it out with compressed air. Just make sure to hold your hand over it so it doesn't go flying and land in a place that you cant find.

 

[North Idaho Wolfman]

Hold a rag over it, not your hand.

 

[EdF]

Thanks to both NIW and cviola2005 for the good points. I'll zip tie a work glove over the valve to catch the seat. One last question.....is it acceptable to use RTV blue in addition to o-rings when reassembling?

 

[JeffL]

Best to stick with the o-ring seal design only. RTV on the oil ring will make it leak. RTV on the body surfaces will change the distance the O-rings are crushed; lowering the amount of pressure they will seal. Jeff

 

[EdF]

Thanks JeffL will heed your advice.

 

[EdF]

Just an update on progress. Got the valve seat/o-ring out only after soaking with a 50/50 mix of acetone & transmission fluid. That sucker just would not budge with air pressure. Anyway need to revisit Messicks to get correct 2 o-rings for the control valve to lift cover. Will provide feedback once the reassembly is complete and tested.

Thanks to all for your input.

 

[EdF]

Just an update on progress. Got the valve seat/o-ring out only after soaking with a 50/50 mix of acetone & transmission fluid. That sucker just would not budge with air pressure. Anyway need to revisit Messicks to get correct 2 o-rings for the control valve to lift cover. Will provide feedback once the reassembly is complete and tested.

Thanks to all for your input.

All back together again and no leaks so far with all new gaskets, o-rings etc. Even took care of a nasty chattering when lifting the 3 point which existed since I bought the machine with 250 hrs on it. The B7100 is a great tractor!

Thanks to everyone for the input to get it back to normal.