I am in the middle of replacing the housing which was busted when the rockshaft extended too far. I will follow the adjustment procedures for the "position-sensing feedback", "draft-sensing feedback", and, if you guys think I should, the "main relief valve adjustment".
I'm guessing that the linkage came out of adjustment and caused the problem. Is there anything else I should consider while I'm putting this thing back together? I don't want to buy another housing for $2100.
BTW, I'm new to this site and glad I found it. I can use some help ocasionally with the big stuff. I've got this tractor, a 4120, two 3225 fairway mowers, and a 1500 aerator here at the golf course.
Roland, it sounds like you are doing what you need to do. The position feedback linkage is most crucial to prevent housing breakage. If the linkage is adjusted properly, the cylinder does not bottom out on the housing. You want about an inch of free travel on the draft arms when rockshaft is fully raised. I would definitely check the system relief valve setting also. Excess pressure allows you to lift too much weight and can stress the housing. I am wondering what you were doing when the housing broke? Another thing that can break the housing is if you are carrying a heavy implement probably at road speed and hit a large bump. The heavy implement can be tossed up by the bump at a high rate of speed and when the rockshaft bottoms out on the housing, it can break it. Or if you back up at high rate of speed and the rear implement strikes something hard and shoves the the rockshaft up hard. These housings are pretty tough. It takes alot to break them.
Thanks for the input. The only thing we have attached to the back of this tractor since I've been here is a VERY heavy Rotodaeron tiller. The busted housing was noticed a couple months after it was disconnected. We don't think going over a bump at a high speed ever happened. I'll give an update as I get this back together.
Got most of it back together and can raise and lower the arms, going through the adjustments but I have a big oil leak. It looks like between the SCV (dual selective control valve) and the rockshaft control valve. The parts and service books don't show any sealant to be used between these surfaces and I don't remember scraping any off when I took it apart. I'm puzzled.
Leak is fixed and I got the rockshaft position linkage adjusted so that when it tops out I have a little freeplay. So when I lift up on the arms after they are in the up position I still have about 1" of travel before I feel the cylinder butt the housing.
I adjusted the draft linkage as close to the specs as I could and when I pull the draft arm all the way up the arms go beyond the original up position limit and it goes all the way till the cylinder butts the housing. At this point I can hear the hydraulics start to stress. We are planning to just not use the draft for the time being.