Replacing the 3-point lift piston seal

   / Replacing the 3-point lift piston seal #1  

WestPalmBob

New member
Joined
Jul 1, 2017
Messages
10
Location
West Palm Beach, FL
Tractor
Shibaura SD2243D
This relates to another posting I made in the Grey Market forum that probably should have been here. That post includes a number of photos and questions / observations before my getting to this point.

Anyway - in case anyone else can benefit -

Yesterday I decided to tear into the 3-point lift problem. I removed the housing and subsequently, the lift piston. In case anyone else could benefit, here is what I did and what I found.

To gain access to the housing, I removed the seat, and the sheet metal deck between lift housing and the seat. It was held in place from bolts accessible from the front, and through the fender wells. There was a single rigid high-pressure hydraulic line attached with a banjo bolt high on the left side of the housing. The housing is attached to the transmission case with with M10 (17mm hex head) fasteners mostly bolts but there were two studs with nuts because the hydraulic control above prevented clearance for bolts. It was necessary to remove the top lift mount on the rear of the housing to permit the bolts to be removed. The housing was a bit heavy but can be lifted by one person.

I removed the head (forward) end of the cylinder which was held in place with 6 M12 (19mm hex head). The cylinder assembly slid easily from the housing and the piston slid easily out of the cylinder.

There is an O-ring (about 3.25 inch diameter) between the head and the housing and a small O-ring on the head itself. I imaging both should be replaced. The cylinder seems undamaged but the piston seal is shot. It is hard and brittle. I believe when it was new, it was slid over the piston which seems to be a machined casting. The piston diameter is just under 3 inches I measured 2.954.

I expected a C cross section but this seems to have a rectangular cross section. I am going to go to a hydraulic place tomorrow and see if I can find a replacement. I will take the piston and cylinder since such a place will have been tools for measuring than I do. IMG_20180929_123647.jpgIMG_20180929_123738.jpgIMG_20180929_125258.jpgIMG_20180929_150004.jpgIMG_20180929_150007.jpgIMG_20180929_150012.jpg

One thing I noticed, I see sensors perhaps limit sensors to prevent the hitch from being raised above to predefined limit. None of that is connected my my tractor. In fact almost all the electric is disconnected. I have no lights, or turn signals, and see other disconnected wires. I have no idea what their original function was.

This is the first time I have seen into the transmission housing. The portion below the lift housing is for the 4-speed PTO and the diff lock. They look like I expected except that the parts are more beefy than I am used to from automotive work and, there are no obvious spider gears so I am not sure how the diff works when the diff lock is off. I will attach some images.

I realize I should have blown off the area around this before removing the housing. Access was difficult. I'll be very careful to clean it well without allowing any debris into the transmission case before I reasemble things.

I would welcome any tips or comments from this or the other post I made in the Grey Market forum.

- Bob
 
   / Replacing the 3-point lift piston seal #2  
I can supply parts for shibaura tractors. Email with what you are looking for.
 
 
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