982 hydraulic cylinder rebuild help
 

I've done hydraulic cylinder rebuilds before on my tractors and equipment, but haven't run across anything like that dang front cylinder head retainer wire! What confuses me is why it has spanner wrench holes in the head but evidently no threads, just a locking retainer. Before I start cranking on it and break something expensive, is a spanner wrench used to turn the head in order to find the ends of the retainer wire in the case window, as I suspect? Thanks!

OK then! After excrutiating inspection, I figured it out and dismantled the hydraulic cylinder.......except for one thing. I'm tryng to figure out how to unscrew the piston from the rod without buggering up the piston. That's on there TIGHTLY. I can't find my old smooth-jaw pipe wrench, and the rubber strap wrench don't budge it. A little heat maybe?? I like torches!

deputyrpa:

I have had no experience in rebuilding Hydraulic Cylinders. Can't help you. But I am interested in your procedure and progress. Continue to keep us posted and we would like pictures.

Hopefully, someone has some experience in this arena and will chime in.

:WWP:

Try duct tape on the part being (trying to be) turned a few wraps will do, and s strap wrecnh with a pull handle if needed.

Alright, I'll step back and recap the steps so far.

I removed the two hydraulic fittings from the body assembly (case). I placed the case in my small pipe vise cushioned with rubber gasket material. I applied a liberal amount of PB Blaster in the slot, or window that exposes the case head retaining wire. Using a pin spanner wrench, I turned the head until the ends of the wire were exposed in the window, With one end at maximum exposure, I lifted it up with an L pick and grabbed it with a needle-nose pliers. I continued to turn the head while pulling the wire outside the case until it was removed. I twisted the head back and forth until it loosened sufficiently to allow removal by hand. Leverage was applied by slowly pulling on the rod until the piston forced the case head off. I removed the piston o-ring with a small hook-tip pick.

Now for the visual effects! I tightly clamped the piston in a vice, cushioned by cork flooring scraps. (note that any vice work requires oil-free parts and grippy cushion material - a slip may result in marriing, even in a smooth-jaw) I used a MAPP torch to quickly heat the piston/rod threads. Only loctite can hold like this sucker was being held! I put a large screwdriver through the rod eye, and turned the rod out.

While they were cooling, I attacked the two case head seals. The inner o-ring was removed with a small combination-tip pick. The outer seal was compromised. it was hard, and melted into the seat. The seat has a knurled lip that is thin, so care must be taken when removing this seal. The seat and seal are terraced, and the lip holds the seal in place. Mine came out in pieces, and I wound up smoking the remaining rubber with the MAPP torch and brushing the rest out.

That's as far as I got because I had to make bison and scallop kabobs for the annual work picnic. Tomorrow I will clean and recondition surfaces and complete the reassembly with the new rings and seals.

More pics....

Another note: Due to it's angle, the case head fitting can only be removed by clearing it as the point where the rod is welded to the eye. The rod is necked down there and provides the only clearance to turn the fitting - at least on this one. You do not want to scratch the rod!

982 hydraulic cylinder rebuild
 

I am repainting the case while it is apart rather than after assembly, because it's clean now, but will be oiled for proper re-assembly. The rod, piston, case head rod hole, and inside of case were polished with Mothers Mag and Aluminum polish.

Waiting for paint to dry in 95% humidity.......

What kind of paint will you be using ? I have had a hard time getting paint to stick where anything oil/fluid is on around. Looks like a fine job so far, the rod/piston is ground, which I'm sure you knew from the precautions you have been taking... just a note for anyone else doing this use precaution take care not to damage anything while doing this. Keep us updated.

I'm just using rattle can Plasti-Kote etching primer and IH tractor/implement paint. I took everything down to bare metal, cleaned and degreased it, and masked off all fitting and seal areas. For me, the idea is to protect against rust, make it look decent and not to do a full resto......for now.

You are correct about the rod and pistons. They are precision pieces, care must be taken not to nick or scratch them. As you notice, I work on wood. If it does happen that you marr internal parts, you must take off the high spots, becaust that is what rips rings & seals. The seals will continue to work over low spots. I have gouges on my backhoe bucket cylinders from rocks and boulders, which have been no issue because I have taken off the ridges and high spots.

The paint has dried enough for me to do the final polish & prep for reassembly. The color is not bad - just a shade brighter than the tractor, which may be due to fading.

There were a few really (really) light scratches near the case lip, and the inevitable light rust. I took most of the rust off earlier, and what was remaining was basically discoloration. I whipped out the Dremel and polished the area with light polishing compound. I also hand-polished the rod and piston with Mothers. It's all shiney and ready for reassembly tomorrow.