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Lift Cylinder

Posted: July 18th, 2016, 7:53 am
by wv model AA
My 31 AA Dump Truck is a Heavy Duty Wood's Bed.

My Lift Cylinder leaks when in used from the stroke rod. A common problem.

The questions is, do you all know a recommended site that may have replacement seals?

I got "sticker shock" over the phone estimate from a professional hydraulic shop to reseal the cylinder.

Thoughts?

Re: Lift Cylinder

Posted: July 18th, 2016, 9:23 am
by Bob C

Re: Lift Cylinder

Posted: July 18th, 2016, 9:55 am
by wv model AA
Here are some pics.

Re: Lift Cylinder

Posted: July 18th, 2016, 10:36 am
by Stakebed
since you have it out of the truck can you take it to a shop and see what they say? ask around at hyd shops, semi truck repair places, even construction equipment dealers.

OR take the seal out and start taking measurements to see what you find.

Re: Lift Cylinder

Posted: July 18th, 2016, 10:53 am
by wv model AA
I'm going to take it apart myself.

I called a Hyd. Repair Shop and they estimated $500 and up, up, up to repair it including charging $85 p/hour. :shock:

Re: Lift Cylinder

Posted: July 18th, 2016, 2:29 pm
by Bob C
I looked in a Gar Wood catalog and they say four piston rings are used with separate grooves for each ring.
Maybe similar to an engine piston and rings.

Bob

Re: Lift Cylinder

Posted: July 18th, 2016, 9:05 pm
by tiredtruckrestorer
These older cylinders usually used a rope packing type material. You have to remove the collar where the piston shaft exits the cylinder body. There are two threaded studs with nuts on that hold the collar to the cylinder. Once you remove the collar the packing material should be underneath it. There are usually several layers of packing rings. You'll have to dig these out and try to get measurements. When installing new packing you cut the ends of the material at a 45 degree angle, not a straight 90 degree one. Stager the ends much like you do piston rings. McMaster Carr has packing material. Use the end collar to press the packing material in using the long studs and nuts to press it in. Sometimes you'll have to remove the collar and add more packing. Just don't crack the collar by tightening it up uneven. Sometimes a piece of pipe could be used to help press the packing in before using the collar. The hydraulic pumps and PTO's also used packings quite often back then rather than the seals we think of using today.

Keith

Re: Lift Cylinder

Posted: July 19th, 2016, 4:46 am
by wv model AA
Thanks. One more question ! So, the Collar will be able to remove and I shouldn't have to remove the end cover plate?

Most questions I ask are common sense before trying something for the first time on my own. I just want to cover my bases.

The first time I watched this dump bed raise up & down on my AA, I was excited like a little kid. :D

Re: Lift Cylinder

Posted: July 19th, 2016, 5:08 pm
by gunmetal 2
Take the bolts out of the plate, under that there is probaly a O-ring. take it to a hyd. repair shop and tie to get the O-ring. If you e-mail a pic of the pcs. I can better understand what you have. my e-mail address is 1929oldlady@gmail.com good luke

Re: Lift Cylinder

Posted: July 21st, 2016, 5:56 am
by wv model AA
Update: I know what the culprit to cause my cylinder to leak. The collar was cracked, welded, and cracked again. Furthermore; the dimensions of the collar that inserts into the cylinder cap has a lot of “slop” by my machinist standards, like .030 because the mounting holes don’t line up which force the cylinder to lift and add pressure against one side of the seal that results in leaking.

So my questions....Does the chamfer or do this design look familiar for a Wood's Collar for a Lift Cylinder ???

Re: Lift Cylinder

Posted: July 21st, 2016, 9:12 am
by drtrcrV-8
It's probably a waste of time to repair that collar: it's been brazed & re-broken, so it's probably quite brittle by now. If you have access to a milling machine(or know someone who does) I recommend making a new piece out of mild steel (instead of what looks like cast iron) for several reasons :1. it won't be brittle(bend instead of breaking) 2.much easier to make(the old piece, if repaired properly, needs to be machined anyway) 3. cost the same or less than the repairing the existing piece & wind up with a better part.

Re: Lift Cylinder

Posted: July 21st, 2016, 9:53 am
by wv model AA
Oh, I will definitely make a new part from mild steel with tighter tolerances.

Re: Lift Cylinder

Posted: July 21st, 2016, 5:02 pm
by tiredtruckrestorer
Yes, the chamfered collar looks typical of an older hydraulic cylinder. That should press against the packing material inside squeezing it against the cylinder shaft. Was there any packing material left inside?

Keith

Re: Lift Cylinder

Posted: July 22nd, 2016, 4:48 am
by wv model AA
The only thing I see what appears to be a "rubber" seal. It looks fine and I don't believe its correct for the time period.

One a happier note. I laid a 12 scale against the shaft. Its perfect shape & straight.

I'm highly convince the old collar is the problem.