Power Shift Piston Shrinkage

1370rod · Aug 21, 2014

A few times when taking apart a Power Shift I have found a piston stuck tight in the carrier. Always when this happens there is signs of the clutch disc's getting hot. Apparently the heat causes the piston to shrink and become stuck in the carrier. The ID of the piston shinks tight on carrier and will no longer move causing that clutch pack to drag all the time. I have to split the piston to remove them, anyone else seen this occur? Rod.

Brokengun · Aug 21, 2014

No i have not. I have had a tight piston before but never to the point of having to cut the piston.

Did the operator run the tractor rear end out of oil?

I have heard of guys running a case tractor out of oil destroying the differential but not a powershift

Ranchingelec · Aug 22, 2014

I had to drill 2 holes across from each other and threaded holes into the piston. Then used the bolts to push piston out. Someone had only put in one belville washer thus causing drag and heat build up.

2290 · Aug 22, 2014

Hi Rod

I've had to cut them out several times in the past.
There is no other way.

Marlin

mEl · Aug 22, 2014

Yup Rod, had that several times, heat is the culprit.

Agri King · Aug 22, 2014

Hello Rod, this was the C-1 piston in a 2096. The plates were fine so I reused them, I think there was just enough crap wedging it in the carrier. A snap ring had broke back on the input shaft chewing up the oil distributer, then of coarse warping C-2 C-3 plates.....odd deal

Thad · Aug 22, 2014

Yes we have had to pull many of them out like you said clutches had been scorched in them.

dcb 930 · Aug 22, 2014

The piston isn't the problem, the piston carrier is. The steel carrier expands from heat at a different rate than the aluminum piston. When the piston binds and can't move the clutch pack, the clutch pack will ultimately slip and destroy itself. Chances are the carrier wasn't machined to the proper tolerances or distorted over time. If you install a new piston on that carrier you'll probably see it back again with the same problem. I've seen many clutch packs burnt up for various reasons and the piston isn't stuck. When we get one in here (through the school of hard knocks)with the piston stuck in the carrier we automatically replace the carrier. IMHO

Agri King · Aug 22, 2014

Well to each their own but I can't remember seeing a carrier even discolored from heat. If the carrier can take shearing off 6 3/8 or 1/2 inch grade 8 bolts & not be damaged a little heat isn't going to hurt anything. Just my thoughts.......

mEl · Aug 23, 2014

I have never replaced a carrier after removing a stuck piston and I always replace the pistons with the Oring/square cut seal type. When the piston gets badly overheated it grows and when it cools it grabs the hub and has to be forcibly removed.

Power Shift Piston Shrinkage

1370rod

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Brokengun

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Ranchingelec

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2290

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mEl

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Agri King

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Thad

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dcb 930

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Agri King

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mEl

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