Trencher Motor Replacement

[BobRip]

After trenching around a good size stump, I noticed that oil was leaking around the shaft. I had noticed earlier that a small tree has gotten up around the shaft seal. I suspect that this damaged the seal. I lost about 2 quarts of oil.

To replace the motor I found that I have to get a special socket from Power Trac. They "loaned" it to me. I gave them a credit card number and they shipped it to me. After use I mailed it back and hopefully they will credit my acount.
The socket is designed to go into the hollow of the drive sprocket shaft and loosen a castellation nut. See attached picture.

Bob Rip

 

[BobRip]

I used a gear puller to get the sprocket off.
To put the chain back on I called a neighbor. The chain seemed to weight about 100 pounds (no I did not weight it), so I fiqured I would need help. It also takes about 4 hands to hold the chain and put the bolts and brackets back on. We got it back on and realized it was backwards, so we had to take it off again. No big deal, but it was nice to have help. (I did dig about 200 feet of trench for the neighbor a few years back and this is the same guy I pulled a gate post out for.) I doubt that I could have done this alone, so many thanks to Pete.

One thing I should have done is put some grease between the front idler socket and the bolt going through it. I will probable try to spray some grease in there.

To adjust the chain tension, you put the trencher bar horizontal and adjust the tension (or slack actually) until the gap between the bottom of the bar and the top of the chain is about the width of 4 fingers on your hand (for me that's about 3 1/4 inches). I am told by Power Trac, that this gives the correct tension. It seems to work fine.

Attached is a picture of the trencher with the chain removed.

Bob Rip

 

[BobRip]

Actually, as I now remember, the hardest part was pulling the socket out after I retighted the nut. I think the socket was not machined perfectly, and I had to pound it in a little bit on initial nut removal. I ended up loosening it up, spraying it with some PB Blaster, and then putting it back in rotated to another position.

My best advice is do not let vines or anything else get caught in the seal of a hydraulic motor shaft. I had earlier got a tow strap caught in the stump grinder motor and had to have it rebuilt.

The rebuild price which included a bearing and seal replacement was less than $80, plus shipping back and forth and shipping the socket back and forth.

I figure my trencher has about 1500 feet of trench on it. It is rated at 5000 feet.

Bob Rip

 

[MossRoad]

That socket looks like a hydraulic motor coupling with the shaft hole machined out to fit a square drive.

 

[BobRip]

Actaully it fits a castellation nut. I think they did take a regular socket and machine it.

Bob Rip

 

[BobRip]

Oh, I understand now. Maybe your right.

Bob Rip

 

[MossRoad]

Nah, I guess I'm mistaken. I thought my coupling on the shaft for the brush hog had 6 tangs, but each half only had three tangs and the rubber spacer between them has 6 tangs. Here's a link to one at Northern tool that is similar to the one on my brush hog.

 

[BobRip]

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To replace the motor I found that I have to get a special socket from Power Trac. They "loaned" it to me. I gave them a credit card number and they shipped it to me. After use I mailed it back and hopefully they will credit my acount.
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The good news is that PT did credit my account for the returned socket.

Bob Rip

 

[BobRip]

I took the PT over to a friend's house today and trenched about 150 feet of trench in two hours. The worse problems were getting rocks stuck in the trencher. This happened about three times. I always carry a hammer and chisel and it takes about a minute or two to knock a rock out.

My friend had prevously thought of the PT422 as a riding mower, now he talks about buying one just for the trencher. I doubt that he will, but he understands better what at PT can do.

Bob Rip

 

[stray]

How did the trencher do cutting through roots. Say 1 to 3 inches in diameter. I have a job coming up. 180 ft through a wooded area, 3 ft deep. I have the mini hoe but no trencher. any recommendations?