Hydrostat issue...with video - Page 5

darkminion_17 · #41 02-18-2021, 07:46 PM

I just wanted to see if anyone asked about a clogged oil line.

sawdustdad · #42 02-18-2021, 07:59 PM

Quote:

Originally Posted by ol'George

If you pull the rear end and sit it on the back cover,( on a wooden block) you can unbolt the hydro, and not have to drain the oil as the hydro is then sitting on top of the reservoir. Yes?
( you will have oil in the hydro as you know, but not much more than a Qt.

Yes, I've done that before, but not so easy with this grader. I just removed the gear case top cover and sucked the oil out with an oil extractor.

OK, now I have some more info.

I removed the pump swash plate because it looked like wasn't traveling as far as the one in my spares bin. I took some measurements and it wasn't so I suspected that it was in upside down. It was not upside down but I found a surprise. (see pic)

I reseated the bearing but it came loose again as I drove the swash plate pins back in. I reseated it with a long punch through the center of the swash plate but it doesn't look like it's going to stay unless I put a bushing on the outside to keep the rear end of the pump shaft from sliding back into the case.

I'm not exactly sure how (if) this displacement of the pump shaft would affect operation of the pump. The pump block would be a bit further down the shaft but it doesn't look like that disengages the splines. The spring in the piston block is just compressed more than normal. (I did notice the pump block was taller than the motor block, but didn't immediately suspect anything wrong, attributing the difference to the two different swash plates.)

Ambush · #43 02-18-2021, 08:25 PM

I believe the spring in the barrel will push down on the shaft. There is a washer that sits under the spring and that sits on the narrow band of spline. I don't think there is any retainer for those bearings? I wouldn't "add" anything.

How much lower is the motor barrel? Did you check the assembled height of the rotating groups, with valve plate, and measure how much above the housing, including gasket, they both sat?

darkminion_17 · #44 02-18-2021, 08:33 PM

I know it takes a lot of effort to remove that bearing as it is pressed in, looks like it was over heated? Maybe a new bearing with some loctite will help or do you have a housing you can swap out with one already installed.

Cubcadet_107 · #45 02-18-2021, 08:52 PM

Well, that was definitely unexpected! Good catch though. Not entirely sure how it would, but with these hydro pumps being such a precision assembly I'm sure the out of place bearing affected it to the point where it wouldn't work.

I'm guessing that maybe the belt broke when that bearing came loose. Perhaps when it first loosened it sat crooked on the shaft and caused a temporary binding.

For kicks, I went and took a look at the splines on my old hydro pump, and they pretty much look exactly the same as yours do and work just fine. Guess that wasn't the problem after all.

IMG_20210218_191704.jpg IMG_20210218_191804.jpg

Good to see that it seems you've figured it out though!

Ambush · #46 02-18-2021, 09:55 PM

Guaranteed that loose bearing is not your problem, and for sure did not cause your belt explosion.

sawdustdad · #47 02-18-2021, 10:14 PM

Quote:

Originally Posted by Ambush

I believe the spring in the barrel will push down on the shaft. There is a washer that sits under the spring and that sits on the narrow band of spline. I don't think there is any retainer for those bearings? I wouldn't "add" anything.

How much lower is the motor barrel? Did you check the assembled height of the rotating groups, with valve plate, and measure how much above the housing, including gasket, they both sat?

There is no retainer for that bearing. If it was originally press fit, it is only a bit more than a slide fit now. (I thought about staking it in place...)

With the bearing back in place, the pump and motor blocks (without valve plates) both sit about 1/8 inch above the edges of the case. The case is about 1/4 to 5/16 inch apart (due to valve plates' additional thickness) before tightening the bolts and compressing the springs in the piston blocks.

Before I discovered the bearing problem, the pump block sat about 3/16 higher than the motor block. That bearing is tight on the shaft.

I now have two hydrostatic rear ends that I've agreed to buy plus the 1210 tractor I committed to the other day. I'll pick them all up next week. They are 150 and 100 miles away, respectively.

If the narrow band of spline sits on a washer in the block, would that prevent the pump block from getting as close to the swash plate as it should, possibly preventing the pump from pumping? Even with the spring compressed? Is that the issue?

sawdustdad · #48 02-18-2021, 10:24 PM

Quote:

Originally Posted by Ambush

Guaranteed that loose bearing is not your problem, and for sure did not cause your belt explosion.

And I was thinking I had found the issue...Hmmm.

sawdustdad · #49 02-18-2021, 10:30 PM

Quote:

Originally Posted by darkminion_17

I just wanted to see if anyone asked about a clogged oil line.

Verified all the lines clear, but that was one early thought. I actually pulled the rear cover off the differential to be sure nothing was blocking the suction tube from the inside.

sawdustdad · #50 02-18-2021, 10:39 PM

Quote:

Originally Posted by darkminion_17

I know it takes a lot of effort to remove that bearing as it is pressed in, looks like it was over heated? Maybe a new bearing with some loctite will help or do you have a housing you can swap out with one already installed.

I don't have a usable spare housing, the one I have is cracked (it was towed, slippers piled up and punched a hole in the side of it).

Your Locktite idea is a good one. Red, right? Maybe I should epoxy it, LOL. Locktite makes a super glue version I think.