Woods RM990 repair

[yoderjac]

Years ago I bought an old Woods 990 heavy duty finish mower. It is configured like a finish mower with a belt and 3 blades, but it is almost as heavy duty as a bushhog. It has been a great implement for me. The belt go around an idler arm that is connected to the frame with a large spring. The purpose is so that if you hit something hard, the idler arm stretches the spring temporarily loosening the belt. As you move forward past the obstruction, the spring pulls the belt tight again and the blades begin spinning.

The idler arm is welded to a sleeve that goes over a pin sticking up from the deck. I believe it has a ball bushing in the sleeve that lets it rotate on the bearings rather than just spinning on the post. Over the years, I think the bearings have frozen. The symptom is this. When I hit an object or heavy brush puts pressure on the blade, the idler arm rotates stretching the spring, but the spring does not pull it back. I have to open the cover and kick the idler wheel back into place. I did replace the spring with a new one, so that i not the issue. In order to remove the idler wheel, I had to rotate the arm. The only way I could move it was to use a hammer. I could only rotate it about 20 degrees each way and it does not get any easer to move if I hammer it back and forth. I presume the entire ball bushing is turning that 20 degrees rather than the ball bushing working like it should.

I looked online and it looks like Mesick's carries the idler arm and I presume it comes with the ball bushing but I'll call and check before I order it.

This presumes I can remove the existing idler arm which is my problem. A pry bar won't budge it. Today I tried a 5 ton gear puller. It was close but I could not get it to fit in either 3 or 2 arm configuration. The jaws would not fit over the sleeve. I think it is just too narrow for this tool. A puller needs about 4 1/2 inches of depth which is how far the pin sticks up off the deck. There is about 1/4" between the bottom of the sleeve and the deck where jaws could fit. I could fit one jaw under the sleeve but when I tried to the the second one under it changed the angle and they wouldn't both fit.

I found a puller online that looks like it might fit: https://www.amazon.com/gp/product/B07QKJHC61/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I ordered it. If necessary I'll modify it to fit if I can.

If this tool does not work, I'm looking for other suggestions. Often we can take a torch to things that are stuck, but I'm not sure if that will work with a ball bushing in the sleeve.

Thoughts?

Jack

 

[yoderjac]

Here is a pic that might help

 

[Tree Spud]

Have you inspected for a snap ring?

 

[yoderjac]

Have you inspected for a snap ring?

I didn't see one. There is a washer, felt pad, and cotter pin that go on what you see in that sequence. I wouldn't think they would have both, but I'll double check in the morning.

Thanks,

Jack

 

[Tree Spud]

I can't imagine there are any ball bearings in there, it looks like a straight bushing. Galling should not be an issue with dis-similar metals between the shaft and bushing.

Clearly not a precision tight fit machined bearing surface and low rotational, low stress bearing surface.

Good chance either metal surface failed and you have metal fragments binding, or after years of use the combined plant fibers, metal fragments, grease, etc. have built up and seized the surfaces. Understand that many plant fibers are very abrasive even to metal surfaces.

Try finding a pipe or socket the will match the bearing diameter and start tapping the bearing head diameter only to see if you can stress the moving of the bearing. This is not a muscle man test, but rather a slow continuous strike force to the bushing. to slow break the grip of the contaminates that are lodged to break free.

 

[yoderjac]

Good thoughts. The only reason I suspect ball bushing in the sleeve is that the idler wheel has one in it and they look similar. You are right, of course, that the thing only rotates no more than 45 degrees and that would only happen when an object is hit, so there probably is no need for it to be a ball bushing.

I've put penetrating oil on top multiple times but evidently it is so tight it does not make it in. I've used a hammer to bang on the side of the arm and I can only rotate it about 20 degrees with a lot of pounding. I would think that working it back and forth a few time would have had some impact but it is just as tight as ever.

I try the jaws I ordered when they come in next week. If I can't budge it, I'll try a torch.

Now let's see, Heat causes metal to expand, So it looks like I want to heat the sleeve, not the pin right?

Thanks,

Jack

 

[yoderjac]

Well, I ordered this tool: https://www.amazon.com/gp/product/B07QKJHC61/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I knew it would be close, but it did not quite fit. I could almost but not quite reach under the bottom of the cylinder with it. It was soooo...close. I tried 3 or 4 times with no luck. One jaw or the other would pop off. I finally decided to try to put the claws under the bar instead of the cylinder. There was plenty of reach for that, but the tool would be at a slight angle. I presumed it would slide off as I tightened it, but I got lucky.

A combination of BreakFree sprayed on, the tool, and heating the cylinder with a torch, finally got it to move. I figured once I broke it loose it would come off easily but that was not the case. It took about the same force until about the last inch.



The cylinder was full of rust. I first soaked it in a bucket with hot water and dawn to remove the grease. I then went to Lowes and buying a 1" copper tubing reamer brush used to clean out copper fittings. I cut off the handle and put it in my drill. I used that to remove the rust from the cylinder on the arm.

The rain stopped, so I quit working on it and went hunting. Tomorrow I'll use some steel wool on the post and clean that side up then lubricate it with Teflon dry spray and reassemble it.

Next step in maintenance is to turn it upside down and drain the gear oil. I can't find a drain plug so I'll just empty it through the fill plug.

Thanks for the help!

Jack

 

[yoderjac]

I finished cleaning it top today. I used some steel wool on the post. Sprayed them both with Teflon Dry Lube. It now rotates freely like it should. I reassembled it and all is well.

I may wait for warmer weather before trying to invert it to drain the gear oil and replace it.

Thanks,

Jack