LT 28 Idle wheel bolt backing itself out.

Omer · May 24, 2019, 10:57:08 PM

Hello all, I have been battling a weird issue for the past week. I have a 2017 LT 28 and its a joy to run. I was sawing last week when I noticed a bad vibration in the blade, I could actually see movement in the blade forward and backwards about 1/8th inch relative to the guide. So I shut it down and found that the 5/16th bolt and washers on the idle wheel was backed out about 1/4 inch, the idle wheel had about 1/2 inch of wobble when I pulled on it. Frankly, I'm surprised it didn't throw the band. I cranked the bolt back down and checked that the idle wheel spun freely and without noise. I finished the log and called it a night.

Next day I called WM service line, the tech advised that I check the bearings, and if needed put some locktight on the bolt and snug it down.

So I double checked that the idle wheel spun freely, check.
Bought a new 5/16 x 1 inch bolt, new lock washer, reused the big washer.
Installed the hardware with a gob of blue locktight, let sit a day.

Two days later, cut for four hours... had to snug up the bolt 5 times.
Today had to snug it up twice in 4 hours... so I checked the alignment, seems within book specs, took off B57 and made sure no dust was under it, tried several different blades... frustrated.

So my question is, has anyone else done battle with a self loosening idle side bolt? Anyone have any insight that might help me solve this.

Thanks, ill post a photo or so if I remember to take one tomorrow.

Southside · May 25, 2019, 12:11:39 AM

Is a portion of the idle wheel proud of the bearing or somehow otherwise striking the big washer? Can you chase a tap through the threads to make sure they are not damaged or have debris in them causing the bolt to not torque down?

Just trying to think of possible mechanical reasons that may be happening.

Chuck White · May 25, 2019, 06:33:24 AM

Is it warmer to touch than normal, excessive heat can affect a lot of things!

Omer · May 28, 2019, 01:45:15 AM

Chuck and Southside thanks for your ideas, I actually had the chance to see my Grandfather, a tool and die machinist this weekend. He said the only way that there could be enough force to back out a bolt like that would be if the inner race of the bearing was spinning due to a seized bearing. Sure enough.. the inside bearing was destroyed. I took a few photos of what I found.

Looks like the bearing was spinning on the axle and cut away at the bearing shield and if there were cages, they are now gone.

v

The post is scored from the bearings spinning on it but it appears to be useable. I have new bearings, washers, and a bolt on the way and hopefully it will be a quick fix.