pulley bolt keeps loosening

[Wheel]

My 99 Craftsman GT keeps having the crank pulley (Kohler 20HP Vertical shaft) bolt loosen. I've pulled it out, checked the threads, lock washer is intact, cleaned it and installed blue Loc-Tite, but it still comes loose 3-4 times a season. I do try to check it regularly, but when I miss it, loose again.

Should I just replace the bolt and washer ?
What am I missing here ?

 

[old1]

Maybe tighten it tighter? How much torque are you putting in it? Also I prefer red loc-tite, and have never had any trouble removing bolts that I have used it on.

 

[jeepman3071]

I'd check a few things:

1. What are the torque specs for the bolt? Are you tightening it down to the proper specs?

2. What kind of condition are the bolt threads/ lock washer in?

3. When the bolt is tight, is the pulley fully seated on the crankshaft?

4. How are your engine to frame mounts? Are they loose? This would cause vibration.

5. When the belts are engaged (tight) is there enough slack in the belts that you can wiggle them a little? You want them to be tight enough so they won't slip but not too tight so that they put strain on the pulley.

6. How's the condition of the threads on the crankshaft?

 

[brandini]

NordLock washers are pretty nifty and deal with vibration really well.

 

[Phishin]

Get a new bolt. I'd start there. Make sure the female threads are clean as well. If not, soak them for a bit to help get rid of corrosion.

I'd use Red Loc-Tite on pesky bolts (like on my vibrating scooters and motorcycles). I use the "chapstick" version.

Then with the virgin bolt, tighten it real good. And leave it alone. This has done the trick for me before.

 

[Wheel]

Thanks everyone, I'm going to hunt up a new bolt and lockwasher and clean up the crank threads with carb cleaner. Then I'll loc-tite it up and torque it to spec. I will look over the frame mounts too.

 

[Brybo86]

+1 on the loctite

 

[4wheeldog]

You could also add a nylock nut to back up the locktite installed one. Not instead of locktite, but in addition.

Belt and suspenders.

 

[ironman_gq]

lock washers (the split variety) are basically a one time use only, the edges dull and don't bite like they should and they loose tension and tend to flatten out.

 

[Lubener]

New bolt and lockwasher are in order.Apply locktite blue and do not worry about corrosion, if anything that would help the bolt stay put. I wonder if anyone ever used anti seize on this before.Maybe there is a slight wobble to the pulley causing it to loosen.

 

[andyd]

Wabbout an internally toothed washer? They have a good bite. If this bolt has to come off to change a blade or a belt, I wouldn't get crazy with loc tite.