My Tractor Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
83 Posts
Discussion Starter #1
I did a blade sharpening on my Gravely 50" deck, and I noticed the nut on the pinions shaft of the gearbox had worked loose, and was actually wearing on the deck surface (metal on metal). I removed the gearbox carriage assembly, tightened the loose nut, and re-assembled everything. I tensioned the belt and when I went to mow, I had this screaming noise I never had before, coming when the deck was engaged. I'm not sure where it's coming from, and I re-tensioned the belt idler to make sure it was not too tight, with no spring play other than the .015" required. Any ideas on how to determine where the scream is coming from? I don't know if it's a spindle, or a pulley, but it sure is loud. I hate removing the deck again, but I may have to. Anyone had this issue and resolved it?

THANKS !
 

·
Premium Member
Joined
·
2,574 Posts
Re: 8000 serues with screaming 50" deck

I'd remove it, disconnect the belt and turn everything by hand to isolate it, including the gearbox. I had a stripped set of splines on a sheave pully and spindle last year that only manifested when I was in tall grass ( at first). I would describe it as more of a grinding sound, however. Root cause was a loose top nut on said spindle. Lesson learned. Had to rebuild with new spindle, bearings, races and sheave pulley. I also went to nyloks on the top of all spindles and snugged them down good.

Sent from my SCH-I605 using Tapatalk
 

·
Registered
Joined
·
83 Posts
Discussion Starter #3
Re: 8000 serues with screaming 50" deck

I'd remove it, disconnect the belt and turn everything by hand to isolate it, including the gearbox. I had a stripped set of splines on a sheave pully and spindle last year that only manifested when I was in tall grass ( at first). I would describe it as more of a grinding sound, however. Root cause was a loose top nut on said spindle. Lesson learned. Had to rebuild with new spindle, bearings, races and sheave pulley. I also went to nyloks on the top of all spindles and snugged them down good.

Sent from my SCH-I605 using Tapatalk

Thanks. I guess I'll have to bite the bullet and pull the deck off, AGAIN. I'm no youngster, and it's a big job for me. I use a floor jack under the front axle tree pivot, then jackstands, and then drag it out from underneath. I'm thinking about a mow-jack, or similar, to get it up more easily and accommodate the deck removal. Gotta raise it pretty high to clear the deck for removal, and the jack is to full extended up position to get it out, right now.
 

·
Premium Member
Joined
·
2,574 Posts
Re: 8000 serues with screaming 50" deck

There's a better way.

Go to your local harbor freight and pickup three three-wheeled dollies.

https://www.harborfreight.com/3-Wheel-Steel-Dolly-63683.html


Place one under each deck guide wheel and the third on the front nose roller. After disconnecting the driveshaft and lift arm, the deck will slide right out the side for you.

Sent from my SCH-I605 using Tapatalk
 

·
Registered
Joined
·
83 Posts
Discussion Starter #5
Re: 8000 serues with screaming 50" deck

There's a better way.

Go to your local harbor freight and pickup three three-wheeled dollies.

https://www.harborfreight.com/3-Wheel-Steel-Dolly-63683.html


Place one under each deck guide wheel and the third on the front nose roller. After disconnecting the driveshaft and lift arm, the deck will slide right out the side for you.

Sent from my SCH-I605 using Tapatalk
I think that would be a good idea....gonna pick up 3 of those tomorrow, and see how it goes.

THANKS !
 

·
Registered
Joined
·
1,769 Posts
If the gearbox nut was loose than I expect the bearings on the vertical shaft may be shot. The only time I've seen that nut loosen up is when the bearings fail and pressure on the nut is relieved. I agree with RedRider about checking everything over though. Spin everything by hand, if you can hear the spindles and idlers as they turn than the bearings are shot and should be replaced. The idlers use sealed bearings so you just replace the whole idler. If you have to rebuild the spindles than be sure when you reassemble them to lock both the top and bottom spindle nuts down tight so the shaft spins as one assembly. If you lock those nuts down and the spindle binds than you need to shim the spindle between the machined center spacer and one of the bearings, or replace the spindle shaft entirely. Don't ever run the spindles with a nut slightly loose to adjust for bearing load, you'll destroy a spindle in very short order. The spindles are designed to be run with the nuts locked down tight since the machined center spacer automatically sets the bearing load.

The gearbox is similar to the spindles when you rebuild it. The shaft nut should be locked down tight. If the bearings on either shaft bind than you need to install a shim between each set of bearings until you achieve proper free play, or replace the entire bearing/spacer assembly from Gravely, which tends to be more expensive.

Rick
 

·
Registered
Joined
·
83 Posts
Discussion Starter #7
If the gearbox nut was loose than I expect the bearings on the vertical shaft may be shot. The only time I've seen that nut loosen up is when the bearings fail and pressure on the nut is relieved. I agree with RedRider about checking everything over though. Spin everything by hand, if you can hear the spindles and idlers as they turn than the bearings are shot and should be replaced. The idlers use sealed bearings so you just replace the whole idler. If you have to rebuild the spindles than be sure when you reassemble them to lock both the top and bottom spindle nuts down tight so the shaft spins as one assembly. If you lock those nuts down and the spindle binds than you need to shim the spindle between the machined center spacer and one of the bearings, or replace the spindle shaft entirely. Don't ever run the spindles with a nut slightly loose to adjust for bearing load, you'll destroy a spindle in very short order. The spindles are designed to be run with the nuts locked down tight since the machined center spacer automatically sets the bearing load.

The gearbox is similar to the spindles when you rebuild it. The shaft nut should be locked down tight. If the bearings on either shaft bind than you need to install a shim between each set of bearings until you achieve proper free play, or replace the entire bearing/spacer assembly from Gravely, which tends to be more expensive.

Rick
Great summary. I was thinking about the issue, and is it possible that I over-tightened the blade nuts, and put pressure on the spindle somehow causing a binding? I unfortunately used an impact gun this time, and was thinking I might have forced that spline cradle into the spindle somehow? Is that possible?
 

·
Registered
Joined
·
1,769 Posts
Great summary. I was thinking about the issue, and is it possible that I over-tightened the blade nuts, and put pressure on the spindle somehow causing a binding? I unfortunately used an impact gun this time, and was thinking I might have forced that spline cradle into the spindle somehow? Is that possible?
You can't really over tighten the spindle nuts, (top or bottom,) on a Gravely spindle of this style, nor can you force the cradles into the shaft. Bearing load won't change no matter how tight the spindle nuts are, unless you're shaft or central cylinder on the bearings is worn. But typically if those are worn than your spindle will destroy itself by the time you've noticed that either of those parts are worn. This is why the top and bottom spindle nuts need to be run tight. Everything on this style Gravely spindle is a slip fit, so the spindle rely's on the top and bottom nuts to be tight in order to keep the parts firmly on the shaft and the assembly working as designed. Otherwise the cradles, pulleys, and bearings are free to move about on the shaft and destroy it. I've rebuilt probably 100 of these style spindles and I assemble each one with an impact driver of about 150 max ft lbs. Any blades changes I do with the same driver, and I've never had an issue.

Rick
 

·
Registered
Joined
·
83 Posts
Discussion Starter #9
You can't really over tighten the spindle nuts, (top or bottom,) on a Gravely spindle of this style, nor can you force the cradles into the shaft. Bearing load won't change no matter how tight the spindle nuts are, unless you're shaft or central cylinder on the bearings is worn. But typically if those are worn than your spindle will destroy itself by the time you've noticed that either of those parts are worn. This is why the top and bottom spindle nuts need to be run tight. Everything on this style Gravely spindle is a slip fit, so the spindle rely's on the top and bottom nuts to be tight in order to keep the parts firmly on the shaft and the assembly working as designed. Otherwise the cradles, pulleys, and bearings are free to move about on the shaft and destroy it. I've rebuilt probably 100 of these style spindles and I assemble each one with an impact driver of about 150 max ft lbs. Any blades changes I do with the same driver, and I've never had an issue.

Rick
OK, Rick, thanks. I thought maybe I over-tightened the blade nut, and caused binding somehow in the spindle.

I'm gonna pull the deck, clean everything up, check all three spindles, and go from there. My sense is that the center spindle would be the one of concern, because it's harder to access and grease. HOWEVER, IF I'M LUCKY, maybe I only have a bad bearing in a pulley somewhere in the belt system. I have a new belt, but it doesn't sound like belt noise, doesn't "smoke" the belt (no glazing, either). We'll see. Thanks for all the input.
 

·
Premium Member
Joined
·
2,574 Posts
If I had to guess, based on your description of the sound, I'd say a bad idler bearing. I was surprised to learn recently that some people go to the trouble of installing new bearings in idlers. I just pitch them, as it's not worth the hassle.

Sent from my SCH-I605 using Tapatalk
 

·
Registered
Joined
·
83 Posts
Discussion Starter #12
Problem located. The idler arm is missing the bushings to keep it centered and maintain the clearance between the idler pulley and the deck. Somehow (don't ask) someone installed the idler spacer and bolt in the arm and lost the bushings, it appears. I've ordered two of them, and with those installed, the deck-to-idler-pulley clearance will be restored. (I checked all the spindle bearings and pulley bearings, and they're all good).
 

·
Registered
Joined
·
14 Posts
Haven’t read all the threads, as I am not fully awake, but the first thing that comes to mind is to go in the house and count all the kids and cats, lol
 

·
Registered
Joined
·
14 Posts
Sorry, but that’s how my crazy mind works first thing in the morning.... I like the dolly idea, where’d you find them? ‘Nuther thing that works for me is a hoyer lift.... they use them in nursing homes for transferring patients from bed to chair, etc. they can lift 400 lbs +/- works great for taking blades off to sharpen
 

·
Inveterate Putterer
Joined
·
2,964 Posts
Re: 8000 serues with screaming 50" deck

I think that would be a good idea....gonna pick up 3 of those tomorrow, and see how it goes.

THANKS !
They do, indeed, work great, but the surface they are on also matters. They did not work well on my rough blacktop driveway; the little triple casters can't handle side force if they get caught in the slightest rut. That's why I built a very low dolly with more robust casters. The HF dollies work great on smooth concrete.
 
1 - 15 of 15 Posts
Top