My Tractor Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
267 Posts
Discussion Starter #1
well guys, i have had more trouble. today i was mowing with it and the front grill popped off and i didnt know it and ran over it. the grill was tangled up in the blades. i got it untangled and it ran fine. i went out to mow some more and the belt popped off. this is atleast the 4th time in a week its came off. why does it keep coming off? am i mowing too fast, turning the PTO on with the throttle too high? the panels on the deck that protect the belt are off. i dont know why they are off but the guy that worked on it didnt put them back on. is that a possible reason?


:thanku:
 

·
The Magnificent
Joined
·
20,952 Posts
The belt shields are there for both your safety and to keep large objects from getting caught in the belt. Let's assume you are not mowing over rocks and branches, so it is unlikely either of these are causing the belt to jump loose.

Engaging the PTO at too high an engine RPM is not good, and may stretch the belt over time, but unless the belt is jumping when you engage the PTO that is not the problem.

Is the belt old and stretched? Is it the correct belt? Is it a JD belt or a generic cheapy? Is the belt routed correctly? Is the belt tensioner working properly and not rusted so that it does not move? Are all of the deck spindles rotating freely?
 

·
Premium Member
Joined
·
796 Posts
Hey JDO
on my 420 it has a dual belt system on the front PTO and a separate tensioner assembly. If the belts are coming off then you may want to check the lower PTO bearing for excessive play or the tensioner for the same. You may also want to check and make sure the belts are running in alignment.
Good luck
D
 

·
USMC
Joined
·
19,146 Posts
There is a difference in the JD belts. If your not using a JD belt this may cause some problems and they won't last as long. slkpk
 

·
Registered
Joined
·
264 Posts
I am confused. If the it is the two belts that drive the front PTO shaft, I agree with above you may have a bearing going on the shaft or the tensioner not set. If it the deck, like said above those covers need to be on for safety and to prevent sticks from causing the belt to jump off.

I have mowed hundreds of Hrs with a 420 never had a belt come off. I have had belts break - always was a reason. Check every idler and spindle, do they turn free and true.

Something is not aligned write or bearing is worn and can move or is slipping creating heat and then belt stretches. Good luck.

Yamadoo
 

·
Registered
Joined
·
86 Posts
well guys, i have had more trouble. today i was mowing with it and the front grill popped off and i didnt know it and ran over it. the grill was tangled up in the blades. i got it untangled and it ran fine. i went out to mow some more and the belt popped off. this is atleast the 4th time in a week its came off. why does it keep coming off? am i mowing too fast, turning the PTO on with the throttle too high? the panels on the deck that protect the belt are off. i dont know why they are off but the guy that worked on it didnt put them back on. is that a possible reason?


:thanku:

Sorry to read your 420 is giving you problems. The grills do just pop in and out, kind of weird how JD designed them like that. You can find a new one for about 100 bucks or even less.

I doubt you are mowing too fast, I have 3 of these machines and have mowed for thousands of hours at pretty high rates of speed without having any belt issues. I will say that JD belts are far and away the best for these tractors with 60 inch mowers, I am amazed at the amount of hours I get out of mine. I bought one of them with 1800 hours, the deck belt was cracked and dry rotted and it is still working fine on the machine with 2300 hours on it.

I did recently have my first and only deck belt failure on one of my 420's, it was due to a severe deck vibration. There was a noticeable knocking noise coming from the deck, the local JD dealer never found it. I was shearing deck driveshaft roll pins and keyways every couple of days-about 10 hours or 20. First a deck bearing failed, then the belt let go. Even after putting a new housing and bearings in the deck there was still the knocking noise that a well trained ear could notice, about 20 hours later the PTO pulley let go. I replaced the pulley and the splined shaft that goes through it, the knocking noise is much less noticeable. Checked the gear box componets and it is pristine.

My deck is really worn and rusted from the underside, so much so that it is almost junk. I do wonder if it is so thin that perhaps there is enough flex or movement in the deck that things get out of align and the vibration starts and then the belt gives up the ghost.

Sorry for the long post, but check everything from the PTO pulley to the driveshaft to the gear box to see what might have excessive wear. And trust me when I say all of those componets are $$$.
 

·
Registered
Joined
·
267 Posts
Discussion Starter #7
also guys, the deck sets kinda crooked. when the deck is all the way up, the wheel on the right is dragging but the one on the left isnt. how do i adjust that?
 

·
Registered
Joined
·
86 Posts
The deck wheels shouldn't be dragging when the deck is all the way up....are you talking about the front swivel wheels? If so they should have 4 or 5 slotted spacers that are about 3/8 inch tall each that limit the travel of the wheel up and down.

The deck itself should be square to the tractor, should be no tilt or cockeyed look.
 
1 - 8 of 8 Posts
Top