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400 Front PTO belt size

3029 Views 2 Replies 2 Participants Last post by  56chevy
Anyone know the size of the dual V belts on these 400's?

JD part number is AM35380.

The inner belt on my 400 got chewed up. When I pulled it apart I found that the tightener arm was out of alignment due to wear on the shaft. Strangely the pulleys didn't line up well. The engine pulley was about 1/4 inch too far back for some reason. The engine and frame don't allow for any adjustment so I have no idea how they could be slightly out of alignment. So I machined a collar for the engine pulley to bring it out the proper distance and rebuilt the tightener assembly by drilling the holes in the arm and installing a sleeve. JD didn't put enough bearing surface into their design here.

Anyway long story short. I forgot the one good belt at the farm last trip so I have nothing to compare to so if someone knows the dimensions it would be greatly appreciated.
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Hint: Register with JD Parts and you get individual part specifications. With proper alignment and adjustment an OEM set would last a long time. Typically tandem belt sets are "matched" for best service life meaning replace them both at the same time with the same brand so that they equally share the power transmission.

Here is the 400 PTO belt spec cut and pasted from JD Parts:

Weight: 0.62 LBS 0.28 Kg
Belt Section HA
Effective Length 41.270 IN
Number of Belts 2.000
Width 0.550 IN
Thickness 0.310 IN
Matched Set 2HA
Angle 32
Material Spec
Note D
Thanks for the reply.

The idler pulley was only working properly on the outer belt since the mounting pin for the tightener arm was so worn. The inner belt had slipped off the tightener so it got chewed up. I rebuilt the engine on this machine couple winters ago. Never noticed the wear on the pin at that time.

I can't see how the two pulleys could be 1/4 inch out of alignment following that. The mounts have only one place to go. The parts explosion doesn't show a sleeve behind the crankshaft pulley that I could have misplaced. When I get these parts re-installed it should last a long time. Something that's easy to keep an eye on too.

I rebuilt the 60 inch deck this summer.

This is one fine machine. We really enjoy it. Makes quick work of the farm yard. The tiller however is a bit large though. Bosses the 400 around in tougher soil conditions. Have to take smaller cuts.
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