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mtheaded_gw

John Deere 325 Garden Tractor Belt Issue

mtheaded
9 years ago

Hi all!

I recently acquired a 19 year old John Deere model 325 garden tractor with a 48 inch mower deck from my dad who has decided to give up mowing his own grass at the age of 81. The tractor is in excellent shape as he has had it serviced every year and it runs great. He didn't use it last year at all and I loaded it up on my truck and brought it home a couple months ago.

When I got it home and started it up, I couldn't get the blades to engage and the primary deck drive belt that connects the PTO to the mower deck was very, very loose (so much so that it would just slip off when trying to engage). I figured that maybe the belt was just worn so I bought another (John Deere brand OEM cross referenced in the original owner's guide which came with the tractor) and, while it did not fall off it just barely engages the blades and they move like a ceiling fan on low. This belt is also clearly too loose and yet I have tripled checked and it is the correct part number (Original part # M118684 now replaced with part # M143019).

I have had the mower deck off and inspected everything more than once and see nothing wrong (and I had a buddy look through it with me and he sees nothing wrong either). The John Deere has a pretty simple setup with a spring loaded tension arm that can only be moved to a stop for max tension and the belt itself only connects from the PTO spindle to the mower spindle (no other spindles in the path). I can only think of a couple things here:

1. The tension spring is somehow damaged or worn and I am not getting the proper tension. It looks fine (nothing is bent or broken) so I'm not quite sure how it would be damaged without being able to see it.
2. Somehow the PTO is not in the proper position (on the mower deck side the spindle is not movable and there is nothing bent or damaged on the mower deck) but I would think it would be impossible for that to shift.
3. Lastly, it is the wrong belt but I have checked multiple times and, according to the original manual and John Deere's online manual for this garden tractor with a 48 inch deck, it is not.

Anybody have any ideas or see anything I am missing? I have thought about buying a new tension spring but I hate to buy random parts as none of them are cheap. Does anybody think it could be the tension spring even though it visually looks okay or know how I could test it? Is it even possible that the PTO spindle has somehow 'shifted' and is now too far back? Would it be a really bad idea to just buy a ribbed automotive belt about an inch shorter than the John Deere belt (which is 1/2 inch by about 63 inches) and try it?

I really want to use this mower as my old Craftsman is one its' last legs and I am being held up by nothing but lack of tension on a belt!

As always, thanks in advance for any and all suggestions!

Comments (13)

  • jimmy56_gw (zone 6 PA)
    9 years ago

    Are you sure the tension pulley is working probably, Make sure it is moving freely but there is tension on it, You should be able to move it by hand but it will be strong, Also you said the belt is too loose so make sure you put the new belt on the right way so the tension pulley draws it up tight.

  • tomplum
    9 years ago

    Agreed. The rear stack pulley has to move freely. it isn't uncommon to see them not pivot and bind- but it normally happens where you can't release the belt tension. Maybe it was stored with the tension off? Work in some lube to free it up at the pivot bushings. Ideally, you would work the pivot off the stem and clean it all up and reassemble w/ new bushings.

  • mtheaded
    Original Author
    9 years ago

    Thanks guys, but the tension pulley is fine. Everything moves freely on the mower deck and the PTO pulley. Once I put the belt on (original or the new John Deere brand one) and engage the tension I can still grab the belt and move it freely. I can probably even remove the belt with the tension engaged as it is that loose. My issue is simple a way too loose belt which indicates either a shift in the location of one of the two pulleys (which seems impossible from what I can see), a wrong size belt (which seems highly unlikely as it is straight from the owner's manual of the deck) or, possibly, an issue with the amount of tension being provided when the tension rod is engaged, which seems to be controlled by the tension spring (which doesn't APPEAR to be damaged in a visual inspection).

  • jimmy56_gw (zone 6 PA)
    9 years ago

    Are you sure the mower deck is on correctly, Make sure it is align up correctly and fasten to the tractor with it's pins or latches.

  • mtheaded
    Original Author
    9 years ago

    LOL - Yes, the deck is installed correctly. The JD (as compared to my old Craftsman) is extremely easy to remove and install the deck and there is really no way to get it on except correctly. I've been working on my own garden tractors (with some great help from this forum!) for more than 10 years and this is the first one that has me stumped. Hate to do it, but I might have to break down and take this one to the JD dealer. There goes a lot of money and time if I do!

  • rcbe
    9 years ago

    might try reposting your situation over in the weekendfreedomachine forum... quite a few of the JD types hang out over there.

  • jimmy56_gw (zone 6 PA)
    9 years ago

    Can you take a string and wrap it around the pulleys and deck then measure that to your belt to make sure it is the right size, Really don't know what else to suggest except as rcbe said.

  • justalurker
    9 years ago

    Primary belt M143019 is the correct belt for both 48" decks used on both the 325 and GX325 so no problem there unless you have the wrong mowing deck on that 325 or the deck is not mounted properly. Could be incorrect front deck hanger (u bolt or pivot) or misassembled and the deck is forward of where it should be.

    The PTO can't go anywhere unless the engine is loose or you are not relaying the facts accurately.

    You could post some pics and we might spot the problem or you need to get the 325 to someone familiar with the brand and model. It will cost what it costs and since you can't resolve the problem you have to pay someone with the knowledge and experience to do so. Chalk the expense up to tuition and you'll gain some knowledge... and it might be a cheap fix anyway.

    This post was edited by justalurker on Wed, May 7, 14 at 22:38

  • mtheaded
    Original Author
    9 years ago

    Thanks for the tip about the JD forum, rcbe! I didnâÂÂt know that existed but I visited there last night (havenâÂÂt posted anything yet) and it does seem that all those âÂÂJDâ types hang out there! LOL

    I took a pic with the tension rod engaged and disengaged. I took an eyeball measurement of how far the pulley moves forward when it is engaged and it is about 3/4 of an inch which sounds about right to me.

    Now here is the interesting part: Thanks to jimmy56 (and I have no idea why I didnâÂÂt think of this!), I put the deck back on and got out the string and, when the tension rod is engaged the length of the string is 60 and 1/4 inches. The belt for the 48 inch deck according to the documentation (M143019) is 63.386 effective length (outside circumference) and is supposed to be .410 thick making the inside curcumference just a hair short of 63 inches. That is 2 1/4 inches longer than my string measurement!

    I'm not sure what to make of this but I have made absolutely sure that the deck is assembled correctly and attached to the tractor correctly. I can't vouch for all of the parts (like the deck hanger) being the correct part but I was told it was 'fine' the last time it was used to mow (which has been more than a year now).

    Thanks for all the suggestions to date. This is a great forum full of great people. I think I will cross post this over to weekendfreedommachine forum and see if any of the JD heads have any advice. Stil very open to any other advice if this latest post clicks with anyone!

  • justalurker
    9 years ago

    If you don't have the owner's manual for that 325 here it is...

    http://manuals.deere.com/cceomview/OMM143471_E0/Output/OMM143471_E013.html#48003

    It details step by step removing and installing the deck drive (primary) belt

  • mtheaded
    Original Author
    9 years ago

    Thanks, justalurker I do have the owners manual. I still have the original copy that came with the tractor and the electronic version as well. I also have a PDF version of the repair manual for this tractor and see nothing in there that would indicate a problem. Having looked over the tractor one more time thoroughly this weekend I am purchasing a 60 inch belt and giving it a try. In the meantime, I am also cross posting this to the weekendfreedommachine forum. I hate mysteries! Even if the shorter belt works I still want to know WHY!!

  • vbbeach520
    8 years ago

    Just saw this thread now, probably too late. I have the same mower deck, and when the belt went bad, bought the one John Deere calls for, and it was too long. Couldn't tension it up. Searching across the internet, and all parts lists showed a similar belt, but couldn't make it work. It calls for a 1/2" wide belts besides, which is an A-belt. I ended up trying two other shorter belts before getting one that worked. The belt that came off was also shorter than what was called for. The pulleys are wider than 1/2", I thought next time I'll go with a B width belt, which will take up some of the length of the belt making it ride further out on the pulleys where it belongs instead on the bottom of the v.

  • krnuttle
    8 years ago

    I looked at a mower picture on

    http://jdpc.deere.com/jdpc/servlet/com.deere.u90490.partscatalog.view.servlets.HomePageServlet_Alt

    And it seems like you have the belt path wrong. Of course not being able to see the deck with all of the guards of may give me a wrong impression of the belt path.


    Also while I did not dig deeply there appears to be two 48 inch decks on the JD 325

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