48" JD deck (L 120)

OK. I've got 645 hours on 'deere and deck rusted through. The tensioner assembly dropped down slightly. I brought the tensioner pulley assembly back up to height (what appeared to be original location by matching the broken sections) and tacked it in place (weld). I put a new belt on ($40+/-), mowed half of my yard when it threw and chewed another belt:-(...I broke weld and shimmed the bracket so the pulley tilted slightly upward (went to Lowes and looked under some to the 'deeres decks and noted the upward angles). I have to admit I don't remember the pulley on my deck at such an angle. Well, I've thrown 3 belts (new) and figure I'd better ask if any one has the specs or a picture of the L120 48" deck showing the pulleys and their angles/positions before I destroy another belt. Being a DIYer, it really bugs me when I can't figure something out. Any helpful suggestions/info would be much appreciated.

I really hadn't planned on ridding myself of this 'deere even if it has plagued me with problems (mainly steering). I'm going to hang on to it 'til I get this right ., but I did go out today and purchased a new ztr (residential) delivery FRI....then to practice in my neighbor's yard. jk!

ps I did buy this mower NEW from JD dealer (Reynolds-Noblesville, IN), not big box store.

I have a LA 140 deck is 48 and off I could post a couple good pics if its the same I'm not sure

Thanks RDA. I know the L 120 and L 140 are similar (both in same JD shop manual...schematics, mechanicals, etc.) I don't know the "LA" designation but I appreciate your offer. thnx

I'll try to find a decent tape that way you can see the distance from bottom of pully to top of deck. I think they are the same mine is a 08 model yours is approximately 05

From looking on Google they appear similar. My deck has 2 idler pullys one on spring tensioner and one across from it. I'd ask Bert'smobile maybe he or someone else has a better idea

As a repairer I strongly recommend that as soon as you season is over take the deck off, strip it down, send it out for sand blasting to bare metal.
Inspect the deck very carefully for cracking around the welds particularly on the deck hangers.
If you find some reweld them and add some stiffener plates underneath.
When you are happy with the mechanical soundness of your deck, chemically clean it then prime & repaint it.
I use the POR 15 system and have 100% success with it , even under the deck and it can be brushed on as it is thin & self leveling.

If it is an "EDGE" series deck, check it for warping, because the spindles are steel they give the deck merry hell when you hit things you should not.
Unlike the alloy spindle housings which simply break.

Check the price of a new deck shell.
Down here it is cheaper than stripping, repairing & repainting in may cases on JD's deck pans go around $300-$500 where as others start at $ 1000

Thanks Bertsmobile. I didn't realize there was an "edge" deck, but sure enough after years on this mower I saw an EDGE decal! Will follow through on your recommendations.

RDA- Thanks for the pic, it look like the same setup on my deck except it doesn't have sheets of J Deere yellow paint peeling off.

Measured from the back of the deck ruler against the belt keeper on the other pulley its 2 and 1/4 inches on the low side

My bad on the high side not low side

I removed the mower deck from my John Deere L120 mower to clean, inspect and lube yesterday. I used a torpedo level to check the level of the pulleys on the mower deck. They all checked level except for the belt tension pulley. The distance of the pulley to the deck measures – front 2 3/8 inch, back 2 ¼ inches. I have attached a few pictures that might be helpful.