Lawson 1 #1 Posted July 20, 2018 Hello everyone: I'm looking for a replacement deck drive belt. The belt currently on the tractor is a 1/2" belt. I think it should have a 5/8" belt on it. Can anyone say for certainty what width the original belt was. The 1/2" belt just can't seem to get the job done. The original part # was 6771.I haven't been able up to now to find the size spec. It is not on the parts list. Thanks in advance for any help. Share this post Link to post Share on other sites
Lawson 1 #2 Posted July 20, 2018 Oh, just realized I forgot to give the model # it is a 1257. Share this post Link to post Share on other sites
daveoman1966 3,612 #3 Posted July 20, 2018 (edited) The correct deck drive belt is on the schematic of the mower deck....not the tractor parts list. What is your mower deck model #? Use that model nuymber to find the right drive belt. A typical 1967 mower deck would be RL-426 . That is a 42" side disch deck and the drive belt for it is # 6737. Belt $ 6737 spec is 69" x 1/2". That is the same belt used for the 36" deck too. There may be a cross-over to NAPA belts...not sure. However, the Wheelhorse belts of this era...late 60s - 70s... are proprietary and after-market belts are not geometrically the same. That is, the aftermarket belt will ride either too high or too low in the Wheelhorse drive & idler pulleys, or not match perfectly to the V shape contour, leading to either slipping belt and/or causing less than optimum performance and premature degrading. Frequently they will 'roll-over' in the V of the pulley and the only cure for that is ...get another belt. When Toro took over in the mid 80s, this was largely corrected. Edited July 20, 2018 by daveoman1966 1 Share this post Link to post Share on other sites
Sarge 3,462 #5 Posted July 20, 2018 The belt profile wheel horse used on the early run prior to '73 was HA - almost non-existent today. There are a couple of manufacturers that still make belts that are compatible (Q-Power is one), but they are not identical to the original equipment belts. I've bought NOS transmission drive belts that were old dealer stock due to wearing out a rare drive pulley for my old 1277 - the standard and more common A profile belts will wear a bad groove into those pulleys and destroy them, causing premature belt wear and slippage. It's the same deal with the older decks - unless you convert to the newer style tach o' matic system and use a more modern deck. For your 12hp model, 42-48" decks from the late 70's through the '90s will work easily with the addition of a C series model mule drive and frame bracket - then you use the standard C series deck belts. There was a kit back in the day for converting the older model tractors to use the newer tach o' matic and mule drive - those brackets bolted right on the front frame rails. The C-series is easier to use, just make sure to grab the longer axle pin that goes with the bracket. I'm sure someone has some pics...my phone isn't working properly to load them on the computer right now. Sarge 1 Share this post Link to post Share on other sites
Lawson 1 #6 Posted July 20, 2018 Thanks for replies. As I said in previous post the part number is 6771. That came from the deck parts list. It is a RL-486 deck. The pulleys are in good condition. I'll try the q power route. Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,504 #7 Posted July 20, 2018 Belt dimensions are on this page. Click on the picture Garry Share this post Link to post Share on other sites
peter lena 8,072 #8 Posted July 20, 2018 I thought SARGE was spot on, having done some deck detailing on belts and pulleys as well as mounting points , it all adds up to a much easier and smoother running deck. I run a 1" shorter pto/mule drive belt to stay on the shorter engagement point on the mule drive. that is also a stronger drive point, I often see guys running a mule drive at the far end of adjustment, that will also set up a vibration to your belt drive. those mule bearings are often forgotten , even thou they are sealed , chain and cable spray in mine made a big difference, as well as the threaded adjustment rod. detail it, pete Share this post Link to post Share on other sites