Bill D 1,932 #1 Posted September 17, 2019 My friends 312-8 (Model 73428, S/N 8900145) keeps going thru drive belts. He had two belts fail since he got the tractor two years ago (at my suggestion). The belt is rubbing the brake rod, but we can't figure out how to stop it. None of my tractors have this problem, but they are older units with different engines. Everything appears to be aligned correctly. Any help would be appreciated. Bill Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,090 #2 Posted September 17, 2019 They had a problem with the engine drive pulley and pto sliding too close to the engine under high pto clutch pressure so added a spacer behind the drive pulley. Different complaint but may be related. Spacer part number 100-3549. If you happen to get one would like to know the dimensions of it. Garry 1 Share this post Link to post Share on other sites
peter lena 8,716 #3 Posted September 17, 2019 you might try removing the drive belt side guard for a total look see . that way you can watch it action and go after it. this varidrive system is pretty bombproof , aside from belt age and wear , there should be no issues, you might also detail check the spring tension pulley ( just inside of rear wheel on the frame ) that maybe part of your issue. i replaced mine with a much stronger unit , from a belt /pulley shop. there are also a number of pictures on this issue on this site , look up drive belt set up. probably hiding in plane site , pete Share this post Link to post Share on other sites
peter lena 8,716 #4 Posted September 17, 2019 add this to your think tank, even though its a hydro the set up is the same, pete Share this post Link to post Share on other sites
WVHillbilly520H 10,374 #5 Posted September 18, 2019 9 hours ago, peter lena said: add this to your think tank, even though its a hydro the set up is the same, pete Sorry Pete not so much the hydro and manuals route the belt differently plus the manual has extra tabs to keep the belt aligned while clutching... Check out this video... Share this post Link to post Share on other sites
wallfish 17,078 #6 Posted September 18, 2019 21 hours ago, Bill D said: The belt is rubbing the brake rod, but we can't figure out how to stop it. Post some pictures with the belt guard off. This rubbing is causing the belt failures Share this post Link to post Share on other sites
Bill D 1,932 #7 Posted September 18, 2019 The tractor belongs to a friend of mine I will try to get some pictures from him to post. Bill Share this post Link to post Share on other sites
Lee1977 6,774 #8 Posted September 18, 2019 That is a 1998 model with the newer engine. I just checked my 312-8 and there is 1/2" to 5/8" clearance between the belt and brake shaft. The 12 Magnum the PTO shaft is up 6" to the center above the frame. There are so steel mounting channels under that engine. What does it measure from the frame up to center of the PTO shaft. The drive pulley behind the PTO should be 4" in diameter. Some one could have put a hydro pulley on that tractor they measure 5 1/2" in diameter. That would cause it to rub. Share this post Link to post Share on other sites
Alrashid2 286 #9 Posted Wednesday at 04:21 AM @Bill D did you ever figure this out? Having the exact same problem! Drive belt rubbing brake rod Share this post Link to post Share on other sites
Bill D 1,932 #10 Posted Wednesday at 05:05 PM 12 hours ago, Alrashid2 said: @Bill D did you ever figure this out? Having the exact same problem! Drive belt rubbing brake rod I believe we adjusted the location of the drive pulley on the engine. This was so long ago I forgot I posted this. He no longer has the tractor. Share this post Link to post Share on other sites
Alrashid2 286 #11 Posted Wednesday at 06:47 PM Aw, time flies doesnt it? Thanks for letting me know! I'm hoping I don't have to mess with the drive pulley. Thanks again Share this post Link to post Share on other sites
johnnymag3 2,521 #12 Posted Thursday at 03:43 PM (edited) Alrashid2 Adjusting the pulley or pulleys is super easy...Go for it if that is the issue Edited Thursday at 03:43 PM by johnnymag3 . Share this post Link to post Share on other sites
Alrashid2 286 #13 Posted Thursday at 03:45 PM Thanks for the advice @johnnymag3. You know of any instructions or a post outlining how to do it? So the drive pulley can be adjusted in and our horizontally? Share this post Link to post Share on other sites
mrc 840 #14 Posted Thursday at 04:09 PM if you try to move the pulley on the engine be aware that sometimes there are 2 set screws in each hole. one set screw on top of the other one. 1 Share this post Link to post Share on other sites
Alrashid2 286 #15 Posted Thursday at 04:10 PM Thanks for the heads up. Have not touched it at all yet. Do the 312-8s with the K301 have adjustability of the drive pulley? I didn't know they could be moved Share this post Link to post Share on other sites
