manant 57 #1 Posted August 16 I want to replace the transmission drive belt on my c160 automatic. I Purchased an after-market #7478 belt (NAPA 5L840W that is a nominal 5/8" x 84" - Actual 21/32" x 84" OC) I found it extremely hard to get on, and it was very taut (no slack when disengaged). I am afraid that the belt will not slip on the engine pully when disengaged. The old belt may have worn and stretched some and does have some slack. I know the old belt was not so hard to get on, My questions are how much slack should there be? Would it damage the transmission if the belt turns continuously (not slip on the engine pully)? I do not have a photo yet. Share this post Link to post Share on other sites
squonk 44,092 #2 Posted August 16 You have the right belt #. And it's ok to use non OEM belts no matter what other's say. Check it to make sure the belt you got is actually an 84" belt. sometimes people return belts in the wrong sheave. If it's correct, sounds like you got it routed wrong. I don't have a pic of a new belt on ,but here's my C-160 when I changed the belt 2 years ago. Share this post Link to post Share on other sites
ri702bill 9,656 #3 Posted August 16 1 hour ago, manant said: The old belt may have worn and stretched some and does have some slack True, and not-so-true. True, the old belt is worn. Belts do not stretch, the 2 Vee sides wear, the belt sinks deeper in the pulley grooves, giving the impression it had "stretched". Look at the difference how both belts ride in the transmission pulley - the new one sits up higher...... Share this post Link to post Share on other sites
manant 57 #4 Posted August 17 The belt is routed correctly. My old belt looks like the one on your c160. When I got the new belt on it was so tight I could not disengage the brake. The new belt number is "B81 or 5L840" it also has a 5024 number on it, I know the 5L840 indicates a 5/8" x 84" belt. Regardless I put the old belt back on and will use that for now. For a little background - I was mowing about a month ago and got into some high wet grass too quickly and the engine started to labor. I heard a loud clunk and thought I may have broken the piston rod. I immediately released the PTO clutch, and the engine kept running. I got it back to my shed to look it over. After some checking I found out that I had sheared the flywheel key and the friction material on the PTO clutch disc had broken. The friction disc had shown a lot of wear and I was looking to rehab it soon. I ordered a new friction disc and was going to replace the belt with the new disc. My old belt was not in bad shape. The flywheel bore and the crankshaft were slightly scored by the broken key. I used some valve grinding compound to lap the flywheel bore and the crankshaft. I then used some auto polishing compound to further the lapping. The flywheel is back on and torqued to 60 foot pounds. Any thoughts on my repair? Share this post Link to post Share on other sites
Gary S Minnesota 59 #5 Posted August 17 I too just replaced the drive belt on a C-160 Auto, 1977 model. Our local TSC store did not have the 84” in stock and didn’t know when to expect a restock so I ordered on line and it arrived in 3 days. Once I got the belt guard removed the new belt slipped over the pulleys and under the idler with no problem. Reinstalling the belt guard and properly positioning the belt above the lower guide and above the 2-3 inch upper guide of the belt guard was a bit challenging and took me two tries to get the belt positioned in the guard properly and everything bolted back on. I now notice I have a bit of belt slap? I can hear it occasionally at low rpm. Is a bit of belt contact on the guard normal? Share this post Link to post Share on other sites
squonk 44,092 #6 Posted August 17 6 hours ago, Gary S Minnesota said: I too just replaced the drive belt on a C-160 Auto, 1977 model. Our local TSC store did not have the 84” in stock and didn’t know when to expect a restock so I ordered on line and it arrived in 3 days. Once I got the belt guard removed the new belt slipped over the pulleys and under the idler with no problem. Reinstalling the belt guard and properly positioning the belt above the lower guide and above the 2-3 inch upper guide of the belt guard was a bit challenging and took me two tries to get the belt positioned in the guard properly and everything bolted back on. I now notice I have a bit of belt slap? I can hear it occasionally at low rpm. Is a bit of belt contact on the guard normal? Yes some is normal. You can quiet some of the noise down by putting some rubber edge guard material on the bottom edge of the belt guard. Available on amazon Share this post Link to post Share on other sites
peter lena 9,340 #7 Posted August 17 @manant typically find a belt issue is related to OVERALL , BELT DRIVEN , COMPONENTS , never just one spot , what is the related pto clutch issue telling you ? broken clutch disc , is directly related to combined bearing failures . never had a disc break . or wear into the rivets , often refer to deck moves by hand at pto to mule drive belt down area ? that is telling you of a combined lubrication failure track . on your unit , there are 12 related bearings , in that set up , what could you possibly do ? looking at every stage , is showing you , combined drag . definitely not a one and done . that clutch base needle and sealed bearing , alone can cause this , you have other areas as well , a drawing layout will show you the fault areas . pete Share this post Link to post Share on other sites
manant 57 #8 Posted August 17 Thanks for the reply Pete! I have never known how much pressure the trunion should place on the friction disc. My c160 is a third hand tractor that my neighbor gave to me 12 years ago. I have learned a lot about the c160 - over the years I have rebuilt the k341 twice; replaced all of the mower spindle bearings, replaced the PTO bearings, rebuilt the transmission, rebuilt the transmission friction lever mechanism, replaced all of the belts several times, etc. This FREE c160 has cost me thousands over the years and worth every penny. The mower double pulley was damaged when I got the tractor and I have repaired it several times until it finally gave up the ghost this spring. I had searched for this pully for years and finally found a new one right after my old one died. I replaced the double pulley, put in a new spindle shaft, and new bearings in the center spindle, and greased all of the spindles. The blade spindles spin freely, the mule drive pulleys spin freely, and the PTO outer housing spins freely with no noise. The idler pulley on the brake lever spins freely also. The friction material on the friction disc had worn nearly to the rivets and there was movement between the friction material and the friction disc - like the friction material holes for the rivets were enlarged. After it failed, I drilled out the rivets and was going to replace the friction material, but decided to replace the whole disc. There was no bonding between the friction material and the disc except the rivets I think that when the flywheel key sheared, the play in the friction material caused the material to break at two of the rivets. I normally tension the mule drive belt, by squeezing the belt together as the manual states, but sometimes have to tighten it some after mowing for a while. I have the new disc installed, my old belt back on, and plan to get the engine cowl back on, and reconnect the coil, solenoid, battery etc. and start it up tomorrow. Wish me luck! I have backed off the PTO trunion several turns and will readjust it necessary. Thanks again for your thoughts. Any comments on what I have done? Share this post Link to post Share on other sites
