I have a craftsman LT1750 Riding mower just replaced both mandrels a new belt and added a spring that was missing to keep the idler wheel tight and I still have a problem with the right side not cutti

Safety and Preparation Serious injury can occur if the engine or mower blades accidentally start while you are working with lawn tractors. To prevent this, drive the Murray lawn tractor onto a flat work surface and disengage the mowing deck cutting blades. Engage the parking brake to keep the mower from moving; chock the wheels with a wooden block or brick. Adjust the mowing deck to the lowest position. Turn off the engine and remove the key from the ignition. While not necessary, you may even wish to disconnect the spark plug wire from the spark plug. Mowing Deck Removal You must remove the mowing deck on a Murray lawn tractor to gain access to the belts. Remove the adjustment rod hairpins, followed by the adjustment rod pins from the front left and right sides of the mowing deck. At the rear on the left and right sides, pull out the retaining hairpins and slide the mowing deck suspension links from the adjuster plates to separate the rear mowing deck from the frame. Remove the blade control rod stud, including the hairpin and washer, from the top of the blade control lever shift linkage at the left rear of the deck. Remove the front hanger rod, including the hairpin and flat washer that hold the rod in place. Loosen the belt guide retaining bolts with a socket wrench and remove the engine stack pulley belt so you can slide the mower deck out from under the tractor Transmission Drive Belt Installation Slide the new transmission drive belt between the engine stack pulley belt guides, over the belt guide plate and under the engine stack pulley. Fit the transmission drive belt around the top engine stack pulley. Push the free end of the transmission drive belt up through the transmission shifter hole in the lawn tractor floorboard. Slip the transmission drive belt loop over the transmission shifter. Pull the transmission drive belt down through the transmission shifter hole. Fit the transmission drive belt around the transmission drive pulley and tighten the transmission drive pulley belt guide retaining bolts to hold it in place. Fit the transmission drive belt flat side around the idler pulley. Slide the idler pulley onto the idler pulley stud while holding the belt in place. Tighten the transmission idler pulley retaining nut with a socket wrench to secure the idler pulley to the idler pulley stud. Mowing Deck Drive Belt Installation Pull back on the right side mowing deck mandrel pulley spring-tensioned belt retainer. Guide the new mowing deck drive belt around the right side mandrel pulley and release the belt retainer. Pull the drive belt spring-tensioned retainer away from the mowing deck idler pulley, guiding the deck drive belt around the idler pulley. Fit the mowing deck drive belt around the left side mandrel pulley and under the rear mowing deck cross link rod between the right and left side mandrel pulley. Slide the mowing deck under the right side lawn tractor frame, reconnecting the deck to the frame in reverse order of removal. Engage and disengage the mower deck while driving the mower to test the belt for proper operation.

Sounds like the idler isn't releasing for some reason. Check that idler spring is in place and check that clutch cable as they tend to bind up as they get well used. Also the idler arm itself for binding.

You need to replace the blade clutch cable that runs between the blade engagement lever just to the right of the steering wheel and the the spring to the idler/clutch wheel on the top of the mower deck. Over time the cable binds in the sleeve/cable jacket preventing the blade from disengaging

sounds like you may not have the right mandrels making the belt to tight and it cant be left loose enough to allow the blades to quit turning.Otherwise you didnt put the belt back on correctly if it is around the tightener pully the wrong way that to will make the belt to tight

look on the bottom of the foot rest sears places a label there

Your deck should have a couple "idler" pulleys on them in addition to the main mandrell pulleys that have tension on them via springs to keep tension on your deck belt. Maybe you need to really examine the condition of those "idler" pulleys and also the main pulleys to find the problem.

Have you check the tensioners? The idler pulleys that are on the arms with springs on them. My reasoning is, if the arms are rusted, or stuck for some reason and not moving freely then the springs can't pull the belt tight. If that's the case, I could see where the belt could be slipping more than it needs to and prematurely wearing out. Just something to check. Good luck.

You'll be working underneath the mower, so it is helpful to raise the mower chassis up -- at least in back. Use your automobile jack, then put jackstands underneath the chassis to do this. Take off the deck drive belt first by releasing the idler spring(s). Unbolt and remove the "anchor" that keeps the PTO clutch from rotating. Disconnect the electrical wires leading to the PTO. Release the tension on the idler for the hydrostatic drive belt. Now you can thread the new hydrostatic belt over the engine pulley and around both wheel motor pulleys. The idler pulley presses it inward to provide tension. Refasten the idler spring - a pair of channellock pliers works well to hold and pull the spring. Now reinstall the wires and the PTO anchor, then the mower deck belt. Good luck! Please rate my answer if helpful, thanks!

recheck ur drive belt either wrong belt or spring/idler/tentioner pulley needs attention adjustment replacement also check free wheel actuator that not partially activated

Look at the Idler pully on the deck ther should be a Spring that keeps tension on the belt if it does not have that feature on that deck then there is a stay pin missing or the belt has just gotten to big (streached)