Z121s Drive belt replacement

[Jim Stinson]

Spent all day looking at videos to see how it's done, and no good.

I have the belt around the clutch, but cannot get it around the pumps and tensioner. There is a rod sticking down from above that blocks the way.

Any help would be appreciated!!

 

[Jim Stinson]

 

[lugbolt]

View attachment 81577 View attachment 81577

that rod is a belt guide. Take it off. 17mm socket as I remember, right in the middle of the pulley. The pulley won't fall off there's another nut holding it on--you'll see it once the guide is removed. There's another guide on some of them over near the RH side transmission that makes the job easier if you remove it as well.

 

[Jim Stinson]

that rod is a belt guide. Take it off. 17mm socket as I remember, right in the middle of the pulley. The pulley won't fall off there's another nut holding it on--you'll see it once the guide is removed. There's another guide on some of them over near the RH side transmission that makes the job easier if you remove it as well.

Thank you, lugbolt. So the flat bar comes off and the rod comes with it?

 

[Jim Stinson]

Thank you, lugbolt. So the flat bar comes off and the rod comes with it?

OK, lugbolt. Cannot get belt around pump pulley on right side do to no clearance. Too big of hand. Next trick is to remove gas tank.

Any trick to that?

 

[JasonW]

I changed mine on my ZG127S last year or so, definitely didn’t have to pull the gas tank that would be ridiculous. Just remove the guide rod that is pictured

 

[Jim Stinson]

I changed mine on my ZG127S last year or so, definitely didn’t have to pull the gas tank that would be ridiculous. Just remove the guide rod that is pictured

Still not enough room to get my hand to the RH hyd pump pulley. Removing the pin helped with the LH pump, but not the right. I even had my son who has considerably smaller hands try.

 

[Jim Stinson]

Still not enough room to get my hand to the RH hyd pump pulley. Removing the pin helped with the LH pump, but not the right. I even had my son who has considerably smaller hands try.

I do agree with the RIDICULOUS comment, tho'

 

[JasonW]

Still not enough room to get my hand to the RH hyd pump pulley. Removing the pin helped with the LH pump, but not the right. I even had my son who has considerably smaller hands try.

Have you tried holding the belt in both hands and pushing it over the pulley? Also do you have it up on blocks or jack stands? I backed mine up on a set of ramps and left the front nose down. Try to get the right side on first if it’s the most difficult.

 

[mikester]

On my old RFM I had to loosen the spring tensioner significantly to get the belt on.

Feeding serpentine belts can be a game of Tetris. First, let your new belt sit in the sun a while to warm up. Cold tightly wrapped coils of belts can be an SOB to deal with. Usually there is an easier and harder sequence to feed the belt, and the final pulley you select may make things either easier or harder. Watch out for getting the belt on the wrong side of guide pins.

Can you post the belt diagram?

 

[lugbolt]

the gas tank does in fact come out but it's a pain in the butt! Don't take it out unless you want to exercise your right to almost completely disassemble the mower. Once the tank is out, you're not too far off of total disassembly....

take the wheels off. Use one hand to guide the belt over the pulley from the outside and the other hand from underneath to put the belt in the general location where it needs to be. Sometimes makes it a little easier.

LOTS easier on a lift. I don't know how many thousands of HST belts on the Z series I did, but 99% of them on a lift. I did mine at home while laying on the ground. No fun at all, in comparison.

The belt will fit in there, trust me. ASSuming you have the correct belt, of course. K3011-13560 or K3011-13561 I think. Some of the parts store belts are wider and won't quite fit, and they don't stay on either. The vee angle can be different too. Always use OEM belt.

Remove blade belt from the clutch. Remove belt guide(s) from idlers (you already did). Remove spring if it didn't already fall off. Remove pto clutch limiter bracket. unplug pto clutch wire and fish it through so it's just hanging underneath. Now put the belt around the crankshaft, between the pto clutch and the top pulley--don't put it on the upper engine pulley, that's the last step. Fish it around your hst pulleys first, then around the idlers. Put the spring on, should go on by hand. Now, grab a 14mm or 9/16 wrench (IIRC that is the size of the crankshaft bolt that holds the clutch on). With one hand, work the belt slightly over the engine pulley, and using the wrench, turn the pto clutch retaining bolt (which turns the engine/pulley) while you push the belt into it's groove. It kinda walks itself in if you do it right. Reinstall the guide/bracket. Reinstall the blade belt. Reinstall the blade belt guide if you took it off (and you should, if you have one--they don't all have it). Reinstall the clutch limiter bracket. Fish the wire up through the frame and plug it back in.

 

[Jim Stinson]

the gas tank does in fact come out but it's a pain in the butt! Don't take it out unless you want to exercise your right to almost completely disassemble the mower. Once the tank is out, you're not too far off of total disassembly....

take the wheels off. Use one hand to guide the belt over the pulley from the outside and the other hand from underneath to put the belt in the general location where it needs to be. Sometimes makes it a little easier.

LOTS easier on a lift. I don't know how many thousands of HST belts on the Z series I did, but 99% of them on a lift. I did mine at home while laying on the ground. No fun at all, in comparison.

The belt will fit in there, trust me. ASSuming you have the correct belt, of course. K3011-13560 or K3011-13561 I think. Some of the parts store belts are wider and won't quite fit, and they don't stay on either. The vee angle can be different too. Always use OEM belt.

Remove blade belt from the clutch. Remove belt guide(s) from idlers (you already did). Remove spring if it didn't already fall off. Remove pto clutch limiter bracket. unplug pto clutch wire and fish it through so it's just hanging underneath. Now put the belt around the crankshaft, between the pto clutch and the top pulley--don't put it on the upper engine pulley, that's the last step. Fish it around your hst pulleys first, then around the idlers. Put the spring on, should go on by hand. Now, grab a 14mm or 9/16 wrench (IIRC that is the size of the crankshaft bolt that holds the clutch on). With one hand, work the belt slightly over the engine pulley, and using the wrench, turn the pto clutch retaining bolt (which turns the engine/pulley) while you push the belt into it's groove. It kinda walks itself in if you do it right. Reinstall the guide/bracket. Reinstall the blade belt. Reinstall the blade belt guide if you took it off (and you should, if you have one--they don't all have it). Reinstall the clutch limiter bracket. Fish the wire up through the frame and plug it back in.

Thanks, lugbolt. Will give this a try as soon as the temp drops below self ignition outside. Here in Louisiana it's in high 90's and 70% or more humidity. Makes for miserable working conditions.

Thanks again!