New to me 13ag601h729 in good condition but neglected.

[Forest#2]

How was the drive motion acting before you changed the drive belts.

I seen a owners manual/parts list download at the sears link.

MTD 13AG601H729 front-engine lawn tractor manual

Download the manual for model MTD 13AG601H729 front-engine lawn tractor. Sears Parts Direct has parts, manuals & part diagrams for all types of repair projects to help you fix your front-engine lawn tractor!

www.searspartsdirect.com

Keep a heads up when working on the brake if replacing the pucks. The steel bolts will twist off easily in the aluminum housing.
Try adjusting the brake first.

 

[ritalz]

Drive motion was working as it should before the belt broke. I have printed off a copy of the manual and will look through it again. Thanks for the heads up on the brakes.

 

[Forest#2]

Look at page 30 of the owners manual.
It appears that maybe on that machine:
When you are not on the forward or reverse pedal the belt going toward the engine pulley should be loose/slack enough that it slips on the engine pulley for neutral. Also make sure it's routed correctly per the diagram. Make sure the engine pulley motion drive belt is the correct length and width if you do not ever get it to be in Neutral.

The owners manual is not really any help for replacing the motion drive belts on your machine. They know it's not a easy user friendly thing, but a learning experience and requires patience and might involve sacrificing some skin and meat when doing the rear belt. Good to hear the drive was ok before new belt replacement. That lets us know that the double sheave vari speed variator pulley is most likely ok. (bearings ok and the center shaft not rusted)

I see the brake adjustment on pg 17.
A easy way to adjust the brake after you locate the 1/2 inch adjustment nut per page 17 is to put the non-running machine in neutral, lock the brake pedal down and try to push the machine forward with both rear tires on the ground.. If it rolls easily turn the 1/2 nut CW 1/2 turn and try again. You will eventually get brake if the brake pucks are not worn out or their push pins re not rust seized. When you get close to correct adjustment a 1/4 turn of the adjustment nut will be brake and no brake. I've made those pucks from old disc brake pads.
The brake system is the wimpy type, so do not expect the brake to slide the rear tires, it just kinda slows the machine down. Do not trust the brake when on a hill or steep slope.

I would leave the deck off and test drive the machine really good before re-installing the deck AND always use safety stands when laying under the elevate machine.

 

[ritalz]

Spent the afternoon working on this problem. Verified the belt routing and adjusted the idler all the way to the edge of the threads. It still pulls a little when put in gear but it is better. Moved on to the brakes and found the whole setup rusted and not moving. The slide pins were forced out and cleaned and lubed. The brake pad and holding piece was cleaned and reinstalled. Had a hard time getting the springs and pressure arm back in the right order. After several attempts the adjusting nut seems to be correct as the mower now stops when the pedal is pressed. Gonna leave it alone for now and hope the drive belt wears in.

 

[Forest#2]

On your idlers make sure that they are the correct OD.

It's quite common now days to order the correct v belts by part number but the size you receive is not per specs for the tractor.
I use a upholstery tape measure, cloth type tape 1 inch wide and about 12 ft long from wal mart sewing section, low cost.
The cloth tape measure is more user friendly than trying to use a string or rope and then have to measure the rope. The cloth tape is also really accurate about v-belt lengths.
I also had a pile of unknown length V-belt and I now have them tagged/labeled as to their size.
When I take off a v belt I measure it's OD length and then compare to the belt being installed BEFORE I install the replacement belt.
This gives me a heads up as what to expect especially if the old belt has been operating correctly in the past.

I've seen several v belts from Randy engine repair on ebay that have the same part number but are not same size.