I recently purchased a pricy zero-steer riding lawnmower from Troy-Bilt, a Mustang with a 50-inch deck. The design is such that there are two independent hydrostatic drives to each of the rear wheels, enabling the zero-steer capability.
After approximately seven hours of use, I started to lose torque to one of the wheels. Concerned, I jacked up the mower, crawled under it, and found that the drive belt had a twist in it. The drive belts on riding mowers are simply V-belts routed around a series of pulleys. One belt supplies power to the drive wheels and another supplies power to the mower deck. Since the machine was assembled by employees at the store where I bought it, I figured this was just an oversight. I corrected the belt and was back on my way.
It didn't take long for the condition to repeat itself. With the belt corrected, I feared that one of the expensive hydrostatic drives had gone bad. It was severe enough that I would have to have the unit repaired. This did not sit well.
I decided to try fixing it myself before I went through all the time and expense to return the unit for repair. I went online to see if there were any threads referring to hydrostatic drive slippage on riding mowers. There were some that talked about the oil getting low and causing the problem. I then checked my manual to find that my drives were sealed, so there would be no oil leak, and they wouldn’t need to be topped off. I then did some testing of the drive system on a steep hill to ensure that it was only the one drive that was having a problem. I found that the other side was also having a problem, but it was not as bad as the initial side causing the issue. That was actually good news. I couldn't imagine that both independent drives would go bad at the same time and after only seven hours of use.
Since I have a car lift, I lifted the mower up in order to get a better look at the drive belt system. I was getting the feeling that it was the culprit. Since the drive belt is routed from the engine pulley to one side drive and then the other, it is possible that if it were slipping, then the side closest to the engine drive pulley would slip the least and the conditions that I was witnessing could be explained.
When I looked at the drive belt again, it was once again twisted. No blaming it on the store employees this time. I then noticed that the tensioner arm sat very close to a bolt head that was underneath the engine securing the engine to the frame. I manually articulated the tensioner and found that the tensioner arm could hit the bolt head, which would cause a momentary loss of tension on the drive belt, allowing the belt to twist and lose its tractive power! What a huge blunder!
It was a miracle that I found a button head bolt exactly the same size in my shop to replace the standard hex head. This way, there would be nothing for the tensioner arm to hang up on. I also radiused the tensioner arm with a grinder so that there were no sharp edges to catch on anything else. Finally, I got a new belt, one that was a little bit shorter than the original, to help pull the tensioner away from the trouble area and give more tension on the belt.
After spending several hours of my time fixing something that shouldn't need to be fixed, I can say that the mower is now better than new.
This entry was submitted by Chris Clouser and edited by Rob Spiegel.
Tell us your experiences with Monkey-designed products. Send stories to Rob Spiegel for Made by Monkeys.
Good point, Ann. I don't know if Chris went online to see what other owners were experiencing with this lawnmower, but I would suspect there is a forum with a thousand complaints. This sounds like a design flaw rather than an individual problem.
He did mention the machine was assembled by employees at the retailer. I have this vision of some highschool boys earning minimum wage turning wrenches and finding one hex head bolt that they have no tool for. "Hey Bubba, go to the hardware department and find me a bolt of this size with these threads." The original fastener then went into the trash, the unit worked, the boss was in happy denial, and the customer suffered after seven hours! Did the parts manual show a hex bolt or something special? Home Depot type places do not hire "professional" assemblers and do not have any quality assurance programs. I have seen these methods of misassembly before, even at the professional level.
Island_Al; Pardon me while I RANT: It's always easy when it is someone else's problem. Sort of like the other thread about the missing crank bearing cap - such an easy-to-find problem.. Human Resources and Upper Management seem to have no respect for 'hands-on' and technical workers. It is possible the mower was assembled by student 'less-than-minimum-wage' workers, who had never seen a mower before. I was at one stone shop that had installed a $250k machine, and then hired students to run it. I thought that might be a good idea because students might be more computer-savvy. The real reason was students could be paid less than minimum wage. At Panasonic Factory Automation we had a consultant session to explain to us that machines didn't have to be assembled in a strict order. For example, her husband had to read instructions to assemble their daughter's bicycle, when clearly it wasn't necessary. My response was that the handlebars go through the stem more easily before the basket is attached. And surface mount assembly machines are a little more complicated than a bicycle.
My other rant is 9/16-18 thread. It can be right-hand, left-hand, taper pipe, straight pipe, SAE, JIC, swivel-pipe, gasket seal. O-ring seal. Just because you can make it fit, doesn't mean it is the proper fitting for the application. I have had to just shake my head and walk away from some self-proclaimed 'experts'.
I have a Troy-Built leaf vacuum/chipper which does neither job satisfactorily. Run to repair-time ratio is about 2:1. It is too good to throw away and I don't hate anyone enought to try to sell it to. My impression is Troy-Built made a name for themselves making what is arguably the worlds best Rototiller, then sold the business to MTD who apparently is run by bean counters interested only in short-term profit. Replacement parts are unavailable; assemblies are sold in big-box-stores with no after-sales support, factory service is unavailable and the buying public is largely unaware of other purchasing options. Designed-by-Monkeys indeed! Designed by a committee may be more accurate.
I absolutely agree! Although I do have a 5hp MTD snow thrower which has been 100% reliable for the last 5 years, and does perform well. So maybe the bean counters/committee missed this one!
I received an email from the Product Marketing group at MTD Consumer Products. The message came from the manager who handles the Zero Turn Rider Product line, under which this blog falls.
He noted that "When this was brought to my attention, I engaged our Chief Engineer. We have since made a change to the drive belt on this model, shortening it almost an 1". That has rectified the issue Chris Clouser discusses in the blog."
He also noted he could have a new belt sent to Chris' attention.
1) TROY-BILT used to be very respectable garden-maintenance equipment. As another blogger pointed out, when they were gobbled up by MTD, that product quality ethic was the first thing to be thrown into the dumpster!
2) So many of these "horror stories" are about products purchased recently. I wonder IF the engineering depts. at these manufacturers have switched over to "ultra-advanced" 3-D CAD design software, relying solely on its ability to ferret out any incompatibilities and/or impossibilities? Then, totally relying on those drawing sets, go into full-scale manufacturing mode, only to either discover (OR deny!) any problems when the product is in use.
3) In all the years that I've read these MADE by MONKEES, SHERLOCK OHMS, etc., I believe this is the first time I've seen it reported that the manufacturer has directly responded to the complaint. In that regard, one MUST give the people @ MTD a gold star for being forthright. Maybe someone there DOES have a conscience????
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