Bolts loose - why?

[southerniltractor]

Howdy folks,

Recently helped my neighbor on his tractor search. He chose to purchase a new LS MT235 hydro with front end loader and backhoe. Very nice little tractor.

Anyway, I'm a bit "particular" as my wife likes to say. As I did with my new Kioti, I went over the machine shortly after it was delivered. At about 10 hours on the meter, I opened up his owner's manual and started getting torque values for wheel lugs/nuts and various other metric fasteners attaching the sub-frame to the machine and those used to keep the subframe together.

Please note we did use his backhoe to dig a trench in VERY dense, sticky and compacted clay. After about 45 minutes of struggling with this task, we stopped that endeavor and found a larger machine to complete the work. During this effort, I began to suspect stuff was loose.

I found only a couple wheel lugs/nuts tightened to the specified torque, but they were not horribly loose. I think they would have been fine. Then I moved onto the subframe fasteners. I determined the torque values by measuring the diameter of the shank as described in the link below. Then, I used the numbers on the bolt head to ascertain what type of bolt I was working on. All were 10.9. Using these two values (shank diameter and bolt type), I looked in the manual at a chart of torque values for various hardware to determine the torque range of each fastener. I went slow and worked each lose fastener up in steps (100 foot pounds, then 130, then 150 and so on).

Metric Bolt Measuring Guide | How to measure a Fastener | Pro-Bolt

Can't sugar coat this one. Only one of the bolts I checked torque on was tightened to specification. In fact, a few were obviously missed during the process of attaching the subframe, loader and backhoe. Many of them turned easily with a small 1/2 drive ratchet over half a turn before they got firm. Two of the fasteners lacked the appropriate flat washers, therefore were unable to provide appropriate clamping pressure on the parts they joined. There is a photo of this as I discovered it. I installed appropriate flat washers and torqued up all his fasteners.

In addition, I found a nut holding the ROPS mounting bolt almost completely spun off the bolt. I tightened all of those bolts/nuts also.

None of the bolt holes were stripped and all tightened up nicely. Also, I didn't see anything odd with holes being oblong as many of the subframe holes are a bit large to aid in assembly.

Anyway, has anyone here discovered anything like this in a new machine? Could all of this had been caused by our 45 minutes of unproductive digging? I'm left scratching my head.

My neighbor is suddenly VERY concerned with the long-term viability of his new tractor. I've had very good service from my Kioti, but I purchased my machine from a very well established dealership. His dealer is very new to the tractor game.

Appreciate your thoughts.

Thanks,
Mike

 

[LouNY]

That is one issue with any piece of equipment,
it is usually assembled by the lowest paid greenest hand many times without adequate instruction.
And I would doubt that they had or used a torque wrench or even torque sticks.

 

[grsthegreat]

Every piece of equipment i have ever owned had to be retorqued after 10 hours of use, and retorqued every time its serviced. My kioti came with a sticker twist tied on loader arm reminding owner to retorque loader and lug nuts after 10 hours use. All were kinda loose.

As a side note. Im an electrician and i use torque wrench to tighten up main feeder lugs on new panels i install. If i recheck that same lug in a few days, they are always looser than when installed, and i retorque.

 

[jaydee325]

Not unusual as discussed above.

My experience has been once torqued to the proper spec, the fasteners will stabilize after a couple of retorques. Having said that, good practice to recheck during normal service intervals.

 

[radios1]

even bolts on motorcycles loosen up, vibration and stresses..

 

[Cat_Driver]

Vibration on all equipment, nothing new. On all equipment I check bolts I can see and if tehy are loose or critical I remove and use loc-tight on them

 

[southerniltractor]

Appreciate you thoughts folks. I'll be eyeballing these fasteners again at the 50 hour service.

Be well,
Mike

 

[Agvg]

Bolt should not loosen by them selves, with correct torque and proper engineering.

Don't see people running around big 50t wheel loaders retorque bolts and nuts. Do you check all bolts on your car several times a year? Why does loader brackets get loose?

 

[grsthegreat]

Bolt should not loosen by them selves, with correct torque and proper engineering.

Don't see people running around big 50t wheel loaders retorque bolts and nuts. Do you check all bolts on your car several times a year? Why does loader brackets get loose?

have no idea....but they do. the worst was after 50 hours of use. now with 1200 hours on it there isnt the same problems. but i still check them

 

[Agvg]

Might be to much flexing in the frame and the tractor it self, did look at a large Fender and there the loader bracket was just bolted in with four bolts on each side.

 

[ruffdog]

I NEVER had "kinda loose" bolts on my NH TC33D. I had a nut on the hydro pedal linkage come loose after 350 hours....that's it. But of course, the dealer gave me a good trade in value for it saying "they don't make them like that anymore".

 

[Jstpssng]

If anything I would blame the dealer, not the tractor brand. While LS does seem to make some pretty darned good tractors, most of what you describe could be attributed to sloppy assembly after shipping.
If the local LS dealer is representative of their distribution base, that could be the weak link in the system.
I know that he's why I wouldn't consider an LS... I dealt with him- once- when he was a transmission repair shyster- er, repairman. My friend's on bought a Montana from him when he became a dealer... watching that unfold was strikes 2, 3, and out.

 

[mikester]

Has anyone mentioned that theres a torque spec for dry and lubricated fasteners? Some vehicle manufacturers specify that lug nuts never be lubricated otherwise you risk having them vibrate loose.

 

[DieselBound]

With some 1,050 hrs that I've put on my B7800 (it's got 1,800 hrs on it now) I only found one loose bolt and I believe it was one of the ones on the loader cross bar. I'm not sure a person could work a machine harder than I've worked the B7800.

I had a bolt that holds a pin in the lower link arms on my NX5510 disappear on me, which resulted in the pin popping out (fortunately it fell and stayed on the top of the draw bar plate) and the arm dangling (was getting frustrated that the brush hog seemed to be digging in and I could't correct it!). Wasn't quite catastrophic, but it could have been. I locktite'd the new bolt and the one on the other side: I also informed the dealer; recommended that they do the same.

Lots of assembly takes place at the dealer's. Likely lots of things that people find loose can be blamed on their dealer.

 

[jeff9366]

My experience has been once torqued to the proper spec, the fasteners will stabilize after a couple of retorques. Having said that, good practice to recheck during normal service intervals.

My experience also. Wheel bolts fastening two part wheel rims are particularly prone to loosening during first 100 hours of operation.

Knobby tread tractor tires produce a lot of wheel vibration when running on hard surfaces.

I would blame the dealer, not the tractor brand. Most of what you describe could be attributed to sloppy assembly after shipping.

Yes. All the Backhoe fasteners should have been torqued to spec at the dealer.

 

[k0ua]

I found lots of loose bolts on wheels and loader frame up until the first 100 hours. Check at 10, check at 50 and check at 100 for sure. Then check at the 400 service interval where you change all the fluids. I haven't seen any loosen up since 100, but still good idea to check. I don't see anything unusual at all with having loose bolts at the 10 hour check. You did good to check. I think paint compression may be part of the problem in new units. In any case, checking bolts is always a good idea.

 

[oldballs]

That is one issue with any piece of equipment,
it is usually assembled by the lowest paid greenest hand many times without adequate instruction.
And I would doubt that they had or used a torque wrench or even torque sticks.

That happened to me on my third Kubota purchase. The 2009 (B2660), the 2012 (B2620) were fine..........but the 2018 (B2650) not only had many loose bolts right after delivery.........but had several totally missing. The dealer fired that hand and ultimately the service manager.

But now, the ball is in my park.....i.e. do some torque checking soon!!

Cheers,
Mike.

 

[ultrarunner]

Bolt should not loosen by them selves, with correct torque and proper engineering.

Don't see people running around big 50t wheel loaders retorque bolts and nuts. Do you check all bolts on your car several times a year? Why does loader brackets get loose?

This is why cars of yesteryear often used Castilated Nuts with cotter pins...

Present day restorers find Locktite Blue most helpful...

 

[Jstpssng]

I used to put NeverSieze on my pickup log nuts, until I found out that it can be a bane as well as a benefit.

 

[LouNY]

I use never-seize on all of lug nuts and most all threaded fasteners on every thing that I work on.
When someone else does something tothem I can hear the muttering a they come away all silver,
but it unbolts nicely even up here in the super rust belt.