Mahindra bolt torque chart

[doneill127]

Was doing some maintenance on my tractor (about 150 hrs on it) and was going to check the torque on the bolts. It's a Max with FEL and Backhoe. Noticed that all of the bolts for the FEL and Backhoe are ISO metric or SAE and the manuals for these have recommended torque values and torque charts for the different size and grade of fasteners. However most of the bolts on the tractor only have a single number, mostly "7" or "10". After doing a fair amount of digging on google and TBN forums I believe theses are JIS (Japanese Industrial Standard) bolts and the numbering is the old bolt grade indication. For example 4 of the 6 engine mounting bolts get changed when the FEL subframe is added. They're replaced with
12mm x 1.25 x 40 Grade 10.9. They have a 19mm head. The 2 remaining OEM bolts are also 12mm x 1.25 but have only the number 10 stamped on them and they have a 17mm head. Based on the size and head it is a JIS bolt. Had a heck of time trying to find out what grade the bolt is and what it should be torqued to and then I found this old Toyota chart that I think explains things. http://www.toyotadostlari.com/uploads/03-Service-Specifications.pdf.

So I was wondering if anyone has a Mahindra bolt torque chart that defines JIS bolt grade by number, i.e.: 7, 10 etc to confirm what I've found. Note that there's a significant difference in recommended torque for the 12mm ISO (93 ft/lbs) vs the 12mm JIS (116 ft/lbs)

 

[Navasot]

:confused3:

 

[rokit]

While I understand what you're getting at, and appreciate your desire to get it right...when it comes to most of these chassis/FEL bolts the main thing is that they're tight.

They slam these tractors together with impact drivers. Time is money. They might have torque sticks in between the driver and the socket, but those are not known for accuracy. They could easily be wandering around within the 25% band between 93 ft*lb and 116 ft*lb. More likely is that the fasteners are actually beyond the torque spec, but as long as they don't yield and/or don't come loose everyone's happy.

Critical bolt torque is really only paid attention to in things like engine and transmission internal assemblies, where differences in clamping force can really make the difference between failure and survival.

 

[doneill127]

Rokit you're probably right, and the fact I'm using a Harbor Freight torque wrench probably adds to the inaccuracy. Really just looking for a starting point. Don't want to crank down on a bolt that I think is a grade 10.9 only to have it snap off because it's a grade 2. I hate removing broken bolts especially when it's my own stupidity.

Off the subject, I spent some time in beautiful Ridgecrest in my younger days. Did some work out at the old KerrMcGee plant in Trona and there were no hotels there. Kind of warm in the summer though especially in a hardhat, coveralls, gloves and respirator.

 

[rback33]

I can tell you loader mount bolts ARE torqued at installation. That is something that is very critical and I have personally witnessed it in Chattanooga. Any damage caused by loose bolts won't be covered by warranty on our end and they make sure to torque when installed.

 

[oosik]

When I checked my loader mount bolts I noticed two things - they aren't in the most convenient location and looked like a knuckle busting episode and the recommended torque values were pretty high - 240 to 275 foot pounds if I remember correctly. So..... I removed them, one at a time and put blue Locktite on each before reinstalling and torquing down. There WERE two bolts, one on each side, that brought on bloody knuckles even with leather gloves on.

 

[doneill127]

For what it's worth, all of the loader and BH bolts had witness marks on them. Not sure if it was from the factory or dealer prep. Checked the torque on all the bolts and only found 2 loose ones on the rear of loader/BH subframe.

 

[dickfoster]

Just so you know I think most of the the loader and BH subframe bolts are installed at distribution. A few back hoes may be dealer installed but I think most loaders and back hoes are distributor installed items. On my tractor they did a good job on the loader but rushed the backhoe and messed it up doing a rush job plus it was obviously done by someone who was not up on the job. Then again the distributor was relatively new to the game as well so they may not have had backhoe installs quite dialed in.