Torque specs for flywheel

   / Torque specs for flywheel #1  

Randy Blankenship

New member
Joined
Jul 27, 2022
Messages
2
Tractor
2003 farm pro 2425 4wd
I have a 03 farm pro 2425.I’m in the process of replacing the clutch disc and was gonna go ahead and replace the bell housing bolts because I was told that they were bad to come lose due to them stretching or something like that.well after taking the flywheel bolts out I decided against doing this because I figured that if it wasn’t a problem all this time I should just leave it alone.well I saw that the torque specs were between 44-51 ft lbs.to me it seems like that isn’t nearly enough but then again I’m not anywhere close to being a mechanic.I’m definitely gonna use loc tite but would it harm anything to tighten them a little more?probably a stupid question but I’m known for that so🤷‍♂️.
 
   / Torque specs for flywheel #2  
"Some" bolts are designed to stretch a certain amount as the final torque is set. Usually these are one time use only bolts (or studs in some applications). Once this bolt has been torqued to final spec it is "used" and even if you did it two minutes ago and have to take it out to do something you forgot, it is supposed to be replaced.

Now to complicate things further, some bolts are "required" to be replaced any time they are removed. This is usually seen on things like brake calipers and differential locking bolts. Typically this is because the new bolt has a factory installed locking compound that would no longer be effective if it were to be re-used. I believe there are two reasons for this "requirement" from the manufacturers:
1) it increases sales of parts
2) it insures that even the dealership mechanics do things the factory way, cutting the liability tail between the dealership and the manufacturer.

For bell housing bolts, are they coarse thread and screw into a blind hole or do they go all the way through and have a nut on the other side?
What diameter is the bolt? (not what size is the head)

Take a look at the number on the top of the bolt head. It should be something like 8.8 or 10.8. This will indicate the grade (strength) of the bolt. You can then look up the standard torque setting for a bolt of that diameter and strength rating.

Keep in mind that most times when a bolt is threaded directly into cast iron it will be course threads and the torque values will be lower as the bolt is likely stronger than the threads in the casting. This keeps you from striping out the casting.

Do you "have" to use new bolts? Absolutely not, but you have to decide how important that bolt is and the cost of it's failure. If you do re-use them and the use of a locking compound is appropriate, just make sure you get the old compound completely removed and that you apply new compound to clean and dry threads. Also choose your compound carefully to match the application. In other words, if you need to heat it to break it loose the next time, can that be done without damage to nearby components.

You might check with a parts house to see if new bolts are available, what the price is and if they have pre-installed locking compound.
 
   / Torque specs for flywheel #3  
As an aside, I have become a convert to these lock washers. Currently using them on a large wood chipper application where there are slotted adjustment holes using 10.9 bolts, eliminating split-lock and flat washers.

 
   / Torque specs for flywheel #4  
Those were mentioned on a machining forum I frequent but I hadn't looked into them. Ingenious little buggers and priced accordingly!

The statement that they work on tension not friction is a little misleading. Yes you have to increase tension to override the cam and loosen the bolt, BUT it still relies on the friction of the serrations biting into the base material and the head or nut. If that bite fails, the whole system fails, just like a split or toothed washer.

However, the serration system does look to have superior holding power vs a single tooth on a split washer or the coarse spacing of a toothed washer.

The next time the 3 point pins on my back blade come loose, it may just tick me off enough to spring for a couple of sets of these.
 
   / Torque specs for flywheel #5  
So far seem to be holding well with high impact vibrations in the chipper. The chipper came with an anaerobic (Loctite type) applied to the threads from the factory. I omitted it when I changed blades. So far, so good. Using them on 10 mm 10.9 bolts against mild steel. You can also get them on Amazon.
 
 
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