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Discussion Starter #1
The pto bolt on my 335 keeps coming loose. I have used thread locker like recommended. The fit between the bolt and the crank isn't all that great. Any thoughts how to get this bolt to stop coming loose?
 

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Blue Loctite and a lock washer.
 

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The cupped washer may have lost its tension. I would try replacing the cupped washer and the bolt and reinstall with thread locker. If you're not cleaning the bolt and bolt hole in the crank with carb cleaner or brake clean, I would do so.

Have you been able to get the proper torque on the bolt?
 

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That bolt does need to be torqued to the correct setting. Most are a 7/16th inch bolt in either Grade 5 or Grade 8. The correct torque spec is 41 ft-lbs for Grade 5 and 58 ft-lbs for Grade 8.
 

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That bolt does need to be torqued to the correct setting. Most are a 7/16th inch bolt in either Grade 5 or Grade 8. The correct torque spec is 41 ft-lbs for Grade 5 and 58 ft-lbs for Grade 8.
I just looked it up in my JD service manual. They call for 45 ft-lbs.
 

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Discussion Starter #9
John Deere shows the bolt as m10 x 90 . I replaced it with a 100 mm but it still feels sloppy in the crankshaft. I have been using blue thread locker. Will try the red.
 

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Where are you getting these bolts from? Just like the SAE bolts, metric bolts also have different grades. Standard grade is 800-830 MPa, next toughest is 1040 MPa and the step up from that is 1220 MPa. You definitely do not want to put a lesser grade bolt there and try to torque it to something it is not, hardened bolts are a royal PITA to get out when they break.
 

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I have been using blue thread locker. Will try the red.
You might regret that decision at some point down the road if it works.


I would look at Loctite Form-A-Thread and ensure that you have the proper grade bolt, JD cup washer and torque the bolt properly before I used red Loctite.
 

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Most likely the torque shoulders on the top of the PTO clutch and the bottom of the traction drive pulley are beat up from the bolt coming loose. If these surfaces are not square to one another and smooth the PTO clutch will **** when tightened up. This puts a lot of imbalance into the equation and the bolt loosens again further beating up all the surfaces that need to be smooth and square.
 

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Do not know is this can be done in your case but at times when a bolt keeps working loose I install a long stud using a thread locker, (not the red permanent type thread locker) (using two jam nuts to install the stud) then install lock washers or cup washers and even two jam nuts. If you do not get your issue correct soon the threads in the crankshaft are going to most likely if not already get wollered out and ruined.
 

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Do not know is this can be done in your case but at times when a bolt keeps working loose I install a long stud using a thread locker, (not the red permanent type thread locker) (using two jam nuts to install the stud) then install lock washers or cup washers and even two jam nuts. If you do not get your issue correct soon the threads in the crankshaft are going to most likely if not already get wollered out and ruined.
What he said ^^^^^^^:tango_face_wink:
 

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It would seem that unless the crank threads have somehow been damaged....an unlikely event....I'd suspect the bolt has been compromised or replaced at some point by an incorrect bolt. I'd chase the crank threads with a correct size tap, then get to the dealer and obtain the correct bolt and washer. Correctly torque the bolt. A breakable thread locker would be optional.

Just one opinion.
 

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Thread locker is great, provided the parts fit correctly and heat rating of he locker is not exceeded. After all, heat will soften the thread locker and it will become useless. Bunged up threads, wrong bolts, bad clutch bearings, egged out threads from abuse will lead to poor repairs. Chase threads with bottoming tap and try the correct bolt. If it has lateral slop, then no amount of thread locker will help. To much thread locker will cause a hydraulic lock in a blind hole and you will never get it tight
 
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