Manifold nuts on 8n won,t stay tight

[oldude]

Hey all. I'm new here so I,m hoping to fing some good answers from people with more experience with these old tractors than me. Anyway here goes. While bushhoging my old intake/exhaust manifold broke off at the exhaust pipe flange. So I got a new manifold, new gasket, new nuts and lockwashers, installed and torqued to 27lbs. Ran like a top. My problem is the nuts won't stay tight. two or three weeks an its starts sucking air. What am I not doing that I should? Thanks

 

[hosspuller]

If you're sure the nuts are turning loose... (Torqued when hot) ... double nut the studs. torque the first nut as normal then while holding the first nut in position tighten another nut on top.

Or use the deformed style of lock nuts ... see here GRAINGER APPROVED VENDOR Deformed Thread Locknut, 1-8, PK 10 - Locknuts - 2TJ48|2TJ48 - Grainger Industrial Supply

 

[Soundguy]

there won't be enough stud to add a pal nut.. and by no means do yuo want a steel nut on that stud. brass nuts don't seize.


at best I'd use a lock washer and retorque a few times. gaskets may be settling in and letting it loosen up

If you're sure the nuts are turning loose... (Torqued when hot) ... double nut the studs. torque the first nut as normal then while holding the first nut in position tighten another nut on top.

Or use the deformed style of lock nuts ... see here GRAINGER APPROVED VENDOR Deformed Thread Locknut, 1-8, PK 10 - Locknuts - 2TJ48|2TJ48 - Grainger Industrial Supply