can not keep bolts tight

[terryggoround]

so I have a 1970 gmc jimmy 4x4 and just had a new rear driveshaft built and installed. The problem I have been having before this was done was various bolts keep coming loose. The exhaust down pipe bolts , the valve cover bolt, the bolts on the cross brace for the engine and transmission. No matter how much I tighten and even using lock tight the bolts still come loose after a few weeks. The truck is a 1/2 ton with a 350 V8 and a 4 speed manual transmission with 1st gear is a granny gear. The rear driveline was changed to a 1 ton 1350 series. Any suggestions would be greatly appreciated. Also I noticed the the brace that attaches to the frame and the transfer case is not there. could the weight of the tranfercase bouncing around be causing my bolts to loosen?
Thanks
Terry

[1rippen6]

I do have that bracket on the for sale forum if you want to give that a try.

http://67-72chevytrucks.com/vboard/s...d.php?t=668163

[jaros44sr]

Originally Posted by terryggoround

so I have a 1970 gmc jimmy 4x4 and just had a new rear driveshaft built and installed. The problem I have been having before this was done was various bolts keep coming loose. The exhaust down pipe bolts , the valve cover bolt, the bolts on the cross brace for the engine and transmission. No matter how much I tighten and even using lock tight the bolts still come loose after a few weeks. The truck is a 1/2 ton with a 350 V8 and a 4 speed manual transmission with 1st gear is a granny gear. The rear driveline was changed to a 1 ton 1350 series. Any suggestions would be greatly appreciated. Also I noticed the the brace that attaches to the frame and the transfer case is not there. could the weight of the tranfercase bouncing around be causing my bolts to loosen?
Thanks
Terry

Terry, you could try using lock nuts, the ones that are squeezed slightly on the crossmember. It is more of a mechanical lock, then the lock tight, which won't work on a heat application, I use brass nuts on my exhaust downpipe, lock washers won't work here as well because of heat. Heat is what you use to release lock tite

As far as the brace for the transfer case goes, that discussion has been going on for years down in the 4X4 section, go read it and then decide if you want it or not. If you want it LMK as I have brand new bushings for it, with a painted bracket

valve cover bolts, not sure whats going on there, other than you keep squishing the gasket, try using rubber gaskets with metal inside. I think fel-pro makes them. Use a torque wrench!

[notsolo]

What Jim Said, Brass nuts on the down pipe, Double them up if you can also gives you a chance to remove them later without breaking the stud off in the manifold.

[terryggoround]

Thank you for the suggestions I will try the brass on the down pipes and will read the stuff in the 4x4 section. As for the valve cover gaskets I think that is what I had used, I'll have to go back and check.
Thanks again for helping to keep all the best trucks on the road!