Is it necessary to torque leaf spring bolts??

I searched all over but could not get a straight answer. im doing leaf springs tomorrow and I'm not sure if i should buy a torque wrench to torque the U bolts and 2 bolts on both ends of the leaf spring. some people say you should torque it and others said just hit it with a impact. any thoughts ? ?

 

Just buy a torque wrench because it is super nice to have anyways. Nearly everything on your vehicle has a torque spec, even the oil drain plug.

 

I prefer to torque my bolts/nuts when working on vehicles/motorcycles. A torque wrench is a worthwhile investment IMO.

 

Cross threaded or torqued to spec, tight is tight.

 

Every bolt on your truck has a torque value.

For a reason? Sure. Maybe not to save your life, but it's easier to torque it properly than it is to go out of your way to rip the shit out of it with an impact.

 

Thanks guys. I'll buy a torque wrench tomorrow. better safe than sorry

 

A torque wrench is a must-have for u-bolts and wheel nuts, among other places. And don't torque your u-bolts to the 37 ft-lbs spec in the factory service manual either, that is WAY too low. 73-80 ft-lbs with lubed threads works well for 14mm u-bolts which these are, and was the spec for previous generations of Toyota pickups / Tacomas.

 

It will make your life easier in the long run!

 

Ill torque the u bolt to 80-90. what about the shackle and front leaf spring bolt? anyone have a torque on that? ive seeb numbers from 60 to 120

 

Spec is 89ft-lbs for the spring eye and shackle bolts. Leave them loose until everything is assembled and the truck is sitting on the suspension to prevent excess torsion of the rubber bushings in the normal position, which will accelerate bushing failure. Unless you are using polyurethane bushings, in which case it doesn't matter.

http://www.customtacos.com/tech.old.../06toyrm/06toypdf/06rmsrc/rm2006ta/039012.pdf

 

These are the best torque wrenches. They're high-quality AND affordable.
http://www.torqwrench.com/tools/C.php

 

Cross threads are strong threads.

Also adding a little Loctite also helps.

 

Don't lube the threads! 80 ft-lb with lubed threads would be like 160 ft-lb dry, which is too much and can cause the U-bolts to yield or crack.

 

I use a torque wrench on all moving suspension areas. Not to make sure it's tight enough, but to avoid over tightening. And it's important to know if a component is supposed to be torqued while loaded or unloaded, so you don't get binding.

Also use for engine internals, spark plugs and sometimes on really light torque items, like ones measured in inch lbs.

Everything else is done by feel. 'Cause I feel good (@lotuscupcar)

 

NO, it would not be equivalent to 160 dry. Depending on the lubricant, and any plating on the threads, the difference is roughly 10%. So 73 lubed is roughly equivalent to 80 dry, but with more consistent clamping force on all legs of the u-bolts.

 

How can you tell if bolts should be torqued while loaded or unloaded? Im assuming Leafspring, shackle and ubolts should be loaded when torqued?

 

Easy. If the bushing is a captured bushing, you torque it with load. Captured means the bushing is bonded to the shell/sleeve. If the bushing is not, and you could theoretically spin the control arm/leaf spring/component 360 degrees without the bushing binding, you can torque it any way you wish.

 

Good to know thanks

 

everything has a torque rating for a reason

dont mess with good engineering!

 

Re-torque the U bolts after driving around too. I re-torqued mine once a week for about 5 times lol. The nuts kept tightening a little more until finally one day there was no more movement, everything truly tight and even. I did 90 ft-lbs dry, with OME U-bolts/nuts on OME springs with an angle shim.