Dealer Torqued U-bolts to 75#

Checked last night, that when the dealer did my Leaf TSB, they torqued the Ubolts down to 75#. I kept going up in 5# incriments to see how tight they had them. I know the FSM Spec is 37#, which even I think is crazy low. 50# sounds better... but is 75# to much?? The bolts look large enought to handle the torque.

 

That's what I'm saying. But IIRC the TSB even states torquing them to 37#. From the factory the Ubolts were under 40#.... I torqued them to 50# at my 5k oil change.

Bolt Dia is 1/2" I believe. It takes a 3/4" (19mm) Socket.

 

75 ft pounds on a 1/2" bolt isn't lots. Too much torque will stretch (weaken) a fastener. Depends on the material of course. 37 pounds seems low... then again, I'm surprised at the low torques used for some fasteners. Eg bolts for running board brackets were 10 ft lbs. When the wrench clicked, it was way too little torque for me to feel comfortable, so I added a 1/2 turn.
That they torqued them is great. They didn't just run 'em down with an impact wrench...

 

Yeah, 75# seems about right. Even for a grade 5 bolt they say 75-85. So I should be plenty safe. On my previous F250 they were 110#.

 

hmm, it does say 37 ft lbs.

That must be a mistake.

 

When I did my Jeep U-bolts, they're TIGHT. Probably closer to 100lbs.

There are situations (mechanically) where the torque specs are very important.

In terms of U-bolts.....I'm a firm believer in *tighter is better*

 

Hmmm, now I gotta go out and check mine....

 

Tonight I'm going to check/torque the front Leaf bolt, and the two rear (shackle) leaf bolts. IIRC all 3 are at 90#.

 

Ask any mechanic and he is going to say you are crazy for only tightening a 9/16" u-bolt to 37#. It is critical for u-bolts to be torqued correctly. Torque needs to be 75-100lbft. after installing a block or an add-a-leaf it is important to re-check the torque (especially with new u-bolts) after a couple hundred miles. Whether toyota will admit it or not. The Spec of 37lbft. has to be a typo.

 

I'm with you YotaDan. Glad the tech came up with 75# also. That's honestly probably where they need to be. how can lug nuts be at 85, and U-bolts be 37? Over and done with though. thanks for the input guys. I think we should have a sticky for this issue and recomend 75#. Save a lot of folks a lot of hassle. But you still have to wonder, why did the factory only torque them to 37? b/c with only 5k miles They were less than 40#. Oh well.

 

I've seen this happen multiple times while offroading....it ain't pretty.

And if you have blocks - I've seen pieces of broken blocks fly out and hit people standing near the trail. The pumpkin twists upward and the driveshaft & u-joints can rip holes on the underside of your body/rig.

 

yup. I don't do blocks. I laugh at the "mall crawlwers" riding around in a F350 with 12" blocks. If they only knew how dangerous and stupid they look.

 

A lot of those trucks have blocks in them from the factory. The 04 Dodge Ram that I owned had about 3" blocks in it from the factory.

 

same wtih the F250 and 350. 2" & 3" blocks.

 

guess Virginia need to update the State Inspection Manual..b/c last I read blocks on the leaf springs would not pass state inspection...

 

Along with Maine. No blocks allowed. I'm assuming they mean aftermarket hill billy blocks. 8" block ontop of the factory 2" block.