Tow Hook Bolt Torque

[Shedkept]

Being a little bored I decided to clean up the areas susceptible to road rash, in this case, the tow hooks and mounting area. Cleaned, de-rusted and coated. Just surface stuff but I did get the chance to prep the tow hooks better than the factory since they were painted on the frame. All wrapped up now with the chassis U-Joints greased as well as the drive shafts. Can't get to one without a right angle grease gun extension. All the others "played nice".

Anyhow, I have a spec. sheet but no way in heck are these going to torque to the 12 x1.25 standard shown.

Toyota Land Cruiser: Standard bolt - Service specifications

www.tlacruiser.com

Anybody?

Thanks in advance.

 

[spazzyfry123]

It's in the link you provided. Am I missing something?

59 ft-lbs for a 6T M12 flange bolt.

EDIT: Okay, I see. I am reading it as the two "marks" not as "11".

When I exchanged mine out for the Trail Tailor hooks, I needed new hardware and got 10.9 hardware. I want to say I torqued that down to 90 ft-lbs.

 

[gaijin]

Being a little bored I decided to clean up the areas susceptible to road rash, in this case, the tow hooks and mounting area. Cleaned, de-rusted and coated. Just surface stuff but I did get the chance to prep the tow hooks better than the factory since they were painted on the frame. All wrapped up now with the chassis U-Joints greased as well as the drive shafts. Can't get to one without a right angle grease gun extension. All the others "played nice".

Anyhow, I have a spec. sheet but no way in heck are these going to torque to the 12 x1.25 standard shown.

Toyota Land Cruiser: Standard bolt - Service specifications

www.tlacruiser.com

Anybody?

Thanks in advance.

View attachment 2811401

ARB says 88 ft-lbf when installing their recovery points - should be the same for stock.

HTH

 

[Shedkept]

It's in the link you provided. Am I missing something?

59 ft-lbs for a 6T M12 flange bolt.

View attachment 2811435

EDIT: Okay, I see. I am reading it as the two "marks" not as "11".

View attachment 2811452
View attachment 2811453

When I exchanged mine out for the Trail Tailor hooks, I needed new hardware and got 10.9 hardware. I want to say I torqued that down to 90 ft-lbs.

My dumb arse was reading the wrong line. It's a flange bolt but still marked 11. With the nuts being captive (I guess) in the frame I wasn't keen on putting Gorilla torque on them. Thanks!

 

[Julian73]

Kaon says 126 Nm (94 ft-lbs) for their installation using Grade 10.9 M12 x 1.25 bolts

 

[Shedkept]

In

Kaon says 126 Nm (94 ft-lbs) for their installation using Grade 10.9 M12 x 1.25 bolts

Into the stock captured nuts?

Thanks!

BTW: Besides the welds on the U-Hook, this area that catches everything. Nice and shiny (for) now.

 

[bloc]

This doesn't happen often but I can't find it in the FSM.

Will keep digging..

 

[Julian73]

In

Into the stock captured nuts?

Thanks!

BTW: Besides the welds on the U-Hook, this area that catches everything. Nice and shiny (for) now.

View attachment 2811521

Yes into the factory frame location. So Kaon says 94 ftl-bs, ARB 88 ft-lbs, (both within a +/- 3 ft-lbs margin) both for grade 10.9 bolts into factory nuts.

 

[Muddy.au]

Did my Kaon bolts up to 124Nm and used the special Nord-Lock washers supplied

 

[Shedkept]

Did my Kaon bolts up to 124Nm and used the special Nord-Lock washers supplied

View attachment 2811705

Tasty looking setup. Thanks for the information.

Did my Kaon bolts up to 124Nm and used the special Nord-Lock washers supplied

View attachment 2811705

 

[linuxgod]

The FSM shows this as an "11T flanged" bolt. If the bolt is 12mm then the spec is 130 ft lbs (bottom right of the second table).

 

[Shedkept]

I couldn't do 130 lb/ft!
You read it the same way I did but 130 lb/ft seemed like overkill and why I questioned the table. It sure didn’t feel like 130 lb/ft coming off.
Thanks!

 

[linuxgod]

I couldn't do 130 lb/ft!
You read it the same way I did but 130 lb/ft seemed like overkill and why I questioned the table. It sure didn’t feel like 130 lb/ft coming off.
Thanks!

Torque spec depends on the bolts, which is why the Toyota bolts require 130 but ARB only requires 88. You basically need to apply enough force that the bolt is almost to the point where the threads/bolt start to stretch, but not quite so far as to where they actually do and you strip them. (Or at least that's the most simplified engineering explanation I can provide).

Honestly you could probably apply some loctite and torque these to 60 or 70# and they would be fine. Most of the force in a recovery is lateral, and so long as the bolt doesn't work it's way loose from repeated snatching/kinetic recovery it would likely hold up.

 

[Julian73]

The FSM shows this as an "11T flanged" bolt. If the bolt is 12mm then the spec is 130 ft lbs (bottom right of the second table).

View attachment 2812024

View attachment 2812027

The OEM bolt is definitely not torqued to 130 ftlbs and I question that the foundation can even take that.

 

[bloc]

For the fastening system to work correctly you also need enough clamping force.. this creates friction between the tow hook and frame, and prevents it moving around or trying to shear the bolts off.

My issue with the above chart and why I've been putting so much effort into finding the number in the FSM is the brake caliper, front hub bearing-to-knuckle, and rear lower shock bolts are all the same size/pitch, all have 11 stamped on the head, and all go to 72-73 ft/lb. I'm sure there are many more but those are the ones that I know to be the same size and I had spares on the shelf to verify "11". Plus our sway bar link and front lower shock bolts are larger than 12mm, have 11 on the head, and only the much larger shock bolt goes to 133.

So no, definitely don't try to go to 130 on these. As @Julian73 says the insert in the frame will not appreciate it. I think using the number from the other locations with similar bolt on these vehicles is appropriate, and loctite as @linuxgod suggests is a good call. I'd use blue, not red.

Not sure why ARB/others are recommending what appears to be a higher than stock number when the insert in the frame stays the same. I won't put the effort into comparing Toyota 11T to metric 10.9 or whatever.. the insert stays the same.

 

[spazzyfry123]

I enjoy the conversation and like to follow the "big book", but I really think you'll be good to crank it down with some decent force and call it a day. They're not head bolts or anything like that. I was in the neighborhood of 90 ft-lbs and recently used mine as a tension point to spool up my 80 winch line. No one died just yet.

 

[bloc]

I enjoy the conversation and like to follow the "big book", but I really think you'll be good to crank it down with some decent force and call it a day. They're not head bolts or anything like that. I was in the neighborhood of 90 ft-lbs and recently used mine as a tension point to spool up my 80 winch line. No one died just yet.

I mostly agree.. it just irks me a little that this doesn't seem to be in the service manual anywhere.

 

[kcjaz]

Good bolt torque conversion here. My $0.02 is this: A bolt torque table is just that. It only considers the bolt. It’s really telling you the maximum torque for the bolt which is not necessarily what you may need or even want for a specific situation. Always try to find the FSM specific value. When there isn’t one, use the bolt tables as a guide but understand that the bolt torque table doesn’t know that you are threading the bolt to a tack welded captive nut. Only you know that.