Installing larger Tow Mounts Trail Tailor, ARB etc . Be smarter than me

[Romer]

I bought a set of Trail Taylors Tow Mounts. I should have thought. Hmmm, these are thicker than stock I need a longer bolt. I used the stock bolts, they tightened up and seemed fine.

I am in a parking lot a work turning out of a parking spot and there is a side walk burn (Raised stone 2ft mound) as I am turning a 180 I see the burn on my right and a open space at my passenger side and open space on the drivers so I pull forward and CLUNK. The passenger open space was a cross walk and there was a 2ft wide Burn under my hood I couldnt see. No damage except the tow hook is plopped off and the bolts are sheared. The hook circled in blue is the one that broke off

Yes there is some rust there that I cleaned up after wards

To get the bolts out I had a friend with a welder who welded nuts on the ends and we turqued them out. Took a lot of nuts as they would break off after a few turns

Finally got them out and came home and ran a M12 1.25 Tap through to get the holes clean

I had bought replacement bolts from Fastnel, Trail Taylor also sells them among others. I bought M12 1.25 45mm 10.9 strength bolts as that is the same thing TT sells to use with his tow hooks

I validated the other tow hook had stock bolts, has an 11 stamped on it. I removed one and saw the stock bolt was much shorter

Doo'h I should have figured out I need longer bolts right away

So either I didnt really have stock bolts on the passenger side or the shorter length of the stock bolt did not provide the same support.

In any case, don't forget to use the right bolt size Be smarter than me

 

[KLF]

...and Anti-Sieze.

 

[GordJ]

But if the bolts sheared the length isn’t the reason they sheared, is it? I would have thought that 3 threads penetration or 3” penetration would have the same result when you stop 3 tons that way.

 

[Roy Park]

But if the bolts sheared the length isn’t the reason they sheared, is it? I would have thought that 3 threads penetration or 3” penetration would have the same result when you stop 3 tons that way.

I had the same thought.

 

[Romer]

I thought that as well. It is possible I had the wrong bolts in there. I will never know since the heads popped off. The remaining bolt was jacked at an angle a bit. It is possible that if the bolt was longer it would have had less movement with more bolt in the threads then above. I will never know. Still having longer bolts is the smart thing to do

 

[OregonLC]

I think you're fortunate those came off in the parking lot and didn't turn into a missile on a recovery! And, hey, you have a 14! Turn on your automatic front camera and you'll see the birm next time!

Good reason to have recovery points up higher where they won't plow. The picture below shows them on a GX bumper. They're directly in front of the frame mounts for full pull strength. There's been a number of times that I've rubbed my skid plate when crossing barriers. On my 100 I kept my factory hooks on simply as a 'wear part' for that reason.

 

[GordJ]

Still having longer bolts is the smart thing to do

That is true.

 

[TeCKis300]

Is it possible you didn't torque the bolts down tight enough? With enough clamping force, the bolts don't take as much shear as majority of the force is translated between the mount and frame mating surface.

Though the way it failed probably caused you much less headache in the end. Only bolts broken, and not something more serious.

 

[Romer]

Anything is possible

 

[gaijin]

FYI, I also used longer 10.9 bolts when installing my aftermarket recovery points. ARB recommends 88 ft lb, but my research on 10.9 bolts yielded a recommendation of 92 ft lb:

So ... 92 ft lb looks good to me if you are using Class 10.9 M12 x 1.25 bolts.

HTH

 

[GordJ]

Is it possible you didn't torque the bolts down tight enough? With enough clamping force, the bolts don't take as much shear as majority of the force is translated between the mount and frame mating surface.

That was my next thought. It would be hard to apply that much shock force unless you were using a chain so the missile scenario would be very rare wouldn’t it? Still better to make it not happen. Not an engineer, merely experienced at breaking stuff.

 

[M1911]

Don’t the ARB recovery points come with appropriate bolts?

 

[cruiseroutfit]

Don’t the ARB recovery points come with appropriate bolts?

Yes

 

[Romer]

Mine were Trail Taylor recovery points. He sells them, but they do not come with. I should have realized and likely had I read other posts I would have figured it out as well.

 

[M1911]

Thanks, Kurt. I just got my ARB recovery points back from a machine shop. I had him round over the edges so I can use a soft shackle. I’m putting some paint on them tonight, and hoping to install tomorrow (assuming I can get the factory bolts off), so I didn’t want to have to go look for different hardware.