Fuel tank strap - Houston, we have a problem

I may be wrong then. I bet @Last Call knows.

It seems like there's a sweet spot that's tight enough to keep the tank from moving and not too tight.

 

there is no way, that I'm aware of anyway, to get an accurate torque on those bolts. limited space and bad angle

 

@Oxbow is correct there is a torque value I don’t remember what it is for sure it’s either 65 or 75 ftlbs I usually just tighten them with a 1/2 drive standard length ratchet good and sung with 1 hand that will get you in the close proximity also every time you remove the straps replace those lock nuts and if you notice those nuts are deeper than a normal locking nut. Those nuts are designed strictly for that Application .. The reason I asked about the webbing is because if it’s not new when the strap is replaced or removed the old webbing has been flatted and compressed it is designed to do so it shouldn’t be reused think of it kinda like a head gasket so to speak .. I always replace it if I have to take a strap off for any reason .. there’s a more technical name for that webbing again I can’t remember it either .. but if you look on Dirks web site the kind they sell is by far the only kind I would use because it is equivalent to the OEM quality it’s not cheap but it’s well worth the cost it costs about 100.00 per strap in . In fact if you were to order it from Midwest Peterbilt that is what they would give you .. this is just my opinion but on a 150 gallon tank or lager I would double strap it just as in the picture as @lester posted yes it’s very costly to do that but.. so is a broken tank and a fuel spill.. This is all just my opinion and some lessons I learned via the school of hard knocks

 

BTW @blairandgretchen I forgot to complement you on the polish job on your tank in the picture it looks very nice and just FYI I noticed you have the old school chrome guards around your chicken lights if you ever need more give me a shout out I have box’s of them

 

Many moons ago, a tank strap broke on the Mack R model I was driving at the time( late 70s). I didn't even know it, not something you'd see from the drivers seat, another trucker got on the CB, and we pulled into an Ill tollway oasis. The tank was just inches off the ground, the front mount held. We jacked up the tank he had, a small piece of chain, he had, and I made it back. Got an attaboy for that one. When drivers helped other drivers.

 

Lots of flex in that area when tightening the straps, especially since most use an impact. I always oiled the threads, lock washer, standard nut, then double nut.

Not using an impact to tighten and oil on the stud, and you'll lose that flex when torquing. I haven't seen a strap that I've replaced crack since.

 

I was thinking about torque too.We had some older t 800's in the fleet,old Carlile trucks.The big fuel tanks always wanted to vibrate and roll up in the saddle over time.It pinched off the fuel line on me once.Those trucks had close to 1 million miles on them but ran great,nice smooth ride.

 

#4 and #8 in this thread may help with torque specs.

Torque Spec on Fuel Tank Straps

My 23 389 has the doubled up straps..4 on each tank.

 

More research says it’s 30 for aluminum tanks..

 

I looked up the torque specs in my service manual for a 359 I can’t help but think a 379 would be the same anyway it’s says 65 ft lbs it also recommended supporting the tank with a jack when torquing I always use a trans jack here’s the webbing I mentioned early it is self adhesive on the back side it’s all I have ever used myself probably have done a dozen or more tanks in the last few years so far I haven’t had a issue