Adding bigger fuel tanks and mount spacing

CrazyCooter · April 29, 2016

With only 200 gals available capacity, I have been wanting a bit more so I can get to the destination and back without fueling on the road. I mentioned this to a friend of mine who has a late 90's vintage Peterbilt that is equipped with a pair of 150's and he would like the weight savings of the smaller tanks and wants to trade me.

Looks like plumbing is the same on both trucks. The biggest difference I can see is the location of the tanks mounts. My tanks are 46" long with strap spacing of only 19.5" wit the tank pretty much centered. His tanks are 72" long but judging by the pics, his mounts are at least 50" apart.

I can't seem to find anything on the net about a documented spacing recommendations, but I can't see hanging a 72" tank that weighs at least 650lb full from the center at 19.5". It appears that my x-member just behind the driver's seat bolt pattern is the same as the tank mounts and if I used a pair of existing holes from the x-member bolts/holes and drilled a new pair, I could set the mounts at about 40" which I think could work. His we would have to probably redrill for at least one mount.

You guys have anything that could solve this?

NoDirectionHome · April 29, 2016

Are they the same diameter?

CrazyCooter · April 30, 2016

Yes, both 26" dia.

tyates007 · April 30, 2016

On my Kenworth with 150 gallon tanks there is a third strap added. I don't have the truck at the house right now to measure the exact spacing

porky69 · April 30, 2016

The way Peterbilt tank mounts are designed one single bracket will hold a 150 gallon tank full of fuel by itself(have seen it when a mounting strap bolt breaks), however it is not very stable and would kink and crumple a tank if you tried to drive like that.

I would think that other than looking a little goofy, the 19.5inch spacing would work, but I am not a Peterbilt engineer. Call your local dealer and they should be able to contact the factory and get you an answer.

My Peterbilt which had 26inch 150 gallon tanks had 4straps holding them(mostly for looks) but my buddies truck only had 2straps holding the same tanks on his truck.

CrazyCooter · April 30, 2016

Talked to the dealer tonight while getting some parts and the parts guy didn't have anything, but on a Friday night can't expect much.

FYI, TRP batteries made by East Penn in the USA, Group 31 batteries are on sale for $70ea. Going to get 4 new ones since at least one of mine are weak.

beyerjf · April 30, 2016

I would try to mount them as similar to the donor truck as possible. The aluminum tank is not a very robust assembly. I have sizable dents in mine just from hitting debris on the highway and I have seen them punctured that way more than once. Unless you have a significant reason to avoid purchasing fuel on the road(using off road fuel at the farm for instance, a big no no) I wouldn't consider modifying the situation. If you do, it sounds like drilling the frame for new mount positions are probably in your future. Not the end of the world, but a lot of work.

The economics doesn't justify it.

And just for info. I used to live about 30 miles from the East Penn (Deka) battery plant and over the years bought a lot of 1st and 2nd quality batteries for a variety of vehicles. I have not been impressed with the savings/longevity. I had 1 of a set of 4 group 31's internally short circuit and blew that case. I am sure they build a good product, but they also build some low level stuff too, I just can't tell the difference.

CrazyCooter · April 30, 2016

At worst we will have to drill 4 holes in each truck which isn't bad. I can't see me making this change any other way and he is probably thinking the same thing. If it isn't an easy swap, we'll just skip it cause it isn't the end of the world either way.

You could be right about the batteries. TRP could be specing out that battery to make a price point. Might give them a try. Just can't justify spending $230+ each for AGM when I know at least one will bite the dust before the other 3 and then I will have to buy 4 more. Since this truck doesn't see all that much use and is kept on a tender might be worth the chance. The counter guy couldn't comment on the quality other than he has not warrantied a single one yet.

Scrap · April 30, 2016

Straps are usually set equal from the ends and frame locations and frames are layed out on a grid so something is bound to line up with something somewhere along the line as long as you both have the same hood length. Different filler locations tend to screw things up too as the strap from end location changes. I'm not the best polisher in the world, but I have a mother of a time getting rid of the ghost of old strap locations on the tank. So I'm another vote for donor truck locations and hoping something matches a hole in the rail.

CrazyCooter · May 1, 2016

I was hoping you would pipe in here Scrap. He is a long hood 379 60" sleeper and mine is a short hood 385 48" sleeper.

CrazyCooter · May 4, 2016

Well it was all for nothing! I was 2" short of having enough room to fit those bigger tanks...... Darn!

Darryl&Rita · May 4, 2016

Hammer time.

CrazyCooter · May 4, 2016

That would have worked. The fitting/regulator coming out of the right air tank was the biggest issue. I could probably relocate it and install a flush mount pipe on the left and get it in there. I thought about sliding the bed back a bit too, but my exhaust and brackets would be an issue too.

Pretty much wanting to be done with this truck so I can just drive and enjoy it. Dropped it off at the body shop for some needed paint work this morning......Couldn't really justify the $11K and up price tag on a complete, so were just making it presentable for now. Getting excited.