When specing a new Tanker-PSA

[Coaldust]

Have the dealer switch the rear-air suspension dual-leveling valve to a single.
It’s not optimum to run a dual leveling valve because if one side fails, the load can shift, creating a surge condition that can push you off the road. Especially, going around a sweeping, off-camber corner. A failure with a single leveling valve will simply lower the chassis at a controlled rate.

It’s just best practice. Is there a plague of Kenworth tanker rigs falling off the road with dual leveling valves? Of course not.

That is all. Carry on.

 

[Birken Vogt]

Maybe on a highway truck, but off road we always had a single leveling valve and when you stopped to make a delivery or whatever, all the air ran from the low side to the high side and the low side was left on the bump stop making it look real precarious. I never heard of one tipping over, though. Got so I just ignored it.

 

[cfherrman]

Good looking out. I only buy trucks 2007 and older though

 

[Truck Shop]

Dual leveling has been around since mid 80's. And yes not wise with live loads. No real advantage
with dual leveling. But what I see that's worse is the air disc, garbage.

 

[Coaldust]

Another trick that Seneca Tank Truck does is to spec with an over-inflate kit when the tanks have front sumps. Kenworth also has a 1” front end lowered sales code available for the T880. Allows full drainage. Popular with line-haul rigs doing station drops.

 

[Truck Shop]

Semi-car hauler axle.

 

[Coaldust]

I like to purchase pre-2007 trucks, too. But, they stopped making them in 2007.

 

[crane operator]

I have dual leveling valves on two cranes, one has never been a problem, one has issues all the time with one side not reinflating like it should. I've debated junking the dual valves on the troublesome one, but haven't really gotten around to it. These are on the welded up walking beam suspension, with the two air bags on the rear of the pivot on the long leg. I think hendrickson makes it.

 

[Truck Shop]

Either the valve or adjusted wrong, should be able to use one.

 

[crane operator]

I replaced the valve and had no change, still would randomly not inflate. Found out theres a small check valve in the air line plumbing of the leveling valve, and it gets crud in it and hangs up. I disassembled the check valve and cleaned it all up and "fingers crossed" it hasn't been hanging up again.

 

[crane operator]

This is the small check, I think when the air goes away in dump, this spring loaded valve lets the air go to discharge, and when its in "fill" the air pushes against the spring filling the bags. It hangs up and the air goes right to dump and won't fill the bags.

The little side holes are exposed, and this is right where the wheels kick up road spray. Someone has tried to cover them with a piece of inner tube zip tied over it, but they still get crud in them and it sticks the valve.

 

[Coaldust]

Here is the wide-hipped girl that inspired this thread. She is coming along well. But, unable to locate PTO’s. Errrg! She won’t make the July 25th sailing to SW Alaska. Hopefully, I can get her on the September 6th sailing. Because, that’s the last boat of the season. Maps on my iPhone is telling me I’m 4,499 miles from my office. The furthest distance I’ve traveled for a service call. Might borrow a PTO from another rig to wet test & prove the meters, button it up, ship it, and install the new PTO’s in Alaska.

This lady is a full-meal-deal, big power x15, 18 speed pup-pulling beast. All work and no play. But fate has it, She will only see Highway speeds on the four day, cross country trip to Seattle . Her life will be spent packing 4500 gallon loads of Jet A on muddy 25 MPH dirt roads. Probably never wear the paint off the pintle hitch.

 

[Old Doug]

Maybe on a highway truck, but off road we always had a single leveling valve and when you stopped to make a delivery or whatever, all the air ran from the low side to the high side and the low side was left on the bump stop making it look real precarious. I never heard of one tipping over, though. Got so I just ignored it.

How many have a dump valve i cant remember if its on the the hose reel door or were they were?

 

[Birken Vogt]

Some had a dump valve on the dash but not many as I recall. However I did not like using them because when reinflating the high side inflates much easier than the low side and makes the tilt worse. Also you don't dare crawl out with the suspension still dumped, much too hard of banging metal to metal of the arms and the frame or whatever. I did however use the dump valve to get the last product out if the last stop was downhill.

 

[Coaldust]

ALMAC builds many of their tanks with front sumps. To compliment that feature, PACCAR has an option to lower the front suspension by 1”. It’s just enough stance to make a clean gravity drop, like a gas station UST.

Seneca Tank Truck goes one step further and installs a overinflate valve to raise the rear a few extra inches. It’s a nice feature for a line haul rig.