Peterbilt — Low Low Air Leaf

Description

Also known as the Kenworth AG400L, this air suspension reduced its weight 325 lbs. compared its predecessor, Peterbilt’s Air Leaf. It has considerably fewer parts, a higher weight rating (40k), and improved ground clearance. It is approved for use in belly-dumps and when lower fifth-wheel heights are necessary (high-cube van, reefer, bulk-haul, car carriers and high center-of-gravity loads.)

This suspension is similar in concept and design to the Freightliner FAS II and the International Corporate Air/IROS.

Peterbilt Low Low Air Leaf — Kenworth AG400L

Fast Facts

Peterbilt — Low Low Air Leaf
Type	Air suspension with maximum capacity of 40,000 pounds
Features	Fewer parts, higher weight rating (40k), and improved ground clearance.
Problem Areas	The biggest maintenance concern is the bonded bushings; the spring eye opens up and the bushing can walk out. With a bonded OE-style rubber bushing, the pin is not allowed to rotate, so the entire bushing can be forced to spin within the eye of the spring thus leading to the wallowed out spring eye.
ATRO Solutions	ATRO sping pin and torque rods

Tech Tips and Additional Resources

With a bonded OE-style rubber bushing, the pin is not allowed to rotate, so the entire bushing can be forced to spin within the eye of the spring thus leading to the wallowed out spring eye. Bonded rubber bushings attempt to combat this with an inboard flanged outer sleeve encased in a ring with detents for “gripping” the edge of the spring’s eye.

ATRO spring pin solution (PB46-26268; UB20500-OS):

Rotating pin design with flanged outer sleeve limits travel
The revolving inner pin eliminates bushing wind-up and prevent entire bushing spinning
UB20500-OS, an over-sized version (+.060"), is available if the rubber bushing has opened up the spring eye slightly. The spring must still meet specifications. If not, the spring must be replaced, not rebushed.

ATRO torque rod:

Uses ATRO torque rod TR00-41009 (OE# C65-6002.) This is a small-eyed rod with TS00-22500 in each end. The bushing in these rods will not fit OEM or other aftermarket rods. To rebush the OE or other aftermarket torque rod, use ATRO’s PL1146 (no rim and doesn’t rotate) or TS50-22691 (retaining rims and doesn’t rotate)
Rebushable