Hendrickson — Primaax
Description
This is a heavy-duty air suspension for vocational, severe-service and heavy-haul applications. It is approved for use by the OE for crane, dump, heavy-haul, logging, mining, cement mixer, oil field, tanker trucks and waste haulers.
There are multiple versions of this suspension. The variations in design are usually found in the shape of the hangers, length/location of the shocks or unique air springs but the overall design idea is the same.
Fast Facts
Hendrickson — Primaax | |
---|---|
Type | Heavy-duty air suspension for vocational, severe-service and heavy-haul applications. |
Features | Approved for use by the OE for crane, dump, heavy-haul, logging, mining, cement mixer, oil field, tanker trucks and waste haulers. |
Problem Areas | |
ATRO Solutions |
Tech Tips and Additional Resources
ATRO offers a full complement of bushings and torque rod options for Hendrickson’s Primaax.
ATRO’s pivot bushing, PB50-26648, utilizes a low friction intermediate sleeve to ease rotation and improve resistance to wear.
Note: The OE's pivot bushing, 58648-000, is used in Primaax, MaxAir and Twisted Sister. Though ATRO offers a direct cross-reference with its PB50-26648, it is only for use in Hendrickson’s family of Primaax suspensions.
Wear Items
- Frame hanger attachment area becomes oblong
- Usually caused by loose pivot bolt fasteners or overloading
- Check transverse torque rods for wear
- Torque Rods
- Longitudinal rods – bushing walks out of rod
Check for improper alignment or worn bushings.
- Transverse torque rods
- Check for incorrect axle alignment, incorrect pinion angle, incorrect frame hole location or if axle bracket weld is off
- Worn bushings
Key Parts
Details

Hendrickson Primaax
Frame, frame bracket, and ATRO PB50-26648.