What This Air Spring Does
This is a rolling-lobe air spring with a composite piston, mounted on the drive axle suspension. Air pressure inside the sleeve carries the load and sets ride height. The sleeve rolls over the piston as the axle moves, so the bag flexes constantly, every mile, under whatever weight is on the frame.
Approximate dimensions on this unit: 21.5 in extended height, 6.1 in compressed height, 9 in top plate, 10 in piston. Measure your old bag before ordering. Two air springs can carry the same brand number in different catalog years, and piston diameter is the detail that most often catches people out.
When it fails, the truck leans, the height control valve chases pressure it can never build, and the air dryer purges more often than it should. On a tandem, a soft bag on one side dumps load onto the other, which is how you end up replacing two after ignoring one.
Why These Numbers Cross
W01-358-8468 and W01-M58-8468 are the same physical bag under two Firestone catalog conventions — the M in the middle marks a later cataloging series, not a different assembly. Both describe the same reversible-sleeve air spring with the same plate, piston and stroke, which is why shops see them used interchangeably on parts tickets.
Goodyear lists 1R12-654 and 1R12-1049 against this application, and ContiTech carries 75561. Volvo's own number for the drive axle bag is 21132005, and Mack 21244322 covers the Volvo-architecture chassis that share the same drive axle suspension. Torque TR8468 and Triangle AS-81206 are aftermarket numbers built to the same envelope.
All of these numbers are listed here for identification only. PartStop is not affiliated with, endorsed by, or authorised by Volvo, Mack, Firestone, Goodyear, ContiTech, Torque or Triangle. The crossing works because the mounting geometry and load rating match, not because the numbers came from the same plant.
Before You Order
Cross-reference is a starting point, not a fitment promise. Confirm by VIN or by reading the number stamped or moulded into the old bag before it goes in the scrap bin. Air spring numbers are usually on the top plate or the side of the piston — clean the road grime off and look before you cut it loose.
Check the mounting studs and the air port thread on your old unit. Also inspect the height control valve linkage and the piston pedestal while the bag is out. A bent linkage arm or a cracked pedestal will destroy a new air spring the same way it destroyed the last one.
W01-358-8468 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to W01-358-8468. Use them to identify the part — then confirm the exact fit by VIN or the number stamped on your old unit before you order. An interchange is a starting point, not a fitment guarantee.
| Brand / Line | Cross-Reference Numbers |
|---|---|
| ContiTech | 75561 |
| Firestone | W01-M58-8468 |
| Goodyear | 1R12-654, 1R12-1049 |
| Mack | 21244322 |
| Torque | TR8468 |
| Triangle | AS-81206 |
| Volvo | 21132005 |
Frequently asked questions
Is W01-358-8468 the same as W01-M58-8468?
They describe the same reversible-sleeve drive axle air spring under two Firestone catalog conventions. The physical bag, plate and piston are the same. Still verify against the number on your old part or by VIN before you order, since catalog numbering has changed over the years.
Will this fit a Mack tractor?
It fits select Mack tractors built on the Volvo-architecture drive axle suspension, and Mack 21244322 is listed as an interchange for identification. Mack used more than one drive axle setup, so confirm by VIN or by pulling the number off the bag currently on the truck.
How do I know the air spring is bad and not the height control valve?
Soap the bag at full ride height and look for bubbles at the sleeve, the crimp ring and the air port. If the bag holds and the corner still sits low, work the height control valve arm by hand and see if it fills. A valve that fills on manual override but not on its own is a linkage or valve problem.
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Run your VIN and we’ll match parts to your exact truck, or call the counter — a person who knows trucks verifies fitment by OEM number before the order ships. No wrong-box returns.
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