What This Air Spring Does
This is a reversible-sleeve air bag for the drive-axle position on the Kenworth Airglide 100 (AG100) rear suspension. The rubber sleeve rolls down over a composite piston as the axle travels, instead of folding like a convoluted bellows. That rolling action gives a flatter spring rate and longer sleeve life on rough haul roads and off-highway work.
Working numbers on the PartStop replacement: roughly 13.3 inches extended height, 3.8 inches collapsed, and 5,895 lb rated capacity at 90 psi. Those figures matter because ride height on an AG100 is set by the leveling valve linkage, and a bag with the wrong extended height will park the axle outside its normal travel window.
Application is the AG100 rear drive-axle suspension on C500-series severe-service tractors, including C500, C501, C508, C509, C510 and C540 variants, plus other heavy-duty Kenworth chassis running this bag position. Confirm by VIN or by the number printed on the bag you are pulling off.
Why These Numbers Cross
Air springs get built for a suspension, not for a truck brand. One manufacturer tools the bellows and piston for the AG100 drive-axle position, then the suspension builders, axle suppliers and truck OEMs each assign their own part number to the same assembly. That is why a single bag carries a stack of interchange numbers.
So W01-358-9422 shows up as Kenworth K303-15 in the truck parts book, Goodyear 1R11-028 and ContiTech 99-12 P 314 from the air spring side, Hendrickson S-13032 and SAF-Holland 57009422 from the suspension builders, Watson & Chalin AS-0017, Triangle 8314, and Volvo 85101148. Same physical bag, different catalog.
These numbers are listed for identification only. PartStop is not affiliated with, endorsed by, or authorized by Firestone, Kenworth, Goodyear, ContiTech, Hendrickson, SAF-Holland, Watson & Chalin, Triangle or Volvo. Use the cross-reference as a starting point, then confirm against the number on the old part or the VIN before you order.
Failure Signs And Install Checks
Typical failure is a split or chafed sleeve where the rubber rolls over the piston shoulder, or a bead leak at the crimped end plate. Symptoms: the truck squats on one corner overnight, the compressor cycles more than normal, or the leveling valve keeps hunting. Soap the bag at ride height and again with the suspension unloaded, because some tears only open under travel.
Before install, deflate and block the suspension, then inspect the piston mount and upper plate for corrosion and cracked studs. Clean the mounting surfaces so the bag seats square. Check for anything rubbing the sleeve, air lines, brake hoses, mud flap brackets, and replace bags in pairs across the axle so ride height stays even. Reset the leveling valve linkage after install.
W01-358-9422 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to W01-358-9422. 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 | 99-12 P 314 |
| Goodyear | 1R11-028 |
| Hendrickson | S-13032 |
| Kenworth | K303-15 |
| SAF-Holland | 57009422 |
| Triangle | 8314 |
| Volvo | 85101148 |
| Watson&Chalin | AS-0017 |
Frequently asked questions
Is K303-15 the same air bag as W01-358-9422?
They reference the same drive-axle air spring for the Kenworth Airglide 100 rear suspension. K303-15 is the truck-side number, W01-358-9422 is the air spring manufacturer number. Cross-reference is a starting point only, so verify against the number printed on the bag you are removing or by VIN.
Do I have to replace both bags on the axle?
Not strictly, but it is the better practice. A new bag next to a bag with years of heat cycling and sleeve wear can give uneven ride height and put the leveling valve in constant correction. Replace in pairs across the axle and reset the ride height linkage after install.
How do I tell a reversible-sleeve bag from a convoluted bag?
A reversible-sleeve bag has a smooth cylindrical rubber sleeve that rolls down over a piston at the bottom. A convoluted bag has one, two or three visible rubber lobes stacked like a bellows with no piston. The AG100 drive-axle position uses the reversible-sleeve style with a composite piston.
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