What This Air Spring Is
This is a rolling lobe, reversible sleeve air spring for the primary trailer axle suspension. Compressed height is 7.2 inches, extended height is 21.7 inches, and the top plate measures 11.31 inches. The air port is 1/4 NPT. Those four numbers are what you match against the bag you pulled off, not the brand name stamped on the piston.
Reversible sleeve means the rubber rolls down over the piston instead of folding like a convoluted bag. It gives a softer, more consistent rate through the stroke, which is why it shows up under dry vans, flatbeds and reefers hauling mixed loads. It also means the piston surface matters — a scored or corroded piston will chew a new sleeve.
The PartStop unit is an aftermarket direct replacement built by Zhuhai Fengli and carries a 6+ month warranty. It is not an OEM part and we are not affiliated with, endorsed by, or authorised by any suspension manufacturer. Other brands' numbers appear here for identification only.
Why These Numbers Cross
Air spring numbering is fragmented because the bag builder, the suspension builder and the trailer builder all assign their own number to the same assembly. Firestone's W01-358-9177 is the number most shops know. Goodyear catalogues the same envelope as 1R14-028 and ContiTech lists 64342. Same rolling lobe, same plate, same piston interface.
The suspension manufacturers then number it by where it mounts. Hendrickson calls it S-2065, SAF-Holland lists 90557003, Ridewell uses 1003589177C, and Watson & Chalin shows AS-0010. Aftermarket lines add their own: TRP AS91770 and Triangle AS-8316 both describe the same reversible sleeve spring.
What ties all of them together is the physical envelope — 7.2 in compressed, 21.7 in extended, 11.31 in top plate, 1/4 NPT port — plus the stud and mounting pattern. If the number on your old bag is in that list, this is the same part. If it is not, stop and measure rather than assuming.
Before You Order
Read the number off the old bag first. It is usually moulded into the rubber near the bead plate or printed on a paper label that survives if the bag failed dry. Cross-reference is a starting point, not a fitment promise. Confirm by VIN or by the number on the part you removed before you commit a set to the trailer.
Check ride height and mounting while the axle is on stands. A bag that is the right envelope but the wrong ride height will run the suspension outside its travel and fail again. Inspect the piston for rust scale and the top plate studs for stretched or pulled threads. Blow out the 1/4 NPT port and check the air line fitting for cracks — most repeat failures are a leaking fitting, not the bag.
W01-358-9177 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to W01-358-9177. 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 | 64342 |
| Goodyear | 1R14-028 |
| Hendrickson | S-2065 |
| Ridewell | 1003589177C |
| SAF-Holland | 90557003 |
| TRP | AS91770 |
| Triangle | AS-8316 |
| Watson & Chalin | AS-0010 |
Frequently asked questions
Is W01-358-9177 the same as Hendrickson S-2065?
They describe the same reversible sleeve air spring assembly — same 7.2 in compressed and 21.7 in extended height, same 11.31 in top plate, same 1/4 NPT port. Firestone numbers it as an air spring, Hendrickson numbers it as a suspension service part. Verify against the number on your old bag or by VIN before ordering.
How do I know if my air bag is bad or if it's just a leak?
Air the system up, shut the truck down, and spray the bag, the top plate studs and the 1/4 NPT fitting with soapy water. Bubbles at the fitting or plate mean hardware, not rubber. Bubbles through the sleeve, or a visible tear, split or bulge in the rolling lobe, means the bag is done. Also look for a scored piston, which will kill a new sleeve fast.
Do I have to replace air springs in pairs?
It is standard shop practice to replace both bags on an axle at the same time. A new bag paired with an old, hardened one gives uneven load sharing and pulls ride height off side to side. If one bag failed from age rather than road damage, the other is usually close behind.
Not sure it fits? We check before you pay.
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.
More cross-reference guides
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Every part below is a Premium Quality aftermarket Direct Replacement with published OEM cross-reference numbers, a 6+ month warranty and same-business-day shipping from Tacoma, WA. Not sure it fits? Run your VIN — or call and a person who knows trucks will verify fitment before you pay.