What This Air Spring Does
This is a cab and sleeper suspension spring, not a chassis or drive axle bag. It sits between the cab mount bracket and the frame, carrying part of the cab weight and isolating the driver from frame inputs. On an AEROCAB setup it works with the cab shocks and a leveling valve to hold ride height while the truck is running.
The physical numbers on the sleeve style W02-358-7109 are a 7.87 in. bellows, 10.0 in. extended height and 2.40 in. collapsed height. Sleeve bags are reversible — the rubber rolls over the piston as the cab moves instead of folding like a convoluted bag. That rolling lobe is where the rubber eventually wears through.
Typical failure is a slow leak, not a bang. The cab settles overnight, sits low on one side in the morning, and the air dryer purges more often than it used to. If the bag is still holding but the ride went harsh, check the cab shocks and the leveling valve linkage before you condemn the spring.
Why These Numbers Cross
Cab air springs are built to a fixed set of dimensions and a fixed mounting pattern, because the bracket and stud spacing are designed into the cab mount. Once bellows diameter, extended height, collapsed height and end fitting type match, the part is interchangeable regardless of whose name is on the box. That is why one AEROCAB spring picks up so many part numbers.
W02-358-7109 is the number most shops recognize. Kenworth cataloged the same spring as T81-1000 for dealer parts counters. ContiTech lists SC29-Y109 along with 69624 and 68037. Link uses 1102-0077 and 1104-K002. Automann shows ABSZ70-7109 and Torque shows TR7109. Different catalogs, same sleeve bag.
All of those numbers are listed here for identification only. PartStop is not affiliated with, endorsed by, or authorized by Kenworth or any other manufacturer, and their numbers remain their property. Use the list to confirm you are looking at the correct spring family, then verify against the part you pulled off the truck.
Check Before You Order
Pull the old bag and read it. Sleeve air springs almost always carry a molded or stamped number on the end cap or the piston. If that number appears on the allowed cross list above, you are in the right family. If it does not, stop and verify by VIN through a dealer parts counter — cab suspensions were changed mid-production and a visual match is not proof.
Measure ride height with the system aired up before you tear into it. If the cab sits low on one side only, that is usually one bag or one leveling valve, not both. If it sits low across the board, look at supply pressure and the protection valve feeding the cab circuit first.
Replace in pairs where the truck runs two cab bags. A new spring next to a ten-year-old one gives you uneven cab attitude and puts extra travel through the older bag. Also inspect the shocks, the mounting studs and the air line fittings — brittle nylon line at the fitting is a common second leak found right after the bag is changed.
W02-358-7109 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to W02-358-7109. 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 |
|---|---|
| Automann | ABSZ70-7109 |
| ContiTech | SC29-Y109, 69624, 68037 |
| Kenworth | T81-1000 |
| Link | 1102-0077, 1104-K002 |
| Torque | TR7109 |
Frequently asked questions
Is this the same bag as Kenworth T81-1000?
It is the aftermarket direct replacement for that application. T81-1000 is the Kenworth number for the same sleeve-style AEROCAB cab spring listed under W02-358-7109. We list their number for identification only. Confirm by the number on the spring you remove or by VIN before ordering.
How do I know if my cab air spring is leaking or the leveling valve is bad?
Air the system up, then spray the bag and every fitting with soapy water and watch. A leak at the rolling lobe or end cap means the spring is done. If the bag holds but the cab will not come up to height or keeps hunting, the leveling valve or its linkage is the more likely cause.
Will this fit my T800 if it is older than 1999?
This spring is for AEROCAB-equipped conventionals from mid-1999 and later. Earlier cab suspensions may use a different spring and mounting. We do not guarantee fitment from a model name alone — verify your suspension model, mounting style and ride height, or check the number on the old part.
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
Need the part, not just the reading?
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.