M915/M915A1 Steering Axle Upgrade


Feo, Fuerte y Formal
Supporting Vendor
Memphis, TN
M915A0s come with a Meritor FF-931RDAX61 Axle. Basic fitment Decoded F= Front, F=12,000-13,200lb, 9= Basic Series, 3= Larger Axle Beam and Knuckles, 1= Straight King Pins,
Axle measures 32.5 center to center. This is a 12,000lb axle.

M915A1s are equipped with an Eaton H1006388 steer axle. Rated at 12,000lb. Eaton reference # EFA-12-F3. 32.5 center to center as well. EFA = Series, 12 = 12,000#, F = I beam standard overall width, 4= 3.5in to spring pad.

Upgrade axle for either truck will be an FL-931, FL-941, or EFA-18(20)-F3.

FL-931 is a 16-20,000lb axle, direct swap replacement. Hubs on these axles will be dayton or budd. Single steering arm.
FL-941 is a 20,000lb axle, direct swap replacement. Hubs on these can be budd or hub pilot. This axle is equpped with a dual steering arm on the passengers side much like the M939s use. This is optional and does not have to be used. Found in Paystar trucks mostly. The 20k beam uses the same 3.5in beam drop as the EFA-12-F3
EFA-18(20)-F3 is an 18,000lb or 20,000lb (whichever you choose) axle. Direct replacement. Hubs can be budd or hub pilot. Found in modern trucks like Pete 320s and other dump trucks. I have noticed that most of those trucks are 34" wide center to center and very few are 32.5 or 33s.

The eaton axles are quite a bit more expensive being in the $1500 to $3000 range. VS the Meritor axles can be found in the $500 range for complete hub to hub setups.

Planning on doing this swap on my truck this weekend and will update once done.

FL-941 axle pictured below.

Fl-941 information https://www.meritor.com/en/products/axles/front-non-drive/fl-941-fl-943


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