Your cart is empty
Browse our catalog to find the parts you need.
These images are illustrative and may not match the product exactly. Always verify by part number — or confirm instantly with the assistant using a photo or VIN.
Wabco · Air System
R955378
In stock · ships from Knoxville
This is an ABS modulator valve for trailer air brake systems, part of the Meritor WABCO Easy-Stop family.
Confirm the part fits before you buy. Applications and interchange numbers are researched and audited per part.
Verified fitment for 1 applications
Add your truck to see whether it's one of them
All confirmed applications for this part number.
Other applications
Other applications
This older-style valve has a threaded 3/4 in. NPTF exhaust port and a 3-pin electrical connector. Trailers produced on or after April 1, 1999, use the S4721950330 valve with a bayonet-style cable. The R955378 can be replaced with the newer valve using an adapter cable, as in Wabco kit 4006120090.
Part data verified against 5 catalog sources
Numbers this part supersedes or interchanges with. Showing 9 of 9.
Different year, make, or config? Get a confirmation against your truck in under a minute.
It regulates air pressure to the brakes during ABS events, preventing wheel lockup and maintaining control. The R955378 version is specifically for trailers built before April 1, 1999, and uses a threaded 3/4-inch exhaust port instead of the later bayonet connector. You would replace it when the valve leaks, fails electrically, or when servicing a pre-1999 trailer's ABS system.
Part Number: R955378
ABS MODULATOR VALVE-FITS OLD
Unit: ea
Dealer: Knox Trailers
Compatibility, alternatives, and more
Parts commonly needed alongside air system
