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.
Automann · Brakes & Wheel End
138.1010
In stock · ships from Knoxville
This is an automatic slack adjuster designed for heavy-duty truck and trailer air brake systems.
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
Verified to be a Gunite‑type automatic slack adjuster with 5.5‑inch arm, 1‑1/4" diameter, 10‑spline, and straight clevis. Exact vehicle makes/models are not specified by the distributor listings; always confirm length, spline count, and arm orientation match the removed unit.
Part data verified against 2 catalog sources
Numbers this part supersedes or interchanges with. Showing 2 of 2.
Different year, make, or config? Get a confirmation against your truck in under a minute.
Slack adjusters connect the brake chamber pushrod to the S‑cam shaft and automatically correct for brake lining wear, keeping brake stroke in adjustment without manual intervention. You replace a slack adjuster when it fails internally—often indicated by the brake not adjusting properly—or when the splines or clevis become worn or damaged. This 5.5-inch arm, Gunite‑type unit fits 1‑1/4‑inch diameter camshafts with a 10‑tooth spline and comes with a straight clevis for standard pushrod attachment.
Part Number: 138.1010
GUNITE SLACK ADJUSTER 5 X 10 SPLINE X 1 1/4
Vendor: Automann
Dealer: Knox Trailers
Compatibility, alternatives, and more
Parts commonly needed alongside brakes & wheel end
