Automatic Slack Adjusters
Automatic slack adjusters in the 1-1/2 inch, 28-spline pattern with a 5-1/2 inch arm — the size most road tractors run — plus manual units with 5, 6 and 7 inch arms. Interchanges we carry include R801073, R801075, AS1150 and 40020227, fitting Freightliner Cascadia and Volvo. Spline count and arm length are what make it the right part; the brand on the box is not.
5 results
In Stock30% OFFPartStop
R801073 Automatic Slack Adjuster Fits Freightliner Cascadia Air Brake 2018-2024
Part # R801073
$79.99$55.99ShippedView
Pick up at store$41.99
In Stock30% OFFPartStop
Automatic Slack Adjuster 28 Spline AS1150 Fits Freightliner Fits Volvo F01633
OEM R801074
$89.99$62.99ShippedView
Pick up at store$41.99
In Stock30% OFFPartStop
R801075 Automatic Slack Adjuster 1-1/2" 28 Spline, 5-1/2" Arm Universal AS1172
Part # AS1172
$95.70$66.99ShippedView
Pick up at store$41.99
In Stock25% OFFPartStop
R801073 Automatic Brake Slack Adjuster, 28 Spline 1.5” Dia, 5.5” Arm Length
OEM R801073
$178.80$134.10ShippedView
Pick up at store$41.99
In Stock30% OFFPartStop
Manual Slack Adjuster 5 in, 6 in, 7 in Arm 1341041 , KN47001
Part # KN47001
$52.85$36.99ShippedView
Pick up at store$18.99
All 5 slack adjusters
- R801073 Automatic Slack Adjuster Fits Freightliner Cascadia Air Brake 2018-2024
- Automatic Slack Adjuster 28 Spline AS1150 Fits Freightliner Fits Volvo F01633
- R801075 Automatic Slack Adjuster 1-1/2" 28 Spline, 5-1/2" Arm Universal AS1172
- R801073 Automatic Brake Slack Adjuster, 28 Spline 1.5” Dia, 5.5” Arm Length
- Manual Slack Adjuster 5 in, 6 in, 7 in Arm 1341041
Automatic Slack Adjusters — common questions
5 premium-quality aftermarket direct-replacement listings for slack adjusters. Every listing shows its live price, stock and the trucks it is made for.
Parts in this category are listed for Kenworth, Peterbilt, Freightliner, Volvo, Mack, International, Isuzu. Fitment is set part by part, so check the listing, run the free VIN lookup at partstop.net/vin, or match the number on your old part — or call (253) 600-1351 and we will confirm it for your truck.
No. PartStop sells premium-quality aftermarket direct replacements, not genuine original-equipment products. Manufacturer names and part numbers on our listings are used for cross-reference and identification only.
Orders placed before 3:00 PM PT, Monday–Saturday, ship the same business day; after 3:00 PM PT they ship the next business day. Standard delivery is 3–5 business days, with an Overnight option at checkout. Standard shipping is free on orders over $100, except oversized freight items, which show their freight charge before you pay.
We offer a 60-day return policy on unused items in their original packaging. If you receive a defective or incorrect part, we'll cover the return shipping and exchange it at no cost.
Every PartStop part carries a 6+ month warranty against manufacturing defects. If a covered part fails within the warranty period, we'll replace it. Contact support with your order number to start a claim.