Mack Md, model years 2020 to 2022. Filed by Mack Trucks, Inc. and reported to NHTSA on 1 September 2021. 2,823 vehicles potentially affected.
What the notice says Mack Trucks, Inc. (Mack) is recalling certain 2020-2022 Mack MD vehicles. The cotter pin that retains the brake pedal clevis pin may not have been properly installed, which could result in an unsecured brake pedal.
Is your vehicle included? Check with your VIN at NHTSA, or ask a dealer. This page is an independent copy of the notice, kept so you can see what changed after it was published. It is not the authority, and the authority’s own text is the one to act on.
Mack's own number for this recall: SC0429. That is the number on the owner letter and on the dealer paperwork. 21V684 is the number NHTSA gave the same campaign, and the number this page is filed under. They are one recall, written two ways.
What owners ask about this recall
- Which vehicles does recall 21V684 cover?
- Mack MD, model years 2020-2022.
- What is wrong with them?
- Mack Trucks, Inc. (Mack) is recalling certain 2020-2022 Mack MD vehicles. The cotter pin that retains the brake pedal clevis pin may not have been properly installed, which could result in an unsecured brake pedal.
- What can happen if it is not put right?
- An unsecured brake pedal can cause a loss of braking ability and increase the risk of a crash.
- Is there a fix yet?
- Yes, and it is free. Owners are advised to not drive their vehicles until the remedy has been performed. Dealers will inspect the cotter pin installation and repair it as necessary, free of charge. Owner notification letters were mailed on September 13, 2021.
- What should I do now?
- Check your own vehicle by its VIN with NHTSA, which is the record to act on. Mack calls this recall SC0429, which is the number on the owner letter and the dealer paperwork.
Answered from the register this site holds. NHTSA is the record to act on.
What the authority says can happen if this is not fixed: “An unsecured brake pedal can cause a loss of braking ability and increase the risk of a crash.”
affected
in the notice
caught
| Campaign | 21V684 |
|---|---|
| Filed by | Mack Trucks, Inc. |
| System at fault | Service Brakes, Hydraulic:Pedals And Linkages |
| Reported to NHTSA | 1 September 2021 |
| Model years | 2020-2022 |
| Vehicles named | MACK MD |
This is not an ordinary campaign.
- Owners are told not to drive the vehicle at all. NHTSA applies this to a small minority of campaigns. 28 of the 1,399 we currently hold.
What the notice says today
The consequence
An unsecured brake pedal can cause a loss of braking ability and increase the risk of a crash.
The remedy
Owners are advised to not drive their vehicles until the remedy has been performed. Dealers will inspect the cotter pin installation and repair it as necessary, free of charge. Owner notification letters were mailed on September 13, 2021. Owners may contact Mack's customer service at 1-800-866-1177. Mack's number for this recall is SC0429.
What it said before
This campaign is in the register but not yet in the dated wording archive, so we cannot yet say whether its text has moved. It enters the archive on the next pass.
This is one of 583 notices in the record whose component field names service brakes, hydraulic. Across that group the median wait before owners were written to was 37 days.
Last checked . No change has been recorded in the wording.
The models named here, across their whole recall history
How to cite this record
Quoting the wording on this page means quoting a version, so the date belongs in the citation:
CarsMultiverse, recall 21V684, wording as read on 16 September 2026. https://carsmultiverse.com/recall/21v684/
The cross-border matches used on this site are deposited as a citable dataset: doi:10.5281/zenodo.22087136. The recall wording itself is published by the national authority named above and is theirs, not ours.
The recall record and its wording are published by the US National Highway Traffic Safety Administration and are US Government public domain. The dated archive, the comparison and any before-and-after above are CarsMultiverse. How fresh every engine behind this page is, is public on the status page. To check a specific vehicle, use NHTSA’s own VIN lookup.
Other Mack notices we hold
- 26V515: 2027 Anthem AN (4) and Pioneer PR (4)
- 26V509: 2025 TerraPro trucks
- 26V351: 2026 Anthem (AN), 2026-2027 Pioneer PR (4), Pinnacle (PI/PN), Granite (GR), and 2027 Anthem AN (4)
- 26V261: 2025-2027 Pioneer (4) and 2026-2027 Anthem (4)
- 26V207: 2025-2027 Pioneer (4) and 2027 Anthem (4) trailers
- 26V139: 2022-2027 TerraPro trucks
- 26E055: Grote replacement marker lights with part number 78513681
- 25V867: 2010-2016 Granite (GU) trucks
All 113 Mack campaigns we hold · Every manufacturer in the record
The fingerprint of this notice
We take a SHA-256 of each of the three blocks of text the authority publishes and keep the first eight characters. As we last read campaign 21V684 on 23 August 2026, they were:
- Defect summary
05359beb - Consequence
90338570 - Remedy
a46f5bdb
We first read this notice on 21 August 2026. It has not moved since. If it ever does, these characters will not match, and the change will be dated here.
The wording we hold for 21V684 · how the whole register is watched
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Owners of these cars
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