# NHTSA recall 91V080000

A recall listed here may apply to a vehicle of this year, make and model. Only the manufacturer can say whether it applies to one vehicle: check the VIN with the official lookups.

- Published by: NHTSA \(United States\)
- Campaign number: 91V080000
- Manufacturer: MACK TRUCKS, INCORPORATED
- Reported: 1991\-05\-23
- Owners notified: 1991\-05\-02
- Component: STEERING:HYDRAULIC POWER ASSIST SYSTEM
- Units potentially affected: 35

## What is wrong

INCORRECT MANUFACTURE OF THE HYDROBOOST CYLINDER ALLOWS THE BALL SOCKET CLAMP TO CONTACT RIGHT SIDE STEERING LEVER ON AN EXTREME LEFT TURN AND CAUSE FLEXING OF THE CYLINDER ROD .


## What can happen

THIS FLEXING CAN CAUSE SEAL FAILURE OR CYLINDER FAILUREOF THE HYDROBOOST UNIT AND RESULT IN LOSS OF STEERING CONTROL AND RESULT IN AVEHICLE ACCIDENT.


## The remedy

REPLACE INCORRECTLY BUILT BOOST CYLINDERS.


## Notes

SYSTEM: STEERING POWER ASSIST, HYDROBOOST ASSEMBLY.VEHICLE DESCRIPTION: CF AERIALSCOPE MODEL.


## Vehicles this campaign lists

- [1988 MACK CF](/makes/mack/cf/1988/recalls.md). Built 1988\-03\-01 to 1989\-06\-01.
- [1989 MACK CF](/makes/mack/cf/1989/recalls.md). Built 1988\-03\-01 to 1989\-06\-01.

## Investigated as EA91009

This recall followed 1 NHTSA investigation. An investigation is NHTSA looking into a possible defect. It is not a finding that a defect exists, and it does not say that any one vehicle is affected.

- EA91009: Engineering analysis, opened 1990\-11\-30, closed 1991\-05\-28. POWER STEERING FAILURE. STEERING:HYDRAULIC POWER ASSIST SYSTEM.

From NHTSA's investigation file, as of 2026-10-19. JSON: [/v1/recalls/nhtsa/91V080000/investigations](/v1/recalls/nhtsa/91V080000/investigations)

## Check a VIN

- [NHTSA recall lookup by VIN, United States](https://www.nhtsa.gov/recalls)
- [Transport Canada recall search, Canada](https://wwwapps.tc.gc.ca/Saf-Sec-Sur/7/VRDB-BDRV/search-recherche/menu.aspx?lang=eng)

JSON: [/v1/recalls/nhtsa/91V080000](/v1/recalls/nhtsa/91V080000)

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