NHTSA ID Number: 10226382
Manufacturer Communication Number: PIT3665L
Summary
This Preliminary Information communication advises the technician that the Hydro-Boost is not serviceable and will need to be replaced if the brake pedal moves or applies on its own at a full turn.
Condition / Concern
On vehicles with a Hydro-Boost System, customers may notice during full lock turns or near full lock turns that the brake pedal will move down or self apply. This can be caused by the internal dump valve of the hydro-boost not seating properly due to contamination in the steering system. The hydroboost assembly is not tolerant to certain types of contaminates that may be present in the steering system.
Recommendations / Instructions
The Hydro-Boost System is not serviceable and must be replaced.
275 Affected Products
Vehicles
| MAKE | MODEL | YEAR |
CADILLAC | ESCALADE | 2001-2004 |
| CHEVROLET | ASTRO | 1998-2005 |
| CHEVROLET | AVALANCHE 1500 | 2002-2004 |
| CHEVROLET | EXPRESS | 1998-2022 |
| CHEVROLET | EXPRESS 2500 | 2023 |
| CHEVROLET | EXPRESS 3500 | 2023 |
| CHEVROLET | SILVERADO 1500 | 1998-2023 |
| CHEVROLET | SILVERADO 1500 HD | 2001-2005 |
| CHEVROLET | SILVERADO 2500 | 1998-2023 |
| CHEVROLET | SILVERADO 2500 HD | 1998-2004 |
| CHEVROLET | SILVERADO 3500 | 1998-2023 |
| CHEVROLET | SUBURBAN | 2001-2004, 2016-2019 |
| CHEVROLET | TAHOE | 2001-2004 |
| GMC | SAFARI | 1998-2005 |
| GMC | SAVANA | 1998-2023 |
| GMC | SIERRA 1500 | 1998-2023 |
| GMC | SIERRA 1500 HD | 2001-2005 |
| GMC | SIERRA 2500 | 1998-2023 |
| GMC | SIERRA 2500 HD | 2001-2005 |
| GMC | SIERRA 3500 | 1998-2023 |
| GMC | YUKON | 2001-2004 |
| HUMMER | H2 | 2003-2007 |
1 Associated Document
Manufacturer Communications
Bulletin No.: PIT3665L
Published date: 10/18/2022
MC-10226382-9999.pdf 103.433KB
NHTSA ID Number: 10178353
Manufacturer Communication Number: PIT3665J
Summary
This Preliminary Information communication advises the technician that the Hydro-Boost is not serviceable and will need to be replaced if the brake pedal moves or applies on its own at a full turn.
1 Associated Document
Manufacturer Communications
Bulletin No.: PIT3665J
Published date: 06/26/2020
MC-10178353-9999.pdf 102.195KB
NHTSA ID Number: 10162149
Manufacturer Communication Number: PIT3665H
Summary
This Preliminary Information communication advises the technician that the Hydro-Boost is not serviceable and will need to be replaced if the brake pedal moves or applies on its own at a full turn.
1 Associated Document
Manufacturer Communications
Bulletin No.: PIT3665H
Published date: 06/24/2019
MC-10162149-9999.pdf 102.301KB
NHTSA ID Number: 10161004
Manufacturer Communication Number: PIT3665G
Summary
This Preliminary Information communication advises the technician that the Hydro-Boost is not serviceable and will need to be replaced if the brake pedal moves or applies on its own at a full turn.
1 Associated Document
Manufacturer Communications
Bulletin No.: PIT3665G
Published date: 05/13/2019
MC-10161004-9999.pdf 102.918KB
NHTSA ID Number: 10129088
Manufacturer Communication Number: PIT3665F
Summary
This Preliminary Information communication advises the technician that the Hydro-Boost is not serviceable and will need to be replaced if the brake pedal moves or applies on its own at a full turn.
1 Associated Document
Manufacturer Communications
Bulletin No.: PIT3665F
Published date: 01/23/2018
NHTSA ID Number: 10113364
Manufacturer Communication Number: PIT3665E
Summary
This Preliminary Information communication advises the technician that the Hydro-Boost is not serviceable and will need to be replaced if the brake pedal moves or applies on its own at a full turn.
1 Associated Document
Manufacturer Communications
Bulletin No.: PIT3665E
Date: Jan-2017
NHTSA ID Number: 10078876
Manufacturer Communication Number: PIT-3665-D
Summary
THIS PRELIMINARY INFORMATION COMMUNICATION ADVISES THE TECHNICIAN THAT THE HYDRO-BOOST IS NOT SERVICEABLE AND WILL NEED TO BE REPLACED IF THE BRAKE PEDAL MOVES OR APPLIES ON ITS OWN AT A FULL TURN.
1 Associated Document
Manufacturer Communications
Bulletin No.: PIT3665D
Date: May-2016
NHTSA ID Number: 10112546
Manufacturer Communication Number: PIT3665C
Summary
This Preliminary Information communication advises the technician that the Hydro-Boost is not serviceable and will need to be replaced if the brake pedal moves or applies on its own at a full turn.
1 Associated Document
Manufacturer Communications
Bulletin No.: PIT3665C
Date: Nov-2012
- Auto & Truck Maintenance
- Country of manufacture: United States
- Manufacturer: VALVOLINE
- High quality power steering fluid and conditioner
- Stops Noise
- Stops slipping
- Helps prevent unusual wear
- Protects seals
- Adds Lubricity to help stop wear and improve performance
- Seals and helps prevent small leaks
- Foam inhibitors help extend fluid life
- Protects against wear and pump breakdown caused by abnormal wear, oxidation, and foaming
- Performs even in sub-zero treatment
- Specifically designed for power steering units
- The service solution for ALL European, North American, and Asian vehicles (Honda fluid recommended for Honda/Acura vehicles)
- Reduces friction and protects seals and hoses - extending the life of the power steering system
- Provides excellent cold and high temperature performance eliminating "morning sickness" stiffness
- Excellent for use in electric hydraulic systems
- Cleans and frees sticky turbines and pumps
Last update on 2026-05-27 / Affiliate links / Images from Amazon Product Advertising API
SEOCONTENT-START
Bulletin No.: PIT3665L Published date: 10/18/2022 Preliminary Information PIT3665L Brake Pedal Moves or Self Applies at Full Turns Models Brand: Cadillac Escalade Model: Model Years: 2001 – 2004 VIN: from to All All Engine: All All Transmissions: Chevrolet Chevrolet Chevrolet Chevrolet Chevrolet Chevrolet Chevrolet GMC GMC GMC GMC Hummer Avalanche Tahoe Suburban Suburban 3500HD Express Silverado Astro Vans Savana Sierra Yukon Safari H2 2002 – 2004 2001 – 2004 2001 – 2004 2016 – 2019 1998 – 2023 1998 – 2023 1998 – 2005 1998 – 2023 1998 – 2023 2001 – 2004 1998 – 2005 2003 – 2007 All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All All With Hydro-Boost Brake System Supersession Statement: This PI was superseded to update the model years. Please discard PIT3665K. Condition / Concern On vehicles with a Hydro-Boost System, customers may notice during full lock turns or near full lock turns that the brake pedal will move down or self apply. This can be caused by the internal dump valve of the hydro-boost not seating properly due to contamination in the steering system. The hydroboost assembly is not tolerant to certain types of contaminates that may be present in the steering system. Recommendations / Instructions The Hydro-Boost System is not serviceable and must be replaced. IMPORTANT: • Before replacement of the Hydro-Boost System, the entire steering system (including power steering pump, lines, cooler, and gear box) must be flushed to avoid a reoccurrence. • If the vehicle has been in with the same concern within 20k miles of previous repair then it is recommended that the entire steering system (including power steering pump, lines, cooler, and gear box) be replaced. • For vehicles no longer under warranty, inform the customer that replacing the Hydro-Boost unit only, could possibly result in a shorter lifespan of the unit itself and that the customer may choose to replace all other steering system components if desired, at their own expense. Warranty Information For vehicles repaired under the Bumper-to-Bumper coverage (Canada Base Warranty coverage), use the following labor operation. Reference the Applicable Warranties section of Investigate Vehicle History (IVH) for coverage information. Labor Operation Description Labor Time 2441730 Power Brake Booster Replacement Use Published Labor Operation Time Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. © 2022 General Motors. All Rights Reserved.
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