Brakes - Soft/Spongy Pedal Feel, ABS Code
89chevy05GMC NUMBER: 89-T-19
GROUP: 5 - Brakes
DATE: January, 1989
CORPORATE
NUMBER: 865019R
SUBJECT: SOFT/SPONGY BRAKE PEDAL FEEL
MODELS: 1989 M-VAN AND S/T TRUCKS
ISOLATION/DUMP VALVE:
Some 1989 M-Van and S/T Trucks were built with Isolation/Dump Valve Assemblies (see Figure No. 1) that may contain small metal particles. These metal particles may lodge themselves between the Dump Valve Check Ball and Ball Seat. If this occurs, a pressure differential will occur between the Isolation Valve and the Dump Valve, causing the instrument panel brake light to come on, and set a Code
4. This condition will not affect the normal braking of the vehicle. However, Rear Wheel Anti-lock will be deactivated (and dash brake light will so indicate that the system is not active) and brake pedal feel will be soft/spongy.
IMPORTANT: The small metal particles will remain trapped inside the Isolation/Dump Valve and will not migrate into the remainder of the hydraulic system.
To eliminate this condition, replacement of the Isolation/Dump Valve is required.
PARTS INFORMATION
IMPORTANT: No affected Isolation/Dump Valve Assemblies were ever shipped to GMSPO.
Parts are expected to be available on February 13, 1989. Until then, normal part orders win not be accepted by GMSPO. Only verifiable emergency VIP orders will be accepted. SPO will make every effort to obtain parts. All parts will be placed on 400 control to waive VIP surcharges. However, the part will be shipped premium transportation at dealer's expense. All other order types will be cancelled as incorrectly ordered while the 400 control is in place.
PART
NUMBER DESCRIPTION MODEL
15618244 Isolation/Dump Valve S/T and M
For repair to vehicles under warranty, use:
Labor Op: H2480
Labor Time: S/T 1.0 Hr. M .9 Hr.