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Service bulletin 300800

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id619026
Published by NHTSA2001-05-10
Manufacturer's number300800
Manufacturer's date2000-08-30
NHTSA componentSERVICE BRAKES, HYDRAULIC:FOUNDATION COMPONENTS:MASTER CYLINDER

NHTSA's summary

SUBJECT REGARDING A GEL-LIKE SUBSTANCE FOUND IN THE MASTER CYLINDER RESERVOIR IN LARGER TRUCKS, CONVENTIONAL, LARGE TILT AND SCHOOL BUS MODELS. *TT

The document

No address for NHTSA's copy can be built for this communication. Ask the dealer for it by the manufacturer's number.

Components

Brakes, Brake master cylinder

Vehicles listed
CHEVROLET CHEVROLET TRUCK
CHEVROLET MEDIUM DUTY
GMC GMC TRUCK
GMC MEDIUM DUTY

Listing a model year does not mean every vehicle of it is concerned: the document says which.