Master cylinder specs

TWEBB101

MEMBER
1984 CHEVROLET TRUCK
7.4L
V8
2WD
AUTOMATIC
1 MILES

Hey guys! I'm needing to replace my master cylinder, but am finding several options for my truck, based on the brake RPO code. However, my RPO sticker just not have any "J" codes for the brakes. I'm thinking it's for JB7, but I don't want to guess, and I'm not sure on the brake pad size either. Based on the VIN, are you able to tell me what I need?

3 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning,

The difference is the size of the rear brake shoes. It is either 11 or 13. The fact you have a 7.4 tells me you have a 2500 truck and they should come with 13 inch rear shoes. I attached a picture of the master for you from Rock Auto.

https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system

Roy

Caution: Brake fluid will damage electrical connections and painted surfaces. Use shop cloths, drip pans and fender covers to prevent brake fluid from contacting these areas.

1. On vehicles with manual brakes, disconnect master cylinder pushrod from brake pedal.
2. On all models, disconnect all wire connectors from master cylinder components.
3. Disconnect brake lines from master cylinder.
4. Remove master cylinder mounting nuts, then the master cylinder.

For additional information see Notes, Warnings, and Hints. See: Brake Master Cylinder > Fundamentals and Basics

Images (Click to make bigger)