DIY Network

1938 Packard: Rebuilding Master Brake Cylinder From "Classic Car Restoration" episode DCR-405

In this episode of Classic Car Restoration, host Mark Lambert evaluates the brake system on our 1938 Packard, checking the hoses and master cylinder. He removes and rebuilds the master cylinder and then re-installs it. He also shows how to make new brake lines using a metal tubing bender. Lastly, he bleeds the brakes and makes the final adjustments. In this second segment of episode 405, Lambert cleans and rebuilds the master brake cylinder.

Note: This is a summary of steps included in the automotive restoration procedures shown in this episode of Classic Car Restoration. These are general guidelines for restoration procedures on this particular make and model of vehicle, and for the level of restoration selected for this project. There may be variations in procedures depending model, condition of vehicle, level of restoration undertaken and the types of replacement parts or upgrade kits selected. Always follow proper safety precautions, and read and follow manufacturer's guidelines, diagrams and safety notices that come with any replacement parts or kit that you select.

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Materials used in this episode:

Standard automotive tools (socket-wrenches, screwdrivers, nut-drivers, etc.)
Regular drill with break honing bit
Replacement break fluid
Replacement master cylinder kit
Tapered drift punch
Tubing cutter
Tubing flaring tool
Tubing bender
Brake spoon

Disassembling and Cleaning the Master Cylinder

	Figure A
	Figure B

• Position cylinder in a vice (figure A) and begin disassembling.

• Remove boot.

• Drain brake fluid (figure B).

• Pop the cylinder apart.
  

• Remove the main piston (figure C), the main seal (figure D) and the spring (figure E).

  Figure C

  Figure D

  Figure E

  
  

• Clean your cylinder. Begin by using a brake hone tool (figure F). Place lube on it (brake fluid) and spin it in there easily (figure G). Go fast at first, then slowly, keeping the stone moving to create a 45-degree crosshatch pattern like you would have on a cylinder bore in an engine.

  Figure F

  Figure G

  
  

• Feel in there to make sure all the rust and ridges are gone. Ours felt good, so we were ready to rebuild our master cylinder.

Rebuilding Master Cylinder

• Start off with your rebuilding kit.

• Lubricate the bore with brake fluid and insert the valve seat into the bore(Picture) and walk that down in using a bar.
  

  	Figure H
  	Figure I
  	Figure J
  	Figure K

• Assemble bleed back valve on the end of the spring (figure H). You will want to use brake fluid here just to keep everything well lubed. Insert the bleed back valve in to bore.

• Next is the main cup seal with a protective brass washer built into the end. That meets up with the next item, a sweep seal (figure I). Again, lubricate and install.

• The sweep seal goes in at the end of the bore to sweep out any kind of residue that gets past that main seal (figure J).

• Install the clip that holds the system in place.

• The cap and washer then go back on. Leave the cap loose (figure K) so you can fill the cylinder with break fluid after you install it.

• Put boot back on.
  
  
  

  RESOURCES :
  
  
  Resources and Special Thanks for Classic Car Restoration 400 series
  
  
  The Packard Club
  Columbus, Ohio
  (National & regional clubs, car shows & judging, magazine, resources, etc.)
  The Cormorant magazine
  The Packard Club
  www.packardclub.org
  
  Packards International Motor Car Club
  (National owner's club, judging rules, magazine, newsletter and other resources)
  Santa Ana, CA
  Packardsinternational.com
  
  Packards of Chicagoland
  (Regional affiliate of The Packard Club)
  Elmhurst, IL
  Packards of Chicagoland
  
  America's Packard Museum
  Dayton, Ohio
  www.americaspackardmuseum.org
  
  The National Packard Museum
  Warren, OH (the birthplace of the Packard)
  www.warren.org
  
  The Packard Motor Car Foundation
  (Foundation for preserving the Packard marque) Restoring the Packard Proving Grounds and other Packard activities.
  www.packardmotorfdn.org
  
  Motorbooks International
  www.motorbooks.com
  
  Automobile Inspections LLC
  (Nationwide automobile appraisal & inspection services, including classic cars)
  Hartford, CT
  www.automobileinspections.com
  
  Classic Auto Appraisals (Evaluation of Classics, Street Rods, Antiques, Competition Cars, Exotics, Commercial Vehicles and Hand Crafted Vehicles).
  www.autoappraisals.com

  ALSO IN THIS EPISODE:
  	1938 Packard: Checking Brake System, Brake Hoses and Removing Master Cylinder
  	1938 Packard: Rebuilding Master Brake Cylinder
  	1938 Packard: Master Cylinder Installation, Metal Brake Tubing Demo
  	1938 Packard: Bleeding Brakes, Final Brake Adjustment