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Old June 3rd, 2008, 01:14 PM
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Warthog Warthog is offline
Join Date: Mar 2008
Location: Midwest City, OK
Posts: 639
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Default Master Cylinder Conversion - Upgrade

Hey Jon, do you want to add this to the manuals section?

Upgrade of Master Cylinder to Dual Cylinder

I know that many of us have done this conversion and fumbled our way thru it. This has been discussed many time but I have never seen any step by step with pictures. (Who needs instructions, just show me a picture)

I have the privilege of being mechanically inclined by learning from my dad many years ago. Wow… it’s been 34 years now, I sure miss him

I read most of the postings about this conversion and understood them but thought others might be confused.

This is not the only way of doing this….your mileage may vary…..

Some of the links on conversions:
Hey, Lets talk BRAKES some more!!!!

and many more. Just do a search on master cylinder

I chose to use the late 60’s early 70’s master cylinder. Mainly because it was in stock.

Here is my parts list:

Master Cylinder #10-1331 - $16 plus $10 core

Napa 3/16 Union Inverted Flair – Female 3/8”-24 Inverted - BK 641-3290 $1.29 - far left
Weather Head 3/8” Inverted Flair - Plug - #131x3 - $1.79

I used these fittings because I was cutting my line to length and wanted to cut down on connections
Napa Brake Line Fitting 1/2”-20, BK 641-3321 $3.95
Napa Brake Line Fitting 9/16”-18, BK 641-3323 $3.95

If you buy ready made lines you will need these adapters. They are pictured on the right
Napa 9/16” Adapter – BK 641-3309 $3.49
Napa 1/2” Adapter – BK 641-3305 $1.99

3/16” steel brake line ~$5
1/4” steel break line. ~$5
(I purchased a 51” line because I was bending my own and I knew I would mess up, which I did. lol)

Remove you old Master Cylinder and mount the new one

Remove the line going to the rear cylinders and the line going to the master cylinder.

Install the plug going to the rear ( I removed the block to clean it and for pictures)

I used a coat hanger to get the general shape of my brake lines. There are many website that talk about making the brake lines. Just Google it.

Here is the end result. I chose to not install a booster at this time.

Notice the single fittings at the master cylinder?

All that is left is to bench bleed the M/C and bleed the system

Until next time
Wart Hog
Live like you will die tomorrow. Dream like you will live forever!!!
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