Replace Single Reservoir Master Cylinder on 59 thru 62? Cadillacs with a Dual Resorvoir

 

Background

 

While I wanted to maintain the original appearance of my car, I just couldn’t bring myself to relying on the original single reservoir master cylinder – one leak and that’s it.  My mission was to install a dual reservoir master cylinder that wasn’t a complete hack job.

 

I needed to find a dual reservoir master cylinder designed for drum brakes on all four wheels.  I also wanted to find a model that was readily available through my local auto parts store so I could get an immediate replacement if I had any problems.  After some research using the web site at http://www.autozone.com/ I discovered that Cadillac had all wheel drum brakes in 1968.  In addition, a rebuilt booster and master cylinder costs less than $100 and is available through all major auto part houses.  Whether you shop at Autozone, Napa, or Kragen, make sure the parts are rebuilt by a reputable shop.  In the case of Autozone, the units are rebuilt by A1 Cardone (a very established rebuilder).  The Autozone part number is 50-1117 and has a lifetime warranty.

 

Install

 

The bolt pattern on the back of the booster is slightly wider than the original.  As a result, the holes on the firewall and brake pedal bracket need to be slightly elongated with a rat tail file.  In addition, the pushrod is ¼ inch longer than the original.  Since I didn’t feel comfortable shortening the rod by cutting and re-welding it, I shimmed the brake pedal bracket from the firewall using washers.  The bolts on the booster are more than long enough to allow you to do this.  You could also shim the booster from the firewall, but this would leave a noticeable ¼ inch gap between the booster and firewall.  If you don’t shim to accommodate the longer push rod, you will have problems.

 

The next step is to isolate the front and rear brakes.  This is easy enough as there is a distribution block below the booster on the frame.  You will also need to get some fittings so the ¼” brake line will hook up to the master cylinder.  Be sure to get fittings designed for brake lines (Napa has them and they are usually manufactured by Weatherhead).

 

One other tip:  If you decide to fabricate brake tubing, spend the extra money to get a really good double flare tool.  The ones available at most auto stores and made overseas and don’t work worth a damn on steel tubing.  Instead, I purchased the tool made by Rigid (made in U.S.A.) and it was worth every cent.  A number of vendors sell them mail order, but I got my tool through my local Grainger store since I wanted it right away.  Home Depot sells the Rigid tool, but it is the single flare type – you need the double flare type.  You could special order the double flare tool through Home Depot if you want to save some money, but it will take several weeks as per the store manager.  I’ve used this tool to fabricate all my brake lines and the cooling lines to the transmission.  The results look totally professional and I saved a couple of hundred dollars over purchasing pre-fabricated brake lines.  The same goes for the tubing bending tool – get the one from Rigid.  It’s a few extra dollars and well worth it.  Home Depot carries the Rigid tube bending tool.

 

 

Don’t Scrimp – Get the right tool.

 

As you can see from the picture below, the fit looks professional and there is no interference with other parts:

 

Perfect fit.

 

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