Re: 120 dual master cylinder

Posted by Ross On 2017/12/26 18:02:22

I submit that if you did a statistical risk assessment, that adding adding a dual master cylinder has no appreciable benefit to the safety of the car if the car is not operated on salty corrosive streets. A far vaster improvement in safety is achieved if all of the steel lines are replaced and the hoses changed. In another 40 years change all of the steel lines again. I am a bit of an emphatic crank that NO Packard should still be equipped with its original brake tubing.

I hold this view based on observations:

In 45 years with old cars I have never seen a brake hose fail by bursting. Stopped up, yes, perhaps 3 times. Burst, no.

I have seen any number of burst and weeping brake tubes in the same period. They corroded externally, usually from salt, and internally by means of ancient brake fluid.

So if the system is brought up to snuff the only likely cause of sudden failure is road debris cutting a line. Unlikely.

Now lets turn to the dual cylinder. It needs a long stroke from the pushrod in the event of a line failure. Better make sure your 36 can provide a stroke long enough to operate the brakes served by the undamaged half of the system. If they are not in good adjustment they will not be applied. My friend found this out when a line burst from corrosion on a 10 year old pickup. There was no response to the pedal.

Dual cylinder conversions are very popular with the Studebaker crowd. But if I open any one of the bleeder screws I have no brakes. Hmmmm.

All of this to say the most beneficial thing for any Packard is to be retubed, and probably with that copper nickel tubing. It is a dream to work with. After that keep the brakes in good adjustment and change the brake fluid from time to time.