Solution For Four Wheel Drum Brake Owners

[hbarbee]

First, let it be clear that I understand that disc brakes are far superior to drum brakes and if you have a Toronado that came with factory disc brakes, then you are much better off. However, I disagree that the brake system conversions that are often discussed are necessary for the typical Toronado owner. I do not drive my 45 year old car at freeway speeds tailgating crowded traffic where multiple panic stops and the resultant brake fading would be an issue.

If you follow the process below, your car will stop as good as it did when delivered from the factory. But you have to do ALL the steps or you will be disappointed.

Replace all of the components with new (or rebuilt if new is not available). This includes power booster, master cylinder, all wheel cylinders, all wheel springs and fasteners, adjuster assemblies and the brake drums. All of the items are readily available from NAPA.

This is the most important part, that most restorers overlook: Do not get the brake shoes from any auto supply. I located a service (http://brakematerialsandparts.webs.com/) that will custom build the brake shoes. The material must be a “soft composite, non-metallic” material, bonded (not riveted) and arced to fit the brake drum. Arcing removes some material, so riveting will severely limit life.

Brake shoes sold by auto supplies use modern hard metallic material made to last longer. You do not want this. It needs to be soft and non-metallic so friction in maximized. They can be replaced easily for as often as one would drive a classic car. In addition, the surface must be arced to fit the curvature of the drum. Very few places will arc shoes anymore. If you are using new drums, then the service I mentioned above they will arc them to the 11” spec. If not, you have to send the original drums to them for fitting.

The primary factors that contribute to restored drum brake systems not working properly is old drums that have been turned mated to brake shoes that have not been arced to fit the drum and brake shoe material that is too hard. This results in a very small area of very hard material contacting the drum.

With the above work done, my 1969 stops as well as it did when it left the factory.

[Schurkey]

If you follow the process below, your car will stop as good as it did when delivered from the factory.

They didn't stop all that good when new.

Replace all of the components with new (or rebuilt if new is not available). This includes power booster, master cylinder, all wheel cylinders, all wheel springs and fasteners, adjuster assemblies and the brake drums. All of the items are readily available from NAPA.

I might suggest "Inspect and test, replace as needed"; and specifically include the three brake hoses in that list. On my vehicle, I replaced the rubber hoses with steel braid-over-Teflon liner brake hoses for better pedal response. Doesn't make the brakes more powerful, but it does help make them more controllable.

This is the most important part, that most restorers overlook: Do not get the brake shoes from any auto supply. I located a service (http://brakematerialsandparts.webs.com/) that will custom build the brake shoes. The material must be a “soft composite, non-metallic” material, bonded (not riveted) and arced to fit the brake drum. Arcing removes some material, so riveting will severely limit life.

Brake shoes sold by auto supplies use modern hard metallic material made to last longer. You do not want this. It needs to be soft and non-metallic so friction in maximized. They can be replaced easily for as often as one would drive a classic car. In addition, the surface must be arced to fit the curvature of the drum. Very few places will arc shoes anymore. If you are using new drums, then the service I mentioned above they will arc them to the 11” spec. If not, you have to send the original drums to them for fitting.

The primary factors that contribute to restored drum brake systems not working properly is old drums that have been turned mated to brake shoes that have not been arced to fit the drum and brake shoe material that is too hard. This results in a very small area of very hard material contacting the drum.

With the above work done, my 1969 stops as well as it did when it left the factory.

Soft linings tend to work well when cold, but lose effectiveness as the brake temperature rises.
Higher-temperature linings tend to be less effective when cold, but once warm, work very well.
There's always a trade-off.

There was a time when brake shoe arcing was done at any competent local shop. Eventually the shoe manufacturers began pre-arcing the shoes to fit "typical" drum sizes, with the expectation that "close enough" really was close enough--the shoes would soon wear to the appropriate arc. Of course, concerns about brake dust generated by arcing became a workplace-safety issue. I haven't seen a shoe arcer in decades.