63 Brake Failure "Corvette Restorer"

[Robert I.]

In the new Corvette Restorer, an article talks about a brake failure on a 63.

The brake shoe welded itself to the drum.

Anybody know how that would happen?

[Ken A.]

Re: 63 Brake Failure "Corvette Restorer"

Poor maintainance. In the olden days brakes would be inspected routinely or at least 1Xyear. Or, a defective shoe in which lining comes off causing metal to metal contact. The resulting heat should weld things together.

[Stuart F.]

Re: 63 Brake Failure "Corvette Restorer"

Have only skimmed the Restorer Article today and saw the pictures, but I can add to what can happen with the Sintered Metallic brakes as it did for me in 1963. We had driven in off the desert into Las Vegas and parked at a motel on an incline. Set the parking brake which brought about a complete welding of the rear shoes to the drums which had to be torch cut off the next morning at a dealers shop. Don't know much about the standard shoes, or if that would be possible with them.

Stu Fox

[John D.]

Re: 63 Brake Failure "Corvette Restorer"

For some reason both of my 63 coupes have/had metallic. My driver had horrible brakes. Seemed that when you pushed on the brakes when the car was cold it actually felt like the car was going faster.

[Steven B.]

Re: 63 Brake Failure "Corvette Restorer"

Back when I worked for a brake and clutch lining manufacturer we would test lining in a number of ways. One was to spin the drum at varying rpm and apply full pressure, or lock them up. A number of times on hot linings and drums we would shear the lining material and the generated heat would weld the shoe to the drum.

As a note, we used various oils mixed with asbestos to mold lining material in rolls. The oil that worked best at the time, tolerated high heat, sheared at higher pressure, etc., was cashew nut oil. The problem was the cost. Semi-metallic with cashew oil worked really great when warm-hot. I tested a set on my then new '74 VW and stopping distances were greatly improved, it just took awhile to get up to speed.

Steve

[Duke W.]

Re: 63 Brake Failure "Corvette Restorer"

A 40-50 year old car may look and drive okay, but chances are a lot of problems are lurking under the covers.

Many of our cars may have had only "keep it running" repairs, and there are usually no records of maintenance, repairs, and inspections.

The reason why general aviation aircraft seem to last forever is that they are required to have rigorous inspections and overhauls in order to maintain their airworthiness certificates. If cars were maintained like airplanes, they would last forever, too.

In this case it's likely that all this car ever saw during its life is new shoes and maybe some new or rebuilt hydraulic components as they failed. The hydraulic components usually develop leaks because the brake fluid was never changed, and absorbed moisture corrodes the system internally. Wheel cylinder pistons can get sticky due to corrosion and/or sludge buildup, which can cause the brakes to drag.

In my own experience, a sticky parking brake cable caused the rear brakes to drag.

Dirt and corrosion can foul up the operation of self-adjusters, and backing plates can develop ridges on the shoe pads.

My recommendation to this owner is to completely go through the brake system including all the hydraulics. If linings are serviceable and there are no obvious issues like pull or chatter, they can be reused along with the drums without turning them. So you may end up spending little for parts, but a lot of labor is involved, which is what restoration is all about.

OE metallic linings are known to easily last over 100K miles in normal service, and I have recommended to owners who have cars with original metallic linings with plenty of friction material left to completely overhaul the system including the hydraulics, but reinstall the original linings and drums (in the exact same positions from which they were removed) since the linings/drums will probably never wear out at a few thousand miles per year mileage accumulation.

I advise this owner to do a compete teardown and inspection of the brake system as there may be similar problems elsewhere in the system.

Once everything is cleaned, rebuilt or renewed as required, and properly lubricated, the brake system will likely last indefinitely with periodic brake fluid flushes to prevent corrosion and sludge buildup in the hydraulics.

A quick way to get an impression of your brake system condition is to simply remove the master cylinder cover and look at the fluid. Is it clean, or does it look like week old coffee? Scrape the bottom of the reservoir with a spoon and see what you get. If the fluid is dirty and there is noticeable sludge at the bottom of the reservoir, it's time to completely overhaul the system or you could end up with a similar problem as the originator of this thread.

Duke

[Bill M.]

Re: 63 Brake Failure "Corvette Restorer"

I read the article and the brake failure was called catastophic, i'll bet it was a series of small problems that led to the end result. the brakes as said should be inspected often

[Craig B.]

Re: 63 Brake Failure "Corvette Restorer"

After looking at the picture of the brake shoe and the obvious wear on the one edge I have to believe that the retaining spring or pin was incorrect to begin with allowing the brake shoe to rub on its edge and finally to break which eventually welded to the drum when the car stopped. In addition I would add that most of the spring and retainer kits I have seen in recent years are universal for drum brake cars and are either manufactured in China or Mexico, buyer beware.