Rusty recycled steel, “sticky” dashes and bolt strength

Question:

There has been a discussion in Auto Restorer about 1970s cars being prone to rusting out. I had heard that in the early 1970s recycled metal was put into production parts and they had not realized the rapid corrosion that would occur without additional protection. At least that was the word at the service stations we would hang at.

Empirically, I saw 1969 to 1972 Fords disintegrate in two years from road salt. Fords got a really bad rap for rust that took them decades to recover from. I saw a new 1974 Olds Cutlass start showing rust after only a couple of years as well. After cutting up Oldsmobiles for panel replacement I saw why. There was no coating of any kind in some inner panels; there was just bare metal! In contrast, my 1997 Ford F-250 has epoxy primers and galvanizing.

Is there a wax-based product that will coat nooks and crannies without cracking or collecting dirt? All rust-proofing dries out and allows moisture in. I am using motor oil and automatic transmission fluid pumped into cavities to displace saltwater on my drivers.

My second question concerns 1973-76 Olds Cutlass dash pads that can become “sticky.” I am trying to discover what this is and whether there are any remedies to cure it. It seems like the dash pads curl at the edges and develop a flypaper-type surface that can’t be cleaned off.

And, lastly, in an engineering class that I took I learned that with a 1⁄4-20 bolt threaded 1” into a steel block it would take 500 pounds of force to shear the threads out vertically. So, be assured that four 3/8-inch bolts will safely lift any engine and transmission.

Answer:

I’ve been told that recycled steel is more prone to corrosion because it has a higher percentage of impurities. I’ve also been told that recycled steel is not more prone to corrosion and any rust-inducing impurities are eliminated in the manufacturing process.

Regardless, recycled steel is very widely used in all sorts of products, including the production of new cars and trucks so there is really nothing you can do to avoid it.

The propensity of many vehicles from the 1960s, 1970s and, to a lesser extent,

the 1980s to rust quickly and severely is mostly a function of their poor design and little or no corrosion protection in crucial areas.

I’m not aware of a wax-based product that you can use to prevent rust. One problem with this, as with conventional tar-based rust-proofing products, is that they can trap moisture against the steel and clog drain holes that would otherwise allow water to drain out of areas where it tends to accumulate.

Frequent application of oil and automatic transmission fluid will certainly discourage corrosion but it’s usually quite messy and troublesome to apply. And, of course, once you’ve coated everything with oil it’s quite difficult to subsequently apply paint or any sort of rust-proofing because it won’t stick to the metal.

The dash pads in your Oldsmobiles and various other vinyl parts in all sorts of cars sometimes become sticky because they are oozing oil that’s in the vinyl.

I, too, have experienced this and have tried to find a solution short of the obvious—replacing the affected parts—without success.

The strength of a good-quality new steel bolt in a good-quality new engine block or other part is easily determined, but what if you are not really sure about the quality of the bolt because, perhaps, it was made in a third-world country? What if you don’t really know whether and to what extent the integrity of the threads you’re engaging the bolt with has been compromised? When it comes to your safety, not to mention potential damage to your beloved car, don’t take unreasonable and unnecessary chances!

Answer:

I do not think the majority of folks who tinker with their cars realize how important and dangerous the adjustment of the brake system can be. It does not take but one time after fully applying an emergency brake while in motion to realize how fast the rear end will pass up the front (a tactic used profusely on TV crime shows).

Perhaps a good topic for discussion would be about panic situations in our cars. I never see any discussion about residual valves, which are used in drum brake cars. A quick answer would be the proportioning valve takes care of that. But it really doesn’t, especially in emergency situations.

I say this because I was involved with this situation in a 1954 race car that was being prepared for the Mexican Road Race (La Carrera Panamericana which at the time allowed the use of front-only discs for safety).

We tried various proportioning valves and tested the car on a skid pad. This was due to trying to use drums rear and discs front with new equipment (a dual master cylinder).

We learned from an old brake guy about residual valves, which reside in the master cylinder, and keep a small amount of pressure against the shoes to keep them from backing off too far from the drums. We could never find any good solution for using discs and drums together. There was no master cylinder with the proper hydraulic ratio that contained a residual valve, especially for the rear only.

We ultimately used four-wheel discs for which adjustable proportioning valves are actually made and changed the rules.

There have been discussions or questions in your magazine, which were about problems using different front and rear brakes. Perhaps you could explain this more clearly. Especially about how dangerous it could be when you’re least expecting it.

Answer:

It is important to make sure that every aspect of your car’s braking system is correctly configured for the vehicle and application, and in good working order. There is nothing inherently dangerous about a front disc/rear drum system. This was standard fare in tens of millions of vehicles made over the past few decades, and is still commonly used to this day.

Problems with inherently incompatible parts really doesn’t exist with OEM systems from major car manufacturers. However, when hobbyists alter their vintage vehicle’s brake systems, incompatible parts are a real danger.

Because of that, I normally recommend against cobbling a braking system together from disparate parts, and instead suggest buying a complete system engineered specifically for your vehicle by a competent person or company.

When designing a brake system, another factor that should be considered but is often overlooked is the capability and condition of other, related parts of the car.

For example, braking action imparts loads to the steering, suspension, wheels, chassis, tires, and various other parts and if you’re increasing a car’s braking capacity you need to consider the effects of this on other parts of the car.

Regarding residual valves, as the name implies these are designed to maintain

some level of residual hydraulic pressure in the braking system at all times. Drum brake systems use a residual valve to maintain about 10-pounds of pressure in order to keep the brake shoes very close to the drums. This reduces the lag time between when the operator presses the brake pedal and when braking action occurs, and helps maintain a high, firm pedal. Residual valves are also used in braking systems that have a master cylinder mounted lower than the calipers or wheel cylinders to prevent the fluid from draining back toward the master because of gravity.