correct finishes on suspension bits

[Pete O]

Does anyone know what the correct finishes should be on the front

suspension hardware for a 1951 Super? I imagine that the major

pieces, like the lower A arm, shock absorber, knuckle, etc., are

painted chassis black. But what about the fasteners? Should the

bushings and grease fittings be painted black, or left unfinished?

What about the roller bearing and the caps for the kingpin? Thanks

for your help!

[Bill Stoneberg]

When I was doing my 1950 Wagon, I painted all the suspension parts black as they were black when they came apart. Also the nuts and bolts were black. I would imagine that the 51 was the same. Bushings are made of rubber, so I left them alone. Grease caps and fittings I left alone,meaning I did not paint them. Caps for the kingpins are black.

[Pete O]

Thanks Bill! The parts for '50 and '51 suspensions are the same. I guess it makes sense that everything is painted. You have to think about how they probably did things on the assembly line. I bet everything was bolted together unpainted, and then the whole completed chassis was sprayed afterward.

Pete

[NTX5467]

To fully understand the whole situation, you'd need to know the assembly order of the parts and such. For example, the frames would most probably be delivered to the assembly plant "coated" with some sort of stenciled part or ID number on them, maybe even a color code daub too. From what I've seen, that pretty much carries on to modern times (on body/frame vehicles), but with bar code tags added into the mix too.

As for the suspension items, it would depend upon what was assembled when and then where it went after that. Note, too, that any surface that will mate with another surface (as in having something bolted to it) would not be coated until after the two items were joined together, typically. ALSO, rather than spray the parts, it's very possible that they were "dipped" (a layer of paint floating on top of water in a container, hence the "runs" and inconsistent paint thickness). If the bushings were installed prior to the dipping and then were coated, it would be possible that paint would get into the sleeve in the bushing and possibly cause problems in assembly to the chassis itself or later on as the paint deteriorated or was "worn" from the mating surface of the sleeve and the bolt (why many control arms are coated partially, as the bushings are already installed with the dipping being done as a final labor operation).

It's also possible that some sort of oxide coating was applied to the suspension control arms as an anti-corrosion measure, rather than paint per se. Probably a dull grayish color? Hence, no "black" paint and the part could be assembled (with some reasonable care to prevent scarring the coating) with all other items (grease fittings, bolts, bushings, etc.) being "natural".

The OTHER detail item would be the specified gloss of the black paint used on the assembly line in comparison to what many perceive to be correct. GM might have used "black" paint (and lots of it), but it was typically of a satin to dull satin gloss rather than the shiney black that many perceive was used--by observation. A good example of this might be GM pickup truck chassis, probably prior to 1996, in the underhood fender skirt panels and general chassis coloring. Therefore, what many restoration companies sell for "chassis black" might not be accurate in all cases--especially for high level judging events. GMSPO did catalog "Reconditioning Paint" in their Standard Parts Catalog, both in spray cans and in 4-quart cases. Others have found charcoal grille "black" paint to be somewhat accurate and not show fingerprints as the GM paint might. I suspect that the one black paint used would be noted in some of the later model vehicle asselbly manuals, up in the front where it lists all of the lubes and coatings and such, but that could be a variable issue. There might also be something in the paint supply (complete vehicle) listings at DuPont, etc., as there can be for engine enamel.

Where you end up in this deal can be related to the ultimate use of the vehicle. Restoration-oriented individuals would most probably lean toward accuracy more than "show", whereas those oriented toward "show" would, by observation, lean more toward the shinier black paints as it generally "shows better" in indoor car shows (and is somewhat the public "expects" to see).

Just some thoughts . . .

NTX5467

[Pete O]

Bill, One thing I found when taking appart the suspension was that there was in fact no rubber in the bushings. True, the dust seals are rubber, but the bushings are of made of steel, and they run steel to steel on the threaded shafts that they rotate on. Very different from modern suspensions, where some degree of compliance is built into the flexible rubber bushings so that the wheel will deflect a little when going over bumps. Maybe this is needed nowadays to compensate for modern stiff walled tires, whereas the old bias ply tires acted as the cushioning back in the day?

[Pete O]

NXT5467,

Thanks for your input. I wonder if the assembly steps that were used are documented anywhere? Maybe the AACA has something in their Library.

Pete

[Bill Stoneberg]

Ok Pete,

I am confused, which bushings are we talking about ?

Bill

[Pete O]

Bill- I'm not sure what the proper name for the part is, but it's the shaft that connects the outer end of the lower A arm to the upper lever (coming off the shock absorber.) The kingpin goes through this part to attach the spindle. I'm referring to the bushings that thread into the upper and lower ends of this shaft, as well as the bushings where the inner end of the lower A arm attach to the frame. They are hex shaped, and have grease fittings in them.

Pete

[NTX5467]

Somewhere, in that mix, there should be some bronze bushings (reamed/honed to size) for the friction interface of the harder steel pivot items. They should be inside one of the cast housings. They will wear out with use, just as any softer metallic interface is designed to do--one "hard" item runs against a "soft" wear item that is replaceable.

The caps you describe sound similar to what's on the end of the upper control arm shafts on '90s era Chevy C-series pickups. The hex end is the actual "bearing" itself in that particular vehicle and sounds just like what you're describing, except possibly in another capacity in the earlier style suspension architecture.

In reality, the earlier bias ply tires had a significantly stiffer and thicker sidewall than modern tires. The "cushion" came from the angle of the "ply" cords to each other, which was consistent throughout the tire casing and the fact that many of them were spec'd to run 24psi at "normal load and speed". A bias ply tire, at normal inflation pressures, will tend to flex "around" an object rather than "run over" it as a belted-tread tire will do (due to the stiffer tread section). One reason the bias ply tires generated more heat and generally required more power to roll them against the roadway (heat and power consumption decreased with higher inflation pressures, as in 30-32psi, provided those pressures were not needed to compensate for added loadings of the vehicle).

Enjoy!

NTX5467

[Pete O]

NXT5467,

The only bronze bushings I came across were in the steering knuckle, for the kingpin to ride in. All the other bushings are steel. I'm attaching a picture (that I stole off another post!) that shows a close up of one of the bushings I'm referring to. I think another reason for the bushings being steel, which would prevent any compliance in the suspension, was the design of the suspension itself. With the shock absorber lever acting as the upper A arm, you wouldn't want any additional movement that would tend to put a lateral strain on the shock.

Pete

[NTX5467]

Thanks for the picture and clarification. One reason for rubber bushings would be compliance (i.e., to absorb impact harshness) and the other one is being between two metal pieces for noise supression. Perhaps they figured that the rubber body mounts would be the better place to have noise isolation?

Thanks,

NTX5467