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Posts Tagged ‘sheet metal’

Hood Receiver Plate

Thursday, February 11th, 2010

The hood receiver plates through all of the Advance Design years (1947-1955) interchange. It is their attached hood release lever that is different due to the grill change in 1954.

Note: The accompanying photos show the extra length of the 1954-1955 lever. To add extra stability to this length, a groove was stamped in the lever to prevent bending.

hood receiver plate 1

hood eceiver plate 2

1947 Advance Design Cab

Thursday, February 11th, 2010

The differences found on the cab during the beginning of the Advance Design years are subtle, yet on close study soon become quite evident. It probably exists on all vehicles when a body style is first introduced. Lab tests on a vehicle tend to overlook a few problems that later surface when it is in the hands of the consumer. Thus engineers made various corrections on the 1948 cab leaving the first year of this series with several unique differences.

Beginning with the Advance Design trucks in mid 1947, the top of the body cowl directly below the rear of the hood is smooth. This is the space between the rubber hood lace and vertical firewall panel. GM soon discovered that in this area an error in design existed. During heavy rain all water that flowed past the hood lace could run forward and then down the firewall. This allowed water on important items such as the voltage regulator, fuse box, wiring, fresh air heater motor, the rubber grommets that held tubes, lines and the original cotton braided wires.

By mid 1948, an appropriate stamping change was made which remained through the end of the series in early 1955. This was a groove or trough running side to side in the top of the cowl. These troughs drain rain water down the cowl sides onto the recessed area by the hood hinges and protect the firewall components. Now 50 to 55 years later we are noticing a rust condition due to these water drain troughs. Seldom will a 1947 cab have major rust in these hood hinge indentations. The cabs between 1948 and 1955 will usually be showing rust out or at least much surface rust when stored outside for many years. There is only so long this recessed area can resist the regular attack of water runoff from the troughs before it begins to show deterioration.

1947 advance design cab

No water troughs

Another very noticeable feature on only the 1947 Advance Design cab is the lack of a hump in the lower part of the dash above the steering column. On 1948-1955 cabs the hump is necessary to allow the three speed column shift lever to pass down to the shift box. During the developing stages of the Advance Design cab, after World War II, the 3-speed truck transmission with column shift did not exist. Both 3 and 4-speed transmissions were using the floor shift system and a column shift hump in the dash was not a consideration.

As the 1947 Advance Design trucks continued using the 3 and 4- speed transmissions of prior years, their park brake lever is also unchanged. It remains secured to the right side of the transmission and is a vertical hand pull lever. With the introduction of redesigned 3 and 4 speed transmissions in 1948 the park brake was activated by a foot pedal on the left side of the cab. This pedal was in 1/2 and 3/4 tons only. The 1 ton and larger continued with a hand pull lever design throughout the series.

The firewall on the 1947 cab is one of its most unique features. It is not only different from the other Advance Design years, but is an excellent example of changes that save production costs. Initially the firewall was a flat sheet of metal welded within the edges of the cowl, etc. To prevent possible flexing of this sheet, GM welded two vertical U-channels, 11/2 inch x 16-3/4 inch to the inside. These two channels are hid by the inside firewall pad and therefore are not normally seen by the owner. Close observation will show the channel spot weld dimples on the engine side of this firewall sheet.

This flat sheet type firewall differs from the other years. By 1948, the second year of this body style, a less expensive method was used. The welded vertical channels were discontinued and were substituted with stamped rounded ridges or stiffeners in the flat sheet. These could be made with one stamping while the necessary holes were also placed in the sheet at the same time.

NOTE: We are now discovering that the unique features on the 1947 cowls were carried over into the early 1948 suburban, panels, and the canopy express. As these large single unit bodies were much slower in sales, it was possible GM had an over supply of 1947 cowls at the particular assembly plant producing them. They continued to use these early cowls until supplies were used.

Premature Body Rust

Thursday, February 11th, 2010

Did you ever wonder why the 1934-46 GM trucks show major rust on their horizontal flat sheet metal? The mystery is solved! These pictures show without a doubt what a wonderful home Chevy and GMC trucks provide for field mice.

After the truck has been abandoned at the edge of a pasture, placed in a salvage yard, or just stored in a shed after harvest season the little rodents soon find them. When the trucks are left alone for 5 or 10 years, just think of the 100’s of generations that have called them home.

This 1940 1/1/2 ton was recently trailered to our shop for a visit. It was removed from a Central Kansas field a few days before after years of waiting for a new home. It was being taken to Western Pennsylvania by its new owners Robert and his son Robert Galet of Jeannett, PA.

What a perfect place for a mouse house. No wind or rain and probably no snakes! The little guys just keep bringing in more nesting materials. They make more and more babies and of course we know what else they do that rusts out the sheet metal.

Attached is a picture of how this 1940 Chevy looked shortly after he got it to his home. The other photos show what was in place when they raised the hood and opened the doors. It looks like Robert Galet and his son will have a big clean up project. We don’t need to guess what the sheet metal will be like!

You can contact Robert Galet at rgalet@hotmail.com

premature 1

premature 2

premature 3

premature 4

Premature 5

1966 Cab Features

Thursday, February 11th, 2010

1966 cab features

Curved Windshield

The large one-piece laminated safety plate glass windshield has an area of approximately 1116 square inches.

Electric Windshield Wipers

Provide constant wiping action regardless of engine load or accelerator position. Wipers have 13-inch blades and a wiping speed of 110 strokes per minute. Two-speed wipers, including a push-button-operated windshield washer, are standard. Wiper arms and the metal portions of the blades have a matte finish.

High-Level Ventilation

Outside air enters through louvers at the top of the cowl – away from road dust, heat and fumes. The air passes into a plenum built into the the cowl, where water is separated from the air and drained out. Air enters the driver compartment through two inlets-one on the right side and one on the left.

Ventipanes

Partial opening of ventipanes permits stale air to be drawn out of driver compartment. Ventipanes can also be swung wide open to force outside air into the compartment. Made of solid safety-sheet glass.

Rearview Mirrors

Standard mirrors on Pickup models are a left-side fixed arm and an inside shatterproof. Series 10-30 Chassis Cabs utilize left- and right-hand 6-1/4 inches fixed arm standard mirrors. Series 50-80 models have a left-side 17-1/4 inches swing arm mirror as standard. A wide assortment of optional mirrors is available on most seines. See the Optional Equipment listing in the Model Specifications sections for exact availability.

Full-View Rear Window

Available as an option at extra cost. Large solid safety-sheet glass area of 762 square inches (331 square inches for standard solid safety-sheet rear window) improves rearward visibility to make driving easier and safer.

Safety Glass

Series 10-50 models have door windows of solid safety-sheet glass. Laminated safety sheet glass with metal window frames is optionally available. Series 60-80 models have laminated safety sheet glass with metal window frames as standard equipment.

Soft Ray Glass

Tinted glass is available as an option at extra cost. It may be ordered for the windshield only or for all windows. Consult the model specifications pages for availability as it varies with the series. The light and heat absorption of this glass reduces eye-strain and helps keep cab temperature more comfortable.

Window Frames

Painted metal frames on series 60-80 give extra rigidity to windows and reduce likelihood of broken or cracked glass. Metal frames are also included with the laminated glass option on Series 10-50.

Door Locks

All cab models include a key-operated left door lock as standard equipment. A right door lock is available as an option at extra cost.

Running Boards

Cabs in Series 50 through 80 are fitted with a running board on each side for ease in entering and leaving the cab. LCF cabs also have two convenient steps on each fender.

November 1, 1965

 

1967 1972 GMC Standard Tailgate

Thursday, February 11th, 2010

1967 1972 gmc standard tailgate 1

To make the base fleetside tailgate just a little different from Chevrolet, GMC kept their letters body color and surrounded them in a contrasting color. On Chevrolet just the letters have the different color.

1967 1972 gmc standard tailgate 2

1967-1972 GMC (above)

1967 1972 gmc standard tailgate 3

1967-1972 Chevrolet (above)

Fender Mistake

Thursday, February 11th, 2010

How did this happen? Strange but true. The 1971-1972 right front Chevrolet pickup fender has one of its two 350 emblem holes punched incorrectly. This causes the horizontal emblem to slope down at the rear. The left fender is correct.

The person that owns this all original 1972 truck states that all 1971-1972 Chevrolet trucks have this unusual feature. You can always recognize an aftermarket replacement fender. Their holes are correctly placed.

fender mistake 1

Right side with slope or 350 Emblem (above)

fender mistake 2

Left side parallel to marker light (above)

Fleet Side Steps

Thursday, February 11th, 2010

fleet side steps 1

The convenience of reaching cargo is ideal in a step bed pickup. The step between the cab and rear fender provides a place for the loader’s feet while reaching into the bed. Thus, this pickup is referred to as a ‘step bed.’

With the introduction of the fleetside box in the late 1950’s, there was no step. Placing cargo in the bed became much more difficult if added from the side of the bed. With some complaints, GM realized there was an opportunity to market a unique dealer installed accessory for this newer truck. A cast aluminum step was designed to actually fit into the fleetside sheet metal. Once the correct hole was cut in the bedside, the new step made access to cargo almost as easy as with the stepside. These were introduced in the mid or late 1960’s. They are a very rare item!

fleet side steps 2

fleet side steps 3

1953-1955 Side Mount Spare

Thursday, February 11th, 2010

side mount spare 1

During the Advance Design truck era, 1947-1955, most all spare tire assemblies were under the bed. Though not always convenient, this kept the extra tire away from the bed box and out of the way.

With encouragement to provide a more easy to reach spare tire, General Motors began offering a side mount unit in 1953. This continued, as an option, even through the later years of the GM step bed trucks.

This new option was added at the factory (not by the dealer) and included a steel frame attached to the left bed side. On the 1/2 ton, not the longer bed 3/4 ton, it was necessary to also have the rear fender with an indention at its front. This indention allowed the tire to be away from the cab and fit parallel to the bedside.

The indention on the 1/2 ton left fender was made no larger than necessary to allow for the mounting of the 6.00 x 16″ original tire. This spacing is so close that the current replacement 6.50 x 16″eplacement tire will sometimes not fit without touching either the cab or fender indention. This contact of the tire against the metal body and fender is not acceptable. The rubbing of a larger tire against the body or fender results in a squeaking noise and finally will wear through the paint. To prevent this, using a 6.00×16 tire may be necessary.

After the 1953 introductory year, it was discovered, the weight of the tire and mount could cause bed side and front bed panel separation (metal fatigue) on rough terrain. Therefore, in 1954 with the introduction of a redesigned stepbed, a small factory bracket was included with the spare tire option. This better held the left front of the bed side to the front bed panel.

An additional item of interest is found in the 1954 Chevrolet truck factory assembly manual. Due to the extra pounds of the added side spare tire and carrier weight, GM added a spacer (left side only) below the rear spring assembly. This helped keep the bed level even though the truck weighed more on the left. See the following Tire Carrier Instructions sheets.

side mount spare 2

side mount spare 3

Bedside Bracket (above)

side mount spare 4

Bedside Bracket Top (above)

side mount spare 5

Bedside Bracket in Place (above)

side mount spare 6

side mount spare 7

Rear Spring spacers for 1954-1959 side mount (above)

We also have two PDF files showing details of the side mounted wheel carrier.

Sheet 2 Model 3104 Click Here for PDF

Sheet 3 Models 3204, 3604, 3804 Click Here for PDF

1940 Tailgate Hinge

Thursday, February 11th, 2010

In 1940, GM began offering a slightly wider bed on their Chevrolet pickups. This width increased from about 46 3/8″ to 48 1/2″.

Of course, the tailgate also required a width change. For some reason GM added a much larger horizontal tailgate roll on the top and bottom. Possibly for added strength. This caused the two hinges to also change. They were now much larger in diameter than the 1939, but this resulted in a new problem! Heavy weight on an open tailgate caused the oversize hinges to bend and split.

In 1941, the tailgate roll and hinge was reduced in diameter, though still larger than the 1939 and earlier design. This new size hinge remained through 1953.

1940 Tailgate Hinges

Solution to a problem: Pure 1940 tailgate hinges are not being reproduced. Even if you have a rare 1940 Chevrolet or GMC pickup with restorable original tailgate, your large hinges may be in very poor condition and not restorable. The solution is now on the market! A non-metal bushing is now available that fits over a 1941 hinge. This builds up the horizontal surface to equal that of a 1940.