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Sheet Metal

Suburban Panel Body Rust Repairs

Thursday, February 11th, 2010

Replacing major rust-out between the rear fender and door of the 1947-1955 Suburban or panel truck can be easier than you think. The curvature in this area is the same shape as the adjacent door.

Therefore, locate a 1947-1955 donor door of limited value due to butchered radio speaker holes or a badly rusted bottom. Remove the outer panel. It has the correct metal gauge and round shape as the Suburban and panel truck body.

Splash Aprons

Thursday, February 11th, 2010

Due to the abuse given trucks when they once considered only for work, many body components today are damaged beyond repair. During the restoration of your 1947-1955, if you would rather not use a running board splash apron from a parts supplier, there is an alternative.

Locate a piece of new flat metal the correct gauge and size of your original splash apron. Gradually begin curving the sheet by bending it over a six inch diameter pipe. Secure the pipe in a table vise or equivalent. This will result in the curve you need without unsightly bends on the surface.

The next step takes more patience but you can be successful. Borrow or otherwise locate a small metal break and bend the original angle on the perimeter. You will need to trim the edges to the approximately 3/4″‘ width as original.

Some hand bending where the apron fits against the ridge of the rear fenders will be necessary. This can require some pliers to begin the rounding. Use a round hedge hammer to continue the curving process. Take your time here!

Slight mistakes on the edges will not show from the outside of the pickup. Making your own running board splash apron is especially a good consideration on a 1 ton pickup. These very long aprons are not available from aftermarket suppliers.

This Tech Tip comes from Richard Pasauage of Wilks Barrie, PA. He personally made his 1950 Chevrolet 1 ton running board splash aprons.

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.

1954 Bed Side

Thursday, February 11th, 2010

1954 bed side

From 1941 through 1953 the GM pickup bed sides are the same, however, a major design change began in 1954. This new style with very few modifications continued to the end of the true step beds in 1987.

The unique feature of the 1954 through 1954 mid series bed sides is the flowing grooves that fit the edges of the rear fenders. These apparently gave a better seal the older design fenders were bolted to the new sides. It prevented mud and dust from passing up from the wheel well area.

For the perfectionist: These sides will probably never be reproduced. The expense of tooling for a step bed side that was only used less than 16 months is not practical. Originals will remain the only source for the correct restoration.

Rocker Panel Moulding Instruction

Thursday, February 11th, 2010

Yes the cabs are the same between 1/2 ton and 2 ton on the 1955-1959, however one extra does exist on the 1 1/2 and 2 tons. These larger trucks have an additional rocker panel! Their panels are held to and cover the regular rocker under each door with nine sheet metal screws. They even extend from the under door area to along the edge of the cab corner.

Check this page from the 1955-1959 Chevrolet Factory Assembly Manual printed in those years.

Tip submitted by Graeme and Helen Howden of New Zealand.
Email howdens@slinshot.com.nz

Their 1956 Chevrolet 2 ton had them missing and the truck was obviously lacking something. They discovered the problem when they found this page during their research.

Click image to enlarge

Step Panel Moulding Instruction

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