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Suspension

Front End Alignment at Home

Friday, October 6th, 2017

Accurate front end alignment on any straight axle can be done in your home garage. Stop unnecessary tire wear and pulling side to side.

This basic blue-print shows it all. It’s a no-brainer! The two small notches on each end of the alignment plate are a suggested place to secure your measuring tape.

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1947-1954 Rear Spring Alignment

Thursday, February 11th, 2010

Tech Tip from Ron Hansen
Wakefield, Massachusetts

Jim Carter Truck Parts

Alignment Solution for Installing a Late Model Rear End in a 1947-1954 Pick Up

On the original rear end, the spring centerbolt is offset to the front of the spring by 2″to 3″. If you install a modern rear end (with an open driveshaft) and retain the original springs, the wheels will end up offset forward (inside) of the original wheel openings in the fenders. To correct this problem, remove the original springs and reverse them end to end (front to back) as they are the same on both ends. This will bring the spring centerbolt to the rear of the axle and place the new rear end in the center of the fender wheel openings.

Click to enlarge

Jim Carter Truck Parts

Early Leaf Springs

Thursday, February 11th, 2010

Leaf spring width on 1/2 ton pickups remained at 1 3/4 inches until the introduction of the two inch width on the Task Force 1/2 tons in mid 1955. The early narrow springs worked well considering the engine horsepower and weight limitations of the 1/2 tons. The two inch springs became standard equipment on the rear of the 3/4 ton in 1946 but their fronts still remained the smaller size. This is because the increased weight carrying ability of the 3/4 ton is mostly felt in the rear. Only 1 ton and heavier were totally without the 1 3/4 inch springs.

With the abuse given pickups in the early days (poor roads, overloading, and almost no lubrication), the springs have held up well. Most mid 1955 and older 1/2 tons continue to operate with their tired original narrow springs.

In today’s world a new variable exists that puts even more demands on these small springs. It is the increased horsepower of later model engines. No problem if these trucks, converted to more powerful engines, are driven as if they still have their original six cylinder. However, problems arise with jack rabbit starts with or with a heavy freight load. Most of these Advance Design 1/2 ton’s with transplanted V-8’s have had their original closed drive shafts replaced with open systems. The replacement axle housings are clamped to the 1 3/4 inch rear springs. When heavy acceleration is forced on these modified trucks, the axle housings try to rotate due to the extra torque. Much of this movement is held in check by these narrow springs. They just weren’t designed for this. Breakage and permanent bending can occur.

Don’t push your 1 3/4 inch rear leaf springs beyond their limits. If you demand fast acceleration with your V-8 1/2 ton, convert to later model 2″ or 2 1/2″ springs. Check specialized suppliers, including Jim Carters Truck Parts (part # HP580), for add-on kits.

Low Cost Front Suspension Upgrade

Thursday, February 11th, 2010

The straight axle ½ ton GM pickups (1959 and older) were built tough! They served their purpose as the best in work vehicles for over 30 years. Other than an occasional kingpin replacement, they were almost ‘bullet proof’.

In today’s world, the reasons for owning an older truck, has generally changed. Most have been retired from work responsibilities and have become ‘fun trucks’ driven with care on smooth streets. Hauling merchandise is far down the list of their use.

The resulting demand for a smoother ride and better braking is the reason for many suspension options available from supply houses. For those willing to compromise on originality for an easier ride, one of the most proven and less expensive upgrades is the front suspension of the AMC Pacer. The price is right and the results are excellent. This coil spring rack and pinion front suspension assembly gives passenger steering and ride qualities.

A specialized adapter plate (available from the catalog on this web site, HP127) allows for the connection to your ½ ton truck. Instructions explain parts to remove from the Pacer assembly before the plate is welded in place. The total assembly is then bolted to the truck front cross member. No cutting on your truck! You can even trim the Pacer coil springs to get a lowered level on the total vehicle.

The adapter plate is not expensive. The main project is locating a good Pacer front suspension. This AMC vehicle was produced between 1975 and about 1982. The later years even had disc brakes.

low cost 1

AMC Pacer (above)

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1947-1953 Advance Design (above)

Lever Action Shock Absorbers

Thursday, February 11th, 2010

Trucks of the early years were often exposed to the rough terrain of local gravel roads as well as the dirt ruts on the farm. Quality, long life shock absorbers were a necessity. Therefore, trucks from the mid 1930’s through 1949 continued with a proven design carried over from earlier vehicles.

The highly successful lever action shocks had been used since the 1930’s on GM cars and trucks. They should not be confused with knee action shocks on the front of mid 1930’s Chevrolet passenger cars. This is a totally different system.

Lever action shocks are simple in design but excellent in quality and long life. Their cast iron fist sized housing, bolted to the frame rail, contains hydraulic fluid and basic internal parts. The fluid is forced through a small internal orifice as the vehicle encounters uneven road surfaces. The slowness of the moving liquid inside the shock gives a cushion action that softens the ride.

The workmanship built into these lever action shocks are an excellent example of quality GM engineering. On many trucks throughout the country these factory shocks are continuing to serve after 50 years and with the abuse of no past servicing.

The weak point is the small rubber bushings at each end of the link, not the actual shock assembly. During many restorations the hydraulic fluid is changed, link bushings replaced, and the shock continues to operate like new.

Single action shock absorbers were standard equipment of the 1/2 ton and 3/4 ton trucks with an optional double action type available for more heavy duty requirements. A single action design has resistance only on the upward direction of the wheel while a double action style slows wheel movement on rough roads in both directions.

Basically the horizontal arm extending from the shock housing is attached to a vertical link that extends upward from the axle. The movement of the tire then causes this link and shock arm to also move, thus forcing of hydraulic fluid between chambers inside the shock housing giving a cushioning to road bumps.

In 1950, the lever action units were discontinued and replaced on new trucks with a modern tube type sheet metal shock. (This design continues to be used on today’s vehicles.) It should be strongly emphasized, the lever action shock absorber was not discontinued because it was inferior, but rather because the new style cost much less to produce and install. It was simply a matter of economics. The fact that lever action shocks had the potential to last 50 years over the 3 to 4 years of the modern unit did not prevent the change over!

lever action shock