By John L. Bellah
OK, it’s time. The steering is loose, a funny wear pattern is showing up in the front tires, the wheels vibrate like crazy at freeway speeds and it won’t stay in alignment. Time to overhaul the front end!
But before you get “down and dirty,” let’s back up a bit and do some planning. This is important, even if you are not doing the work yourself. If the vehicle has a lot of miles, it might be best to look for a complete front-end kit. A kit should have everything: bushings, ball-joints and/or kingpins and tie-rod ends. There are several suppliers that market such kits, and if one is looking for improved handling, there are high-performance kits with upgraded components. Be careful to look for quality components. There are many components and kits that are manufactured off-shore and may be inferior in quality.
Another thing to consider is having a complete inspection of the suspension system to determine that the steering gear box is securely attached, there are no sagging springs and that the frame isn’t bent. These problems, if not corrected, are unsafe and can cause severe handling problems and accelerate tire wear. If there are indications of a bent frame — always possible on an older car you don’t know the history of — the vehicle should be checked out by a shop that specializes in frame straightening to ensure that it is within the manufacturer’s tolerances.
Cars with unitized construction — where the body and frame is one unit or is sub-framed — also should be checked. Let’s face it, unitized bodies also can become tweaked during a collision — and there are a lot of “clip” cars out there. These are “totaled” cars that had a replacement “clip” grafted on to replace the damaged half of the vehicle, then resold to an unsuspecting buyer.
If you do your own work, you will need to have the proper tools available, if you don’t already have them, and the proper shop manual for your car.
Compressed air and a hoist definitely make the job easier. A good quality spring-compressor is a must if you are working on a vehicle with coil springs as the energy from a coil spring suddenly releasing can cause serious, if not fatal injuries – let alone damaging your collector car.
If you don’t do your own work, select a shop that is knowledgeable in vintage vehicles, as the technology has changed over the years. With that in mind, we paid a visit to a local alignment shop in southern California and peeked over the tech’s shoulder as he overhauled the front end on a 1951 Chevrolet. Appearance-wise, the car looked great. However, being 55 years old, the Chevy was showing its age as the steering was loose and tire wear was beginning to show some irregularities.
Dave, the owner of the shop, knows older cars and has been in the business for more than 30 years, following the footsteps of his father, who also did brake and front-end work. While most of Dave’s clientele drives modern vehicles, Dave can be persuaded to tend to the needs of the older vehicle owner.
After an inspection and road test, Dave ordered a complete front-end kit from Rare Parts in Stockton, Calif. Dave deals with them frequently and has a good working relationship with them. Since the front springs were in good shape and had a satisfactory ride height, they didn’t need to be replaced and were re-installed after the overhaul.
After driving the old Chevrolet on the rack, Dave began the disassembly, quickly learning that this was an original and unmolested car that still had the factory spiraled Delco shock absorbers – both front and rear. Another unique thing we learned is that vintage Chevrolets have different suspension pivots, depending on the year. The 1951 pivots are threaded in place and, in 1953, the pivots were pressed in place. Therefore, it is important to know the exact year of the vehicle you are working on as some parts may be different.
Once disassembled, Dave cleaned all of the old parts he intends to reuse, and being a meticulous craftsman, painted the components prior to installation.
After buttoning everything back together, the car was driven onto the alignment rack. Modern technology would call for a Thrust-angle alignment, where the rear wheels are checked to ensure they are running “square” with the front wheels. The rear fenders of the old Chevy didn’t permit his gauges to fit on the rear wheels, so only the front suspension was aligned.
Vintage Chevrolets are similar to other American cars of that era that have kingpin front suspension as they have a pivot at both the upper and lower control arm, instead of ball-joints on later cars. This may frighten the young alignment technician fresh out of trade school. However, old manuals are available to guide those unfamiliar with the older technology. On the Chevrolet, and similar cars with kingpin suspension of that vintage, caster and camber settings are made by removing the rear grease fitting of the upper pivot and inserting the appropriate-sized allen wrench. This rotates an eccentric so caster and camber adjustments can be made.
Since the Chevrolet owner stated he would continue to run bias-belted tires, Dave made the settings for those tires. He commented that if radial tires were used, they would require more positive camber settings, which may be difficult on that vintage Chevy. If the camber could not be set for radials, the result could be that higher steering effort would be required for parking and low speed maneuvers. And remember, Chevys of that vintage had manual steering. Power steering wasn’t offered until 1953.
Centering the steering wheel may be another obstacle for those not familiar with older vehicles as the steering wheel is not centered by adjusting the tie-rods as on newer cars. The Chevrolet has a drag link and centering the steering wheel is done by adjusting it.
After the alignment is performed, a final road test ensures that everything is ship-shape.
Below: All of the Chevrolet’s suspension parts were detailed prior to installation. These parts were installed in the reverse order in which they were removed.
The author, John L. Bellah, is a member of SAE International and has been involved in the automotive service industry and the old car hobby for over 40 years. He has published numerous automotive articles in various publications.