Our friends at Speedway Motors have been working on their project car with Josh Sullivan, the Product Manager for the muscle car market, leading the way. With permission, we are reprinting the company’s latest tech article on Chevelle spindles and control arms. You can view the original article at: project-chevelle-spindles-and-control-arms-tech-article.
Project Chevelle: Spindles And Control Arms Tech Article
Not many parts of the horseless carriage have changed so drastically over the decades as suspension components and design. Looking back at the early buggy springs of the 20’s and 30’s to modern day coil springs, torsion bars and struts; our Chevelle falls somewhere halfway down the timeline, derivable but extremely lacking compared to current standards. Floating down the road at 60 the car is comfortable, but blows through the entire suspension travel easily with the slightest dip or bump in the roadway.
The rebounds of this bump continue on well down the road cycling up and down on repeat. The car immediately strikes me as undersprung and shocks that are too weak. Pat and I have driven this Chevelle in stock form on a short auto cross course never topping 25 mph, but the car felt as though it was going to scrape a rocker panel or door handle on the pavement with the amount of body roll we were fighting. The car responded poorly to steering input and drove unsettlingly hard upon breaking.
These exact issues are the problems set out to be solved by our G-Comp Spindles and Tubular Control Arms. In a long half day of work in the shop, our Chevelle now had a fighting chance of cutting a corner without rolling the edge of the tire under the car. The new compliant ride is much more akin to a modern muscle car, while keeping the plush initial stroke for normal road travel. Let me walk you through our install and a quick overview of the Tubular control arms, G comp spindles, how they are upgrades and why they work so well as a package.
The G-Comp dropped spindles offer many benefits on top of the aesthetics of lowering our Chevelle’s stance. While the rotor pin of the spindle has moved 2″ upward, the overall height of the spindle is also taller in comparison to the factory piece. Lengthening the distance between the ball joints effectively changes the camber curve as the wheel travels upward towards the fender. The end result is a tire that stays flat to the road with the full tread width as it moves through the compression. Factory suspensions gain too much camber and plant the whole car on increasingly less of the outer edge of tread of the tire as it travels.
Had Pat and I continued to autocross all day on the stock suspension we would have worn out the tire on the outer 2″ shoulder of the tread. This problem also leads to lower grip and understeer, far from confidence inspiring. The G-Comp spindle is an easy install with factory brackets for disc brakes and steering arms.
Factory drum brake spindles on A bodies will not accept disc brake brackets. They can be machined to comply, which I have done in the past, but it is not for the faint of heart or done by anyone without a mill they can borrow. It also requires a 5/8 fine thread machinist tap, which is a pricey piece to own for one-time use in your life. Also of note is the second set of lower threaded holes, which leaves your steering arms in a similar location to stock. Allowing for factory clearance for the tie rods and minimizing the possibility of bump steer.
The new tubular control arms are just as much of an improvement when you take into account the overall cost verses how much time and work you will save on your originals. Sandblasting, pressing ball joints and bushings out, reinstalling them and painting or powder coating the arms is a monumental to do list if you value your time at all. These black powder coated arms look great! They are stronger than factory arms and they also move the upper ball joint to the rear slightly, increasing the caster.
This adjustment can also be made with shims, but modern tires and alignment specs typically end with piles of shims on the rear stud, where our new arm will be in a more neutral position after alignment. The improvements of the geometry between these two parts work hand in hand to correct our Chevelle suspension closer to modern 75+ mph corvettes and less of a 1960’s ambulance.
We began by jacking up the car with the Goodyear 1-1/2 Ton Aluminium Racing Jack and putting it on jack stands, removing the brake drums, backing plate and brake lines. The next project on the car was installing new disc brakes, p# 910-31958D but that’s a talk for another day. We removed the bottom t bar shock bolts followed by the nut on the top of the shock stud in the engine bay dropping away some vintage parts store shocks that had similar physics to your 90’s waterbed after a belly flop.
We installed a spring compressor in place of the shock and tightened down on the spring relieving some of the stored energy and danger of the spring. Removed the outer tied rod end from the spindle and placed the castle nut and cotter pin on the work bench to reuse. While removing the cotter pin from the upper and lower ball joints, the nut on the ball joint was backed off of the stud several turns, but leaving the entire depth of thread engaged. This nut is your safety and will catch the separated spindle keeping the spring from ejecting across the shop.
The Tie Rod Ball Joint Pickle Fork was then used on the upper ball joint first using the weight of the drooping suspension to help separate the married parts. For particularly stuck spindles you can also hit the upper ball joint boss of the spindle with a small sledge while maintaining pressure with the wedge of the pickle fork. Once the upper control arm is loose the pressure will transfer to the castle nut left on the upper ball joint. Do not remove it yet, as the weight of the spring pressure is pushing downward on the lower control arm and spindle, taking the top nut off will cause an exciting end to your day.
Use this pressure to your advantage to remove the stuck lower ball joint. Roll the jack under the lower control arm and jack it up to 1/4″ below contact with the control arm as a safety. Use the pickle fork and hammer to separate the lower balljoint and control arm from the lower spindle. Now that the spindle is loose, use the jack to compress the lower arm until the car is almost ready to raise from the jack stands. Tighten the spring compressor as far as you can, this is a long spring you will need the help. You can now remove the spindles and upper and lower control arms. Be sure to keep your control arm shims organized as they will be a good starting point for your alignment and following test drive.
I began the install by checking over all of the components as they were listed on the instructions of the control arms, spindles and brake kit. We painted the spindles before the install, along with our calipers, brackets and anything else we wanted black. I used the Pistol Grip Grease Gun to grease up the 4 ball joints and 8 bushings. While clamping the cross shaft of the upper control arm in the vice, I worked it forward and backward allowing the grease to work it’s way around the bushing.
Installing the upper and lower control arms in reverse order of removal was a straightforward and rewarding task. The only hiccup was having to shorten the rear passenger side upper control arm stud to be able to remove and replace the upper control arm with the engine still in the car, because why remove a Chevy 307? Right, well we’ll get to that soon, too.
Properly placing the spring back into the upper spring pocket with the pigtail seated on each side can be a difficult task. The more your spring compressor has shortened the spring, the easier the task is. We took a couple of tries to get it situated properly while the spring was out on the floor to make it easier to install.
There was a bump stop already on the frame for contact with the lower control arm, and our new lower arms had a bump stop as well. We removed two old crusty factory ones from the frame to keep them from limiting our travel. After Pat and I got the control arms, spindles and old spring back in place, we added some AFCO shocks to complete the new front suspension. Our ill handling lumber wagon was now upgraded and looked part of a well-engineered race car.
As I mentioned, the next major over haul on the front braking system was on deck, so we finished our day with the car still on jack stands. After the install I had to admit a little bit of jealousy as I had done the same work on my GTO 10 years ago. Had there been a tubular control arm set that was available in this price range I wouldn’t have gone through all the work of restoring my stock components and machining the spindles. It took a lot of time to complete and I’m still stuck with stock 1960’s geometry. I feel a dark cloud of upgraded part expenses looming on my horizon.