This Sub Gets Down With Help From Performance Online

IN A PREVIOUS ISSUE, I WALKED YOU through a Cummins swap on this ’69 Suburban (C10G, spring 2018, “Swap it or Leave It,” pg. 68), and this time around I’ve dropped the suspension. I like the look of a ’bagged truck/SUV, but I’m getting older and prefer the dependability of a staticdropped vehicle for daily driving. This family-fun truck needs to get down the road, haul a trailer, and sometimes I need to travel out of state, which is why I chose a complete static suspension from Performance Online (POL).

The Cummins-swapped Suburban was in need of a more modern suspension to navigate city streets. The suspension was stock, and nothing had been replaced since it was new in 1969. If you think removing old stock suspension will only take a few hours, you are sadly mistaken. Plan a full day for disassembly. Spray everything with penetrating oil the day before and have all of your heavy-hitting tools ready to go.

When thinking about suspension, consider the main purpose of your vehicle. Is it a show vehicle or a daily driver? Will it be a weekend toy, or will you use if for work? Once you’ve nailed down your truck’s main use, think about the wheels and tires you want to run. How tall will the tires be? What size wheels do you want, and what will be the offset? If you’re going to run a smaller wheel and also want to run disc brakes, will they work together? What rear gear ratio will you use?

One advantage of going through a company like POL is that it sells everything you need to tackle a big project like suspension. You can work with someone in sales or talk to tech support for different applications. Ultimately, you should do your own research but get confirmation from the manufacturer before you order suspension parts.

After collecting all of the parts I needed, I took the Suburban to Kevin at Grunion Customs in Phoenix. He’s helped with many of my builds and has the best guys working for him. Jon and Robbie have been in the custom car/ truck scene for most of their adult lives, and they’ve worked with Grunion Customs for many years. Kevin had a heavy hand in building my ’63 C-10. This suspension installation took two guys two and a half days to finish and cost about $2,000. The effort and money were worth it. The Suburban not only looks better, it handles better too.

We started by removing the stock drum brakes and all of the front stock suspension, including the factory control arms and steering components. We replaced everything with POL parts.

The disc brakes from POL arrived assembled, so there was no guesswork. The control arms came with everything installed except the ball joints.

Then we placed the control arm on the ground and installed the ball joints; they bolted right in.

Next, we installed the springs and shocks. POL offers a kit to relocate the shocks if needed, but we opted not to do that.

Once the front was complete, the upper and lower control arms from POL were ready for ’bags or springs. We opted for the lowering spring version for a static drop.

POL offers all-new steering components because these pieces get worn out over time. If you line them up as close to their original positions as possible, it makes the installation a little easier. Make sure that you get a complete alignment when you’re finished.

Next, we stripped the rear suspension and removed the springs, shocks, hangers, etc. The hangers were removed to accommodate the POL C-notch.

This is the heavy-duty C-notch from POL. We chose the beefy version for towing.

The C-notch installation is pretty straightforward. We marked the frame, cut, drilled a few holes and installed. It’s easier said than done. If you have ever drilled a C-10 chassis, then you know you need a sharp drill bit and maybe a spare bit too.

The POL rear shock relocators bolt right up. We’ll show the lowers later.

We installed the rear lowered springs and retainers.

The rear POL lowering blocks were next. Notice that they’re installed between the axle and trailing arm. The previous owner had a different set of blocks on the bottom of the trailing arm. Here you can also see the lower shock relocators.

The tow ’bags were next. The ’bags were mounted between the trailing arms and the frame. The upper mounts had to be fabricated, which took about 90 minutes to make from scratch and install. Don’t forget to install the fitting prior to bolting down the ’bags.

We measured and mounted the tabs for the air tank underneath the cargo floor. All of the fittings were installed on the tank before we installed it in the Suburban. The tank was bolted in, and we checked for clearance.

One of the purposes of this build was to pick up future projects. With that in mind, we made sure we could use the air in the tank to fill tires and run tools if needed. We mounted the air gauge underneath the dash.

The valves and the compressor were installed. Everything is neat and not exposed to heat or pinched.

Next up was a new master cylinder and proportioning valve from POL. The valve regulates hydraulic pressure between the front and rear brakes.

The old drum brakes were upgraded to disc, but first we had to plumb them. The old master cylinder had to go, so the new POL master cylinder was benchprepped and put in place. The intercooler pipe on the driver’s side was touching, so we removed and modified it, which added an extra half-hour to our installation time.

The disc brake kit comes with a proportioning valve; we installed it next.

We picked up new brake lines from our local auto parts store and started bending. After half a day of bending new brake lines we installed them and bled the brake system.

I have always used CURT Manufacturing receivers and hitches on my vehicles, and this project was no exception. The hitch that was on the Suburban when I got it was definitely homemade. I wouldn’t have trusted it to tow the smallest trailer. After 45 minutes of cutting and grinding, the old hitch came off. Installation was pretty straightforward.

The last piece of the suspension puzzle was wheels and tires. I ordered a custom set of raw artillery-style wheels from Detroit Steel in 20×8 with 4.5 inches of back space. Then I wrapped the wheels in Toyo Tires Proxes 245/35R20. I wanted all four tires the same size, so they could be rotated. Now the Suburban is really starting to shape up.