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How-To: 1970 Chevy K5 Blazer Coilover Conversion Install
Classic Car & Truck BlogHow-To Articles

How-To: 1970 Chevy K5 Blazer Coilover Conversion Install

Want to get your Blazer a little closer to terra firma? Aldan American has just what you need, whether it’s a coilover conversion kit for a ’63-’87 C10, a ’73-’87 2WD Blazer, or a ’67-’72 Blazer—exactly what Rodney needed for his 1970 Chevy K5 2WD Blazer, our project vehicle.  

Included in the kits are two Aldan Phantom Series 13-inch single adjustable coilover shocks, the upper control arm brackets, POL tubular upper and lower control arms with ball joints, the C10 crossmember cutting template, and all the brackets and hardware needed to convert the 2WD factory front crossmember to ride-height adjustable Aldan coilovers.

Looks good going away too. Before starting, measure and record the ride height of all four corners on a smooth, flat surface. Shoot the front end bolts with a rust penetrant to make removal easier. Move the brake calipers out of the way. Remove them if you’re not reusing the calipers.  Remove the sway bar if there is one, along with the shocks, spindles, springs, and A-arms. Keep the alignment shims and misalignment washers. Know where they go; you’ll need them.

Aldan offers two kits, one for a small block Chevy (Part #300136, MSRP: $2,549.95), and another for a big block (Part #300137). There are also three different rear shock absorber kits, depending on your ride height and whether the rear has coils or leaf springs.

Aldan’s front coilover conversion kit laid out, along with the rear shock absorbers.

Using the tools listed in sidebar (page XX), this kit works with the factory crossmember and will convert the front suspension to fully adjustable coilover shocks with tubular control arms. Aldan adjustable coilovers will add better performance, handling, and ride quality to your Blazer. We also wanted to give a shout out to Jimmy, one of Aldan’s online suspension techs, who helped us determine which parts were used on this install.

ALDAN UPPER COILOVER BRACKET INSTALLATION

Remove the upper A-arm brackets from the frame and crossmember. Four bolts go through the frame, along with four rivets that must be ground from the crossmember. Holes in the crossmember are needed for the new A-arm coilover brackets.
Use four 3/8-inch by 1¼-inch bolts, nuts, and washers to hold the hole-cutting template in place. Note the washers beneath the template so the saw cuts below it.
Cut a hole in the cross member using the 4-inch hole saw through the template. The template can also be used to cut it with a plasma cutter. Don’t damage the holes where the bracket bolts on.
The hole needs to be big enough so the shock won’t rub.
After cutting and deburring, the surface may still need to be ground flat.
The bracket must sit flat with all the holes lining up. Now is a good time to clean up the frame.
Install brackets with the supplied hardware and tighten them after everything lines up
3/8-inch by 1¼-inch bolts bolts, lock nuts, and washers secure the new bracket to the crossmember.
Between the bracket and the frame rail, use 7/16-inch by 1-inch bolts, nuts, and washers.
With the hardware installed and the bracket fitting correctly, torque the bolts to:
3/8-inch bolt torque spec: 30 lb-ft
7/16-inch bolt torque spec: 50 lb-ft
1⁄2-inch bolt torque spec: 75 lb-ft
5/8-inch bolt torque spec: 75 lb-ft

UPPER A-ARM REPLACEMENT

The upper control arm has the same dimensions as the OE arm. Install it on the alignment studs. Remember the shims and misalignment washers you saved? This is where they go.

LOWER A-ARM AND COILOVER  SHOCK INSTALL

There’s a hole in the saddle where the lower A-arms are aligned with a pin. Either reuse ºr buy new U-bolts. If the holes are too small, enlarge them until the U-bolts fit.
Use the U-bolts to secure the lower A-arms in place.
Torque the lower control A-arm bolts to 90 lb-ft.
Grease the A-arm pivot bushings, checking their movement up and down to prevent binding.
Loosely bolt the top of the coilover shock to the upper bracket.
See the 4-inch hole? The movement of the shocks and suspension requires that much clearance.
This is where the bottom of the shock bolts to the lower A-arm.
Thread the bolt through the A-arm and the coilover shock.

Tools for the Job

  • Floor jack or lift
  • Jack stands
  • Tire chock
  • Torque wrench
  • Socket set
  • Drills
  • Half-inch drill motor
  • 4-inch hole saw
  • Other basic hand tools
Torque the lower shock bolt to 75 lb-ft
Go back and torque the upper shock bolt to 75 lb-ft too.

SPINDLE AND BRAKE ASSEMBLY

The kit uses ’73-’87 C10 spindles, brakes, and tie rod ends. The US-made cast iron spindles are exceptionally strong and reliable. Earlier years won’t work.
Bolt the lower ball joint to the spindle using a castle nut.
Insert the upper ball joint into the spindle.
Use a castle nut on the upper ball joint and the spindle is secured.
Attach the tie rod to the spindle.

SWAY BAR

The OE sway bar won’t work with these A-arms. The new 1.125-inch 4140 heat-treated steel front sway bar minimizes body roll while improving handling and control, and is available separately. 

TIP

Change the brake lines and hoses when installing new brakes. Converting from drums to discs will require lines, hoses, a master cylinder, and a proportioning valve that works with the new brakes.

Lube the polyurethane bushings before attaching them to the sway bar.
Slip the bushings over the sway bar.
Bolt the sway bar to the end links, which attaches to the lower control arms.
These sway bar bushings mount directly to the frame to allow for more ground clearance.

FINAL ASSEMBLY

Make sure all the hardware is tight, there’s no interference or binding in the suspension and steering, and the brakes are installed, bled, and operating correctly.

Completed front end assembly.

Bringing up the rear

Aldan’s TruLine series shocks (PN100108 MSRP: $245.95 each) for ’63-’87 Chevys and GMCs are American made, smooth riding, performance shock absorbers. TruLine Series shocks come in stock, lowered, and custom lengths, and are rebuildable, serviceable and backed by a lifetime guarantee.

These TruLine rear shocks for trucks with coil springs bolt on to the upper shock mounts.
Insert the bolt through the truck arm and the lower shock mount.
Completed rear shock installation.

SETTING RIDE-HEIGHT

  • The lower A-arms should be close to parallel with the ground, a good starting point for ride height.
  • Align the front end immediately following installation.

ALIGNMENT SPECS

Camber

  • -1/8 to -1⁄4º street use.
  • -1/4 to -1º track use depends on conditions and driving style.

Caster

  • + 4.5 to 8 degrees street use with additional 1⁄2º stagger to right side.
  • Track use depends on conditions, driving style with caster without stagger.
  • Toe 1/8” total toe in.

Source: Street Trucks Magazine