1979 Chevy Corvette - Part 6: Putting the Suspension Parts Together

With the suspension safe, sound, and ready to roll, the engine is next

Chris Petris Jan 28, 2005 0 Comment(s)
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This is the key to correct bolt torque and proper seating of components.All threads should have a tap run through them whether they have beenpowdercoated, painted, or just cleaned up. The bushing area (gray areabelow tap) has been cleaned with a wire brush to ease bushing-sleeveinstallation. An application of grease to this area preventsbushing-sleeve corrosion to the shaft. Corrosion between the bushingsleeve and shaft makes removing the bushing difficult.

The front suspension parts are back from the powdercoating shop and theylook great. All parts from Corvette Central are here and ready forassembly.

When the suspension parts came back, we realized we should have lookedcloser at the slag left behind on the front lower control arms. Thewelding slag was powdercoated over and will have to stay. Slag is abyproduct of welding, and red-hot pieces stick to the metal surface.Sandblasting or bead-blasting pieces typically removes it, although achisel is needed for stubborn pieces. Having flawed parts or pieces isunsettling, so we took extra time to remove slag from the front framesection before painting.

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This is the correct way to assemble urethane control-arm bushings. Pushthe outer sleeve into the control arm first. Then push the urethanebushing into the outer sleeve; apply silicone lube to ease installation.The inner sleeve should rotate on the urethane bushing, so a goodcoating of silicone lube should be applied to the outer part of thesleeve and a good coating of chassis grease applied to the inner portionof the sleeve to prevent corrosion.

We've invested a little over $300 in sandblasting and durablepowdercoating of the front and rear suspension and steering components.It was well worth the investment, even if we have to look at tiny bitsof welding slag. In addition to the cost of materials, it can take hoursto remove and prepare components for painting, so the cost of sendingthe work out is comparable. Powdercoating doesn't protect fromultraviolet rays, which isn't an issue under the car.

One problem we encountered was loose components on taper-fit areas suchas ball-joint studs in the spindle when powdercoat is left in place. Thepowdercoat is tough, but if there is any movement it will break out ofthe tapered hole, resulting in a loose fit. Most powdercoat facilitiesmask these areas if they're asked to. The threaded holes should have atap run through the threads to remove any powdercoat that was leftbehind.

We put the same coat of PPG DP90 black urethane primer on the frontframe section as we did on the rear. The primer has a semigloss finishthat was achieved by adding thinner to the urethane mix. We put a coatof paint on all of the pieces to prevent corrosion.

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When using urethane bushings, all control-arm-bushing retaining boltsshould have new lock washers and Loctite thread locker placed on thethreads. If the retaining bolts come loose, the control arm bushing willcome out. If the bushing comes out of the control arm, the arm can comeoff the control-arm shaft, which causes loss of steering control.Urethane bushing equipped control-arm-shaft bolts can be torquedanytime. Rubber bushings should be torqued at ride height.

The front suspension bolts were bead-blasted and dipped in DP90 urethanefor protection. We replaced all the Stover lock nuts and applied greaseto the threads during assembly. Stover lock nuts are crimped on one sideto grasp the threads, and they lose retention strength after removal andreplacement.

It's a good idea to replace the front springs to keep the car level andmake the installation easier. The replacement springs are shorter, andinstallation into the upper spring pocket is easy. It's also smart touse coated springs to prevent corrosion.

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Whether you're using factory upper control arms or aftermarket controlarms, the upper ball joint should be positioned toward the rear of thecar. The centerline shows the offset of the upper ball joint from centerto allow positive caster. The upper lines show the offset of the shaftso additional camber will be available during alignment. For propercamber alignment, remember to install the shaft with the offset to theoutside of the car.

If you use factory-length springs, place the spring into the upperpocket, then push it into the lower spring pocket. Be careful when youpush the spring into position--you can easily pinch a finger. If thelower control arm is raised 3-4 inches from its lowest position, thespring can be pushed into position with two stiff prybars and stay thereas the control arm is lifted.

A spring compressor can be used to install the spring, but it can bedifficult to remove the compressor once the spring is in place. We don'tuse one for this reason, but it may be necessary your first time. Youmay have to put the spring in a few times to figure out the compressor.Rental spring compressors are available at most auto parts supplystores. When used properly, spring compressors are safe, but don't tryany shortcuts.

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That powdercoat looks good and the gloss makes it easy to clean. Thelower control-arm shaft has an offset where it bolts to the crossmember.The offset should be toward the crossmember so the shaft will haveclearance between the crossmember and seat properly.

Note the position of the drain hole in the lower control arm springpocket. Place the end of the spring within 1/4 inch of the drain hole.If the spring is out of place, it can cause squeaks. Once the spring isin place, look with a flashlight at the upper spring seat and make sureit's seated properly. After the spring is in, the rest of the work isstraightforward.

Once the spindle is installed on the ball joints, the ball-joint castlenuts should be torqued, then tightened just enough to install the cotterpin. The castle nut should never be loosened to install the cotter pin.The same procedure is used on all tapered seat components (tie-rod endsand such).

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We cut the spring to lower the car. We used a high-speed cutoff wheel tocut it cleanly and with minimal heat. The spring must be cut at the samelocation one coil lower so the spring sits properly in the spring pocketat the top and bottom. After cutting, a grinder was used to take theedge off the cut area, then a drop of epoxy paint was applied to preventcorrosion.

We used new tie-rod ends and heavy duty sleeves with new clamps. Wetried to anticipate where the tie-rod sleeves would be on the tie-rodends before painting to allow partial paint on the threads. Watchingwhere the paint ends and applying grease to the threads allows easyadjustment of the tie-rods during alignment.

We have a good local alignment shop, but if your car has rusty hardwareand you expect an extraordinary job, disappointment is inevitable.Whether you're doing a total rebuild or a part replacement, make surethe components are at least adjustable.

Before we send any car to the alignment shop after a major suspensionoverhaul, we get the alignment somewhat close. Previously, when we werewrapping up the rear suspension, we showed how to do a preliminaryalignment. The same procedures apply to the front end. It's a good ideato let the car sit a few days to allow the new springs to settle. Anyride height changes over an inch affect alignment.

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(above & below left) This is why the steering box should be rebuilt. The gook was lubricantat one time. Luckily, the pitman shaft and sector were salvageable. Thesteering box also supports our theory that the engine had beenoverheating for many years. The steering box had a lot of condensationfrom the engine heat. All bearings and seals were replaced along withthe pitman shaft bushings from the kit provided by Corvette Central.

We dropped the front end approximately 11/2 inches from the stockposition, which keeps the steering geometry correct. If you go beyond 2inches when lowering, steering geometry is affected and high-speedcornering capabilities will be diminished.

Now that all the pieces are in place, the brakes are next. We're leaningtoward the Stainless Steel Brakes calipers, available from CorvetteCentral. So far, we've been cautious with funds. We have someperformance handling components with a mix of many original pieces. Wewant to keep fiscal control of the project, but some things just makesense. The new, lightweight brake calipers will eliminate futureproblems.

While the brakes are in the works, it's time to consider what we shoulddo with the engine. We have a few '87-'90 Corvette L98 engine coresavailable that could become 383 ci. The thought is to build the 383, doa moderate porting job on the aluminum cylinder heads, then let itbreathe through a Holley 900-cfm throttle-body fuel-injection unit. Wealready have a Keisler-engineered Tremec five-speed to replace the tiredoriginal four-speed. The goal is high torque with light fuel usage, so amild cam will be used.

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The other possibility is a GMPP ZZ4 crate engine with the Holley TBIunit. Either way, there are decisions to be made. Many times, spendingthe most money does make the best project car. Hopefully, we can takethe Corvette Central Project Shark Attack on a test ride shortly and letthe public see it in action.

Front suspension torque specifications

Upper-control-arm ball-joint nut: 50 lb-ft

Upper-control-arm shaft to frame: 50 lb-ft

Upper-control-arm shaft-end bolt: 60 lb-ft

Lower-control-arm ball-joint nut: 80 lb-ft

Lower-control-arm shaft to frame rear nut: 95 lb-ft

Lower-control-arm shaft to frame front bolt: 70 lb-ft

Lower-control-arm shaft-end bolt: 70 lb-ft

Steering arm to spindle nut: 70 lb-ft

Upper dust-shield-plate bolt: 90 lb-ft

Tie-rod-end nut: 37 lb-ft

Power steering cylinder to relay rod: 45 lb-ft

Idler arm to frame: 30 lb-ft

Idler arm to relay rod: 35 lb-ft

Sources

Corvette Central
Sawyer, MI 49125
800-345-4122
www.corvettecentral.com
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