1979 Upper Control Arm Bushings

[Walt68]

Good afternoon,

While driving my sons 1979 Mark V I hear a clunking noise coming from the front left side of the vehicle. Upon further investigation, noticed the left hand upper control arm fwd and aft bushings blown out. I plan on changing both sides of course just haven’t done so in the past. I was planning on jacking the vehicle and removing the wheel to relieve some weight but wasn’t sure if I needed a coil spring compression tool prior to removing the nuts to change out the bushings.

[Dan Szwarc]

Replacing the Upper Control Arm Bushings requires removing the front springs, thus unloading the UCA.

This process is described in the shop manual , but is the same for 79 as it is for 1961. Remove stuff in the way, then remove the lower control arm inside bolt and lower the arm to remove the spring.

There's a lot more to this, but that's the gist. It's not really a weekend job unless you put in 16hr days and have access to presses, etc.

It's well outlined in the manual including removing and installing the new bushings.

[1Bad55Chevy]

I will be the bearer of bad news here... its not just the upper control arm bushings that have failed, it's the entire front end. The vehicle needs upper/lower control arm bushings, ball joints, sway bar links, sway bar bushings, tie rods, pitman arm, idler arm and strut rod bushings if they used strut rids on 79. Every wear component on that car has the same amount of miles and age on them. It would be smart to replace the wheel bearings, seals, calipers, and hoses while you have everything apart.

You do not need a press to do this job if you have a quality air hammer. You "pinch" the bushing on two sides and knock them out with the air hammer. To reinstall you put a big socket on it and knock it back in with your air hammer.

And lastly if the front bushings are gone the rears are no better.

[TonyC]

Maybe this will come across as an idiotic question, wouldn't be the first time. But how does servicing the upper A-arm require removal of the springs? There is no spring tension on the upper arms; they only serve alignment purposes.

I have replaced suspension bushings on Frankenstein, front and rear...and really have no burning desire to do that job again. But the front springing has absolutely zero to do with the upper A-arms. The spring presses against the lower control arm, meaning required spring removal when replacing the lower control arm bushings. The upper control (or "A-") arms can be completely taken out with the spring still in place. Granted, a hydraulic jack under the arm is prudent, but the strut rod makes even that a suggestion, not a requirement.

On the other hand, I understand the subject car is a '79 Mark. If its front suspension is designed to place spring tension on the upper control arms instead of the lower like on other full-size cars of the day, then my question is moot.

---Tony

[LithiumCobalt]

I suppose if you are able to trust a hydraulic jack under the lower control arm while you work, that you wouldn’t have to relieve spring tension, but seems dangerous when it doesn’t need to be. Plus, you’d have the spindle, and rotor just flapping around unsupported amongst all that mess. I am more with BadChevy on this one. If the upper arm bushings are toast, dollars to donuts the rest of the suspension needs attention and in that case you’d be disassembling everything anyways

[Lee]

78 factory manual instructions. But agree it’ll probably need everything sooner rather than later. I actually had a lower ball joint pop in a bad pothole in a Diamond Jubilee I had. That will get your attention pretty fast.

[TonyC]

Ouch; I bet it did, Lee. I have a friend who used to have a '95 Thunderbird, and one day when her then-boyfriend was using the car, the left lower joint broke on him. It had been giving warning signs beforehand, in the form of creaking noises when the wheels were turned.

I do consider that possible, that all of the front suspension could need rebuilding, depending on the use and abuse the car in question went through. If the lower-arm bushing needs replacing, then that mandates removal of the spring...and the utmost caution, because that is a very dangerous venture. But where the upper arm is concerned, I dare say it's safer to trust the jack and the car's bars and rods than to remove the spring for a job that doesn't require said removal. A good gearhead can secure the spindle out of the way while the upper A-arm is out. That never was a high risk for me when I replaced the upper ball joints on Frankenstein. In fact, when I replaced the lower ball joints, I had a screw jack secured beneath the lower arms; and that combined with the strut rods still in place took away the high risk.

---Tony

[Dan Szwarc]

Tony, the UCA is attached to the LCA which is pushed down by the spring.

In other words, the UCA is being pushed down by the spring. Remove the UCA and the spring will no longer be constrained. The LCA will move to let the spring out.

But you don’t have to believe me.

[1Bad55Chevy]

Tony, the UCA is attached to the LCA which is pushed down by the spring.

In other words, the UCA is being pushed down by the spring. Remove the UCA and the spring will no longer be constrained. The LCA will move to let the spring out.

But you don’t have to believe me.

You leave the jack under the lower control arm with jack stands supporting the frame and un bolt the upper. When the suspension is at max travel there isn't much tension on the coil spring. Look at Lee's post, nowhere in the shop manual was "remove coil spring".

[Dan Szwarc]

Fair enough.