A weird metallic clunk

[The flying turd]

Hi Everyone,
This is my first post on this site. I am happy I found a place where I can ask questions regarding my 78' GMC. Its called the flying turd because its brown.. it really does not fly, but after 5 years of ownership, has been a great truck and now is going to get the attention it deserves.
I have had this annoying metallic clunk in the steering system since I bought it, its clunks when you turn the wheel 45 degrees or less, mostly turning right, turning around, pulling into parking sapces, backing the truck into the driveway, etc.. I had my GF turn the wheel back and forth rapidly while I was under the front of the truck, watching the wheels turn.. I could not really see anything out of place or damaged, the noise seemed to be coming from the steering box, but not 100% sure at this point. it steers fine on the road, no pulling, shaking and it tracks straight. What's my next step?
Dave~

 

[austinado16]

Welcome Dave!

Could definately be the box. There's a way to tighten the box up, but you have to really use finesse because a little bit goes a long way and you can create a binding situation within the box as you get the steering wheel turned close to full left or right.

On the top of the box you'll find a big nut, with an allen head stud in the center. Crack that nut loose, and hold it with a wrench, while you use an allen key to turn the allen stud inward. Just move that allen stud a small amount, like 1/4 turn. then hold it in that position with the allen key, and snug up the large nut.

You'll have a little power steering fluid leak when you loosen that big nut, but don't panic. Once the nut is tight, it'll stop dripping.

With the adjustment made, have your future X-wife run the steering back and forth just in the area where it was clanking, and see if it's either improved, or maybe completely cured.

Next, turn the wheel lock to lock and see if the steering box binds up. If it does, or gets stiff, you made too much of an adjustment......go back that adjustment off and retest. If the steering doesn't bind, and you're still getting a clank, but the clank is improved, go give that adjustment an 1/8th turn, and retest.

Basically what you're doing is moving the adjuster enough to cure the clank, but not enough to cause binding. If you can't accomplish this, you'll need to just purchase a new steering box.

Lastly, look at the bushings at the front and rear of the front springs, and make sure they aren't all hammered, and causing the clank, as the front frame is sort of twisted by the steering system, and the springs sort of get racked side-to-side.

 

[The flying turd]

Thank you austinado16,

That will be my first plan of attack. I will post what happens next.

Dave

 

[crazy4offroad]

^^Maybe lastly should be firstly since it would be the easiest to check.

 

[The flying turd]

Thanks for all the tips, I'll check those spring bushings and move from there.

Dave

 

[The flying turd]

a question...

Welcome Dave!

Could definately be the box. There's a way to tighten the box up, but you have to really use finesse because a little bit goes a long way and you can create a binding situation within the box as you get the steering wheel turned close to full left or right.

On the top of the box you'll find a big nut, with an allen head stud in the center. Crack that nut loose, and hold it with a wrench, while you use an allen key to turn the allen stud inward. Just move that allen stud a small amount, like 1/4 turn. then hold it in that position with the allen key, and snug up the large nut.

You'll have a little power steering fluid leak when you loosen that big nut, but don't panic. Once the nut is tight, it'll stop dripping.

With the adjustment made, have your future X-wife run the steering back and forth just in the area where it was clanking, and see if it's either improved, or maybe completely cured.

Next, turn the wheel lock to lock and see if the steering box binds up. If it does, or gets stiff, you made too much of an adjustment......go back that adjustment off and retest. If the steering doesn't bind, and you're still getting a clank, but the clank is improved, go give that adjustment an 1/8th turn, and retest.

Basically what you're doing is moving the adjuster enough to cure the clank, but not enough to cause binding. If you can't accomplish this, you'll need to just purchase a new steering box.

Lastly, look at the bushings at the front and rear of the front springs, and make sure they aren't all hammered, and causing the clank, as the front frame is sort of twisted by the steering system, and the springs sort of get racked side-to-side.

So are these bushings on the top side of the springs or bottom? if I peek up with a flash light will I be able to see what's going on?
Thanks again

 

[The flying turd]

Your talking about the control arm bushings?

 

[crazy4offroad]

Todd may have thought you had a 4wd to recommend spring bushings, but yes for your 2wd you need to look at the control arm bushings. You may need to jack it up and do a little prying at the upper and lower control arms watching for bad bushings.

 

[The flying turd]

Thanks for the advice, I have to grin.. I just finished rebuilding the suspension on my 60' Studebaker.. from one to the other..