New front shocks, feels like tires are bouncing.

[Edmduncan]

just changed out the front shocks on my 91 C2500.
It feels like wheel bounce now on the highway even though visualy the tires are planted.
Is it possible my ball joints are going or could it be something like the ujoints or the pilot bearing between the first and second drive shafts.
Im kinda reaching for a answer lol.
It wasn't present before the shocks where changed , truck still had factory original shocks that where totally blown out so basically no shocks lol

 

[TheAutumnWind]

What shocks? How long have they been on?

 

[Edmduncan]

What shocks? How long have they been on?

On one day. They are acdelco . I unloaded them last night and slowly reloaded about 3 times and it seems to have helped allot. Going to give it a couple more goes as I didn't preload them before I installed them.

 

[454cid]

On one day. They are acdelco . I unloaded them last night and slowly reloaded about 3 times and it seems to have helped allot. Going to give it a couple more goes as I didn't preload them before I installed them.

Preload them?

 

[Edmduncan]

Preload them?

I've read some shocks have to be compressed 3-4 before instalation to eliminate any air trapped from factory and prime the shock properly. If that's legit or not I don't know but it seemed to have helped. I lifted the truck front end from the center off the ground letting the suspension fully fall with gravity, then let it down slowly. Did that 3 times and eliminated almost all the bouncing I felt. Now that being said I did check the ball joints and no movement, I am going to snug the wheel bearing up a smidge , but I don't feel that was the source. I'm chalking it up to shocks not being primed per say, as it has almost all but disappeared.

 

[gearheadE30]

Shock priming isn't a thing, for whatever that's worth.

Twin tube shocks can get air around the piston, but that's usually when they are worn out and the internal sealing 'bag' starts leaking and the nitrogen ends up emulsified into the shock oil. The shocks have to be replaced once that happens, and it's not particularly common on new shocks.

Slow motion up and down at the front like riding a wave, or do the tires chatter over sharp bumps? Is it a diesel? If so, they run a pretty high spring rate in the front because of the weight of the engine. AC delco shocks should be fine, but if they're for a 1500 or something it's possible that they are just too soft for the springs.

You might also want to check to make sure the nut at the top of the shock is tight. If it isn't, the bushings on the mounting spindle will have play in them and the shock won't actually be doing anything over small-amplitude impacts.

 

[Edmduncan]

The shocks are from Rockauto, and for a C2500 8500lbs+.
The bouncyness is almost gone now, it felt like a constant tire bounce like you see on some cars with blown out shocks. Driving down the road and the tire is dribbling like a basket ball.
Thats what it felt like, now visually the tires looked planted while driving.
Its kind of odd. They maybe to soft maybe as I was looking jnto a heavy duty. And I may still upgrade as these where on sale and maybe thats why..I will check the nut but I know I tightened it down enough to compress the upper bushing enough to just pass the od of the retaining washer.
It seems odd but just trying to figure out the cause and maybe its one of those mystery symptoms lol

 

[PlayingWithTBI]

Sounds like PFM to me.

 

[Edmduncan]

Sounds like PFM to me.

Lol could very well be.