Occasional Thump at Full Lock

[CaptBeardilocks]

Hey All,

I have a bit of an odd one here.

Sometimes when I'm pulling into a parking space (so full lock left or right turn at slow speed) I get a small bump in the front end that I can feel. Describing it can be hard. The first time was after a long highway run and I thought I just hit a small pothole turning into the parking spot. But it has happened about 5x since then. Doesn't matter if I'm turning right or left. It's just a bump feeling, almost like something catches and then lets go. And it's just one bump, it's def not clicking like a bad CV.

I rebuilt the knuckles when I rebuilt the whole truck about 1.5yrs/25k miles ago. It also got new RCV axles at that point. This turn/thump started happening on my way back to base after an extended trip out west with a lot of mild/moderate off-road driving. Since then I have rebuilt the knuckles again including fresh wheel & trunnion bearings and spindles. Same thump just appeared again yesterday. It does it maybe once every 5-10x I turn full lock.

It didn't do this for the first 23k miles after the first knuckle rebuild and the fresh rebuild didn't seem to fix it. I was wondering if the trunnion bearings could have been binding, but new ones didn't help. And if it was shimmed incorrectly, I would have thought it would have done it from the start, not waiting 23k miles.

Any ideas where a full lock thump might be coming from? What could bind & release occasionally on full lock like that?

Edit to say: 25k miles ago along with the knuckle rebuild it got Slinky Stage 4 suspension with everything baselined correctly (Deltas arms up front, adjustable panhards, Rear dialed in as well, new steering damper, Redhead rebuilt steering box, etc). I'm on Toyo OC 33s.

 

[BILT4ME]

I would look at the following:
Panhard bar. Since adjustable, it may have worked loose.
Cracks in frame or brackets under steering gear.
Cracks in frame or brackets on panhard bar support bracket on passenger side.
Worn or broken body mount.
Loose shock

 

[CaptBeardilocks]

Just after I posted this it occurred to me that about the only thing I haven't checked is the frame for cracks. Sh*t. I'll look into that today.

Body mounts also only have about 25k miles, but one could have worked loose. Good thought. Need to re-torque shocks as well. Everything else suspension-wise has been re-tourqued in the last week.

 

[Shipwreck]

Check the orientation of the clamps on the tie rod ends on both the tie rod and relay rod to make sure they are not making contact with anything.

 

[CaptBeardilocks]

Did a thorough inspection last night and can't find any cracks in the frame near the steering box or panhard mounts. Got it up in the air and spun the wheels back and for and couldn't hear anything. Checked tie-rod pinch points and couldn't see anywhere anything had been hitting.

I did notice that only 1 of my 4 steering stops was adjusted anywhere near properly to actually hit the axle. So I dialed those in. I guess it's plausible that under load & speed I could have been over steering bit and making something angry. Have to see if it comes back now.

 

[Broski]

Did you check all you control arm bolts?

 

[CaptBeardilocks]

Did you check all you control arm bolts?

I torqued them all this week. All were tight. All were new 1.5yrs ago

 

[Godwin]

I'm also dealing with this and it just started this week. The thump seems to be with a full left turn lock and coming from the right front wheel. I'm going to take a closer look at it tomorrow.

 

[CaptBeardilocks]

I'm also dealing with this and it just started this week. The thump seems to be with a full left turn lock and coming from the right front wheel. I'm going to take a closer look at it tomorrow.

Let me know what you find. I’ll report if I’m still feeling it or find anything new.

 

[Godwin]

Let me know what you find. I’ll report if I’m still feeling it or find anything new.

Earlier this week when I did a short drive on forest service roads I had a noticeable thump 2-3 times, and it was random. I couldn't replicate the thump. Saturday I replaced the bushings in the front driver side axle arm. Still had a thump but it was reduced and seemed to be on the passenger side. Today I replaced the bushings in the passenger side front axle arm and the thump seems to be eliminated. Once I had fresh bushings installed I cranked up the 80 and turned the steering lock to lock several times and had no thump.

That's all I can add for now.

 

[Godwin]

Found the thump. The upper rear shock mount on the driver side had sheared one bolt and the other had backed out. The upper shock mount plate was floating around.

Scavenged a couple of bolts from a H42 transmission to replace the broken and damaged bolts of the shock mount plate.