Chasing that "frt end clunk"

[ogdobber]

So could you tell what was loose? Where the noise came from?

It's the rack, 100%


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[Eyespyautomotive]

Right, and I think I know what you mean but I was hoping you could clarify. The rack mounts/bushings, the inner workings of the rack, tie rods, inner outer?

Full rack replacement?

 

[ogdobber]

Right, and I think I know what you mean but I was hoping you could clarify. The rack mounts/bushings, the inner workings of the rack, tie rods, inner outer?

Full rack replacement?

Oh right, duh. I kinda just assumed it was the rack bushings. The mounts are solid and in great shape. But i guess i should slide the boot down to check the inner tie rod (outer is good).
Been looking and i haven't been able to find a rebuild kit, only a seal kit, which sucks because a full rack is not cheap and they charge a core.
I'll report back later today on my findings.


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[EricM]

From what I've read, rebuilding a rack is not possible without specialized equipment.

 

[ogdobber]

Well as i suspected, bad news for my wallet

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[Deleted member 12951]

Hmm, I’ve replaced my rack and that did not stop the clunk. I am suspecting the sway bar on mine.

 

[EricM]

My rack makes the same clunking noise and is leaking (I can make it clunk with the truck off by just lightly rocking the wheel back and forth) but I don't have anything near the noise that was shown in the video from under the truck earlier in the thread.

 

[Canuck714]

Hmm, I’ve replaced my rack and that did not stop the clunk. I am suspecting the sway bar on mine.

I doubt its the sway bar. I took mine off and my clunk remained.
Just pull off the link on one side to check yours quickly.

 

[Hasty]

My rack makes the same clunk with engine off rocking the steering wheel. Washboard roads and it’s the absolute worst. However, around town I hardly notice.

I’ve now confirmed that my front end clunk was coming from 2 different sources and essentially made the same sound. The first cause was a loose top hat nut, I didn’t torque it down properly after the shock swap. It appeared to quiet the ride down but a week afterwards the clunk reappeared and continued to increase in frequency. After checking all mounting points and torque I found low nitrogen on the same shock that I swapped. When I installed the shraeder I didn’t get a good seal and nitrogen dropped from 200psi to 90psi. I reinstalled/sealed the shraeder, recharged the shock and now she’s quiet again on the road.

I know once off-road or on washboards I’ll get the steering rack knock but to be expected. I’ve gone through Ford attempting to get them to warranty but they were not budging. From what I’ve read on other F-150 forums replacing the steering rack isn’t a guaranteed repair, all the racks are reman’s.


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[Eyespyautomotive]

Well guess who's clunk is gone? yup. I am calling this problem solved, for me anyway. Not exactly sure what did it but its gone.

So I spent about 5 hours on the front end of this truck again yesterday, I figured, this is it, either this fixes it or I am done with this MF'er. I went slow, methodically, looked at everything, double and triple checked every nut and bolt. It is 100% fixed, quiet like a new Platinum or King Ranch. I am satisfied. Love the truck.

This is what i did.

-New upper control arms, standard Moog brand.
-New upper Spring hats, Moog stuff.
-Tightened the lower shock bolt in full droop with a large screwdriver jammed in below and pushing up on the shock bottom eyelet.
450 lb ft +
-Pulled the driveshaft and greased the yoke.

So it was one of those things, which one I am unsure, but i have a few ideas.

Shocks...That bottom shock bolt up design sucks, I believe the LCA is shrouded on the bottom so the eyelet doesnt get bashed offroading, but in my opinion there is not enough clearance below the eyelet to compensate for bushing wear, bushing flex, and tolerance stack ups. Thats the reason I tightened the lower bolt in droop plus forcing the eyelet up to maximize the clearance. Even doing it this way i could barely fit a slice of cardboard between the shock and the LCA. Its not right, it is designed to have 5-6mm in there, it doesnt.

Spring hats... People probably reuse the old ones when doing a shock rebuild, I did, but do you know how it is designed? it is a UFO shaped metal piece encapsulated in rubber that cushions the jounce. If that metal piece separates from the rubber internally i think it could make a thump, especially in cold weather when the rubber is harder. They are like 45 bucks, just replace em.

UCA... although my uppers seemed fine, i was a bit leery about them. bushings seemed ok but had noticeably more flex when cycled by hand in position disconnected from the spindle than the new ones, much tighter. Also the ball joint was easy to move but exhibited no play when messing with it. But, maybe under the large forces when going down the road maybe it had a little play? dont know.

Driveshaft yoke... I had no takeoff thump which is the symptom of a dry yoke, but while i was doing things, thought id visit it. it had some lube but not a ton, this thing moves alot in and out going down the road. i packed it full of wheel bearing grease. if nothing else i feel good about checking it.

Well I am done with this, I hope my many many hours on this truck help someone solve their noise. Now my wife and my neighbors can stop wondering why im always wrenching on this thing.