Grimalkin-

weren't you the one who gave me a condescending answer about cab movement when I mentioned this problem a while back? Now it seems you are noticing the same thing I was. If it's not you, sorry, but I'm too lazy to go back and find the thread.

KJB-

Believe me, it is NOT just cab movement.


I said it a while back, and I still believe, that it is a suspension issue. Just my two cents.

 

F150 Diesel...Yes, you are correct. I take issue with the word 'condescending' (now and then)...I was poking a little innocent fun at you for 'pulling your hair out' (sic) over the issue, but my post was misinterpreted. Despite Smilies, etc. the internet is often a poor way to communicate.

Earlier, last fall I believe, I suscribed to someone else's post about the cab mountings and thought the issue was an innocuous peculiarity of the '04. Lately, after 4 months of observance, swapping tires, varying tire pressures, etc. I'm convinced there is some anomaly in the rear of this vehicle related to frame and suspension. I don't think of it as a defect per se, but I do believe it's something that Ford should issue some statement about, maybe just to calm our nerves. I don't have any hair left to pull out.

The remaining mystery is why some vehicles, according to their owners, have the problem and others don't.

 

Has anyone noticed this that has a spray on bed liner? Not sure if it will make a difference but could add some weight and possibly some rigidness to the bed?

 

I said it a while back, and I still believe, that it is a suspension issue. Just my two cents.

Okay, I'll bite...any theories on how the suspension could cause it to shake? From an engineering standpoint, if we assume that the frame is very stiff (a full box section vs a "C" section, etc.) and we see that the bed is attached to the frame and cross-braced, how does the bed move in relationship to the frame? If it does it on the road, especially in large motions, it ought to be pretty easy to reproduce at a stand still. Maybe have someone hop up and down in a corner of the bed and stand outside watching the frame, bumper and bed for flex to see if they move in relationship to each other. Ignore the cab, suspension and tires.

When I look under my truck, it appears that it would essentially take an act of God to get the bed to move in relation to the frame or rear bumper. There's still some flex in the frame from end to end, but compared to any other truck, it's virtually nil. It's impossible to eliminate all of the flex in a frame. In buildings, the structure is "precambered" with a bow upward that relaxes when the load of the structure is in place. You can see the same thing with a 48' trailer that's unloaded. It isn't really feasible to eliminate every bit of flex in any structure, but you can beef things up to handle most of it.

When I look at the structure supporting the bed, I see a bit of overkill. It looks to me like they could have gotten away with less, but didn't. That's the way mine reacts on the road. The suspension is relatively soft, as is the shock tuning and it appears that this is a proper combination for the stiff frame. The suspension absorbs all the loads, and the frame rigidity helps to damp out things before they reach your fanny or your load...sort of like a dirt bike where the tires and suspension are taking almost all of the abuse. I do have the Line-X bedliner, but I don't think that really matters. It was done a good month after I bought my truck and I didn't notice anything odd with the bed before.

I haven't driven behind many 04 F-150s here, but when I did I didn't see anything out of the ordinary. I've read a few threads about the "shake", but haven't actually seen it with my own eyes and I've tried. Maybe if someone posts a video I'll have a clue how it works, because right now I just don't see how it can. I don't see how the suspension matters. The axles could be bolted to the frame or it could have bungies for springs and I don't think the frame/bed relationship would change.

 

I think I made some smart *** remarks about the bed shaking when this first came up, but now it sounds like the problem is more widespread.

I still think something like bed shaking is pretty subjective and it would be hard for anybody here to describe how much movement they are seeing, and determine if it was a "problem" or not. I would hesitate to call this a design flaw since there is a small minority of folks here with the problem, and it's not limited to any bed length or wheelbase.

Don't worry, if the problem is legit Ford will take care of it.

 

Ya, just like they did with the door cracks

That's why I decided to wait for the 05', I learned a lesson after buying an 97' back in the day.

 

My six ft bed, style side will move now and then but I believe its not to the degree you have described... perhaps he was carrying something on the very rear of the bed on the heavy side.. GG

 

I just now drove home from work, and decided to stop off at Starbuck's for a cup of joe before heading home. The streets of Albuquerque I drove over getting to Starbuck's are very rough. The traffic was light, it being 0530 hrs, so I was able to really tromp it over the rough spots, while I watched my bed in my leftside rearview. Yes, as always, I can see some movement back there over the roughest asphalt, but it isn't anything, (IMHO), to worry about. There isn't the slightest instrusion of noise or vibration into the cab during these times. The suspension handles the rough streets as well as or better than any stock truck I've ever driven. I just don't really think this is something to fret over.

On smoother street surfaces, there is no detectable motion in my bed from my viewpoint of the driver's seat thru the rearview mirror. Next time I find myself behind another Screw, though (and there are quite a few of them plying the roads of NM) I will watch with interest.

 

I also have the bed shake on my SCab w/6.5 bed. I have never noticed this on any of my past trucks or other trucks I have ridden in or seen on the road. It is a very noticeable shake. In my opinion if it were the cab moving as some have suggested, I would certainly feel it - but I don't. It looks as if the bed is mounted on springs.

I looked in the wheel wells of my truck and another '04 sitting in the parking lot during lunch today. I noticed that the two transverse beams visible directly inside the wheel wells on both sides are not in contact with the frame. They sit more than an 1/8 th of an inch off the frame. The beams with the bed bolts through them are tight against the frame. I also looked at another F150 (97 - 03 range) in the parking lot, and all of the beams were in full contact with the frame. I am going to try to contact the owner of the other '04 to see if he is noting a shake in his.

Those of you who do not have the shake, please post whether or not the support beams are touching the frame. Also, those with the shake, post inspection results please.

 

KJB...just a comment or two. This issue is NOT a scenario of the bed moving in relation to the frame. That would be impossible unless the two of them were not firmly attached to each other, which is not the case. In this matter, the issue is movement (of everything) aft of the cab.

The only (?) remaining causal agent here would appear to be the rear suspension (shocks/springs) and the tuning (rebound damping, compression damping, spring rates, sprung/unsprung weight ratios, etc., etc.) of those components in harmony (or disharmony) with frame rigidity, tire construction and pressures, etc. By changing any of the above factors, for example, loading the bed, the physics are radically changed.

In the case of a utility vehicle that is required to run empty or loaded, the suspension had a tough row to hoe. My guess is that a small tweak here or there would solve the problem. Maybe in '05.

 

Brannong, I have a spray in bedliner and I see the bed moving. I'm not drunk, I'm not retarded, I'm not seeing things and I'm not insane.

When you hit a bump, the bed moves, and there is a vibration throughout the truck when this happens. When my 1000 mile check up comes about, I will mention it and have the service dept check it out.

 

All of you with the 'bed shake' just need to get a fat girlfriend who loves the fresh air.
Don't wait around for Ford to issue you one.

 

From what I have read here I would say everyone is seeing the cab move on the mounts, just assuming it is the box as you are moving in tandam with the cab and dont notice. I have seen it on my 99 on a washboard dirt road where the cab is bouncing out of sinc with the frame. Just a thought..

 

When I saw the bed shake I was not in a cab I was following the truck on a smooth paved road and as stated it is mostly shaking from the middle section of the bed where the wheel arch is to the rear of the bed.
I have my camera in my company vehicle and the next time I see this guys truck I will get it on video.

I do not have my truck yet, but the first new 04 I test drove I noticed this too but shrugged it off since I was in the cab looking out the mirror.

Trust me when you get behind one you will know lol.

 

Cool, once you catch it on film, I'd love to see what all the fuss is about Since I don't have mine yet, I really can't picture this. We'll have to find a way to post it somewhere so everyone has access to it (as long as the file isn't huge).