F450 Suspension

[fauch]

What makes an F450 rise when a trailer load is applied? No air compressors, no airbags.
Truck drops or 'lowers' when trailer load is removed

[Artemus Gordon]

My new F450 lowers a bit when it accepts the "trailers" weight. It does not move much, but never witnessed it rising again. It tows perfectly level down the road. I would assume the truck is designed like a Weight Distribution system, sending weight to front axle. That said, I really am unknowing?

[Art-n-Marge]

I can only wonder if the trailer is so rearend heavy that it causes the front end of the fiver to raise the rear end of the F450 when you hitch it up. However, this would have to be a significant difference and this is NOT expected even with a very capable F450. What type of fiver hitch do you use? You should get to the scales and weigh everything to find out why this might happen. You need to find the cause since what I initially described might mean the rear axle of the trailer might have too much weight on it compared to its front axle. The only other thing I am aware that might cause this is an air bag system that has a preset aspect so that the bags automatically inflate to raise the rear end, but you report that you don't have this. To fix this you would have to shift weight in the rig towards the front of the rig. I have heard that some trucks have strong front ends so no sag occurs, or the weight of the rig will cause some sag (like in my case), but never have I heard of a truck's rearend rising when putting any load on it. I do need air bags to raise things back up and get the headlights back down from being highbeams to oncoming traffic (When I caravan with others we'll use our lights so we can see each other a little better).

It will be interesting to read subsequent posts from anyone who can post other reasons.

[fauch]

My stepson bought a 2008 F450. when he sets the king pin weight of his SOB on the hitch, the truck rises/maintains height. When trailer is lifted with the landing gear, the truck will lower/maintain level. He has had it on the lift in his shop, and there are no air bags, compressors, airlines anywhere to be found. There is is what looks like an electro=magnetic sensing device or switch in the left side near where the receiver hitch is bolted to the frame of the truck.

Strange goings-on with this truck; we've been keeping an eye out for Rod Serling to appear in the passenger seat one day.

http://www.youtube.com/watch?v=NzlG28B-R8Y

[fauch]

Nope on the rear end-trailer weight theory--- sure enough CAT scale measured 3200 lbs hitch weight. When several pipeline workers get into the back of the truck, it very obviously rises.... riddle me that!

[fauch]

Nope on the rear end-trailer weight theory--- sure enough CAT scale measured 3200 lbs hitch weight. When several pipeline workers get into the back of the truck, it very obviously rises.... riddle me that!

[jlb27537]

quote:Originally posted by fauch

Nope on the rear end-trailer weight theory--- sure enough CAT scale measured 3200 lbs hitch weight. When several pipeline workers get into the back of the truck, it very obviously rises.... riddle me that!

Step away from the bar very slowly. Leave the brown bottle on the bar. Step backwards toward the sound of my voice. Drop to your knees. Cross your ankles. Put your hands behind your head.

Now come with me to the CAT scales.

Jim

[Phil P]

Hi

This sounds interesting! I will do some research and get back to you on this subject.

What year is the truck 3014?

Phil P

[mhs4771]

Sure sounds like some type of leveling system.

[K0LCB]

Magic?

[fauch]

Digging on the inter-webs and grapevine research has resulted in The "electro-magnetic looking" device being a frame vibration damper.

http://mrtruck.net/f_pic/framedamper.jpg

[Art-n-Marge]

This sounds like a nice feature that might even eliminate the need for air bags. I can't believe how hard it is to find out what it is and how it works?

fauch: If I understand the picture you posted, this should maintain the level and not raise the rear end, unless you meant the rear end was raising to maintain the aspect prior to hitching the trailer. I envisioned you described that the truck's rear end was raising to an even higher level but I think this device makes more sense if it's what's under your truck, that the magnetics attempt to keep a sagging rear end to what's normal and appears to raise the truck. Here's the explanation from the Mr. Truck website and the picture you posted: "F450 pickup has a frame vibration damper. The cab and chassis F450 which doesn't have the frame damper, shake at highway speeds with a 4.88 rear axle ratio, while the F450 pickup doesn't."

I guess there might be other benefits that this damper causes like keeping the truck at the same aspect while putting on a load. Nothing that a glance under the truck might reveal. The wonders of technology never cease to amaze.

[Glenn the fifth]

I have a 2008 F450 that I tow my 3402 with. Mine lowers a bit (not much) when I bring in the landing gear. -Glenn

[fauch]

That dee-vice in the linked pic is strictly a harmonic frame vibration damper. We are still trying to figger out how the rise and fall of the truck height opposes the physics of payload change.

[Phil P]

quote:Originally posted by fauch

That dee-vice in the linked pic is strictly a harmonic frame vibration damper. We are still trying to figger out how the rise and fall of the truck height opposes the physics of payload change.

How about a youtube video of this event?

[fauch]

Ill see what i can do on a video. He is currently on a pipeline somewhere in TX

[Phil P]

HI

The Ford dealer and the Chevrolet dealer are owned by the same family in our home town.

While at the Chevrolet dealer this morning seeing about getting more warranty work performed on our new Malibu I happen to see the Ford service manager.

I ask about this suspension on the Ford trucks. His answer was that on the smaller trucks 350 and smaller they have several different systems that do this but he wasn’t familiar with the 450. The one that doesn’t have visible airbags is the one that pumps air into the rear shock absorbers to level the truck. He indicated there is an air pump in the system some are electric and some are engine driven.

Phil P.

[mhs4771]

Sounds like some old Air Ride Caddys. Had a neighbor that had one that leaked, would have to start it up a few minutes before hitting the road so the system could bring it back up to traveling height.