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I'm chocking this one up to the gravitational field of Venus being concentrated at a higher magnitude by the unmistakeable pull on the spacetime fabric when you hook that particular truck to that particular trailer....
I'm chocking this one up to the gravitational field of Venus being concentrated at a higher magnitude by the unmistakeable pull on the spacetime fabric when you hook that particular truck to that particular trailer....
That's the only thing it could be
I would get a 4 wheel alignment done on the truck. I have heard of guyshaving the same done on the trailers just to make sure all is ok on that front.
Dave ----
Try pulling the trailer totally unplugged.. You wont have break lights but if your willing to strap yourself in to a seat on the trailer no brake lights not a big deal. If your too worried about it have your buddy follow you. He can be your lights.
One of the first things I did was to unplug the trailer and back off the brake shoes on the rear axle, (front axle doesn't have brakes). It made no difference.
I can wheel the trailer around the yard with a hand dolly with no problems so its not a matter of rolling resistance or drag.
The only thing so far that's made it better is to use a hitch that lifts the front of the trailer extra high, nearly a foot above level. This helps but doesn't stop the bucking completely.
Something that I did notice is that the wheel base of the truck and the distance between the rear truck wheels and the front trailer axle is the same, when hitched to all my other trucks, (earlier body styles), the two measurements don't match since the older trucks have a shorter wheelbase, (133"), vs. (141.5" on the newer truck).
I'm wondering if the matching distances between axles is helping cause the bucking with only this trailer?
If I let the truck take off without any throttle at all, at idle in gear, by the time it shifts into 2nd gear its bucking pretty bad. Any throttle or brake input at that point just makes it worse.
One trailer shop here told me the trailer has too much rear overhang, but my argument there is that it doesn't do it on any other truck. The Ford Dealer told me they've had similar complaints and that most of the time its due to guys pulling too much weight, but this thing is light, I've towed it with my F150 and had no issues.
I towed it 200 miles last weekend, it shook for almost the whole ride, every so often it would just stop shaking when on super smooth pavement. When I got on old concrete highway it bucked and shook really bad, so much so I had to stop for a bit and check to make sure nothing was coming loose. I had nearly 600 lbs of tongue weight coming home and two tons on the trailer, it made no difference at all how it towed. I took that trailer yesterday with the old truck with the same load almost 400 miles and I could hardly feel it was behind me other then when I got into some steep hills in PA. The 4.9L F150 doesn't have the pulling power that the 6.0L F250 has but it hauled that trailer just fine. All my other trucks are pre 1995 regular cab long bed models, the F250 is a supercab shortbed in the newer body style. The F250 doesn't have any issues with my other trailers, in fact I pulled a buddies John Deere back hoe on his Eager Beaver trailer on a pintle hitch and it towed that fine, so its not a matter of weight. This truck should easily haul a 4 ton trailer without any issue with the right brakes and hitch. The hitch I've been using is a load equalizing Drawtite model with 10,000 lb torsion bars, (which I've not been able to use due to the fact they made the situation worse).
You haven't seen this guy hanging around, have you?
could be? Maybe?
I think it is a sympathetic vibration between the two.
Somehow you need to "detune" the combination.....
Adding mass in the right place would do it, but the question becomes where and how much. Given enough time and information I might be able to take a guess at it.....
What speed is the worst?
What is the distance from the ball to the trailer axle?
Rear truck axle to trailer axle?
Do you have any heavy scrap iron you could bolt to the trailer frame in various locations as a test?
My guess is that there's something loose on your truck's front end. Either steering or suspension. And this trailer is the perfect balance point to take just enough weight off of the front end to get into the "play" area, or "loose zone" of whatever it is (bushings?, etc).
Your other trailers don't have the same fulcrum point as this one, and it's some kind of magic balance point that sets off the oscillation of your loose front end.
The problem's in the truck. I'd start with a highly competent truck front end shop and have them go over everything. Doesn't matter how many miles are on your truck, or how old it is. Something's loose up front, and this trailer seems to set it off.
The only thing so far that's made it better is to use a hitch that lifts the front of the trailer extra high, nearly a foot above level. This helps but doesn't stop the bucking completely.
This make me think there is something wrong with the axle's on the trailer. I would see if a trailer place has a way to check the distance between the two axles. Kinda like an alignment. If not measure best you can center hub to center hub. You may have to take the tires off. maybe one axle has hit something and been tweeked
This make me think there is something wrong with the axle's on the trailer. I would see if a trailer place has a way to check the distance between the two axles. Kinda like an alignment. If not measure best you can center hub to center hub. You may have to take the tires off. maybe one axle has hit something and been tweeked
Ok I see you did try not having the trailer plugged in so rules out any kind of EMI some how.
I was thinking the same thing with the wheels being the trucks WB and distance from trucks rear axle to trailers front axle is the same I would see if I could get the front axle/wheels off the ground for a test drive.
Do you have a longer hitch that would put the trailer farther back changing the distance between axles just as a test?
I did also suggest a trailer alignment that might show some thing not right.
Having someone go over the trucks front end is also good.
Another set of eyes always helps.
Dave ----
The trailer pulls fine behind my other trucks, I can't see how this can be an issue with the trailer. The same with the truck, it pulls my other trailers fine, I've got a 26' Camper, a 20' deck over trailer, an 18' tilt deck, a 24' enclosed car trailer, and a 12' enclosed single axle trailer, all of those are fine behind this truck.
The shocks are new, as in two months ago. It came new with Rancho shocks from Ford, (FX4 package). The front end is fine, the truck is fine at all times other than when towing this one trailer.
The trailer axles are mounted correctly, and pull fine behind my other trucks, the tires on the trailer are less than a year old and inflated to 50 psi. They are 7x14.5" 12 ply tires. When I tested towing it with the hitch raised, I used a different hitch, one that was taller, putting the ball about a foot higher, but its also closer to the truck by about 8". The load equalizing hitch I have on it now is long, it puts the ball about a foot back from the bumper's edge.
With every other trailer I've ever towed with this truck, I simply hook it up to the ball and go, no other trailer ever had any effect on the truck or how it handled, even much heavier trailers. What I'm having a hard time grasping is how such a light trailer can behave so badly behind only one truck.
I thought about pulling the front wheels off, but I basically did that when I tested it with the higher hitch, the front tires were nearly completely unloaded.
The truck is sprung heavy, tongue weight has little to no effect on ride height.
As far as adding weight, I had a Bronco facing forward on the trailer. I tried several positions on the trailer with that truck and it made no difference in the bucking which starts at around 18 mph and continues to about 35 mph. Most of the time it settles down after 35 mph on smooth highway, but if I'm on anything but perfect pavement, it just levels off and keeps bucking. On perfect pavement, it settles down and smooths out over 58 mph but any change of speed, either by letting off the throttle, any acceleration or braking can induce the bucking even at higher speeds.
This isn't a new trailer to me, I've been using it behind my other truck for years before moving back here. The issue only surfaced when I started to use the 03 F250 with it.
When I got this truck out of storage it got all the fluids changed, new tires, new shocks, and all filters. The truck had some electrical issues that have been sorted out. It runs perfect and is getting upwards of 20 mpg on the highway. Its seen a few thousand miles since I started using it again. If there were any issues with the truck think they would surface when towing any of my other trailers, especially the 20' P&J deck over equipment trailer.
I'll get some more measurements when I get home later.
You can say "It isn't the truck" all day long, until you're blue in the face. Chant it every night before you go to sleep.
In the end, it's the truck.
Saying it isn't the truck won't get you anywhere. Get the truck checked out. By a competent front end shop (not all are, actually most are pretty crappy). Take it down there with the magic trailer on it, and take them for a test drive with it.
You can say "It isn't the truck" all day long, until you're blue in the face. Chant it every night before you go to sleep.
In the end, it's the truck.
Saying it isn't the truck won't get you anywhere. Get the truck checked out. By a competent front end shop (not all are, actually most are pretty crappy). Take it down there with the magic trailer on it, and take them for a test drive with it.
Btw, it's the truck.
What your not getting is that this truck has 15k on it, and it pulls at least a dozen other trailers fine. The issue is only with this one trailer, which so happens to pull just fine with 4 other trucks so far.
I do my own work, I have a lift in my garage, both here and at my other house, I retired from doing automatic transmissions for a living 7 years ago and took a better paying job in another field.
I know my way around a truck, car, or anyhing else with a motor. If it didn't have me and most other's here stumped I wouldn't ask.
I pulled the front two wheels off, (pulled the wheel and hubs), it towed better but still had a strong buck or pulsation. The local trailer shop here is just as stumped, we even hooked it to his truck and it ran fine, when we hooked it to one of his tech's truck, the same model and cab configuration as mine, it does the same thing.
So basically what I'm seeing here is that it only does this on a 141.5" wheel base truck. It don't buck behind my 1994 Ranger, or my 1995 F350, or my 1986 F150, or 1993 F150. Its got to have something to do with the wheel spacing. The truck wheel base is 141.5, the distance between the rear wheels and the front trailer axle is the same. On the 133 wb trucks, the rear wheel to trailer front axle is 152".
I'm thinking that its got to do with the fact that the trailer and truck are equal levers on the hitch point. Its the only thing I can figure. I've tried another hitch but I don't have anything drastically different enough to make much of a difference. For now, the trailer gets towed with my older trucks and I'll run the 03 with the longer trailer.
12-07-2016, 01:24 PM
That's the only thing it could be 
