Well I broke it, in Canada

The Artisan

Adventurer
Ok so what went wrong with the ops setup, I believe this the third time it has failed? If you were trying to just dampen the twisting force what if used a dense rubber down the frame rail and ubolts?
Kevin
 

The Artisan

Adventurer
You can't have a frame designed to flex be constrained by a rigid body. Torsion free mounts allow the frame to flex and yet protects the rigid body from that flex. Otherwise cabinet frames will crack and split, plumbing fittings will fail and window and door seals will wear and start to leak.

Cabin mounts need to isolate as well as contain the rigid body. They need to be designed such the body can't roll off the frame, restrain the body from slamming into the back of the cab or sliding off the rear.
If it is anything like this the this is a horrible setup. Maybe it needs to adjusted if it is flexing this much in flat pavement he is just asking for problems on offroad situations. https://www.youtube.com/watch?v=Gi8hlF2seg4
Kevin
 

gait

Explorer
Ok so what went wrong with the ops setup, I believe this the third time it has failed? If you were trying to just dampen the twisting force what if used a dense rubber down the frame rail and ubolts?
Kevin

this last failure was the bolts that hold the rear spring mount on the chassis broke. Not really a big problem, just something that happened, easily sorted on the roadside. Original arrangement would have been rivets. Bolts used when chassis replaced. All sorts of explanations possible, including vibration and/or small twisting and/or bolt size and/or bad landing, etc, for nuts to become loose and bolts shear. Just need to check bolts every so often.

nothing to do with torsion free mounting of sub-frame and body. The sub-frame spring mount just got clobbered when the rear spring mount failed. In original state overload springs may have stopped that.

the Canter chassis can twist a lot. Narrow, shallow, tapered, chassis with hard springs and limited depth. Trying to constrain it with a rigid body is an exercise in futility. Ergo, let it flex.

If it is anything like this the this is a horrible setup. Maybe it needs to adjusted if it is flexing this much in flat pavement he is just asking for problems on offroad situations. https://www.youtube.com/watch?v=Gi8hlF2seg4
Kevin

looks reasonably normal to me. The front wheels came down the step together, the rear wheels one at a time. Just hit a speed/frequency/step size that shows lots of movement in a high body. Just a feature of the basic truck. Ignore at peril.
 
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SkiFreak

Crazy Person
Firstly, different type of truck in that video, so not a realistic comparison.
Secondly, that amount of movement between the cab and box is nothing.

Here is a much better example of what sort of flexing you can expect when going off road in a Fuso.
I should add... this is "normal flexing", as the chassis on these trucks is part of the suspension. It is designed to flex.

Westyss_whipsaw_01.JPG Westyss_whipsaw_02.JPG

If this was a hard mounted to the chassis setup the majority of this flex would go into the camper box and there would be a lot of stress on the chassis between the front of the box and the back of the cab.
As already mentioned here, a hard mounted camper box is not ideal if you plan on going off road with the truck.

Hopefully Westyss does not mind me using some images of his truck in action to make my point. :)
 

The Artisan

Adventurer
Ok cool if its that type of off roading I could see that. I am saying hard mounting but with give (material) in between the two to dampen the shifting. I plan to use mine for parks and such and occasional MTB mountain trips, don't think I would do trails like that...
Kevin
 

Aussie Iron

Explorer
If I was traveling with a group maybe. With my wife I would be scared what was at the end...:)
Kevin

ADVENTURE is at the end. Normally we travel with at least one other vehicle and the Canter has no trouble on trails like that. Yes it flexes a lot but I think we should leave this thread and give it back to the OP.
Corrugations will shear bolts on spring mounts just from the constant hammering and they wouldn't have to be loose. Maybe a look at redrilling and going up a bolt size is in order.

Dan.
 

kerry

Expedition Leader
My truck has a service body attached with U-bolts and the camper is attached to the service body. I don't regularly do the kind of trails pictured but have occasionally driven on similar terrain. There is a fair amount of flex as viewed thru my rear-view mirrors. I can't say it's the same as Westsyss flex and I don't have a video. I also don't know if that flex is concentrated in a different place as a result of having a bolted service body on the truck or that since it's a service body and not a solid box, the service body is itself flexing along with the frame. The service body has been on the truck for 216k miles and so far I've seen no evidence of damage to the frame or to the camper which has been on there for about 40k miles.
 

rocksaltfg84

New member
I have had same issue with broken spring hanger bolts on fg84 chassic. I also have replaced rear rails plus plated up the z frame as required in dump truck specs as stated by Fuso in their builders manual.Hence the riverted hangers were replace with grade 8 bolts 10mm size ,these broke on heavy corrugation. I then replaced 10.9 tensile @10mm, on our last trip away we talking to a chassic engineer and he advised me to remove the 10mm bolts drill out to suit 12mm bolts@10.9 tensile . As the original rivet would have been a solid 10mm where the 10mm bolt has a smaller solid core. Hence on return home all 10mm bolts were changed over to the 12mm by 10.9 rating. our rear chassic rails were replaced at 8,900 klms and we are at 53,000klms 80% of our driving is off road,back tracks and very little sealed roads.also we have 6500gvm with a full composite motor home body , S/S 19.5 toyo ATW parabolic ,Timbren aeon ,rear torsion bar.
 

westyss

Explorer
Firstly, different type of truck in that video, so not a realistic comparison.
Secondly, that amount of movement between the cab and box is nothing.

Here is a much better example of what sort of flexing you can expect when going off road in a Fuso.
I should add... this is "normal flexing", as the chassis on these trucks is part of the suspension. It is designed to flex.

View attachment 408754 View attachment 408755

If this was a hard mounted to the chassis setup the majority of this flex would go into the camper box and there would be a lot of stress on the chassis between the front of the box and the back of the cab.
As already mentioned here, a hard mounted camper box is not ideal if you plan on going off road with the truck.

Hopefully Westyss does not mind me using some images of his truck in action to make my point. :)



I was reading this thread and look at the pics Owen posted and I said " jeeze that looks like my truck" And it is! haha.... no problems Owen, just send me the usual monetary compensation for use of the pic.

That was also the Whipsaw Trail, its in Canada so it goes with the theme of the OP.....pre roof racks and solar, not a trail for those on top! This forum rated that trail but I cant find it now, was a 3-4 out of 8 I think?

For this trip the spring bolts were loosened up a bit to allow a bit more frame movement/flex and after the trip they were tightened up, otherwise the amount of movement between cab and camper would be less than shown now.
 

The Artisan

Adventurer
ADVENTURE is at the end. Normally we travel with at least one other vehicle and the Canter has no trouble on trails like that. Yes it flexes a lot but I think we should leave this thread and give it back to the OP.
Corrugations will shear bolts on spring mounts just from the constant hammering and they wouldn't have to be loose. Maybe a look at redrilling and going up a bolt size is in order.

Dan.
Ok Dan thanks. Where would I go if I wanted to research this more as far as design schematics, mounting locations along rail, what gauge angle iron, diam of bolt, spring rates etc.
Kevin
 

SkiFreak

Crazy Person
The body builders guide is always a good place to start. The Fuso chassis is like Swiss cheese. so it is usually quite easy to utilise existing holes for mounting subframe mounting brackets. Where and how many mounts to use should be dictated by the design and weight of the body.
Not wishing to be rude, but... unless you have a decent understanding of engineering, designing/building your own subframe and mounting system is potentially problematic.
 

The Artisan

Adventurer
Ski that's fair. My fuso is an FE 140 that will be converted to a a 4x4, the frame rails are straight. My pod sits directly on a flatbed and is removable so the bed remains. I did take 4 semesters of Structural classes in Architecture School but that was a while ago.
Kevin
 
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