Aluminum frame Kenworth. from log hauler to dump truck?

[tracyb]

wasn't sure the best place to post this... but anyway-

customer has a kw he says a 1976. has been a log truck its whole life. tells me its the perfect truck has the walking beam rear, trans, motor, everything he wants in a big rig. thing is he doesn't haul logs anymore, all excavation and material hauling now. so he really wants the truck turned into a dump body with pintle to tow a pup.


i've done this before, but only on steel frame trucks. i have never worked on an aluminum frame truck. the good news is the frame is plenty long so it wont need to be added onto. however fitting a dump hinge and tow plate to aluminum i'm worried will just cause cracking problems, i dont even know what grade aluminum the frame would be, i assume 5052?
i'm thinking there are two options-


1- make a big bolt on rear section of steel for the dump hige and tow plate, try to keep the bolting spread out and no so rigid that it will still alow the frame to flex.

2- basically the same as #1 but run a 2-3" sub frame the length of the box, be able to spread out the bolting even more.


want to be good with dot, but not really that big of a deal. the truck will live its life on an island where dot doesn't go. same customer has a 9ft wide truck he runs everyday and has never had an issue.




whats the right way to do this, or is something that i should just stay away from? any insight is appreciated

 

[PAE]

Make sure the transmission has a PTO hole.

 

[Provience]

I'd think option 1 and you are probably right that it's a 5xxxx series aluminum.

Just make sure you use good high quality primer and paint on the steel anywhere it is next to the aluminum so that it has a chance of lasting

 

[arse_sidewards]

1- make a big bolt on rear section of steel for the dump hige and tow plate, try to keep the bolting spread out and no so rigid that it will still alow the frame to flex.

You mean like giant flat plate brackets with the pin mounting features above the frame rail? Yeah that seems like the best of your options.

Can you use something that's geometrically equivalent to stupid big heims on the pin in order to take up the misalignment?

Is there a good way to use a single point mount at the front?

 

[AK_F250]

Personally I wouldn't touch it but if you decide to #2 bolt the rear crossmember and make a subframe that ubolts on with hardwood inbetween the rest of the length so that it can flex. I've seen much newer al frames completely trashed from either corrosion or a rigid box/tank/etc bolted the whole length.

 

[Mvanhelden]

I’ve seen a lot of older trucks with their aluminum frames sleeved, im sure that was a good solution back when, but knowadays that’s a lot of time and money for an old worn out truck.

 

[tracyb]

been stupid busy, but did get a look at the truck finally. the interior of the frame is already sleeved with steel from the back to in front of the drive axles.

so that will make it easy.

jobs still at least 6wks from starting. i'll post it up when it happens

 

[shortbus4x4]

I’ve seen a lot of older trucks with their aluminum frames sleeved, im sure that was a good solution back when, but knowadays that’s a lot of time and money for an old worn out truck.

I think I remember one old time truck mechanic telling me that was the fix to keep the aluminum frames from cracking.