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General Category => Tech - Help Area => Body-Interior-Electrical => Topic started by: MrC. on November 17, 2017, 11:05:05 AM

Title: Flat bed
Post by: MrC. on November 17, 2017, 11:05:05 AM
Hey guys, I am picking up a 11ftx8ft flatbed tomorrow it came off a 2005 Topkick.

The owner says it has 33 in center to center frame rails?. I know the headache rack is going to be to tall, I am considering cutting it down to 9 feet in length as well.

The big question is will it fit the frame?
I have a 94 3500hd.

Thanks
MrC.
Title: Re: Flat bed
Post by: someotherguy on November 17, 2017, 11:21:34 AM
Yep.  It's actually 34" as that is the standard chassis cab dimension so that many beds will fit across as many brands, models, and years as they can.

Richard
Title: Re: Flat bed
Post by: MrC. on November 17, 2017, 11:38:44 AM
Thanks for the fast response SomeOtherGuy

I priced out building one myself, and this one is just to cheap not to buy it.
I may talk myself out of cutting it down to 9 ft. but If I leave it 11ft. the gooseneck will be behind the axle and my currant hitch would be obsolete being 2 feet under the bed.
the flat bed has a built in hitch, But I do not know the rating of it. I'm sure if it was on a topkick it would pull 20k lbs.

Thanks again
MrC.

Title: Re: Flat bed
Post by: MrC. on November 23, 2017, 12:11:40 AM
Hey Guys,

So I picked up the flatbed (from a 2005) Topkick. it is 11x8. My plan was to cut it down.
I have a few concerns before I fire up the saws.

1. If I cut 2 feet off the rear, I could continue to use my frame mounted hitch, but the gooseneck box will be behind the axle about 18 inches.

2. If I cut off the Headache rack and remove 2 feet then reinstall the rack then the gooseneck box will be directly over the axle. I would have to also cut off the hitch that is mounted to the flatbed. (I don't know the rating anyway, and it looks like it's been cut on already.

3. If I cut it just in front of  the gooseneck box (the middle) and take 2 feet out of the middle, this would also require removing the flatbed hitch. But I would want to plate the joint since it would be a butt weld, or at least sleave it.

Any thoughts? I do not own a gooseneck trailer, I don't see buying one anytime soon, but I don't want to make a mistake here either. The PO cut the gooseneck plate out of the Topkick and it is still attached to the bottom of the bed. It looks rough and I would not want to try and reinstall that plate anyways, so I am just mostly concerned about the box and the reinforcement that makes up the access hole (box)

Any thoughts?
MrC.
Title: Re: Flat bed
Post by: ED-NY on November 23, 2017, 07:53:44 AM
Just my opinion...if you don't anticipate using the gooseneck feature and got a "deal" on the bed anyway..build it the safest then easiest way.
Title: Re: Flat bed
Post by: MrC. on December 04, 2017, 07:49:11 PM
Hey Guys,

I have never owned or used a gooseneck, this flat bed I bought has a recessed well with a ball mounted to a plate welded to the bed, I can also see where there was another plate on the bottom that was welded to the truck frame, it seems that they had to cut the frame plate out. I have looked at a lot of beds that the ball is mounted to the bed, not the truck frame. I am wondering if I could tow from this ball being just mounted to the bed and not also to the truck frame? Am I missing something? should I torch off this plate and ball, and just use the well as an access hole? I will post some picks of it ASAP. the bed came off a topkick truck, but I don't think it was factory installed, because it was welded on in a few places, most factory stuff bolts on.

Here is a pic of it cut down to 9ft 3 inches, this is now the same length as my service bed. this also placed the wheels in the wheel wells and lined the gooseneck up over the rear axle.

Thanks
MrC.
Title: Re: Flat bed
Post by: ED-NY on December 05, 2017, 09:19:05 AM
When I made my 3500HD dump bed I bolted the two side supports to the frame, then added a middle support from the hitch to the tank cover. That added support only stabilizes the hitch and doesn't carry any weight.  The bed is completely removable from the  unmodified chassis. 
Title: Re: Flat bed
Post by: ED-NY on December 05, 2017, 09:32:23 AM
OH Yeah...forgot to mention that I relocated the tank fill hose to the rear between the frame rails, then made that trap door to access it. 
Title: Re: Flat bed
Post by: MrC. on December 05, 2017, 07:54:10 PM
Nice looking set up. Did you space the bed up off the frame rails, or mount it directly on the frame?
I want to keep my bed height as low as possible. routing the filler neck is awkward if you don't raise the bed.
can you post a pic from the side, so I can see how the bed frame is mounted to the truck frame.
Thanks
MRC.
Title: Re: Flat bed
Post by: ED-NY on December 05, 2017, 08:39:49 PM
Nice looking set up. Did you space the bed up off the frame rails, or mount it directly on the frame?
I want to keep my bed height as low as possible. routing the filler neck is awkward if you don't raise the bed.
can you post a pic from the side, so I can see how the bed frame is mounted to the truck frame.
Thanks
MRC.


I'll get some pics tomorrow, again I made it a dump bed so the main frame rails are directly above the trucks frame rails.  I wanted the bed as low as possible and accomplished that by routing the fuel filler neck out the back.

BTW: still working on getting these fonts larger!

Title: Re: Flat bed
Post by: SlowBoat on December 08, 2017, 07:13:00 PM
In looking at the inverted bed pic, I noticed that the gooseneck ball is mounted in the bottom of a fabricated box.  Can't tell how heavy of metal that the box is made out of, but didn't see any bracing of the box to the rails or crossmembers.  That would put a lot of stress on that box itself.  You might want to consider some bracing to the main rails and crossmembers to prevent a collapse if it does ever get used.
Title: Re: Flat bed
Post by: MrC. on December 08, 2017, 10:55:21 PM
Yep slow boat
you saw it too. It seem Previous owner welded a goose neck plate to the truck  frame the welded the  flat bed to the goose neck plate. When they separated the flat bed from the truck frame they cut the plate from the frame and left it welded to the flat bed. That box is not strong enough to tow from. Im cutting it all out tomorrow I didnt realize how it was all put together until I flipped it over.
Thanks for the input. I will use the box as an access hole only and install a plate and ball if I ever go goose neck.

MRC.
Title: Re: Flat bed
Post by: ED-NY on December 09, 2017, 07:21:08 PM
Attached some pictures...but realized you aren't building a dump body so my setup won't work for you.  Maybe you could make it a dump and install hydraulics later?
Title: Re: Flat bed
Post by: ED-NY on December 14, 2017, 10:32:20 PM
MrC

Your last post got deleted when this site crashed (today) .... I was trying out some new themes which didn't work.  I know yoy thanked me for the photos and you mentioned putting up some more photos later.

Sorry
Ed
Title: Re: Flat bed
Post by: MrC. on December 18, 2017, 11:34:53 AM
Thanks again for posting the pictures.
I did have one more question.

I have set the flat bed right on top of the frame rails, It is sitting on all the rivet heads in the frame. I want the bed as low as possible, but should I space it up off the rivets and build mounts where it is. or should I put some weather stripping or other material between the frame and bed or just mount it not touching the frame at all, I have looked as a few factory beds, and they sit on the frame, no weather stripping but also no rivets on the top of the frame.

Thanks
MrC.
Title: Re: Flat bed
Post by: ED-NY on December 18, 2017, 01:29:05 PM
That bed looks great on the truck.

Don't know how you are going anchor the bed and frame rails...but I suspect you'll get some squeaking where the rivets make contact.  You could cut a long 1/2" thick strip of spruce along the frame and put holes at the rivet contact points so the spruce won't shift. Could use rubber mats also. 
Title: Re: Flat bed
Post by: MrC. on December 19, 2017, 11:23:53 AM
Thanks Ed,

Its been a lot of work, I cut off the Head ace rack, remove 14 inches from its height, cut off 2 feet from the front, to move the goose neck up where it should be. cut off the mangled hitch, so it would not be in the way of my new hitch. I have decided to raise the bed one inch, above the frame rails that will space it off the factory rivets and bolts, it will also give me more tire clearance. I have some 4 inch heavy wall channel, I will be welding it to the bed and bolting it to the frame. I still have to rewire it and transfer my tag and light.
I hope to run the gas filler hose between the frame of the bed and the bed floor there is 3 inch gap there, I hope it fits.

Q. will I be required to still have a bumper? or does the drop down back of the bed cover that law?

Well, it is short like I wanted.
MrC.
Title: Re: Flat bed
Post by: ED-NY on December 19, 2017, 04:23:09 PM
From what I understand that drop down in the back qualifies as a bumper - here in NY anyway.