Making a pete sleeper into a unibilt

If the truck is new enough to have been available with a unibilt, it should be as simple as cutting the hole bigger and huckbolting the bigger seal ring into place. however there are a bunch of braces missing in a frame mounted cab that prevent you from actually using air ride as on a factory unibilt,

there were also factory unibilt flattop trucks built and you would need the opening frame from a flat top to do the opening conversion

 

Enlarging the opening is as simple as getting both rings and cutting the cab panels to accept the ring. There are guys even doing this to old KWs to gain leg room.

 

I bet Peterbilt of Joplin could give you some info. They've always been accommodating when I've called with questions.

 

I have done Three of these myself. One was a 90 non unibilt i converted to an air ride unibilt. the others were day cab 2001 we attached 36" sleepers to. You can look at back of day cab and tell if it has the rivit outlined for a large unibilt sleeper hole, then it is a breeze. If you have a small opening its not that hard but its alot more work. uni bilt ring sits one inch higher on cab , so if your trying to put on a uni bilt sleeper on an old cab, the ring on cab has to be moved up and if you want to make it air ride there are support brackets along top of doors all the way from front to back that attach to ring. all need to be huck riveted in or cab will twist itself to death. non air ride, not a problem. Then there is the interior issues and seat belt relocation and brackets for those that are going to have to be cut/relocated for a non unibilt style cab. Take your time and plan and measure twice before you cut and drill or you will be hating this job.

 

So I came across this old thread from April 2016, and I'm right at this critical stage at this moment...ready to install the Peterbilt Unibilt frame rings in to make it a big hole, only in an A Model KW cab.

We have the rings clamped up against the back of the cab right now, just eyeballing things. It's a little tough on this A Model cab, due to the height of the ring in conjunction with the bottom of it. We can't get it (the aluminum ring) any lower than it is in the pictures, as there's an aluminum "U" channel inside the cab which is a structural member that can't be compromised, nor should we have to. But the challenge is getting the Aerodyne II sleeper lower on the frame to match up with the overhang over the rear of the cab to look half way decent, so basically we're going to be dropping the sleeper mounts down on the frame, so the sleeper structure rails themselves will only be about an INCH off the top of the truck frame rail flanges to get the proper height and look.

I have been contemplating the idea of cutting these rings in half and lowering the vertical height of them, so as not to have to remove so much material from the fiberglass roof cap of the A Model cab, and also it will enable us to raise the bottom mounting surface up as well. As an estimate, if we remove 8" of height out of the rings and weld them back together, that will take the difficulty out of fastening the bottom of the ring in the cab without interfering with that structural "U" channel member. I don't care so much about the height with this project, as I am focused on the width primarily to get the seats farther back for legroom. That's usually the case anyway with this job in most instances. I don't mind ducking a little to get in the bunk.

The other question that 3 of us working on this job have also is, how the boot actually attaches to the rings. It just doesn't seem mathematically possible doing it on the bench, so we're obviously missing the mark somewhere.

So, I'm looking around for ideas, and the world wide interweb usually provides pics and stories of about anything you need or want to know. I'd appreciate any input from guys that have actually DONE this job, so I can get some accurate info and keep it simple as well.

Once that's determined, we can proceed to cut open the back of cab and front of bunk for the frame (rings) to be fastened in.

Here's some pics of what and where we're at as of 24 hours ago:

 

I am ready to do this myself. I own a 94 Pete with a custom ICT sleeper. I don't want it any longer and I have a 63" sleeper just waiting to be attached. All I need is the ring kit. Can anyone help me with a part number and or where to purchase it from.

 

If anybody has any more info or in depth pictures of a unibilt conversion they did or are in the process of doing that would be great I’m trying to do a conversion on my 86 359 with a subframe under the cab and bunk so I can sit it all down on air ride without the cab crossmembers does it seem like it would work well or could it be problematic I want opinions before I start fabricating brackets a subframe and the ring I want to have the plan ahead of time thanks for your time

 

So how did it turn out?