Swivel seats hitting wall

[alexjt]

Hi all,

I'm the proud new owner of a '76 Birchaven 23 footer. It was partially gutted by the previous owner, and I'll be finishing the job over the next year.

I was excited to try out the "swivel" function of the driver and passenger seats, but on my rig the seats can only rotate about 25-30 degrees before the the seat back hits the outside glass. I've tried sliding the seats forward and back before swiveling, but they always hit. Anything I might be doing wrong? Or do some models not let you swivel the chairs 360? As far as I can tell from old Birchaven brochures, the chairs should be able to swivel all the way around without hitting.

 

[tmsnyder]

Hi all,

I'm the proud new owner of a '76 Birchaven 23 footer. It was partially gutted by the previous owner, and I'll be finishing the job over the next year.

I was excited to try out the "swivel" function of the driver and passenger seats, but on my rig the seats can only rotate about 25-30 degrees before the the seat back hits the outside glass. I've tried sliding the seats forward and back before swiveling, but they always hit. Anything I might be doing wrong? Or do some models not let you swivel the chairs 360? As far as I can tell from old Birchaven brochures, the chairs should be able to swivel all the way around without hitting.

I wonder if someone swapped out the seat bases? The pivot point should be well 'in board' on the seat. If it's swiveling at the center of the seat base then 'someone has been there'

 

[alexjt]

Thanks Todd, I think you are right. Well, I did sign on for a project, time to take the seats off and investigate!

 

[Keith V]

Yeah only factory seats can swivel properly. I have Dodge caravan seats and they hit the wall

 

[dsmithy]

Yeah only factory seats can swivel properly. I have Dodge caravan seats and they hit the wall

I replaced my OEM seats with Honda seats on a third party pedestal and they swivel just fine. I do have to run them full forward to do so. The degree of tilt on the back makes a difference as well. This is not a difficult problem to fix Alex, just a PIA.

 

[pvfjr]

My Glenbrook also has seats from an unknown source. They're not factory, that's all I know. They look like some conversion van or other type of RV seat. They swivel just fine, but they're mounted atop the original GMC swivel bases. I might add, each base is still located on the correct side of the RV as well.

 

[Keith V]

I replaced my OEM seats with Honda seats on a third party pedestal and they swivel just fine. I do have to run them full forward to do so. The degree of tilt on the back makes a difference as well. This is not a difficult problem to fix Alex, just a PIA.

Huh, I should try that, I just tried with them all the way back and reclined!
That would be cool if it worked

 

[alexjt]

I replaced my OEM seats with Honda seats on a third party pedestal and they swivel just fine. I do have to run them full forward to do so. The degree of tilt on the back makes a difference as well. This is not a difficult problem to fix Alex, just a PIA.

Thanks for the advice! I'm going to the auto yard in the next week or two to look at options, as the existing seats are too far gone for me to try salvaging.

I pulled the driver's seat off the base, and did some more research of Jim Bounds' videos. For whatever reason, my seats are on the older "wedgie" type pedestal that was used in '73-'74 models, even though its a '76.

In taking it apart, the pivot point is just a thick bolt through a pipe nestled into a countersunk hole. It's centered side-to-side, and about 1.5 inches behind the center point front-to-back. I'm fairly handy with fabrication, so I may be able to come up with something that doesn't require a new base at all. More to come!

 

[daver]

I had a similar problem and I moved the swivel point about 1 1/2" inboard. Bored a new hole for the bolt and had to also make a new hole for the locking pin. Still not perfect but works a lot better.

 

[alexjt]

This is exactly what I was thinking. I've mocked up a cad model of the plate, and I think I have a good location a bit farther back and inboard. I've also found excellent condition 2009 Honda Odyssey seats at the salvage yard. I went in the car over lunch, so I'll have to back with the truck tomorrow and pick them up.

 

[alexjt]

I replaced my OEM seats with Honda seats on a third party pedestal and they swivel just fine. I do have to run them full forward to do so. The degree of tilt on the back makes a difference as well. This is not a difficult problem to fix Alex, just a PIA.

Do you remember which seat bases you used, by chance? I just finished mounting one of my new seats and it still scrapes the walls. Plus, it feels way too high on the wedge type bases.

 

[sailor man]

Hi all,

I'm the proud new owner of a '76 Birchaven 23 footer. It was partially gutted by the previous owner, and I'll be finishing the job over the next year.

I was excited to try out the "swivel" function of the driver and passenger seats, but on my rig the seats can only rotate about 25-30 degrees before the the seat back hits the outside glass. I've tried sliding the seats forward and back before swiveling, but they always hit. Anything I might be doing wrong? Or do some models not let you swivel the chairs 360? As far as I can tell from old Birchaven brochures, the chairs should be able to swivel all the way around without hitting.

I have removed these seats and replaced them and the bases with used Villa 6 point electrical seats.The seats and bases are available. When I bought my coach, both seats rotated all the way around. The previous owner had a serious back problem, so he used to rotate the passenger seat all the way around, recline the chair back and footrest and slept in it all night.


These are the replacement chairs with the 3 point seat belts. They have their own bases and can rotate around too. I am SailorMan and you can check out my project on https://www.gmcmotorhome.org/thread...-batteries-and-sailor-mans-lifepo4-build.982/

 

[dsmithy]

Alexjt,
My bases were custom made and i bought them from an owner who no longer needed them, so I have no idea where they came from. I had to dry fit them for rotation and measure carefully for height to get them right. Ultimately they mounted about 1 and a half inches inboard and about that rearward of the existing holes. As I said, it wasn't that difficult, just a PIA. The cutting and restoration of the carpet around the pedestal is another PIA. There are active discussions on the security of the floor mounting as well, especially if you have seat mounted shoulder belts. Because of the variation in seats and pedestals, dry fitting and careful measuring are the only route to a successful outcome. Take some comfort in that you are not getting greasy, dealing with dried shit, or burning your hands on a hot manifold. Things are mostly easy to reach as well. Welcome to the GMC world. It IS worth it.

 

[sailor man]

These are the seat bases I have.

 

[Tybalt39]

I replaced my OEM seats with Honda seats on a third party pedestal and they swivel just fine. I do have to run them full forward to do so. The degree of tilt on the back makes a difference as well. This is not a difficult problem to fix Alex, just a PIA.

Any chance you have drawing with measurements for mounting to the original structure for safety? My current 2009 Odyssey seats are bolted just to plywood and I want to remedy that. Plus, I'm replacing them with 2018 Odyssey seats (integrated shoulder belt).

New base...


I just need to create pieces to mount it to the original structure.

 

[sailor man]

Any chance you have drawing with measurements for mounting to the original structure for safety? My current 2009 Odyssey seats are bolted just to plywood and I want to remedy that. Plus, I'm replacing them with 2018 Odyssey seats (integrated shoulder belt).

New base...
View attachment 16826

I just need to create pieces to mount it to the original structure.

This is the best way to do it.

I added two 1/4" steel plates and used the the original 12 bolt positions to fasten the new plate to the aluminum body floor frame as the old steel pedestals were.
I also applied clear penetrating epoxy to both sides of the plates to prevent rusting.
I then took the time to preposition the seats individually, so that I could make certain that the seats would rotate before the 5 fastening holes were drilled.
For my 6 way electrical Villa seats, I needed 4 bolts plus one for the electrical feed.
You can determine where to place the holes for your seats that work the best for you.

In this photo, you can see the 12 smaller bolts that secure the 1/4" steel plate are fastened directly to the aluminum body frame. The 4 larger bolts fasten the seat to the steel plate through the plywood and the white electrical wire is for the seat electrical connection.

I had to reposition the driver's seat because Cliff had the seat in the wrong place, so new holes were drilled and the seat does now rotate.
The old holes where filled with 3M 5200 adhesive sealant with the cardboard patches still sticking to it.

I have found that either the smaller plate bolts or the larger seat bolts can be used to temporarily use lift nut for small block and tackle to lift relatively heavy objects.

 

[dsmithy]

Any chance you have drawing with measurements for mounting to the original structure for safety? My current 2009 Odyssey seats are bolted just to plywood and I want to remedy that. Plus, I'm replacing them with 2018 Odyssey seats (integrated shoulder belt).

New base...
View attachment 16826

I just need to create pieces to mount it to the original structure.

Tybalt39,
As my seats do not have an integrated seat belt I did not do extra beefy mounting for my pedestals. I would look closely at Sailor man's ideas as he has the cash and engineering chops to do it right.