Hi all.

These 2 images show, more or less, the shape the interior is in, in my Grumman.

I know a few of you have done fairly extensive restorations and I was hoping to get some input.

As you can see the roof is not supported except by the walls forward of the bathroom.

In fact the bathroom wall is just attached to wood strips screwed to the side of the fiberglassed wood (?) ribs that run across the roof. These panels or walls do not appear to support the roof at all.

So the big question is....

Are the walls load bearing or do I need to add some support? The roof is clearly very very heavy.

I am eventually trying to make the layout as open plan as possible.

The other thing is it would appear that the channels at the wall bottom where it meets the floor was designed to take a 2 by and be used to frame the wall up.

The previous owner told me he removed no framing and that's just how it was made. Yikes!

Under the window you see there were two vertical pieces of wood joining the two horizontal ones that I replaced due to rot BUT there was no wood that reached either the floor of the ceiling.

I am planning on framing these walls but the big question is whether the roof needs support or if the walls are designed as is to do that?

Thanks in advance for the help!!

PS the window in the 2nd picture is covered and has a small fridge under it and a blue tote lid.

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Replies to This Discussion

Hi Paul,

     I got into the wall on my drivers side rear. I replaced all the 2X2s with some 2X2 strips I cut from a microlam 2X12. You can stand on a 2X2 strip supported with 5 feet of span, try that with a plain 2X2. There should be strips that go from the floor to the roof. At least there were on mine.   It also has support from the bathroom closet wall and the closet near the stove. The partition by the entry well also supports the roof. I cut the microlam to fit into the wall stud channel, and where they crossed another piece I notched them so they fit together. Between snug fits and glue it makes the wall very strong. 

Hi Kirk.

Thanks for the advice. One thing I did notice was that the entry wall ( which I removed ) was built in such a way that the ply that they used was not under the roof bracing ribs but along side it. There are pieces of wood screwed to the sides of the ribs that are flush.The plywood was then attached to that piece of wood with just a 1x1 strip. The bathroom is the same way.

When I first removed the entrance wall I was surprised that it held no weight and was basically a slip fit. The wall of the bathroom is the same way. You can pass a rule between the panel top and the roof. It looks a lot more attached to the wall than supporting the wall. That will change!

I'll get some microlam and frame the walls up properly - great advice.

I plan on keeping the bathroom as is and also rebuilding the lower bunk areas ( both sides )

but I want to lose the entrance wall to the roof. Ideally I  want just the seat back height there.

I am thinking about a support pole just to open up the line of sight.

The other side ( drivers ) I will probably install a fridge and microwave and build it in which will add the strength back in that spot.

The microlam is a great piece of advice that I never would have though of. Much appreciated.

Hi Paul, 

    On mine, I only re-did the drivers side bunk area. It started with a water tank replacement, and ended up with that whole side getting re-worked. I completely removed the bunks on that side and built another closet at the rear. The water tank I used had to be installed on edge due to the filer attachments etc. When you re-use stuff sometimes you have to change things! It worked out so I have a shelf about 8 inches wide for the3 length between the storage pantry and the new rear closet.  The remaining width of the wheel well is framed out for a place for the water pumps and plumbing. The height is the same as the opposite side, and it is built so that I can lay in a couple pieces of 3/4 plywood across the aisle and toss a full sized inflatable mattress on them. For those rare times when I would have company! LOL. Hey, it worked! I framed out the window with the microlam strips then drilled the window frame and siding then used 8X3/4 inch stainless steel screws to attach the windows. Or4iginally they were just sort of sandwiched in with the only thing sealing them was the butyl tape that was in there. Over the years due to settling, wood rot, and vibration over the years. they were leaking every time it rained! 

      The main problem with mine is the roof is cracked between the roof AC and the old vent for the refrigerator.. so there is a few bad rafters in there.  I think the roof is sagging, because all my verticals have weight on them. I haven't even had it started in about 2 years. Need to get back on it.

     Got to go, talk to you later. Kirk.

I just fininished up messing around in there. My roof has no cracks except in the gelcoat. Funnily enough it's the opposite side as yours. My problem area is between the door and the AC unit. The gelcoat has cracked up like a dry river bed in about a 3x2 foot area. Some water has got in over the years and the top is a little soft. The inside skin is super thin right were the entrance wall support is glassed on.
The material that's sandwiched between glass layers has basically moulded and rotted away.
Anyways the rafters seem good still. I'll probably glass a layer on the outside before I seal the roof. I was just up there putting the AC and 2 vents back in.
Decided today to basically put it back together how it was on the passenger side.
On the drivers side I'll frame in a fridge to get the roof support back. Also need to add a water tank ontop of the wheelwell and probably put a bench back in there.
What I dont have are the raised sections
for the passenger seat dinette and kitchen area. If I thought I'd ever find a passenger seat to match the drivers I might have. Ha!
Also after all of this is done plus all new plumbing I'd love to do something with the windshield. I heard the best advice when buying an old RV is to make sure the windshield is in great shape because if it isn't then all your renovations are for nothing if it breaks and you cant replace it.
Mine is delaminating and a bit cloudy around the edges but no cracks. Would love to pop it out and put a new seal in but figure it would probably crack. Right now the rubber is so bad it looks like it's about ready to fall out LOL. Any idea what else this shield was used in? I know Grumman didn't have it specially made. All the glass companies say its obsolete but maybe that's because nothing come up in their database under grumman motorhome. I expect it was used in a shoolbus or fire truck or the like and they are just sitting around somewhere.
LOF didn't keep any records.
Wow. That was a long reply!

Hi Paul,

      Sounds like you're coming along well with your project. I wish I knew more about fiberglass work. I ground out the crack in mine and tapered it, then laid in new cloth and built it back up to maybe even above the original thickness. It looked OK, but now it's leaking again. I think the problem comes from the roof flexing as the rig goes over bumps in the road. There is body twist, and I don't know of any way to eliminate it.

     My old gas/12V refrigerator stopped working, I priced new ones and was astounded by the cost of the RV units. So, I went to the local Walmart and bought a small dorm style 'fridge. I think it's 6 cubic feet or there abouts, it has worked out really well for me. When it's packed full of food for a trip it will stay cold for quite a while. I usually have shore power available where I go, so, I would stuff the fridge the night before I was leaving, so it would be good and cold when I hit the road. I have since installed a generator, so I'm ready for more long distance trips!

     My front passenger seat is the same captain's chair style as the driver' seat. ?The dinette is on the lower level behind the front raised floor.  The old Krager Koach I have uses the dinette seat for a pas. seat. it flips over to face the front.  I'm not sure which type I like better. They both have their advantages!

    I don't know if the Grumman delivery vans, or other trucks used the same glass in the windshield. Mine are getting discolored along the edges too. Years ago, when I was a kid my Dad used to have glass made for our trucks at an auto parts store back home. They could cut the glass, laminate it, and bend it to fit whatever the need was. That place is long gone, but it always intrigued me the way it worked. I don't remember the mechanics of it though. It seemed to have some kind of heated bed that the glass was placed on, then somehow it would roll up to make the needed curve. This place basically would make you a new windshield as you waited! In this "modern" world, I wonder if anything like that exists anymore.   Take care,   Kirk 


Here are some pics of the ceiling.

The first 2 are at the bathroom the next 2 are at the entrance wall.

On the bathroom I have put up the new partition ( shower side ) in the same way as the other.It still needs attaching to the side wall and bunk base of course - when that gets remade What you will notice is that the wall barely touches the truss.

On the front by the door its kind of hard to see but if you eyeball the the ceiling inline with the door frame you'll see a screw hole where that wall was attached to a 1x1.

You'll also see discoloration where the partition entrance wall was against the ceiling. The final picture shows that that wall wasn't directly supporting the truss either. It was attached about 6 inches forward of the truss on a piece of ply that was glassed to the truss. If you look close you'll see the spacing pieces that slid between that ply and the ceiling.

That part of the ceiling is soft and those spacers have pushed thru. So it doesn't offer any support anymore if it even did in the first place.

I'm going to beef it up and add support where I can. And sure with all of the benches and bases and cabinets it would have offered a stronger base for support but I'm thinking either they didn't plan ahead or just didn't take care putting it together.

Every now and then it oil cans on me and I about crap myself! LOL Its usually when Ive ran the ac for a while. There's no insulation down that one wall and I guess the cold temp pops it just enough to frighten me to death! There is no visible movement but you can for sure hear it! A big scary DONG! noise.

You'll also see in the last 2 pictures where the ceiling is back inside. Obviously got wet and turned to mold inside. Ill reglass the top and seal it with tropicool. Inside maybe ill just coat with Kilz?

I would try and cut it out on the inside and replace but I don't know how to defy gravity and glass a ceiling!

I have to get the old genny working at some point too. Just bought an apartment fridge like you after looking at RV fridge prices.

On the glass. Yes that's how they did it pretty much. This glass is LOF (Libbey Owens Ford ) Company has been bought and sold, then part of Pilkington, which is now part of a Japanese glass parent company.

I did all of the emailing and calling that I could to that company and also every vintage RV glass supplier and all came back with the same answer - obsolete.

But the replies were instant like they typed it in a database under Grumman and it didn't show up. The company that now owns LOF said if didn't keep any of that companies records.

There is a College somewhere that has all of their records ( Wisconsin maybe )

But I'm not going to fly there and sift through boxes and file cabinets in the basement. LOL

They key is finding the other vehicles that windshield was used on to cross-reference from.

Maybe I should put a picture up and ask 'does your windshield look like this?" and see if anyone on the forum responds?

Well that's if for now.

More to follow... Ha!

Hi Paul, 

       When I did the inside of my roof, I took a piece of mat, cut it to fit, then set it on a sheet of cardboard with some wax paper between them, wax side up. Then I mixed a batch off resin and soaked the mat with it. Once it was ready I just lifted it up  and stuck it to the underside of the roof. Then squeegeed it to get any air out of the joint. Then I did the same with some cloth. I don't know if that was the right way to do it, but it sort of worked, and I didn't have to wear too much of that damned sticky stuff! 

      I took down the overhead cabinets over the kitchen and dinette area and rebuilt them. They had cardboard on the backs to close up the curved area  behind them. It was bad from being soaked, so, I got a sheet of that thin plastic they sell for milkhouse walls and such. It is thin enough to form around the curve, and isn't going to be affected by any water that leaks in. 

      I have seen pictures of International Motorhomes. I'm pretty sure they were made from the Metro bodies, and those windshields look close. I know Grumman also made Step vans and Fire trucks. Maybe there's something surviving from them

Well, I need to get out to the shed and feed my cats, I'm not looking forward to that, it's only 1 degree out there. You take care, catch you later. Kirk


I was searching the web today looking for anything Grumman motorhome related. Found and old post from a guy in Brooksville FL saying he had a 1973. Post was back in 2002. Long story short he said he blew up the 392 then put in a 345 and scored up the pistons using stainless rings and was looking for another engine. Well Brookville isn't a million miles away from me and seeing how rare these are I started to worry.
Called the guy I bought it from and told him the story. He swore mine has the original 392 with 70k original miles.
Got out the wire brush and the camera.
ID plate says
It doesn't mean it's the same motorhome.
In fact I just called the guy I bought if from and he got it in 1995 so it isnt.
But it made me check and now I'm lost.
So now I'm wondering if I should even bother doing anymore work on this. Will the 304 even have the guts to pull this thing?
Is there any chance I read the plate wrong?
Any thoughts?

Hi Paul,

    Is that the number that's on the right front side of the block under the alternator?  Sure sounds like a 304 to me. Has it got a 2BBL. carb? The 304 doesn't have the power of a 392, but they did OK! I wonder why someone would go to all the work of changing the engine and only use a 304. A 345 would have been a better choice. There were a few 345s that were rated at more HP than the 392. 

     Depending on if you plan on towing anything the 304 might surprise you. I once gave my nephew a ride to Ft. .Benning, GA, towing my 24 foot flatbed trailer with his Chevy 1 ton monster truck and a bunch of stuff in it. The old 392 definitely had her work cut out, She was working so hard pulling up Lookout Mountain that she blew a couple spark plugs right out of their shells. The crimps on the plugs softened up enough that they let the insulator part of the plug blow out! Man was it hot changing those plugs! Of course they were the ones on the drivers side where you can hardly get your hand between the floor and valve cover!

     I have my doubts if a 304 would have got us to the top! I estimate we were pulling close to 5 tons though. But it should do OK on level ground. You could possibly find a 392 to put in as you go along too. There were a lot of them out there, But look for a '74 or 75 "Improved Cooling" version. I have a 392 that used to run good in a 1971 Kragar Koach that I'[m going to be junking. It's been sitting for years and I haven't turned it over, so it might be stuck from sitting. 

      I'm just wondering, you said maybe you read the plate wrong? There shouldn't be a plate, it should be stamped into the block itself. Right front top of the block, just under the head. Good luck!  Let me know how it turns out.   Kirk


Hey Kirk.
Yes its stamped into the block. I'm on my phone and dont have the option to upload an image. I'll do so tomorrow when I'm back at work on the desktop.
I spoke to the previous owner. He told me he bought it in 1992. Supposedly he followed the the guy home for 45 mins down the interstate doing 70mph plus.
It has a 4BBL Holley on it which he says was on it when he bought it but yes I also read that it should be a 2BBL if it's a 304.
So I'm totally confused. I dont know how much is BS and how much is him not remembering correctly.
The way I see it,is if It did run and shift and travel at highway speeds, then I'll keep at it.
Out of interest what speed did yours do with the 392 ?
Is 70mph doable?
I'm over the annoyance of it and just looking to move on with what I have.
Maybe it's a hotted up 304 given the 4BBL
and itll be great or maybe I was just fed a line of BS. It would be nice to know. Lol
Thanks again Kirk!
Oh and maybe I'd be interested in that 392!
Are you scrapping the whole Kragar? That's the one with the cool rubber suspension rright? I was thinking about looking into that.

Hi Paul, 

      I've never heard of a 304 with a 4BBL, I wonder what manifold is on it? I don't think a 345 is interchangeable with the 304, Strange!

       My Grumman seemed to be happiest at 65 to 70 MPH. And got her best gas mileage in that range too. I used to get 10 MPG most of the time. I once took a trip to Texas in a blizzard, with a top speed of 35, pulling my 24 foot trailer, and averaged 3 MPG. The old girl DOES NOT like slow!

     Yes, I'll be scrapping the Kragar. It has a wooden framework body with fiberglass over it. The wood is so rotten that the windows are popping out from it sagging. That Mor-Ryde suspension is really neat, but the rubber block pieces are no longer available, some of then look like they are separating, with the rubber coming loose from the steel parts. like an old motor mount used to do. It sure did ride smooth though.  I never had that one on the road, but a run through my back field that would shake the grates off the stove in the Grumman , hardly even rattled anything in the Kragar!  I think now days some kind of air ride would be really the way to go.

     Now that I'm fully retired, I'll have time to get some of my projects done, I hope! I want to re-model the kitchen area in the Grumman to use the eyelevel oven that was in the Kragar, along with the engine powered water heater, it uses a built in heat exchanger with engine coolant circulating to heat the water. Great for when I'm on the road, but I'll still need the gas heater when parked. There were lots of cool things in the Kragar that the Grumman does not have. There is a gauge panel that has level gauges for all the water tanks, and propane tank. That might be useful in the Grumman!

      If it ever gets back above freezing I can get started on some of my projects. This Winter has been rough, and there is a ton of snow on everything! I haven't even been over to my garage in over a month! I'm hoping for some warmer weather so I can plow open my driveway!  How's the weather by you?     Well take care, and stay warm. Catch you later.




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