1975 GMC Glenbrook

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Wow, I can't believe I haven't given a Glenbrook update since last May. After a long, arduous spring of maintenance on the Palm Beach, it pooed the bed in June, so the Glenbrook stayed in service for another summer. We did quite a few trips camping, towed the toad, towed the boat. It did well overall.
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My daughter and I even did a trip to Breitenbush on our own--a nice quiet weekend with the dogs while the other halves were absent.
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Repairs and upgrades were kept to a minimum, as the Palm Beach is supposed to be our new, main coach. The Glenbrook was tucked away for winter (and by that, I mean left out in the weather, but given a nice dehumidifier).

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Then the wife wanted to go camp near a wrestling tournament just after Christmas. So, I dewinterize and start draining all the antifreeze out of the freshwater lines and into the black tank. Then I hear everything running out on the ground. That's no good. So I backed the Glenbrook up onto some large timbers to take a look:
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Yep, that stinks. I verified with acetone that my tank is not ABS, so it is likely polypropylene. So I've got to weld it up in a tight space. The crack runs across the top of the flange, right where it meets the tank. It seems the PO didn't support the macerator install quite as well as I would like.
 
The Glenbrook has sat for a bit, since I really didn't want to deal with the black tank. I did manage to get a new carport for it (or the Palm Beach, or whichever one leaks the most I suppose).

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I now have access to a lift, so we put it up in the air last night to get a better look at the black tank. I'll probably get cracking on this over the weekend. I prefer to use the airless plastic welder for small, odd-shaped repair work. That will be tricky in this tight space. I'm considering using the hot-air plastic welder instead, and making a custom bent nozzle for the job. I'm less handy with that one, but I really don't want to pull the tank.
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Repairs and upgrades were kept to a minimum, as the Palm Beach is supposed to be our new, main coach. The Glenbrook was tucked away for winter (and by that, I mean left out in the weather, but given a nice dehumidifier).

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Then the wife wanted to go camp near a wrestling tournament just after Christmas. So, I dewinterize and start draining all the antifreeze out of the freshwater lines and into the black tank. Then I hear everything running out on the ground. That's no good. So I backed the Glenbrook up onto some large timbers to take a look:
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Yep, that stinks. I verified with acetone that my tank is not ABS, so it is likely polypropylene. So I've got to weld it up in a tight space. The crack runs across the top of the flange, right where it meets the tank. It seems the PO didn't support the macerator install quite as well as I would like.
You will not be able to weld the Polypro without a cover gas shield. I know, I tried and finally took the tank to a local plastic fabricator. If you want to make a try that just might make it, try using West System G-Flex after flame treating the tank and flange material.
Matt_C
 
I finally got time to weld up the the flange crack on the Glenbrook's polypropylene tank tonight. It was a pain getting everything out of the way (plumbing, propane line, crossmember) but it went very well! I'd say it's better than new at this point, as it now has a proper fillet for reduction of stress concentrations, as well as mesh reinforcement. It was very tedious, and I think I probably used up half a dozen PP filler rods. The Polyvance airless welder ended up being the only tool one I used.
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The crack ran all the way across the top and around each corner a bit, mostly right where the flange was welded to the tank shell. Honestly, the factory weld didn't look all that great. They definitely do it quickly with some sort of extruder laying down beads, but there's no blending to the shell. No wonder it cracks with such a thickness mismatch. It did last quite a while, and the PO did indeed mount things without supporting them well, so I guess I can't complain too much.

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I grooved out the crack with the hot iron, and filled it with the melted rod. Then I filled the valley with more material, smoothed it over, tacked some mesh reinforcement in place, then started working it into the fresh surface from the middle of the bead outward, wrapping the flange edges and spreading up onto the original tank surface. This flange feels SUPER solid now, and no longer deflects like it did. I think I'll get one of those inexpensive flange adapters like @tmsnyder used, and use a Fernco to go from there. No more stresses on this tank! It should last indefinitely from this point forward.
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Once it was all structurally acceptable, I kept the surface warm and did another skim coat over everthing to ensure the mesh was well buried everywhere, but it looks like I didn't get another photo afterwards.

Oh, and I dug a large McDonald's cup out of my friends trash and cut it down to plug the opening (funny enough, it was PP so I could've even tacked it in place if I'd wanted). That really helped cut down on the smells since it was a very close-quarters repair.
 
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I spent some more time on the Glenbrook this weekend. I'm supposed to be selling it, but it may have to serve as our backup camper (despite being the main one for 4 years now) if the Palm Beach doesn't pan out. The Glenbrook needs to come off the lift to make way for the Palm Beach, so it was time to hammer out a few things.

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I had a tough time finding a new seal for the output flange on the black tank. The old seal deteriorated during the cleanup process. I eventually ended up with a nice, fat Caterpillar o-ring from the local auto parts store (that leans heavily toward Ag). They end up with lots of extras from cylinder rebuilds. This one was about 3.5" ID, and about .270" thick, and is nice and plush but also feels very robust. Fingers crossed, it'll do the trick.
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Things are all mounted and supported, much better than before. I used rivnuts into the thick aluminum floor plate this coach happens to have. Ace HW supplies a ridiculously heavy-duty plumbers strapping that is hard to cut and hard to bend, so I used some of that. It's like no plumber's strapping I've ever seen!
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I needed to rework the generator exhaust too. It had taken a hit, and needed some straightening out along with some more legitimate mounting and support. I had a lot of scrap u-brackets laying around that fit conveniently, and some cut-up '78 square body bed-mounting bolts. Keeping things period correct, of course!
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So the back end of this coach is officially sorted out and squared away underneath. Next up is repairing ladder mounting holes and getting the ladder back on there.
 

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Camping season has commenced, and the black tank repairs have been successfully tested! Not one little drop has been detected. Nothing but fun to be had on this trip to the coast.

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Another camping trip in the books for the Glenbrook. This time we went to Silver Falls. I added an electric water heater element to the mix--worked great for the first time in the 5 years we've had this thing. A Camco 04363 fit right in. $15, why didn't I do it sooner? I also fixed the toll window latches with custom mounting hardware. Some 3/16" Chicago screws and some 1/4" plastic bushings from Ace, trimmed to length.


And the day before the trip, we adopted a third dog who's super obese. He fell right into the groove, and is a very sweet guy. He really, really loves the motorhome too.
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I was working on it the night before the trip, and he barged in and took a 4 hour nap. He's spent more time in there than the house! Adding his 127 lbs brings us to 295 lbs of dog. I guess it's time to start factoring them into my payload calculations!
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Poor guy has not been well cared for, but he has a great spirit. He's very, very happy and well adjusted. He's not lazy either, and seems to want to join in on all the activity. He hiked a couple miles with us, waded in streams, and probably had the best time he's ever had. I'm hoping he has hypothyroidism. We're familiar with managing that with our other dog; time will tell.
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It's been a long time since I've done an update on the Glenbrook, since I've been primarily focused on trying to get the Palm Beach sorted out. The old Glenbrook has continued to serve as the faithful backup whenever the Palm Beach has a false start. :LOL: But I'm starting to trust the Palm Beach a little more, so I started getting the Glenbrook ready for sale. My plan was to fix things I'd been "living with" while we camped in it over the years. In a twist of fate, I ended up finding new owners for it without even listing it for sale--or perhaps they found it? In any case, I'm continuing to prepare it for the transfer of ownership.

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The new owners opted to go with some new ION wheels and some fresh tires. I'll be mounting those this week. I'm doing all new brake shoes, a new bearing, new seals, and new parking brake cables on the rear axles. I'm trying to get any necessary maintenance performed before it departs. They'll finish up on the cosmetic stuff and fix it up over time.


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One of the glaring issues was the incomplete floor in the rear bedroom area. I also didn't like how tall the benches were with a flat floor, and determined about a 2.5" raised floor would be ideal. I decided to make a tool storage area out of it. I really like it, and will be doing the same thing in the Palm Beach now.
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The missing wall panel was also a big sticking point, so I've got some luan plywood fitted to that area. Outlet box was fixed up--there was all sorts of strange PO work to undo there. The new owners will take it from here and decide on coatings/coverings for the lower walls and finish up the upper walls. I did manage to recruit a helper one night (actually, he was driving his mother insane and they needed some time apart). We trimmed out the edge of the wall and floor at the door opening with thin aluminum to clean up the edges. I really like how it worked out, and will need to do the same to my Palm Beach now (this is a recurring theme, I really should be working on the one I'm keeping :LOL:).
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I also robbed the dining table from the Palm Beach (which was previously robbed from this Glenbrook). I've always been one table short, but didn't want to make that their problem. I can build something for the Palm Beach if I have to. The old, worn Canyonlands dinette furniture got a quick and dirty covering somewhere along the way. We're not going to call it upholstery or even a proper slip cover, but it's an improvement for now. Function is the name of the game.
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New clearance lights were also added to the front. The old ones were cracking, despite being LED replacements from the PO. The color of those always seemed a little off--I wonder if they were cheap? Anyway, looking better now.
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I also pulled the front ceiling cap out of my parts coach so it could be used in the Glenbrook. The installation will be left up to the new owners. I'm recommending a central support to prevent sagging, and integrating an overhead console. This should take a lot of the stress off these perimeter-mounted headliners. But, the overhead console ought to be done the way the new owners desire, and I didn't want to make all those decisions for them. The front cap was vinyl wrapped at some point in the past, and they did a really nice job. Then they painted/dyed it white, except where the other parts of the ceiling overlapped it. The new owners can decide on their own color if they wish. I also got some new visors for the Palm Beach, complete with vanity light. Hopefully it cleans up OK--it's just a bit dirty.
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Paul,

You scared the crap out of me. I saw the new owners post that he bought your coach. I was very saddened. Now I am so happy to hear you still have your coach and that it was your spare coach you sold.

Good luck to him and I'm happy you are still around.

Take care and stay healthy.
Tom K.
 
Paul,

You scared the crap out of me. I saw the new owners post that he bought your coach. I was very saddened. Now I am so happy to hear you still have your coach and that it was your spare coach you sold.

Good luck to him and I'm happy you are still around.

Take care and stay healthy.
Tom K.
Thanks Tom, and not to worry--I won't be going anywhere. I have an uncurable GMC disease. ;)
I've actually had four GMCs for the last 5 years or so. The Glenbrook was my first about 6 years ago, and has been the primary, reliable one this whole time. The '76 Palm Beach is my new primary one, which I thought would be easy to get on the road, but ended up taking a couple years. I also have a '78 Palm Beach which made the ultimate sacrifice to keep the '75 Glenbrook and the '76 Palm Beach in good order. It's mostly just a shell with an incomplete engine and trans at this point. And finally, I have a '73 Painted Desert 23-footer in poor condition sitting on the back burner. I hope to see if it can be resurrected, and send it on down the road.

Maintaining two complete, operable, good GMCs has been a lot of work, so I'm excited to pass one of them down to a nice local-ish family. Perhaps they'll join here and continue the thread.
 
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"By signing this Bill of Sale, buyer agrees to join The GMC Motorhome Forum"
"..and contact the Cascaders.... " 😁

I mean, with multiple owners in the same city, it would be of benefit to them to avail themselves of the resources. :) I have been proposing a Eugene/Springfield meet-n-greet for a while....
 
"..and contact the Cascaders.... " 😁

I mean, with multiple owners in the same city, it would be of benefit to them to avail themselves of the resources. :) I have been proposing a Eugene/Springfield meet-n-greet for a while....
Dust off the Willamette Valley group and create an event--it can't hurt to try. The new owners have already joined...
 
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