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Brekjeck

New member
Jan 11, 2025
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Hello all,

My name is Brian and just acquired a 1976 26’ Palm Beach. Has just over 100,000 miles on motor and full rebuilt transmission from around 2021 with hardly any miles put on after that.

I live in Buda, Texas (Just South of Austin in Central Texas).

Coach appears to have been a Texas coach all of its life.

I have great paperwork on it. I have every manual and lots of correspondence going back to the 1980’s. I’ll post about all that in the future.

I have a family and two kids. Looking forward to getting this coach back to great condition so we can have fun with it.

Currently there are multiple issues I need to address and lots to learn. Will have to drop the tanks, drain and inspect. About 35 gallons of old fuel in their.

The journey home was about 70 miles from Killeen Texas to Buda. Multiple times the engine (strong sounding) died out multiple times due to contaminants getting in the fuel filter near the carb. Learned real quick about that system and swapping out the filter and nylon ring.

The bags are after market single air bags by CONTITECH? They seem like they are kinda small compared to others I have seen. Currently having issue with them maintaining air over days. I have paperwork from a few years back that said an RV shop replaced the “blue line” but discovered multiple other air leaks and they recommended changing all of the lines.

Other than that I have to reinstall the black tank and macerator.

Has a newer ONAN 7000w generator. I fixed some grounding issues and it sounds like it wants to turn over but isn’t.

Small leak in driver side rear coming from roof. Most likely at the ladder / railing point.

I have made some new friends already that have been amazing help learning so far. Excited to be here and look forward to meeting y’all soon.

I’ll post pictures when I can get some links.IMG_2250.webpIMG_2251.webp
 
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The leak in the rear is most often caused by the aging or missing caulk under the rood rail end caps. There is a ~3/4" hole under the cap where the rear fiberglass section joins the metal main body. Reef out the old stuff and fill up the hole with polyurethane.
 
Welcome and congrats on the new family coach! There are a few of us hauling youngins around.

Post a pic of your airbags and we can help let you know what you've got. There are several different common conversions, and a few of them come with bracketry that adapt shorter bags into place. They all have their pros/cons, but they keep the GMCs on the road--most importantly.

For your air leaks, the lines themselves don't often go bad. Connection points sure do. Get some leak tester and start spraying down every connection and every fitting. Check valves, pop-off valves, solenoids, control valves, tees, etc. Most systems have been customized by the time someone gets to bag-swapping, so it could be tough for us to tell you exactly what you have. On a '76 you would've started out with the Electrolevel rather than the Powerlevel, so you'd have 6 solenoids that could be leak sources if it's still stock-ish. It's easy enough to pipe in a 1/4" NPT shrader valve on the stock bags and fill them manually while giving yourself time to troubleshoot the stock system.
 
pvfjr said:
Welcome and congrats on the new family coach! There are a few of us hauling youngins around.

Post a pic of your airbags and we can help let you know what you've got. There are several different common conversions, and a few of them come with bracketry that adapt shorter bags into place. They all have their pros/cons, but they keep the GMCs on the road--most importantly.

For your air leaks, the lines themselves don't often go bad. Connection points sure do. Get some leak tester and start spraying down every connection and every fitting. Check valves, pop-off valves, solenoids, control valves, tees, etc. Most systems have been customized by the time someone gets to bag-swapping, so it could be tough for us to tell you exactly what you have. On a '76 you would've started out with the Electrolevel rather than the Powerlevel, so you'd have 6 solenoids that could be leak sources if it's still stock-ish. It's easy enough to pipe in a 1/4" NPT shrader valve on the stock bags and fill them manually while giving yourself time to troubleshoot the stock system.
Click to expand...
There is a valve adjacent to the bag installed so manual fill can happen. I have so much to look at it’s all a bit over whelming. Will have to tackle it system by system. I have a nail that needs removed in one tire. Bags deflate after a few days sitting so that’s not going to work.

Was going to have two jack stands in the rear take the weight off the coach while in storage since the bags aren’t working correctly.

Luckily my storage unit is less than a mile from my house, I’m able to bring the coach home, repair and return till I figure out something better.

The bags aren’t working single bags made by CONTITECH. I would like to upgrade to quad bags. I have to research the whole system.

Any recommendations on a leak detector etc.

I’ll be going over the forums on all of the new owner stuff.
 
One quick tip, get some solid wood blocks with handles that slip right under the central bogie bracket whenever you park. If they fit with a little gap at ride height, it's convenient to remove them once your coach is aired back up. Then if the bags leak down, fine. If they don't, also fine. If the blocks are tight, you know you've leaked down. If they stay loose, then you're good to go.
 
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Here's some air leak troubleshooting I did a few years ago with some example leaks:

The Ferrigno Family's 1975 GMC Glenbrook

Last night I took the distributor apart and swapped the pickup coil. At first, I couldn't get the distributor to turn. The calipers revealed that the old pole piece had 1.456" between the peaks on the pole piece, which left .005" or so of clearance against the tips of the opposing teeth. The...
www.gmcmotorhome.org www.gmcmotorhome.org
 
Brekjeck said:
There is a valve adjacent to the bag installed so manual fill can happen.
Click to expand...
If there is a Schrader connection installed, there's a good chance someone also installed a shut off valve. If this is the case, you may find that the bags hold air and the leak is in the lines and connections (so you can fill, shut off the valve, and the bags will remain filled).
 
kidjedi said:
If there is a Schrader connection installed, there's a good chance someone also installed a shut off valve. If this is the case, you may find that the bags hold air and the leak is in the lines and connections (so you can fill, shut off the valve, and the bags will remain filled).
Click to expand...
Yes, that is also what I believe. There appears to be shut off valves adjacent to the shrader valves. They are kind of goofy looking circle turn ones and it is hard to tell if they are open or closed. I did turn them and could hear the air coming out and then turned them again and no air. There is no clear marking on them so it is hard to tell if the valves might be open just enough to allow air to leave. I could definetly replace them with a better system and go from there.
 
pvfjr said:
One quick tip, get some solid wood blocks with handles that slip right under the central bogie bracket whenever you park. If they fit with a little gap at ride height, it's convenient to remove them once your coach is aired back up. Then if the bags leak down, fine. If they don't, also fine. If the blocks are tight, you know you've leaked down. If they stay loose, then you're good to go.
Click to expand...
Nice tip thanks
 
Brekjeck said:
Yes, that is also what I believe. There appears to be shut off valves adjacent to the shrader valves. They are kind of goofy looking circle turn ones and it is hard to tell if they are open or closed. I did turn them and could hear the air coming out and then turned them again and no air. There is no clear marking on them so it is hard to tell if the valves might be open just enough to allow air to leave. I could definetly replace them with a better system and go from there.
Click to expand...
Swapping them out with a half-turn or quarter-turn valve is a good idea (easier to use; probably more stable). The block under the bogie plate is a more sure-fire solution for long term parking, and a lot easier than blocking up the whole vehicle.
 
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kidjedi said:
Swapping them out with a half-turn or quarter-turn valve is a good idea (easier to use; probably more stable). The block under the bogie plate is a more sure-fire solution for long term parking, and a lot easier than blocking up the whole vehicle.
Click to expand...
I actually pulled the trigger on the quadra bag system and am going to swap the whole thing out.
 
pvfjr said:
One quick tip, get some solid wood blocks with handles that slip right under the central bogie bracket whenever you park. If they fit with a little gap at ride height, it's convenient to remove them once your coach is aired back up. Then if the bags leak down, fine. If they don't, also fine. If the blocks are tight, you know you've leaked down. If they stay loose, then you're good to go.
Click to expand...
What size (height/width) blocks do you use? A pair of blocks came with my motorhome but they split and got tossed.
 
74_Coach said:
What size (height/width) blocks do you use? A pair of blocks came with my motorhome but they split and got tossed.
Click to expand...
In the photo below, you can see the 6x6" block I set the Murray on when she is parked at home. I believe they are 7.75" high and give about 1/4" clearance from normal ride height (Measure you own to get an exact height for your coach). I slip them under the rear bogie mounts and release the rear air suspension any time she is parked for more that a few days at home.

DSCN1084-small.webp
 
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RF_Burns said:
In the photo below, you can see the 6x6" block I set the Murray on when she is parked at home. I believe they are 7.75" high and give about 1/4" clearance from normal ride height (Measure you own to get an exact height for your coach). I slip them under the rear bogie mounts and release the rear air suspension any time she is parked for more that a few days at home.

View attachment 14212
Click to expand...
What a fine looking coach! Those rare Alcoas!
 
GMCMI Spring 2026 Rally
Applied GMC

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