Same as oil, tires or your brand of gas, folks have opinions on the rear suspension of a GMC why…. because they can. One guy feels he needs this, another doesn’t and that’s the wonderful thing about living in America… we can disagree and we don’t need to bring it to blows…. so when I give you this, remember this is MY opinion… based on decades of watching problems with the GMC but still… this is my opinion which may fly in the face of your feelings on the matter but remember that’s OK. I will however give you what I feel is a pretty compelling argument so strap in and here we go….
And the first and maybe case resting issue actually occurred last week. Many of you know Nelson W., he has come with me to many GMCMI and Western States rallies over the years 
Boy… there’s some CONFAB going on there!!! Anyway, Nelson came in HobieCat under toe Friday 
A good looking coach, we did the paint several years ago, has Alcoa LTS rims, custom rear bath…. theck out that ladder on the back… yes, Nelson has done a great job of keeping a nice GMC. And a number of years ago Nelson got into the early 4 bagger system then spent shop time trying to reinforce the 1/4″, 145psi drawbacks on them.
From one side his coach looks fine but on the other you can see wht he cut his sailing weekend short 
But wait… there’s a wheel missing… sure nuff, Nelso lost a rear wheel bearing near Tallahassee the night before 
Stopped at a GMC supporters place Marsh W. near where the failure occurred. Check out the nut welded to the spindle shaft 
So, Nelson was able to inflate the bag on the 1 good wheel on the side…. remove the backing plate for more clearance… pinch off that wheels brake line… tie wraped it all together and drove some 6 hours to safety here in Orlando. No jack required…. no changing ties… he had to go chase down the tire still sporting the brake drum… but guys, he was mobile! Try THAT with any single bag system! And the new quad bag system solves the high pressure issure having a nominal pressure of 75 pounds and the structural issue with double 3/8″ steel construction on the stationary vertical supports.
If you have a suspension like this
or this 
even an original air bag system 
you WILL be on the side of the road laying in ants trying to get going….. just pure and simple.
The new design quad bag system uses a 3/8″ steel construction with an air bag for each wheel making the coach have a totally descrete 6 wheel suspension. 
Being a true 6 wheel suspension you have much better side roll control. Towing the coach rides more stable…. less “tail wagging the dog” at higher speeds. It’s a retrofit to allow air bag replacements from Firestone “Riderite”, Goodyear, Continential or Air lift! A great retrofit to new, off shelf replacement parts AND an awesome countermeasure.. backout… second way to go when something goes wrong. For that alone this is a system you MUST have driving a 30 something year old machine to places you’ve never been!
Safety…. is the number one reason but have a new quad bag system and this should be a determining factor but all the rest of the positives makes it a no brainer in my book. Yes, there is a negative… it is the most expension of any rear suspension option you can do. Cost with the usual 6 hour installation runs @ $2200 with us.
Many of our restorations today do not have a spare tire 
A fresh look for sure. Some like the Continental look so you can still sport a spare 
and stil quad bag-it. The important thing is to prepare yourself to have issues on the road. The quad bag system goes for $1650 plus the shipping for 2 boxes 54lb. each ($110 for most of us). Takes @ 6 hours installation with no modifications or welding. Sorry but it’s the right thing to have. The quad bag system was computer failure tested and is professionally water-jet cut, welded and anodized gold zinc for a quality finish. All the parts needed come with it and you can install it with some good jacks, some 3/4″ wrenches and a few will placed cuss words…. Really … and I can talk a mechanic how to install it for you if you like. Guys… sorry but all the arguments folks come with may be valid to you…. THIS is the real thing and this is what you do. Any restoration that goes through here gets a set.
Seriously, a bone stock drive train with a quad bag, a Manny Trans, one of our roller cam motors and man you have reliability. Yes, reliability, serviceability and the ability to fix the dang thing where it drops and get back going should be the mantra for driving any vintage RV. The more reliable you can make it and vigilant for possible problems the less you will need your AAA Plus.. RV endorsement which BTW, you should have as “plan C” …… ALWAYS!
Simple… today, you need a separate air bag for each rear wheel… it’s safer, more reliable, serviceable and has better performance…. Now the last one for you Nay Sayers who say the “creep over bump” concept of the rear suspension is something you wanna keep…… go drive a quad bag system… drive it… highway, in town, sharp turns, stopping and YOU tell me that the coach does not perform better! Never had THAT happen… so you new guys who are on the fence… remember you have to do something when a rear suspension problem occurs… have tools and grease rags ready!
OK, gotta go…. Willie & Nancy’s frig and galley cabinets are coming out well….. 
I’m cutting in the systems control panels today 
. and Willie is getting the galley counter together 
Here take a look at what we have 
Nothing exciting to see on Bill D. work… things are coming together soon… stay tuned.
OK.. I gotta go. I’ve had many of you wonder why I do this page and wonder where I get the time to do it. Guys… it’s sort of therapy and a way to include all of you as well as the customer in the important work we’re doing… it’s time well spent in my book. I’ve gotten many good ideas from feedback for you guys here… keep that up and I hope this too has value to you and your relationship to your vintage classic. Thanks for being a part……
