Towing anything with a GMC is problematic I would caution. The engine and transmission are carried as a single unit by a cradle sub-assembly. Designed to be quickly removed as a complete power package and replaced with another rebuilt ready to go sub-assembly. This was one of the nicer aspects of the GM coaches and was a singular feature of all GM's in City, Suburban, or Highway/Parlor Car service.
Fleet operators could remove and replace the entire engine cradle in about 4 hours and get the bus right back on the road and in revenue service. Very solid and reliable design and interesting because the the whole thing was held to the bus by only 4 attachment point bolts. Two are right under the rear window and the cradle hangs from these two, and the other are at the lower front attaching to the body right at the bottom of the body behind the rear axle on the engine bulkhead.
Even as it facilitates quick change maintenance operations, it also means that the rear bumper, which is attached to this sub-cradle assembly, would be carrying all the loads for any towed anything attached to the bumper. This is NOT a designed in stress load pattern I'd ever want to add to the cradle. There just isn't any really good or proper way to add a tow capability to a GM without jeopardizing the longevity of the engine cradle assembly. Those 4 attachment bolts would be the points of maximum stress buildup and become the failures when anything let go.
I've seen, and tried to drive one, GM 4106, where the cradle was so loose it moved from side to side (left to right) right where it hung. As I tried to pull away from a curb on a slight hill, the bus didn't move, with the clutch fully out, it just sat there and thrashed around with the engine cradle jumping all around at the rear. I was empty at the time and the bus should have easily started up the hill, but all traction motion was being absorbed and translated into this weird rear-end shimmy. Once I figured out WTF was happening, I pushed the clutch in and parked it where it sat and called the shop to come get it. I'm sure this was one of the symptoms and precursors for the famous GM engine falling out of the bus syndrome which happened from time to time on raggedy ass maintained fleets, which as it happened this was one of those. Really, really, bad maintenance.
I know some guys do tow cars with their GM coaches, but I would hope they have engineered the setup to bolster, if possible, the attachment system, as well as making close inspection of the whole engine cradle and attachments a high priority as they operate the bus with the very non-standard loads and stresses. I would advise against towing any vehicle, also since the rear bumper itself is only bolted on the cradle assembly almost as an after thought with 4 to 6 bolts to some steel straps on the cradle holding it away from the cradle, not really very structural in nature or anchored to any solid bus body points at all. Just not designed for towing.
Regarding the bus where it sits right now. First concern should be the batteries and the condition they're in. The very worst thing that happens to batteries is to sit and not be driven. A typical set of brand new batteries will be turned to junk if they sit for 6-8 months without being used or charged. That's a cool $500 Bill min. Learning Experience for a set of two 8D 1300 CCAHr batteries.
Even if the engine starts and it sounds good to you, do you know what a DD 2-stroke sounds like when they're good??? Not likely, no insult intended merely an observation.
Then assuming the air system builds pressure and the air ride suspension raises up as it should, which will take 5-10 minutes at low idle. When air pressure gets to about 60psi flip on the fast idle and if that works the air will build faster and make sure it builds all the way to at least 115 psi or as high as it will go. It's important that you let it build all the way to the air governor cutoff pressure so you can see it works correctly and what it actually is set at. Assuming the air valves for the windshield wipers are leaking as the pressure comes up twist them back and forth and leave them in the counterclockwise "off" position. They always leak air until the pressure builds up and will get better with constant driving of the bus.
Did I mention that yet? you need to drive it about 50 miles a month religiously or all kinds of things will keep cropping up and causing problems. They must be driven.
The air pressure must be s high as possible when it comes time to attempt to release the parking DD3 brakes. Even if the bus starts and sounds good the DD3 brakes can make the whole thing hopeless as a moving vehicle. Push the round black knob at the right of the driver seat down and apply a FULL pedal to the floor service brake application and hold it about 3 seconds. The button should stay down (in) and when the brake pedal is released the bus should be able to be moved, the brakes are released. If they don't release stand up, exit the bus, get in your car and drive away.
If the DD3 parking brake works and the brakes are released then you can TRY to get the thing into 1st gear. Notice I said TRY. Usually when cold the clutch drags so much even when on the floor that you can't FORCE it into gear and it just grinds and won't let you do it. Many times you must stop the engine, put it in 1st gear, then restart the engine. If it won't start look for a "neutral override" switch or button and hold that down when cranking the starter, which should now work. Remember that the clutch is down and the bus is in gear now so be careful. You can now try letting the clutch up gently and see how it engages, watch out though it'll be trying to throw you out of the seat as it comes off the floor and gets immensely harder to hold as it rises up. You'll no doubt stall the engine several times as you get the hang of this.
Welcome to the FUN. From here on out it's just a matter of how much you might REALLY want to ever learn to drive the beast. That's entirely up to you.
Even if this all works OK there's another uniquely GM item which is the nature of the steering gear and how it gets the wheel's motion to the front wheels. Many GM's have some many millions of miles on them that the steering gets extremely sloppy where you might have as much as 1/4 to 1/3 or more of wheel slop making it very difficult to keep it straight and in a lane. This was fairly normal and at the time was an accepted quirk to be compensated for and if it got bad enough could be repaired and parts replaced. But today the parts are not readily available so beware of this.
There are many more gotchas and I don't really want to scare you, (too) much.
I'd pass on this one if I were you. There are so many more, newer, and better coaches, if you insist, for about the same price, which will be much better for you.
Easier to drive, maintain (as coaches go), parts and Manuals availability, experienced mechanics who'll know how to work on them, the list is long. You don't need this kind of brick in the face pain for a first bus experience.
You might want to consider a nice run of the mill well regarded school bus to start off with and learn your "Lessons" on a much less rabidly vicious and quirky vehicle. Believe me that's enough trouble you don't really need but you'll have anyway.
Since I'm totally partial to Crowns which is obvious by my posts, which I recommend you find and read, I'd say that you couldn't go wrong with a well taken care of Crown in good running condition and properly maintained. A Crown has one big advantage that almost all the major running gear components are off the shelf major heavy duty highway truck components still in common use and readily available today. So getting stuck on the road makes it easier, not perfectly worry free mind you, but much better to find parts and service if needed. You can't even say this about all the various mass produced school bus makes. They are usually built on medium duty truck chassis and getting those parts may or may not be to tough, but the school bus body application makes some parts rather more difficult. Plus they have model year styling issues where specific parts are model year specific.
Crowns don't do that and throughout most of their production years they were very much the same styling and body wise and used the same parts.
Crowns are NOT, by any stretch, the cheapest way to go, and you'll pay a premium for what they represent, as they are the absolute best engineered and manufactured coach certainly of any school bus, and they hold up extremely well when compared to true highway coaches like the GMC, MCI etc. They can outlast your lifetime and many will be around for many decades to come, plus they are so well done that I like to say that a Crown will always get you home, and if properly planned, maintained, and you carry some key parts with you, they won't strand you on the road in the middle of the night somewhere. Plus good ones are getting harder to find so the prices are rising as supply dwindles.
That should be worth considering since you plan on taking the family all around. They are superior road buses and a true joy to drive. They can be had with stick shifts or Allison automatics so anybody can drive it. They can be costly to fix sometimes, depending on the problem, just like any heavy duty vehicle but nothing like any coach would ever be. When a Crown is fixed they tend to stay fixed due to the simple systems and over engineering. Usually you don't have to worry about that problem again while you own the Crown since you can't drive it enough to reach the level of service miles they are designed to deliver.
If you should be interested in either a Coach or Crown, contact me directly and I'll look around for you to see what's available. By the way you haven't said where you're located. I can try to get you in touch with operators who would like to sell their vehicles.
mikemcc2k@yahoo.com
