A SUPERIOR COACH
by Peter Sprouse, 1996
I'd heard that the lads had found a Power Wagon school bus, but I really couldn't believe it until we pulled into the driveway at my new home in Austin. That was in 1973, and that bus has certainly been some places since then.
It began as all buses begin, as a cowl and chassis shipped from Detroit in 1954. It's destination was the Superior plant in Kosciusko, Mississippi, where it was fitted with a bus coach called the Pacer. Correspondence with Superior prior to their demise indicated that only about 100 of these bodies were manufactured, and only a few were put on a Power Wagon chassis. The only chassis modification made at the coach plant was the addition of a massive steel channel welded onto the Power Wagon frame. This provided a level platform on which to mount the coach. This bus was shipped to a school district in or near Waco, Texas. Sometime after it was surplussed, it came up for sale on a street corner in South Austin. Some cavers bought it, then passed it on to some other cavers whom I knew when I came into the scene two years later. Our plan became to fix up this bus to use on our caving expeditions to Mexico. It was to be a group project with about 8 or 10 of us kicking in money for shares - a Power Wagon commune of sorts. Periodically we would have bus meetings where the big ledger book would come out, and those of us who had any money would reach into our pockets to finance the replacement transfer case or whatever was needed at the time.
First off we pulled the flathead six out on a rainy fall day. Someone knew someone else who "got his thumb caught in the steering wheel" of his '66 D100 pickup and rammed a tree with it, probably helped along by some beer. Out of this we got a 318 V-8, an NP435 transmission, and top-mounted foot pedals. These items were transplanted into the bus along with the 12-volts electronics. The bottom rear of the vehicle was trimmed off to provide a better angle of departure, as school bus bodies weren't really designed for off-road use, and it looked quite a bit better for it too. Since it had a lot of rear overhang, a rear bumper was designed which had a large skid plate built into it. After about four months of work we were ready for our first caving expedition. This test drive lasted about 5000 miles, and included of all places, Iowa, and the bus performed fine. Throughout the mid-to-late seventies the bus ranged all over between the Canadian and Guatemalan borders. A fair amount of time was spent under the hood, but the bus always made it home.
After a high-speed split ring blow-off and other highway instabilities we decided to put dual wheels on the rear axle. The bus is a heavy rig with lots of human lives on board, and a blow-out at the wrong time could be a disaster. Besides, with the wide bus coach the single wheels were already tucked back under it, so duals would look right as well as add stability. This was initially accomplished by grinding the rivets off a pair of rims, moving out the centers as far as possible, and welding them back together. By downsizing to 7.50x16 tires this would allow enough tire spacing. Some mudflap rubber was used to fashion rear fenders. Standard dual lug nut adapters were available at the nearest big truck parts house. Later on this setup was refined by going to ½ ton WC rims. These rims were made to dual up 7.50x16 tires. Dave Butler has pointed out that these rims were not designed to fit over the larger Power Wagon brake drums, and warns against drum cracking if they don't bolt down all the way with the lug nuts. After bolting on the inner rim, one can use a feeler gauge to check clearance between the back of the rim and the drum. To be sure of clearance, I've taken to grinding a little bit off the lip of the rim where it threatens to touch the drum lip. While this may lead to early rim failure, that was no longer an actual safety threat since a spare was now built in. In addition, real fenders were constructed out of M37 rear fenders. As everyone knows, WM300 rear fenders are extremely scarce, but M37 fenders are readily available. Then a running board of plate and pipe was constructed to connect the front and rear fenders. This improved the appearance immensely, and gave it a real Power Wagon look.
The years passed, and one of the bus owners bought the others out, and moved back to his farm in Kentucky. The bus was relegated to hauling tobacco to the barn, and never made it out again to the caving meets. More years passed, but I didn't forget about the bus, and in 1991 I approached the owner about bringing it back into service hauling cavers again. A deal was made and I traveled up to Kentucky to bring it back. It was up on blocks, brakes and hubs apart, where it had sat for 8 years. Rust was taking its toll in the humid environment, but fortunately the engine and axles had been turned periodically. As I had been unable to come up with a hauling rig, I had to get the thing running to get it to Texas. I'd enlisted the help of a few friends, so for the next 5 days we set about putting it back together. It was a thrilling moment when the bus pulled out under its own power and we test drove it down to Paradise, the place Mr. Peabody's coal train had hauled away. My crew shook their heads as I insisted on giving the old bus a wash before heading down the road toward Texas. It seemed to be doing fine at first, but halfway through Tennessee smoke began pouring out of the exhaust. But it still ran, so we continued on south, adding oil frequently. Near Dallas considerable time was spent fiddling with the distributor, which finally came back to life. At long last we reached Austin, a long 1000 mile trip at 45 miles per hour.
All things considered we did amazingly well taking a vehicle that hadn't run in 8 years, working on it for 4 days, and driving it 1000 miles with few problems. Now the gradual task of renovating the bus began. Removal of the intake manifold revealed a broken valve, a common occurrence with idled engines. For the time being we fixed that, and changed rings and bearings, all without removing the engine from the vehicle. Rust was a serious concern, so we proceeded with body work, welding in patches and filling. My efforts at using body lead were fairly miserable, so despite my initial intentions it was back to plastic filler. Rusted areas that couldn't be removed were treated first with rust-converting primer. After shooting battleship gray paint we installed tinted glass to help cope with the Texas heat.
Finally it was time for its return to expedition use. In June 1994 the bus crossed the border into Mexico for the first time in 17 years, making a long journey across dirt roads of the northern desert on a week-long caving trip. Even with six of us on board with all our gear, plus a huge ice chest, there was room to spare. Mechanical problems were relatively few: worn points, flat tires, and a broken starter terminal. In the fall another Mexico trip proved the bus could climb steep grades in low range fully loaded, even with blow head gaskets! Travel in the high mountains showed that we had a serious overheating problem, one that would prove hard to cure. The next expedition was a long one, but thankfully flat. In a round trip to the Yucatan Peninsula we put another 4400 miles on the old bus.
As you can imagine, with 5.83 gears and 7.50x16 tires, this truck really winds out. To cruise above 50 miles per hour the old 318 would be spinning at around 3300 rpm. But still I was reluctant to give up the 5.83 gears, as I knew we would be carrying heavy loads up very steep, rough logging roads. So rather than take off the bottom I decided to add to the top: overdrive. Over an excruciatingly long period a 5-speed overdrive New Process 540 transmission was put together and installed before the next Mexico expedition. A lot can be said about this conversion, and I intend to do that in a later article. The new tranny has an unusual shift pattern that takes some getting used to, but the 18% overdrive provided immediate relief. Unfortunately the old 318 was still not up to the mountain grades in terms of power and temperature, and our journey down to the state of Veracruz was a long one. But we got there, and survived a week of caving despite unfriendly Indians intent on chasing us out. As we left the mountains the main leaf broke on the front right of the vehicle, groaning perhaps under the weight of the Braden MU2 we'd just added before the trip. So we tiptoed along to the port city of Veracruz in search of a top-notch spring shop. Mexican spring shops are well-known for their abilities, but still we had to check several before we found one who could do the job.
Manufacturing a main leaf was not a problem, but finding old-style 1 ¾ inch spring stock was. So the plan was to build the spring from 2" stock and narrow it where the bolts and straps crossed. We drove the bus into the shop and over a pit, where they attached a chain hoist and lifted the front end. Soon a crusty old mechanic had the rusty bolts loosened and the spring stack on the floor. When the main leaf was extracted from the stack it was strapped on the back of a motorbike and rushed off to the spring factory. This would take several hours so we took a cab to the beach for seafood and margaritas. When we made it back to the shop the new spring had not yet arrived, but in due course it did and the craftsmanship looked fine. The thought crossed my mind that perhaps I should have ordered some spares while I was at it, but all things considered I'd better just be glad to get on the road again. Before long we were, after paying the unbelievably low bill of $15. I really should have ordered a spare main leaf!
Northward we headed along the gulf coast, with the rear end getting ominously louder. We stopped to check the u-joints, but that wasn't it. While we pulled the rear drive shaft an M-601 passed, but he didn't stop to offer us a third member. With the rear shaft out, the bus drove quietly in front-wheel drive, so that is how we drove the next 800 miles back to Austin. Except for a shudder while coasting with gears loaded, it did pretty well in this mode. With the new overdrive tranny, we pushed 60 mph in front wheel drive at times!
So finally the time has come for a new motor. I guess one every 20 years is not too extravagant. The biggest small-block Chrysler seemed a good choice, so a 1974 model 360 was found and bored and balanced. This is being assembled at the moment, along with a re-cored radiator with enhanced tubing. An oil cooler will probably be installed as well for additional insurance. So look for the newly renovated Power Wagon Bus at upcoming rallies.