The main disadvantages are parts non-availability and the final cost of a reliable conversion. In a discussion on the Flxible Clipper, one owner said that restoring a Clipper is not for the faint of heart or the shallow of pocket book. The Flxible highway coaches, MC-5A, MC-6, MC-7, GMC PD3751, PD4501, PD4104, PD4106, PD4107, PD4903, PD4905, Eagle 01, and the Eagle 05 are all examples of classic coaches that many people love and recommend to others. Twenty years ago these were good choices for a conversion, but today new parts are hard to find and for some even used parts are getting scarce. Twenty years from now one should expect to replace major systems because of the non-availability of minor parts. This can be a significant problem when something breaks 1000 miles from home on a short vacation.

People have been updating engines and transmissions for years, and other systems such as axles, brakes, and steering can also be replaced. I am not saying that antique shells should not be considered, or that present conversions in them are valueless. However, anyone starting a new conversion should consider the future problems and costs.

If your goal in building a conversion is to travel with a family and complete the trips in your available vacation time, you need a coach that will probably not break down. If it does, you must be able to find parts and service quickly, anywhere in the country. This generally means that newer is much better than older. Even if the part can be found somewhere in the country, it still takes time to locate the part, get it ready to ship, and to get it to you. This can make a substantial dent in a two-week vacation.

Our first coach, a 1951 GMC PGA 3301 had a GMC 503 in-line six engine that went out of production in the early 1950s. Though it was only 20 years old when we got it, parts for the engine simply were not available, and I was forced to replace the engine and transmission to preserve the coach as a maintainable vehicle. Because of this experience, I would not consider converting a bus with an engine or transmission that has been out of production for more than a very few years. Even if parts are available today, they will probably run out ten to twenty years after the final production. Obtaining simple parts will become a major problem. For another example, I've been told there are no more unused transmission or differential parts available for the GMC 4104. Owners are searching the bus salvage yards to find very expensive used parts. In a few years, even these will be gone. Many people are replacing the engines and transmissions in 4104s with current models; however, this is a very expensive job. When I was considering an MC-5C, I got an estimate to replace the 6V71 with a 6V92TA. Because the engine compartment had to be enlarged, the estimate was $22,000.

Last spring we were about to take our 1951 GMC to the Bus Bash in Columbus, OH. Two days before departure, I was adjusting the brakes when the treadle valve gave out. I took the valve to a store that specializes in air brakes to get a new one. The man behind the counter had never seen one like it, and he had been there almost 30 years. He said that it had been several years since they had a single valve treadle valve, as the industry went to dual valve systems in 1976 per Federal direction (one for the front and one for the back). I had to buy a new dual valve, parts (fittings) to put a Y in the air line going to the valve, and a new pedal as the old one would not fit. In addition, my old valve was not acceptable as a core, and I had to pay a $28 core charge. The new valve is smaller than my old one, and I had to make a steel plate with holes on the outside to fit the holes in the floor and holes on the inside to fit the new valve. Needles to say, I did not get all this done in time for the Bus Bash and we had to get a room in the motel and go by car. What should have taken half a day and cost $86 took almost two days and cost over $200.

Even coaches that we think of as almost new have problems because of their age. I needed a new skinner valve for the Detroit 6V92TA in my 1981 Phantom (a transit). The old one leaked air when the engine was off. Three days ago I went to the local Detroit dealer to get one. They said they probably would not have one for anything that old, and they didn't. They had no record of the valve ever having been made. Part of the problem is that it is 24 volts. I later found a 12-volt one in a salvage yard and took the parts I needed to fix my 24 volt unit ($20). I called the Detroit dealer to see if he had a new 12-volt one based on the number from the one in the salvage yard. They did have a record of it, but had no idea where to get one. Fortunately, Gillig is still very much in the bus business and a call to the parts department found that they have several new 24 volt ones, just like the one in my Phantom. However, they want $117.40 plus shipping across the country. I don't know if that is a good price, but it seemed like a lot for this small unit.

I would suggest that there are several levels of parts availability. Level 1--Almost all running gear parts are available locally. Level 2--Parts can be found somewhere in the country using the standard parts' channels including Wilson Detroit, International Bus & Parts, Universal Parts, etc. These parts must be shipped in. Level 3--Parts are not available through standard channels and you have to know some guy who has a barn full of old parts or you find a used part in a salvage yard. Level 4--The part cannot be found. One must be made or something similar must be modified to do the job. This may involve replacing major systems (like a transmission) due to the non-availability of a small, but special, part.

As a coach gets older, more and more parts fall into a greater problem category. This results in more time being spent looking for them and much more money being spent to get them. While I could find some parts for the 1951 locally (the wheel bearings), most parts were definitely in the level 4 area. Even my 1981 Phantom is in the transition from level 1 to level 2.

I expect that I have heard at least 100 times that parts will always be available for the 71 series Detroit diesels, and I expect that many parts will be available for some time, but they will run out eventually, one part at a time. Having had a slight problem with the Skinner valve for the much more modern 6V92TA, I find it very hard to accept the confidence many people show toward the 71 series. Incidently, there are very few salvage yards that have buses. Often the part can be found at a truck salvage yard if it was also used on highway tractors.

If the challenge of keeping an antique coach on the road excites you, go for it. For less than $4000 you can have it shipped home from anywhere in the US. That is using a shipping company, not a towing company. That gives you time to find the parts, make new ones, or modify similar parts and fix it. I had to do that once with the 1951. If like me, you have gotten too old for that kind of thing, get the most modern shell you can.

If you must stay below $50,000 for your conversion, there are newer coaches available, which make fine conversions, often for under $5,000. These are transit buses and some snub-nosed school buses. While there will always be problems finding parts for any bus, these coaches have much newer running gear than a highway coach in the same price range. For further information on this subject see the article here titled "Low Cost Conversions". For detailed information click on the link to the Epic Conversion Support home page for information on ordering the Coach Conversion Note titled "Low Cost Conversions."