1958 gmc 4104 motor - Looking for input on bus I am considering to buy

[rmelkbusorbust]

1958 gmc 4104 motor was rebuilt about 25000 miles ago. $10,500. mostly converted with some solar and has been used to boondock which is our goal for off grid living. it's aluminum no rust. titled as an RV/antique. It is a detroit 671 diesel with a 4 speed transmission. It has air brakes. 35 ft.

Thoughts? Help, please! I really want this bus but we are newbies and nervous! They say they paid $15000 for shell and now selling because they want a different body style and they've found what they want and want to buy it.

[bigskypc50]

From what I have seen that's not a bad price, I would want to see some paper work on the rebuild and check the age (dot dates) on the tires and if that all checks out go for it.

Hope you do go for it!

Originally Posted by rmelkbusorbust

1958 gmc 4104 motor was rebuilt about 25000 miles ago. $10,500. mostly converted with some solar and has been used to boondock which is our goal for off grid living. it's aluminum no rust. titled as an RV/antique. It is a detroit 671 diesel with a 4 speed transmission. It has air brakes. 35 ft.

Thoughts? Help, please! I really want this bus but we are newbies and nervous! They say they paid $15000 for shell and now selling because they want a different body style and they've found what they want and want to buy it.

[rmelkbusorbust]

Originally Posted by bigskypc50

From what I have seen that's not a bad price, I would want to see some paper work on the rebuild and check the age (dot dates) on the tires and if that all checks out go for it.

Hope you do go for it!

The seller says: It was rebuilt when I got it. So I don't have the paperwork. Sorry.

I asked about the rooftop AC - he said It has one good one and one underneath it isn't working

Seller says: I build custom Harleys in Harley parts for a living.
Has no manual - The manual wouldn't do much good at this point as I have replaced pretty much every wire and hose in the whole bus
I made it so the whole chassis runs on only 8 wires that way it stays simple
The whole bus will actually drive with only one wire that's not turn signals and lighting of course but it will move on only one wire. Its a 35 foot. Yes it will run 65-70. It was a tour bus so geared for highway driving. Brakes are all drum and were in good shape last time I checked them. I have put many miles on it since then.
I do all the maintenence on it so no records. The tires are all in really good shape. Doubt youd need to change the for at least 5 years

[magnakansas]

I urge you to go to youtube and check out "bus grease monkey" you will get an idea of that engine, and those kind of busses.

william

[bigskypc50]

I don't know, my gut would say to maybe skip that one if the guy cut up all the wires and etc might make service a nightmare down the road. I mean it's a 58 so likely only had a few dozen wires at most from the start.

With that new info I would have inspected now, before you pull the trigger.

Originally Posted by rmelkbusorbust

The seller says: It was rebuilt when I got it. So I don't have the paperwork. Sorry. I made it so the whole chassis runs on only 8 wires that way it stays simple. The whole bus will actually drive with only one wire that's not turn signals and lighting of course but it will move on only one wire.

[Mekanic]

ain't nothing inherently wrong with aluminum bodys. In fact i like them. the body on My URV is a 1988 U-Haul aluminum box. It weighs 3000 lbs.
I had to pay $1500 for it due to the price of aluminum scrap at the time.
The really good new it it will NOT rust.

A 6-71 is a fine diesel engine. Just make sure you keep oil in it and you put the correct oil in it it as well.

lots of info here on the 71 series
https://en.wikipedia.org/wiki/Detroit_Diesel_Series_71

[bus-bro]

You better like to drive a 4 speed Spicer transmission. Not your smooth shifting syncro box. No power steering, unless added later. Original engine non-turbo charged. Has airbags, and obselete airbrakes (hard to get parts). Many used buses are said to have a recently rebuilt engine, so without documentation that means nothing.

I'd love to have a 4104, but I'd keep it as a pet.

[sportyrick]

I'd think about it, unless you are pretty handy or have a pocket full of cash you will be paying someone to do your maintenance and it will be a lot, not to mention even if you find parts they will will be made out of unobtaineium.

[Iceni John]

If there's no documentation on the engine rebuild, it was not rebuilt! Every seller like to say their bus's engine was rebuilt X miles ago, but A) how many actually were, and B) if it was rebuilt was it done right with the correct parts or not? A PD4104 is not a beginner's bus for someone new to bus ownership, nor is a 6-71 an engine for someone unfamiliar with diesels in general and with older Detroits especially. You need to research this purchase carefully, and watching Bus Grease Monkey's videos will give you some idea of what pitfalls to expect from a half-century-plus old bus of dubious provenance. My friend Jon Usle is collecting information on all surviving 4104s, so maybe he knows something about the bus being sold - he goes under the name Siberyd on the BCM forum.

Good luck, John

[Brad_SwiftFur]

I'd say go for it. 10K isn't bad for a coach style bus with a desirable drivetrain. There are clues to indicate if the engine really was rebuilt not-too-long ago - look for cleaned/repainted engine block and heads, gaskets that have been replaced, etc. The old Detroits were mechanical engines and as far as the engines themselves they didn't need any electricals at all to run - to that end some even had air starters and mechanical gauges. The fact the electrical system has been simplified would not turn me away but the quality of the conversion is something I would check out. Are the new wires color coded? Appear to be properly sized for the expected load? Routed and secured neatly? Easily identifiable for future repairs and maintenance?


Someone mentioned this old of a bus may have obsolete brakes but I'm not so sure. Ask the seller if he knows what brakes it has and how easily replacements can be had. Many of these old coaches used common and widely available parts.


These old Detriots like to rev and they are known for being loud. It's true they are not engines for beginners (though I did learn on one) and you'll want to do some research to find out exactly what you're getting into. They do have a reputation for dribbling a little oil - one joke goes "When does a Detroit *Not* leak oil? - When it doesn't have any oil left" (not far from the truth either!) but as long as you don't try to 'fix' the oil leaks and keep it full of oil and don't lug it or overheat it (rare), they'll run practically forever.

[Sleddgracer]

Originally Posted by Brad_SwiftFur

I'd say go for it. 10K isn't bad for a coach style bus with a desirable drivetrain. There are clues to indicate if the engine really was rebuilt not-too-long ago - look for cleaned/repainted engine block and heads, gaskets that have been replaced, etc. The old Detroits were mechanical engines and as far as the engines themselves they didn't need any electricals at all to run - to that end some even had air starters and mechanical gauges. The fact the electrical system has been simplified would not turn me away but the quality of the conversion is something I would check out. Are the new wires color coded? Appear to be properly sized for the expected load? Routed and secured neatly? Easily identifiable for future repairs and maintenance?


Someone mentioned this old of a bus may have obsolete brakes but I'm not so sure. Ask the seller if he knows what brakes it has and how easily replacements can be had. Many of these old coaches used common and widely available parts.


These old Detriots like to rev and they are known for being loud. It's true they are not engines for beginners (though I did learn on one) and you'll want to do some research to find out exactly what you're getting into. They do have a reputation for dribbling a little oil - one joke goes "When does a Detroit *Not* leak oil? - When it doesn't have any oil left" (not far from the truth either!) but as long as you don't try to 'fix' the oil leaks and keep it full of oil and don't lug it or overheat it (rare), they'll run practically forever.

one of the forums I go to calls then 'Road Oilers'

[bus-bro]

I'd say buy that bus if you are in love with GMC pd4104's.

Lot's of parts are going to be difficult to source on an almost 70 year old machine. Things like clutch parts are quite expensive now, along with brake chambers, glass, etc, etc.

It's also a v-drive with a counter-clockwise rotating engine. A great bus in it's era, but not something for a newbie. Unless that person is a bus-nut wannabe.

[kidharris]

Originally Posted by Mekanic

ain't nothing inherently wrong with aluminum bodys. In fact i like them. the body on My URV is a 1988 U-Haul aluminum box. It weighs 3000 lbs.
I had to pay $1500 for it due to the price of aluminum scrap at the time.
The really good new it it will NOT rust.

A 6-71 is a fine diesel engine. Just make sure you keep oil in it and you put the correct oil in it it as well.

lots of info here on the 71 series
https://en.wikipedia.org/wiki/Detroit_Diesel_Series_71

You are right that aluminum "will NOT rust". Only iron rusts. However aluminum will corrode into aluminum oxide (a white powder) just like iron corrodes into several different iron oxides (rust). Aluminum corrosion is a huge problem for airplanes around salt water and in construction when in contact with concrete/stucco or dissimilar metals, especially when it gets wet.


I have heard that is also a problem for automotive cooling systems with aluminum parts if hard water is used instead of distilled water.

[elkoskoolie]

Someone mentioned the air-bags in suspension. I believe there is also an air chamber that is metal that is prone to corrosion on these old vehicles. There is not a fuel solenoid as on most modern vehicles, instead an air valve that is electrically actuated. If it's bad it will erratically fail, shutting the engine down at random moments. I had a 4104 for a short time; it's the kind of vehicle that must become a part of you or it and you won't be happy.