Newbie bought 4103

[Dave5Cs]

And 40 non valid ones, 

[ol713]

    Hi and welcome;
          As for my two cents worth, keep in mind the fuel pump.  Depending
          on how old it is, the new fuel can eat the diaphragm on an old fuel
          pump.  Good luck and keep up posted on your trip home.  A few
          photo's would be great also.
                                                 Merle.

[luvrbus]

    Hi and welcome;
          As for my two cents worth, keep in mind the fuel pump.  Depending
          on how old it is, the new fuel can eat the diaphragm on an old fuel
          pump.  Good luck and keep up posted on your trip home.  A few
          photo's would be great also.
                                                 Merle.

I don't think he will have that problem on a gear type fuel pump

[bigred]

I read what you guys are saying about additives ,but surely for a bus that has been sitting for a number of years ,dumping a gal of Marvel Mystery Oil into the fuel wouldn't hurt ,or would it?? Come to think of it they may not make this stuff any more but it will make things slick as snot on a door knob!!!!We used to Use STP to massage the main bearing and rod journals and used the MMO to massage the rings.Sure would make a rebuild turn over!! Had a guy one time that used the STP to massage the rings ,but that's another story!!

[chessie4905]

I would loosen the oil drain plug a couple of turns to check for coolant in pan. Maybe having it hauled to your destination on a low boy or wrecker would, in the long run be a better deal. Pull the valve cover first thing to see how everything looks and check the rack movement.

[opus]

YES, check the rack for sure!

[chessie4905]

And, I would see if it it going to start and run properly before putting in new oil. Also when ready to drive, go easy for about 10 miles without revving it up high or working it hard. Even then out on the road, keep the speed and rpms down. Long way to your destination. What plans do you have in case of major breakdown partway to your home?

[Archer]

Thanks everyone for your thoughts.

Couple more questions-

What is the unladen weight of a 4103?

I realize with the seats out, it would be somewhat less, and with tanks and furniture and appliances, somewhat more that somewhat less.

Looking at tires that are load range G and load range H.

Any thoughts on that?

Also, batteries for running lights and engine cranking, what are options some of you have gone with? Do I need a full set of truck batteries, or will a couple "standard" 12 volts work?

[daddysgirl]

This is just my humble opinion.

I think a good starting point for weight is the bus ID tag. It should tell you weight, per axel. I realize that was for in-service use, but until you have the bus weighed, it'll do.

As for tires, get the best you can possibly afford. New on the front...always. No re-treads. ALWAYS keep them properly filled. And replace them before you head home with the bus, if possible.

I keep my engine and external light batteries separate from my "house" system. MC8 used 2 8D start batteries placed in the right front. I keep them there due to weight equalization, lessening any fire hazard and I figure the engineers of that unit had a reason.... Whatever you do will be good for you. But read the books before making crazy huge changes.

[RJ]

What is the unladen weight of a 4103?

This was never published by GM during the 4103's life.  However, using the federal bridge weight limit laws, your coach (unless otherwise noted by builder, which is wasn't), you're limited to 12,000 lbs on the front axle and 20,000 lbs on the rear, for a total of 32,000 lbs GVW.  At the first chance you get, run it across a CAT scale to find out it's current weight.

Looking at tires that are load range G and load range H.

Your choice and your $$.  Gs are less expensive than Hs, so unless you're going with marble floors and granite counter tops, you probably don't need the extra weight capacity of H range tires.

But more importantly, you need to look for tires that match the original revs per mile that GMC designed the powertrain around, which is 495/mi.  Keeping as close to that number as possible will give you performance similar to when it came out of the factory.  11R22.5, 12R22.5 and 11R24.5 are three common sizes that bus nuts use on their GMs.  You'll also find that the trucking industry is finally getting around to metric sizing, so if that's what you're being offered, remember to choose one that's as close to 495/mile as possible.

Also, batteries for running lights and engine cranking, what are options some of you have gone with? Do I need a full set of truck batteries, or will a couple "standard" 12 volts work?

Two Group size "8D" were the standard batteries on your coach.  If you live in milder climate, two Group 31s are a common substitution, and much less expensive. 

IIRC, a 4103 is a POSITIVE GROUND coach - double check carefully before hooking up new batteries!!  You don't want to let the smoke out of something by hooking the batteries up bassackwards!! (Many folk have converted 4104 and Scenicruisers from Positive to Negative ground, the "how-to" info's out there.)

FWIW & HTH. . .

[Archer]

Hi Team-

Getting ready to fly out late Sunday night to begin this adventure.

Bought online a CD that has 1378 or so pages of photocopied pages of GM manuals for this 4103. A lot of late night reading...

The bus has the original disposable element filters for fuel and oil. I am wanting to take spare elements with me, as the nearest auto parts store there is an hour away, and the industrial parts houses even further.

The part numbers I have gleaned from the cd for filter elements are: air 12.7410, oil 8.4300, fuel 12.0880, and fuel injector 12.6800. These don't seem to correspond with anything on an internet search, and I was wondering if any of you have numbers to ask a vendor.

I am going to check with some local dealers when they open up later today, but I like having too much information rather than not enough...

Two five gallon pails of Delvac 1240 waiting at the oil distributor's will call for pickup on Monday. 

Thanks in advance.

[Archer]

PS, anybody have a part number for wiper blades?

[wildbob24]

Archer,

Those numbers look like group numbers from the parts book. Definitely not part numbers.

Try these Detroit numbers:

Oil: 5573014
Primary Fuel: 5574961
Secondary Fuel: 5574508

Those numbers have probably been superseded, but should be able to be cross-referenced.

Wipers I can't help you with. You'll probably have to match them up at the parts store.

Bob

[Archer]

Bob-

Thank you. Just now (Sat Night) getting back to the bulletin board, flying out Sunday night. The local Detroit Diesel house got me an oil cartridge and a fuel cartridge, they are in the car and not handy for numbers. He was of the opinion that primary and secondary fuel filters were only available in spin on style.

Offhand, what would the cooling system capacity be, so I can get sufficient antifreeze?

Thanks again,


Tony

[wildbob24]

Tony,

Your local Detroit guy is misinformed. The original filters, both primary and secondary, were cartridge style and should still be available.

I believe your cooling system holds about 14 gallons, not including the cabin heating system which adds another 3 or 4 gallons.

Scott Crosby should have a better feel for that. Perhaps he'll chime in.

Bob