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Old 11-06-2014, 11:53 PM   #21
Crown_Guy's Avatar
Join Date: Dec 2013
Posts: 40
Year: 1989
Coachwork: Crown Coach
Chassis: 40ft 3-axle 10spd
Engine: 300hp Cummins 855
Rated Cap: 91
Re: 72 Crown Supercoach RV conversion

Those "dangling boxes" are relays. the black one looks familiar and you can look on it
for a manufacturer and part number and Google it to find out the function and screw terminal
leads and what they are for. The shinier ones are a little unclear in the pic but again it's
most likely a relay of some kind. Usually they were used for things like the High Beams,
Turn signals for sure, School bus red light flashers at the roof front and rear, maybe the
door solenoid valves, (unless you have a manual air valve and no buttons) there can be many
uses for the relays and that style was in wide use at the time for all manner of vehicles,
including highway buses and trucks too. The black one is probably a Delco and the part
numbers were very specific to their function. There are plenty of new ones available which
will work and replace the older ones just fine. This is one place to find just about everything
you could ever want.

In case you wonder where all the fuses might be for the whole bus, you're looking at them
right under the switches on the removable panel. That is a row of self resetting circuit
breakers and they are used for all the major vehicle circuits. I believe those are also still
in use with little change and widely available or update-able. You can most definitely re-purpose
or add as many switches and goodies as you can make room for. That's what makes it so much fun.
It's your bus now, have a ball. You may have a short somewhere or an unknown constant load from
something that's being left on and that's where the zap is. By the way, you sound like you've
been driving it, correct?, then whatever the problem is isn't major but could keep your batteries
from staying up. You might consider adding a proper battery disconnect switch for when you park
it. That flat upright piece above the batteries would be a good place to mount one. All highway
coaches have had one for years and some Crowns as a custom add-on. Cole-Hersee has many types to
choose from. You'll like that site. If it's a serious current draw and you can't find it with a
meter, it might be worth having a shop check and verify all is well and get you a known good
baseline anyway. As for securing the dangling stuff, that's what the holes are for and screws.
No magic, and you can consider mounting them in different locations in there if you intend putting
more gear in this area. Simple housecleaning and tying everything back down so it doesn't rattle
or short out. It's definitely a valuable area and you will be finding many reasons for using it
to your advantage. Like the man says in previous post that's an extremely simple and uncluttered
setup. If you want to see a real rats nest check out any highway coach from about the last 60 years.
That will make you feel much better about working on a Crown.

If I may address the transmission again I think I left out your question regarding how and what
kind of temp sensor to install. The short answer is that there are most likely already tapped
and plugged holes in strategic locations on it's case. If not then drilling and tapping holes
is straightforward and again there are flat sections in the right spots on the case to put the
sensors. These transmissions were meant for trucks and temp sensors were very needed. There are
two basic kinds of sensors, direct reading with a tube and gas in it, or an electrical type that
uses wires to the panel gauge. They both use the same threads and sensor size to screw into the
unit being monitored. All are readily available new or as take-outs from a salvage yard.

You made the comment about only having a "basic" Crown. I'd like to make you feel better by stating
that all Crowns were hand built (literally) by craftsmen, and they were all basically custom orders
to the owners specs. Through the years a de-facto standard configuration emerged where most all school
districts and some contractors always seemed to order the same popular features. This became a sort
of baseline standard with no extra frills. Everything was open to customization and every Crown
usually had some measure of changes from the standard which made them different. In no way would any
of that detract from the underlying superior engineering or materials used.

One important consideration would be the top end road speed found in Crowns. A school district would
have no need for a bus that could go past 60mph since 55mph is the legal limit for a school bus. A
contractor/charter operator would be able to go the legal 65 mph as long as the school signs and
lights were covered. Then it was just another charter bus and not a school bus. That's why a Crown
ordered by a school district would probably only have road gearing for about 62mph and a Crown
built for a charter operator usually was capable of at least 70+mph. In the case of a school district
it may have been ordered with only a 5-spd transmission since that was standard and all they really
needed with the 220 on normal flat ground school routes. If it was a mountain district or a charter
operator they may have ordered the RT-910 and better drive-ability for the Cummins in the mountains.

It's possible that a previous owner exchanged for the Road Ranger but that begs the question of why
he didn't get an overdrive RTO at that time. Maybe couldn't find one, or he had this one for cheap,
no way to know what the story may have been, and doesn't really matter now. You can make any changes
you want and if you're happy with it, and it goes like you want, that's what really matters. Just be
clear that there is no such thing as settling for a "basic" Crown. It's just the way it was spec'd
when built, and it's by far a very common setup. It can be customized and changed any way you want.

A large majority of Crowns were used by school districts and have a similar set of options. It is
the exception to be able to find one that was built for a charter contractor with extra goodies and
usually higher road speed that makes them good to find. All it really means is that WE don't have to
spend any money or effort to make the changes for what we want, a higher speed, customized Crown.

I got lucky and found a very special one from a California desert school district that was built with
factory air conditioning, an overdrive 10-spd with 85+mph road gearing, and a powerful enough engine
(torque)that would pull and sustain those road speeds in overdrive. That's why I grabbed it because I
knew anything else I found I'd have to make the changes, and spend the money and effort, myself.

One other observation about your spare tire situation. This may sound silly but you may just want to
consider not carrying a spare at all. In a worst case real emergency you'd lose a front tire, at speed.
Modern tubeless tires don't "blow-out" usually, they tend to deflate slow enough that with power steering
you can usually get it stopped safely. If you survive all that drama you've lived through 90% of the fun.
Assuming you don't make a habit of going to the most remote possible locations 100 miles from help,
then a cell phone and nearby tire shop/truck stop would be your next step. They all have mobile tire trucks
that will come to you (even in the boonies) and make short work of your problem. Even if that doesn't
work, you should remember that you have four tires/wheels on the rear axle. A Crown is nowhere near
heavy enough that you can't get away with taking off an outside dual and using it up front, or if a flat dual,
just keep driving. That means it's perfectly OK to single out a dual and keep on driving for help if you
have to. Nothing spectacular or dangerous, and if you are worried, just keep your road speed down. I've
done exactly this in a few situations and have driven with a flat dual all day until I got back to the
shop. All you need worry about is if it starts getting hot or spinning loose on the wheel which you can
check periodically by stopping occasionally and feeling it with your hand. Usually Murphy is in charge
and an inside dual goes, which makes having a comprehensive set of tools important, run-up blocks etc.
if you have to remove it. In my experience when I've had tires go it was usually possible to keep driving
until I could reach the closest professional help. If you make a determination to acquire and install good
quality new tires all around (mandatory on the front), I'm quite sure you could drive that bus until the
7-8 year time limit stamped on them expires. With new or nearly new tires all around I dare say that short
of a catastrophic road hazard type situation, you may never have any tire issues. With what a Crown weighs
and the amount of miles you could possibly put on it, it is a flea bite compared to the average mileage
put on them when in revenue or school service. I doubt you could even put visible wear on the tires for
personal use. They should easily go 80-100k miles on a Crown.

I don't intend to keep a spare on mine. It's installed behind the front bumper on a winch arrangement,
laying flat, under the entrance steps. Since I have eight tires on the rear axles and I can use the spare
tire space for other "stuff" which I really need the room for, I'm inclined to just leave it home and
carry enough tools and such to switch and move wheels around if needed.

I hope this gives you some insight and comfort in your learning curve and what to expect as you gain
experience owning a bus. Rest easy that a Crown is the simplest, easiest to maintain, and reliable bus
of any make ever built. I have been able to limp home with a Crown that any other make would have made
me call a lowboy tow operator to get it back. They are just right for a private owner to take on, and if
taken care of should survive both you and your kids. They are much less trouble than any modern motorhome
of any kind. You'll find with time that everything you may need is still available or replaceable with
something still being made. Have fun and enjoy the total driving experience of getting a Crown on the
road. There's nothing like them. I've driven every kind of highway coach and I still prefer the Crown.
Pure fun and predictability in it's handling. They drive in the mountains like it's on rails and you can
really do extraordinary things with complete confidence once you get comfortable with it's size and all.
For me a 35ft Crown is like a sports car, especially after herding 45ft 102" MCI's around San Francisco.
That's real work, and planning to stay out of trouble. No worries in a Crown though. Have lots of fun.
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Old 11-08-2014, 10:31 AM   #22
Bus Nut
Join Date: Oct 2011
Location: Snowflake, Arizona
Posts: 316
Year: 1996
Coachwork: Blue Bird
Chassis: All American Rear Engine
Engine: C-8.3-300 Cummins MD3060
Rated Cap: 40 Prisoners
Re: 72 Crown Supercoach RV conversion

For you crown enthusiasts there is a couple of 1983 Crown school school buses up for auction on in washington state they are automatics with
6v71 motors. One has 350k miles the other has 390k.
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Old 11-10-2014, 10:47 AM   #23
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Join Date: Mar 2011
Location: Houston, Texas
Posts: 4,340
Year: 1946
Coachwork: Chevrolet/Wayne
Chassis: 1- 1/2 ton
Engine: Cummins 4BT
Rated Cap: 15
Re: 72 Crown Supercoach RV conversion

One more Crown for sale --- and, only $7 bucks!.................(ya, it's a toy, but a cool toy).
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Old 11-11-2014, 01:06 AM   #24
Join Date: Sep 2014
Location: Portland, OR.
Posts: 40
Year: 1972
Coachwork: Homemade
Chassis: Crown Supercoach
Engine: Cummins NHH 220, E-F10spd
Re: 72 Crown Supercoach RV conversion

I finally took a picture of the bus out in the open, it's been stuffed in the driveway since day one.
Also a link to my fiancÚ's blog about the adventure.

Check out our new house! It's going to have a tiny studio inside as well. Can't wait for our adventure. Check out our progress at
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Old 01-16-2015, 06:24 PM   #25
Join Date: Sep 2014
Location: Portland, OR.
Posts: 40
Year: 1972
Coachwork: Homemade
Chassis: Crown Supercoach
Engine: Cummins NHH 220, E-F10spd
Thank you! This has been like going to school again;) I'll get the oil analysis done soon.
Working on the ceiling, seems to be a pretty involved project but maybe I'm making it harder than it needs to be.
discovered a leak from the park brake control valve, if the air system has air the exhaust hose from the E brake lever is hissing, with brakes on or off. The guys at the part store are telling me there is no bolt on option for a new E stop valve but my best bet is a Bendix 065661, any one know of a good replacement or fix?

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Old 01-20-2015, 08:12 PM   #26
Jerry Campbell's Avatar
Join Date: Dec 2003
Location: Summit, Oregon
Posts: 117
Year: 1975
Coachwork: Crown
Chassis: Supercoach
Engine: DD 6-71N
Nice bus. Your going to love it.
I don't know what you decided to do about your spare tire. BUT, I carried mine around for a few years and finely gave it away. In 12 years I've had one flat on the rear and a bulge on the rear. You're going to have to call some one if you have a problem so you might as well tell them to bring another tire. The secret is new tires. They don't appear to wear at all. We are on our way to southern Georgia from just south of Portland. We are in Tucson Now.
Jerry and Patty,
1975 two axel Crown 6-71.
Good Luck
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Old 01-28-2015, 09:11 PM   #27
Join Date: Sep 2014
Location: Portland, OR.
Posts: 40
Year: 1972
Coachwork: Homemade
Chassis: Crown Supercoach
Engine: Cummins NHH 220, E-F10spd
I haven't sorted out the spare tire but I did just put new rubber on her all around, today while driving home from the tire shop the bus started making a grumble/rattle noise when revved up to 1600rpms or above. I'm super freaked out as I'm planning on getting on the road for a cross country trip NEXT WEEK.
She was running really good and I recently adjusted the idle to fix the stalling issue (once warm it would die when I let off the throttle)
I removed the bolt over the idle adjustment screw on the fuel pump and turned the idle screw a 1/4 turn and heard no click like I was told to expect, the idle is up maybe 75 rpms and dosent die like before.
The more I drive this bus the more I hear and notice, I think the governor isn't doing anything because I have on occasion (while in gear, up hill or flat land) ran the tach up to 2500rpms and didn't notice any sort of governing action.
Please help me, I'm so stressed out about how much I've spent on this thing already and the road trip across the country to start my full time job next week.
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Old 01-28-2015, 09:12 PM   #28
Join Date: Sep 2014
Location: Portland, OR.
Posts: 40
Year: 1972
Coachwork: Homemade
Chassis: Crown Supercoach
Engine: Cummins NHH 220, E-F10spd
Oh, the noise is comming from the engine I believe but it's hard to tell.
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Old 01-29-2015, 09:03 AM   #29
Jerry Campbell's Avatar
Join Date: Dec 2003
Location: Summit, Oregon
Posts: 117
Year: 1975
Coachwork: Crown
Chassis: Supercoach
Engine: DD 6-71N
Peace of mind to me is very important on a long unknown journey. I've taken mine to Southern Oregon Diesel in Roseburg on my way out of town for at least 10 years. Oil change and everything adjusted and inspected. When I leave I know I'm as good as can be. It's usually a few hundred.
Good luck my friend,
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Old 02-06-2015, 02:28 PM   #30
Join Date: Sep 2014
Location: Portland, OR.
Posts: 40
Year: 1972
Coachwork: Homemade
Chassis: Crown Supercoach
Engine: Cummins NHH 220, E-F10spd
The noise turned out to be the hold down bolt on the fan.
I'm on the road to wilkes barre PA, right now I'm in hermiston oregon.
All the gauges are reading good but I was noticing that this bus does not smoke while driving or pulling a hill. It's alittle smokey out the tail pipe but not noticeable in the mirrors. Everyone said it would put out a contrail up the passes. The top end was rebuilt/ remanufactured and new injectors 10k miles ago by the school district just before retiring.
Also one of my buzzers went off after the first 150 miles, and a red light at the control panel. All the fluids are good and no crazy gauge readings so I unplugged the buzzer. 200 miles later that light is still on and very little oil consumption.
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