How many of us are there? Owners of Dodge based RV's?

[whiteknight001]

I'm new here, and curious.

How many of us in Class C own Dodge B300 incomplete
cab/chassis based RV's? I know two others- Steve aka
Ripsaw, with a 1977 Brougham, and Leroy aka 1978_Dodge
_Delta who owns a 440V8 powered sharp looking 1978
Delta RV. I would like to ask, and offer, help, idea
swapping and comparing notes on our particular RV's
which are based on the Dodge B300 van chassis.

Yeah, I know. These are low tech, podgy old RV's that
would be considered "entry level" for folks like me,
but I have a deep and abiding respect for the quality
of these old "monsters of the open road". And anyone
wanting to pick brains, joke about, share notes or just
brag about our old A- Dodge-io's are certainly welcome
to PM or email me. Between all of us we can form a real
good support group, and help each other with problems
we know we'll encounter with an older vehicle.

Sure. I'd love a new RV. But I'd rather have an older
one already paid for, and a lotta great memories. Call
me frugal, an old hippie, or whatever you will. I'm proud
of my old land yacht.

Mopar Madness Manifest in the flesh,

Mark aka White Knight

P.S. Mine's a '72. Is there an older one out there someone's
motorvating in? Maybe even a Travco? W/K

[Griff_in_Fairba]

Back to gauges ...

If you find you need to replace the instrument voltage limiter, be careful to get a good one. Most (all?) of the limiters in our older motorhomes are electronic and are designed quit passing current when they fail. Some of the cheaper electronic regulators currently on the market go the other way when they fail, passing 12VDC instead of 5VDC to the gauges. The higher voltage tends to fry the gauges.

I have several spare instrument clusters so I might have what you need, once you figure out your problem. If so, PM me with the year and pictures and I'll look for a replacement.

Most of our older motorhomes, as well as most vehicles newer than the mid-60s, have printed circuit boards on the backside of the instrument clusters for "wiring" the cluster.

Broken copper traces is sometime the problem with instrument clusters. Close, careful inspection, with a continuity tester is just about the only way to find these. These can be fixed several ways, depending upon the size of the break. Small breaks can be rejoined with solder. Larger breaks can be rejoined by drilling small holes on each side of the break and soldering in a short wire jumper.

Another problem I've run across is people mistakenly adding a ground wire to the printed circuit board or gauges, apparently not realizing the sensor provides the ground side of the circuit. So, look for non-OEM modifications or additions. (Typically, these changes are evident unless the person did like I do and tried for a professional looking change.)

If one of the three gauges (fuel/oil/temp) is working, your problem is probably elsewhere.

If the fuel gauge is working but the other two aren't, you probably have an engine ground problem, which is the most common problem for oil pressure and coolant temperature gauges. (Ground problems can affect only one of these gauges, without affecting the other.)

After disconnected, broken, or dirty/corroded wires between the gauge and sensor, the most common cause of gauge ground problems is the use of thread tape when replacing the sensor.

In an attempt to prevent oil or coolant leaks, many people put thread tape on the sensor's threads. Unfortunately, thread tape tends to insulate the sensor from the engine ground, resulting in an incomplete circuit. (Thread tape is the first thing I look for when chasing gauge problems.)

To test for ground problems, I use alligator clips and a length of smaller gauge wire, connecting one end to the battery's negative terminal and the other to the base of the sensor. Gauges are designed to be slow reacting so it may take a minute or so to see any change.

Be VERY CAREFUL around running engines. Most surfaces become hot enough to burn skin quickly. Likewise, the fan and belts can also inflict nasty, possibly life-threatening, wounds. Loose clothing can get caught in the fan or belts, pulling your limbs or head into them.

18 gauge wire is best for the jumper wire, but 16 gauge wire is fine if that's all you have. (The smaller 18 gauge wire is fine for the lower current in gauge circuits.) If the gauge starts working correctly, you need to figure out what's causing the ground problem.

If the jumper wire get's very hot, burns off it's insulation, and starts glowing, you have a serious engine ground problem. (This is why I use a smaller gauge wire for the jumper.) Check the condition of the negative (ground) cable between the battery and engine. (I've discussed ground connections previously in this thread.)

Note: If the sensor is hard to reach, I attach the alligator clip to a long metal object, such as a long screwdriver, to serve as a probe.

If things don't change when you use a ground jumper, the sensor, gauge, or wire between the two is probably your problem.

Start with bypassing the sensor by removing the wire from the sensor and connecting the wire directly to a known good ground. (e.g., run a jumper from the wire to the battery's negative terminal.) If the gauge's needle moves all the way to the right, you have a suspect sensor.

If the sensor seems fine, test the wire connecting the gauge to the sensor by bypassing it. Connect a jumper between the gauge's sensor connection and the sensor's stud. (You can also ground the gauge's sensor connection, which effectively bypasses both the sensor and connecting wire but won't show if the sensor is working.)

If nothing changes during these tests, the gauge itself is probably bad. If you want, you can test the gauge using two C cell batteries out of a flashlight. Connect the positive side to the batteries to the gauge's power connection and the negative side to the gauge's sensor connection. Two C cell batteries, in series, will provide 3VDC, which should cause the gauge's needle to move towards the center of the scale. (AAA, AA, and D cell batteries will also work for this test ... I said C cell because I have a Radio Shack battery holder for two C cells that makes life easier ... ideal would be one of the old 6 volt lantern batteries.)

By now, you should have found the cause of your problem and figured out how to fix it ... all that's left is some general notes.

Notice that most of the tests are done on the ground (negative) side of the gauge circuit(s). This is because the tests can be done with little or no possibility of causing more damage, as well as because this is where most of the problems exist. As I noted, too high of a voltage (i.e., 12VDC or more) can damage the gauges. Testing on the ground side allows the voltage limiter to control the amount of voltage flowing during the tests.

Most of these tests require, at a minimum, the ignition switch to be in the run position. (In most cases, gauges aren't energized when the switch is in the accessory position.) Tests that depend on the sensor operation require the engine to be running and warmed up.

Normally, I wouldn't point out the need for the circuits to be energized because I tend to think people are smarter than they actually are. However, I wound up testing someone's vehicle myself because all the tests I recommended "didn't find the oil gauge problem." He realized his mistake when I started the engine to rerun the tests. (I also knew his problem, before I started the tests, when I spotted a lot of thread tape around the base of the oil pressure sensor ... which I verified quickly by grounding the sensor's base to the engine block with a broad bladed screwdriver.)

Alligator clips on your jumper wire aren't necessary but make testing easier and safer. (I've actually used spring clothespin to hold the ends of the wire in place.) Alligator clips allow you to perform the test by yourself, without additional help, by holding the wire securely in place while you start the engine and monitor the gauge(s). They also allow you to stand back from the running engine during the testing.

While most of what I've written seems to focus on the oil and temp gauges, the same tests can be used to troubleshoot fuel gauge problems. HOWEVER, only make your connections with the ignition switch in the OFF position to reduce the chances of a spark igniting stray gasoline fumes.

Finally, you probably will want to run these tests in the reverse order of what I've written. The jumper tests towards the ends are easy to do quickly while test involving the instrument cluster are a PITA due to difficulties in removing the instrument cluster. Of course, examining and analyzing the symptoms, such as one or more gauges malfunctioning, can narrow down your search for a cause.

Questions? Anybody?

[Griff_in_Fairba]

Jer&Ger wrote:
Eyeteeth, on my first RV ('77 Dodge w/360), the previous owner had work done (or did himself) on his radiator and they put on a flex fan AND it was smaller in diameter than needed for the engine. That took me a while to figure out why mine was overheating. I even put in a brand new 4 row radiator that didn't fix the problem. Good luck on your journey. Jerry

A good example of how a change can cause more problems that it cures.

OEM radiators, shrouds, fans, and fan clutches are designed to work together to provide the cooling the engine needs. Varying from OEM is likely to cause problems unless your really, really know what you're doing. That's why I'm wary of aftermarket products intended to replace the OEM belt-driven fan. (You really need an expert's input if you're replacing your belt-driven fan with an electric fan system.)

One of the good things about living in Alaska is you can get away with a less than optimal engine cooling system.

[Jer_Ger]

Eyeteeth, on my first RV ('77 Dodge w/360), the previous owner had work done (or did himself) on his radiator and they put on a flex fan AND it was smaller in diameter than needed for the engine. That took me a while to figure out why mine was overheating. I even put in a brand new 4 row radiator that didn't fix the problem. Good luck on your journey. Jerry

[Griff_in_Fairba]

eyeteeth wrote:
Replaced the thermostat to try and cure a problem running hot. Was fortunate enough to figure out I needed a special Skirted Thermostat. It helped... but only up to about 50 mph. As soon as we got on a freeway, it shot up again. Temp reading at the radiator are around 230. Thinking now we have an airflow problem. Engine was rebuilt a few years back, the radiator was re cored shortly after. There is a transmission cooler and the A/C Cooler in front of the engine radiator... Unfortunately, I need to rebuild the cab over.. not sure I want to tackle that. don't have a place I can really do it... don't have the money to pay someone else... that is my biggest quandary...

Three things on the radiator:

1. Does it have a fan shroud? A lot of times, the OEM shroud gets broken or otherwise doesn't get replaced. The shroud is necessary to getting good airflow through the radiator.

2. The coolers in front of the radiator aren't helping. If you can get rid of them, or at least move them out of the way, do so.

3. The person who re-cored the radiator may have used the wrong core or may have installed it incorrectly. (Did the overheat problem show up as soon as the radiator was installed or later?) Otherwise, something may be blocking some of the radiator tubes. Use an infrared thermometer to spot check various areas on the radiator's surface to make sure coolant is flowing through all the radiator. (I'm not sure but I'd guess there shouldn't be more than 10 or 20 degrees difference between areas.)

As for the cabover, I don't have a garage so I do most of my work outdoors in the summer. Being in interior Alaska, that means 3-5 months maximum, with large tarps when it rains (about half the time). I tend to build small components in the winter in my 12'x12' shop or house and assemble them outdoors during the summer. (I'm working on getting more space but will still need to work outdoors sometimes.) I also have to plan for cooler temperatures (below freezing) because some materials don't cure as well.

[eyeteeth]

Been doing a bit of camping, a bit of racing, and working on little tasks here and there. Got my fridge 'latch' to actually hold the door closed when traveling. No more surprise spills. Fixed the short issue on the passenger side of the coach. Had to entirely remove the TV antenna to do it. Took much longer than expected, but it's nice having light. Still having problems with the Antenna/booster and getting power up to it. Not sure what's happening there. Replaced the thermostat to try and cure a problem running hot. Was fortunate enough to figure out I needed a special Skirted Thermostat. It helped... but only up to about 50 mph. As soon as we got on a freeway, it shot up again. Temp reading at the radiator are around 230. Thinking now we have an airflow problem. Engine was rebuilt a few years back, the radiator was re cored shortly after. There is a transmission cooler and the A/C Cooler in front of the engine radiator... We never use the AC though.. still confused. Resealed a Seam on the roof... fixed the ladder that was pulling out... remodeled the bathroom... again... thought I had the Onan fixed and running right... (nope). Unfortunately, I need to rebuild the cab over.. not sure I want to tackle that. don't have a place I can really do it... don't have the money to pay someone else... that is my biggest quandary...

[Griff_in_Fairba]

Jer&Ger wrote:
Hi Griff, Yes I found it and I hope I don't have to replace it. My big hands will never get at it. The wire is on it too by the way. I'll read your post on figuring out what's wrong now. I had to replace the front brake pads and have found out that my master cylinder is letting fluid bypass, so I'll have to replace it too. That's what I've been working on for the last few days. I'm hoping to be able to use it this weekend, so I'm crossing my fingers.

I'll get back to the gauge stuff before this weekend.

Ran out of materials, money, and tasks on the house at the same time. However, tomorrow is payday so going to town for more materials.

[Griff_in_Fairba]

regis101 wrote:
I also use RockAuto. Browsed their site. Was able to narrow things down by eliminating the obvie. I'm still gonna have to do bit of reverse engineering for my mind to make right. No harm. No foul. I'll pull a front wheel, front shock, and rear shock to take dimensions of pertinent components. It is what it is. I've been finding parts for the '72 also that make better sense. blah blah. Such is life working with forty year old vintage iron while living in a parts-is-parts world .

The calipers and rotors may have casting numbers that can help find the right parts ... especially when there's no catalog listing.

Bearings and races have numbers on them that are also most reliable for finding the right parts.

in a few cases with shocks, it may be necessary send one of the old shocks to knowledgeable people to find the correct replacements, using measurements, etc.

[regis101]

I also use RockAuto. Browsed their site. Was able to narrow things down by eliminating the obvie. I'm still gonna have to do bit of reverse engineering for my mind to make right. No harm. No foul. I'll pull a front wheel, front shock, and rear shock to take dimensions of pertinent components. It is what it is. I've been finding parts for the '72 also that make better sense. blah blah. Such is life working with forty year old vintage iron while living in a parts-is-parts world .

[Jer_Ger]

Hi Griff, Yes I found it and I hope I don't have to replace it. My big hands will never get at it. The wire is on it too by the way. I'll read your post on figuring out what's wrong now. I had to replace the front brake pads and have found out that my master cylinder is letting fluid bypass, so I'll have to replace it too. That's what I've been working on for the last few days. I'm hoping to be able to use it this weekend, so I'm crossing my fingers.

[Griff_in_Fairba]

By the way -- shock technology and manufacturing has come a long way in the last 30 or 40 years. Appropriate replacement shocks may not look anything like the old shocks currently on your motorhome. (The replacement shocks for my RM350 is considerable smaller in diameter than the original shocks.)

Also, your door tag may be incorrect. In particular, if the door was replaced, it may have a tag for a B300 with a lighter weight front axle. This is why I consider the chassis VIN vital to finding the right parts.

[Griff_in_Fairba]

regis101 wrote:
I was almost going to start a new thread since I'm having trouble with my inquiry.
I'll ask here since the issues just came up.

I am also browsing around for front and rear shocks and brake parts. Pretty much everything seems available. But I'm having trouble telling what chassis I have vs the listed axle weights. Should be simple though I would think?

I have the mfg tag on the door and it states, 3300# front and 5700# rear. GVW as mtg'd is 8300#. The rear has duals and the front is a single 8 lug typical one ton type wheel, with dog dish hub cap, not a dually style wheel.

So far, Bilstein seems to be the only one to address the 4k# or non-4k# regarding shocks. I use AutoZone as my go-to FLAPS just because. Their website description(s) can be sometimes no accurate enough for me.

Am I thinking too hard? The B30, B300, CB300, MB300 is spinning me around

B30 is either a typo or something completely different, so ignore it.

Yours is an MB300, with the M meaning motorhome.

The CB300 is virtually identical to the MB300, with the C meaning commercial (i.e., box van). Both are "cut-away" chassis delivered incomplete to secondary manufacturers for use to build a variety of motorhomes and commercial vehicles.

(Apparently, Mother Mopar came up with the "M" designation because some people had hiccups over their fancy motorhome being built on a "commercial" chassis ... Mother Mopar might have better using a "heavy-duty" designation for both, such as H300.)

B300 is simply the complete 1-ton van.

Outside of the body/coach/box, all three are essentially the same in terms of engine, drivetrain, and chassis, with similar variations across all three "models". That means the same parts fit all three, taking into account variations such as front axle weight rating.

Okay, just saw your edit. Because yours has eight lug wheels on the front, stay with the that axle rating.

I haven't much luck with Autozone, as well as other common parts stores. Their business model is heavily oriented towards cars and more common light trucks (i.e., pickups and vans). Their listings for our vehicles tend to be sparse and I've found lots of errors in the few parts listing they do have.

CSK/Schuck's tends to be middle of the road, between few erroneous listings and full appropriate listings. NAPA and CarQuest tend to be better, especially if the particular store caters to commercial trucks and/or has knowledgeable counter people.

When it comes to shocks for older motorhomes (actually all motorhomes), finding the right shocks tends to be a PITA. Shock manufacturers tend to focus on newer vehicles and, while they may have appropriate shocks for older vehicles, they've ceased listing those applications. Generally, you need a parts person who really knows what their doing and, especially, have hung onto the old PAPER catalogs.

I've had the best luck finding shocks through KYB. If you have the old shocks, see if you can find a part number. Also, see if you can find the Dodge chassis VIN on the outside of the frame behind the right front wheel. Many motorhomes have two VIN tags, with different numbers ... one assigned to the chassis by Dodge and the other assigned to the whole vehicle by the coach manufacturer. (Thank Congress and the bureaucrats for that SNAFU.)

In any case, send me the old shock part number, chassis VIN, and any other info you can find in a PM and I'll try to track down a source for the right shocks.

[regis101]

I was almost going to start a new thread since I'm having trouble with my inquiry.
I'll ask here since the issues just came up.

I am also browsing around for front and rear shocks and brake parts. Pretty much everything seems available. But I'm having trouble telling what chassis I have vs the listed axle weights. Should be simple though I would think?

I have the mfg tag on the door and it states, 3300# front and 5700# rear. GVW as mtg'd is 8300#. The rear has duals and the front is a single 8 lug typical one ton type wheel, with dog dish hub cap, not a dually style wheel.

So far, Bilstein seems to be the only one to address the 4k# or non-4k# regarding shocks. I use AutoZone as my go-to FLAPS just because. Their website description(s) can be sometimes no accurate enough for me.

Am I thinking too hard? The B30, B300, CB300, MB300 is spinning me around

Just came from AutoZone website. Looked at front wheel bearings. Looks like the 3000 and 3300 lb fronts are 5 lug. 8 lug lists higher weights than my door tag.

http://www.autozone.com/suspension-steering-tire-and-wheel/wheel-bearing-front/dodge/b300-1-ton-van/...

[Griff_in_Fairba]

PoorGary wrote:
Sorry for the delayed response. I much appreciate your parts number list which I printed and showed the parts dealer guy. He said no worrys he has all that info on his end. All parts I need where available. I was pleasantly surprised as I figured ordering parts for a 37 year old vehicle was going to be a nightmare.
Thanks Griff

You're welcome, I'm glad I was able to help and make your task easier.

Yes, it's surprising the number of parts stores have in stock or can receive quickly when ordered. When I worked at CarQuest, we sometimes had parts in stock for 50 and 60 year old vehicles, much to the customer's surprise. (Back then, a lot of vehicles used the same parts so stores don't have to stock too many parts to service them.)

[my440]

Griff in Fairbanks wrote:

PoorGary wrote:
Need to find brake pads, rotors, calipers for 1978 Dodge Sportsman.
Have not made any attempt to locate parts as of yet.
Was wondering if anyone on here has had a hard time or easy time hunting these parts down.
Thanks

2 CQ DRUMS & ROTORS YH141089 BRAKE ROTOR 1978 Dodge CB300 5.9 L, 360 CID GAS
1 CQ FRICTION GMD269 BRAKE PAD SEMI-MET. 1978 Dodge CB300 5.9 L, 360 CID GAS
1 INTERNATIONAL BRAKE INDUSTRIES 5516A DISC BR HDW KT 1978 Dodge CB300 5.9 L, 360 CID GAS
2 AUTOMOTIVE HARDWARE 13938 CONNECTING BOLT 1978 Dodge CB300 5.9 L, 360 CID GAS
2 DORMAN 484-185 BRAKE HOSE WASHER 1978 Dodge CB300 5.9 L, 360 CID GAS
1 CARQUEST Calipers 18-4076S Friction Ready Caliper w/Installation Hardware - Reman 1978 Dodge CB300 5.9 L, 360 CID GAS
1 CARQUEST Calipers 18-4075S Friction Ready Caliper w/Installation Hardware - Reman 1978 Dodge CB300 5.9 L, 360 CID GAS
2 Brake Hoses SP5586 1978 Dodge CB300 5.9 L, 360 CID GAS
2 CARQUEST Premium Bearings A35 1978 Dodge CB300 5.9 L, 360 CID GAS
2 CARQUEST Premium Bearings A37 1978 Dodge CB300 5.9 L, 360 CID GAS
2 CARQUEST Premium Bearings 15101 1978 Dodge CB300 5.9 L, 360 CID GAS
2 CARQUEST Premium Bearings 15245 1978 Dodge CB300 5.9 L, 360 CID GAS
2 CARQUEST Premium Seals 493291 1978 Dodge CB300 5.9 L, 360 CID GAS
2 Dorman HELP! 05190 1978 Dodge CB300 5.9 L, 360 CID GAS

Included parts you may not need, just in case you do. Included brake flex hoses in case yours are cracked or checked. Included bearings and wheel seals because I prefer to replace seals and check/repack/replace bearings as long as I'm working on the front end.

I assumed you have the 4,500 lbs front axle. Didn't crosscheck to see if parts are the same for 4,000 front axle so you may need different bearings, etc.

CB300 chassis should be same as MB300 chassis.

CarQuest part numbers ... other retailers should be able to cross-reference those numbers.

This is the best I can do but is not guaranteed to be correct. Motorhomes are often neglected or listed incorrectly in parts databases.

I recommend flushing your brake lines before bleeding the brakes.

Sorry for the delayed response. I much appreciate your parts number list which I printed and showed the parts dealer guy. He said no worrys he has all that info on his end. All parts I need where available. I was pleasantly surprised as I figured ordering parts for a 37 year old vehicle was going to be a nightmare.
Thanks Griff

[Griff_in_Fairba]

Note: The 5 volt instrument regulator used to be (and sometimes still is) called a voltage limiter, which served to differentiate it from the 12 volt alternator regulator. To avoid confusion, I will use limiter from now on.

On OEM gauges, the fact one limiter serves the three gauges represents a single point of failure. If the fuel, oil, and temp gauges are all operating erratically or fail to operate, the instrument limiter is probably the cause.

In this case, the limiter may have gone bad or its +12VDC supply may have been broken. Identifying the cause of the malfunction typically requires removing the instrument cluster from the dash, which can be a bit of a PITA.

Instrument voltage limiters tend to be fairly durable so a broke +12VDC supply is a more likely cause. A loose or disconnected +12VDC supply at the instrument cluster should be relatively obvious. Less obvious causes could be a blown fuse or circuit breaker, broken supply wire, or disconnect at the other end of the supply wire.

Use a 1156 bulb and socket, two alligator clips, and a length of 16 gauge wire to make a continuity tester. (You could buy a continuity test but the wire leads on these are often too short to test all circuits.) You can connect one end to a known ground but I usually just attach one of the alligator clips to the battery's negative terminal. Connect the other end to the instrument voltage limiter. If the bulb glows brightly, you have a good +12VDC supply. If the bulb glows dimly, you've found the +5VDC side of the limiter and it's associated wiring.

Two notes: (1) The ignition key must be in the run position for the above test to work. (2) If the bulb glows dimly, your limiter is working and your problem is elsewhere.

I'm going to take a break here to go get some other things done. When I come back, I'll continue gauge troubleshooting and repair.