JBNeal

I agree, that sounds normal. I have deduced that the '49 1ton has a sticking oil pressure relief valve, as my oil pressure is 40psi at cold startup, but after letting off the throttle after driving it around for 10 minutes, the gauge hangs at about 20psi. Doesn't smoke, no crud in the oil, just a low gauge reading...another thing to get to on the to-do list.

I'm gonna be going through the axles soon, when I did this 10 years ago I don't remember needing a puller. The driver side shaft I used the brake drum to pull the shaft with the backing plate removed. The passenger side shaft just walked on out, wasn't tight at all. I recall at the time that didn't seem right, but I didn't see any damage, no scoring or rust was present, and I've put 10k on it in the meantime. This will be an area of concern if the bearing cup just falls out, I don't know for certain how this can be repaired readily. I'll have to take plenty of measurements to see if something is out of whack. Does the loose bearing cup sound like an indication of a looming problem, such as axle shaft failure? YIKES

screwdrivers (big, little, std. & phillips)

pliers (slip joint & needle nose)

crescent wrenches (6" & 10")

baling wire (or coat hangers)

half-used roll of duct tape

starting fluid

a couple of shop rags

piece of 3/4" plywood (24" x 36")

gallon of H2O

a small collection of business cards from area wrecker services (stuff happens)

PCV systems aren't required, they are an engine improvement, much like putting in a 180 thermostat, modern detergent oils or ethylene glycol coolant. Chrysler put out several service bulletins for their vacuumatic crankcase ventilators to replace the draft tube on the flatheads. Evidently, Chrysler engineers recognized a benefit to crankcase ventilation of blow-by gases, but I don't think Chrysler management deemed it important enough to implement this as a design change as the road draft tube system was maintained for years (not including Power Wagon applications).

There should be two vacuum ports on the intake manifold, one for windshield wipers, the other a test port for setting the carburetor. Early PCV systems appear to route crankcase blow-by from the draft tube port through a vacuum check valve (PCV valve) into the intake manifold via the test port. Another tube was routed from the oil filler tube directly to the air cleaner.

What's puzzling to me is that the draft tube ventilation appears to bypass the air/fuel ratio metering done by the carburetor. I would think this would affect the carburetor settings as this represents a controlled vacuum leak. I am considering routing both PCV tubes to the air cleaner so that the air cleaner can trap any particulates as well as the carburetor to correctly meter the air/fuel ratio for maximized performance & efficiency.

I have studied other forum members' PCV installations and noted their performance gains, i.e. cleaner engine oil per mile & reduced sludge in the valve lifter area. But the nagging question remains: does feeding the intake manifold the crankcase blow-by gases adversely affect engine performance? if so, is this negligible? I am inclined to think there is a negligible effect on engine performance, but I haven't done any calculations or performance testing to verify this...I'll put that on my to-do list.

How'bout providing Bunns' books as sources for the info...mention that gas tanks were in between the frame rails instead of in the cab behind the seat, an industry first.

Does the DPETCA have a registry by serial number? Just curious I reckon...

I reckon information from Wikipedia should always be taken with a grain of salt since anyone can sign up and contribute, no matter how correct that information is. The whole notion of 'notorious blind spot' kinda irks me as purt'near all trucks of that era were built about the same with regards to aft visibility and optional corner glass.

As most research goes, it's good practice to find multiple sources that verify particular information. But with the advent of the internet, it's becoming more common that multiple information sources are repetitions from the same source. At any rate, allpar seems to do a decent job referencing historical documents as Don Bunn has done in the past with his publications (IMO).

The axle shafts are bolted to the hubs, the hubs are retained by the large axle nut. The axle shaft splines are not held in place at the differential.

Feel free to remove the axle cover to see how much sludge is in thar and maybe give it a good rinsing out with parts cleaner. I recall draining the gear oil out of the '49 & refilling with diesel. I let it sit for a week, then put the rear axle on jack stands, fired up the motor, put it in 1st, and let the differential gears slosh the diesel around in the case for about 15-20 minutes or so to agitate like a clothes washer. When I drained it out & pulled the rear cover, it got almost all of the crud out, so rebuilding the differential was a snap afterwards.

I agree, the hidden condition can be a real stinker. Dad told me that it was always cheaper to inspect beforehand in the barn rather than pick up the pieces in the ditch afterwards. My brake linings were stuck to the drum, wheel cylinder rubber was hard as a rock, and one of the shoe return springs was broke. I ended up rebuilding the whole axle: seals, bearings, wheel cylinders, shoes & springs...relatively cheap insurance knowing what all has been done and not guessing as to what might need doing.

I'm kinda thinkin' that the '48-'49, maybe '50, had a different crossmember when the fuel tank changed shape so that it mounted directly to the frame without mounting brackets.

here's a few

That might be one of the reasons this design wasn't pursued cuz the tappets would have to be engaged by some kind of linkage rather than a simple pushrod. The head bolts around the combustion chamber would be okie dokie, but yeah I reckon with engine heating & cooling there'd be definite oil leakage in the pushrod area.

I spy a draft tube on the valve pushrod side of the block, and I reckon that's a oil filler/breather cap on the valve cover, but no PCV plumbing. Is that a thermostat housing on the intake manifold? The exhaust crossover pipe is right over the water pump, the plug wires are running over the exhaust manifold; the generator/alternator would be right next to the exhaust manifold too...I reckon they figgered there's plenty of reliability issues with this design so they scrapped it and went on to the Slant 6.

Yep, them axle shafts gotta come out, 'tis a chore and ya really need one of them thar axle nut sockets to do it without bleedin'n cussin'. I think the last time I pulled the rear drums, it took about an hour with the right tools. Luckily, the paper thin gasket that's between the hub & the axle shaft flange leaked, so I didn't need to use the jack bolts to back it out. I used a sharp gasket scraper to wedge the flange off the hub, then a pry bar to pop it loose from the differential.

When using the jack bolts, remember to alternate between bolts, turning about 1/6 at first, then 1/4, and so on. I turned the brake adjusting cam a half turn to get the brake shoes off the drum, it helps to get a little wiggle room when handling them big dudes.

When installing the axle shafts, I made new paper gaskets, but they leaked. So maybe next time around I'm gonna put some RTV on that to keep that nice & clean.

sounds kinda like Marvel Mystery Oil...we buy that stuff by the gallon whenever working on rusty bolts. I've made a dispenser out of a plastic 20oz. DP bottle cuz it has a conical shape and is harder to slip out of the hand. Took a philips screw driver to poke a hole in the plastic bottle cap, keep it at least half full whenever working on a project. With a li'l practice, that plastic bottle can be squeezed to shoot the MMO upwards when working under something. Made the same kind of dispenser for water whenever cleaning batteries with baking soda + vinegar.

Yep, ya got a missing fill plug. Mine fell apart when I put a wrench on it; luckily, the gear oil that leaked out kept the threads from freezing up, so it was easy to clean up. The original was a pipe plug that accepted a 1/2" ratchet drive. I replaced it with a square head pipe plug from the hardware store...I think it was the same size as the drain plug on the transmission. The nut + slotted screw is the drive gear thrust screw + lock nut.

I completely tore the rear end apart, cleaned it thoroughly, installed new bearings as the old ones were spalling, set the backlash & ring gear thrust, and installed a new (leather!) pinion seal. There is a drain plug on the bottom of the axle housing, as well as the gear ratio on the differential housing. I had to do a lot of scraping to find them. I believe the ring gear also has the ratio stamped on its edge, but it's been awhile so that may be a fuzzy memory.

I went ahead and got a sheet of gasket cork and made a couple of gaskets to keep a clearance on the differential housing and cover. I also added a thin layer of RTV to help, especially around the bolt holes.

Fixin' up the motor to get more 'go' is all right I reckon, but ya have to do somethin' bout the 'whoa'...the long stopping distances with the drum brakes makes me drive extra cautious when approaching intersections or merging with traffic.

Since I'm running on bias ply tires and the roads 'round here are on the bumpy side, I definitely keep my speeds down as going over 50mph might toss me into the ditch. I took a lady friend on a ride in my '48 & she commented on how bad my driving was as the ride pitched us to & fro, so I told her to watch the steering wheel. I held it straight & true doing about 40 on a straight back road, and both of us were holding onto our respective doors to keep us from sliding off of that bench seat. With a li'l explanation about bias & radial ply tires, she asked me why I would bother putting those bias ply tires on: "cuz this makes the Blue Bomber (my Ram Cummins 4x4) seem like you're riding on air"

'94s had multipoint fuel injection; '87 & '88 had carburetion, '89-'91 had single point fuel injection. If your engine has an AC, it relies on input from the ECM to cycle the compressor. I'm thinkin' the fuel pump also relies on input from the ECM. There's no electric choke as the ECM controls injector pulse width and air intake. It would probably be easier to upgrade the ECM to a '96 or newer that has the OBDII diagnostic system. Scanners are relatively inexpensive these days, and whenever ya need parts, most parts stores will have'm.

At any rate, it's been my experience that taking the technology out of an engine can be more problematic than trying to upgrade an engine. A neighbor tried to take out the dual point injection system on his 350 chevy & go with a 4bbl carb, and that truck never ran right, it sucked gas in the summer, couldn't start without ether in cold weather, and never had as much power as he wanted when pulling a load, especially on hilly terrain.

It's been my understanding that PCV systems were developed to withdraw excess combustion gases from the crankcase. These gases would build during engine operation as not all charged air would be ignited during the power stroke, collecting along the cylinder wall perimeter on the piston rings, and become entrained in the oil, much like air bubbles can form in oil. This oil would re-enter the crankcase, and the gases would separate from the oil, briefly pressurizing the crankcase a few psi. These gases contained enough hydrocarbons that they could still be ignited if combined in small quantities with charged air entering the combustion chamber. If moisture vapor was with these hydrocarbons, it would also be removed from the crankcase & out the tailpipe, minimizing the opportunity for sludge formation.

Exhaust gas recirculation, on the other hand, can be vastly problematic if not monitored regularly. Excess hydrocarbons in exhaust can still be ignited with charged air; however, these hydrocarbons are more than likely particulates rather than vapor. EGR systems on poorly maintained engines build up carbon, forming a restriction that can cause excessive back pressure and all kinds of problems snowball from there. I recall early Magnum 318s that had plastic EGR valve contraptions that would melt when carbon built up in the intake manifold passages, causing the "check engine" light to illuminate as the O2 sensors were generating readings outside of ECM parameters.

During engine diagnosis of the 218 & 230 flatheads, I've noticed a considerable amount of 'smoke' that would exit the draft tube & oil fill tube at engine shutoff. This 'smoke' would have a definite hydrocarbon odor, a mixture of oil & slightly burned gasoline. Redirecting this amount of hydrocarbon through the combustion chambers appears to be a good way to keep the crankcase oil clean by removing contaminated air from the crankcase. If another problem, such as a failing head gasket, were to put coolant into the combustion chamber &/or crankcase, the PCV system would in effect blow any gaseous material out through the tailpipe, which would be a definite indicator of a problem as exhaust gas would change color & density.

From what I've found on the technical archives & Power Wagon websites, Chrysler recognized the added benefit of a cleaner crankcase with the PCV system, as several service bulletins were issued regarding field fixes for different flathead induction setups. First, the draft tubes were converted to an adapter + check valve to the intake manifold. Later fixes added a vapor tube from the oil fill tube to the air cleaner base. These setups suggest that Chrysler had done evaluation of crankcase oil with & without PCV systems and found that a field fix for existing L6 engines was worthwhile preceding new designs that would incorporate the PCV system on Slant 6 & V8 engines.

IMO PCV systems help more than they hurt. Choosing to not use a PCV system is just that, a choice. Updating a flathead with a PCV system can be considered 'original' as Chrysler had issued service bulletings regarding this topic, complete with assembly drawings, part numbers & installation instructions, much like the dealer-installed radios and heaters of that era.

Happy motoring!

The 1 ton has larger hubs that push the wheels away from the frame, but the front axle and steering mechanism are identical to that in the 1/2 ton. The front clips for 1/2, 3/4 & 1 ton are interchangeable.

Make sure that horn works...it's kinda fun to roll up on pedestrians, hammering on the horn while trying to "stop"...if she smokes &/or backfires, that's even more fun to watch folks scatter after getting too close. Ahhhhh, cheap thrills....

Being a-retentive as I am, I couldn't help but notice the lack of a Little Red Express, a Warlock, a Dude, or a Camper Special. But then that was offset by the appearance of the red '49 1 ton, the '59 Sweptline and '66 & '68 stepsides. Yep, I swear I've seen that '49 somewhar before...

I had a '89 Dakota 2.5L short bed for almost 8 years, got it at 39K, sold it at 119K. It got 25 around town, 28-32 on the highway, and the only speeding ticket I got was doing 45 in a 40...yeah, it was slow. That motor was just as powerful as the 2.2L I had in my '86 Omni, but ran smoother, especially in cold weather.

I traded up to a '92 Dakota 3.9L longbed, and it had waaay more power. It didn't handle as precise as the shortbed going around corners, but that was about the only complaint I had. It ran super smooth in town & on the highway, averaging 22mpg on the highway, 18mpg runnin' around town. I traded that for a '92 Ram 250 only because I needed more payload capacity...I had a tendency to load that longbed Dakota so full with stuff doing chores & whutnot that I'd bottom out the rear axle.

IMO durn near all of the motors set up with carburetors + smog equipment or single-point fuel injection + smog pumps are PITA. They're detuned gas hogs that are the product of well-intentioned goverment regulations & hastily cobbled automotive band-aids. Yards of vacuum hoses, weak vacuum switches, scabbed on EGR valves, power-robbing smog pumps...BLAH Properly maintained multi-point fuel injection systems crank out waaay more power...heck, that new Camaro has a V6 that cranks out over 300hp...YOWZA. Anyhow, I tell people who'll listen to avoid this problematic era in automotive history. A simple carburetor system or a good MPI will get ya down the road for many a mile without too many headaches.

How'bout this nice one or this li'l number?

I had estimated an added .002" when I set the valves cold. Once the engine got hot, valves only needed small adjustments to get them within specifications. I wore an old pair of leather work gloves that had the finger tips cut off, and when I brushed up against that exhaust manifold, no colorful metaphors were uttered. Not counting setup for getting access to the valves, it only took about an hour to set the valves, check them hot, then check them hot again.

For setup, I jacked up the front of my 1 ton so that the valves were eye level when I went to check them while kneeling in the wheel well. I also had lights clamped to the frame under the cab & by the radiator. This took most of the shadows out of the valve lifter compartment.

The lug studs on my '92 had knurled edges and popped out with a press. I had started smackin'm with a 5# hammer, but after putting forth a great deal of effort to get that one out, I moved to the press. On the '92, the lug studs hold the brake rotor to the hub, so when I had to replace the rotors, and there was 16 lug studs to remove, switching to the press was a no-brainer.

But here's where things get a li'l fuzzy. My '49 1 ton has lug studs, and they did not have the knurled lug studs back then. I was told that they used a special tool to deform the head of the stud so that it wedges into the hub, something similar to a cold chisel. I reckon the 3/4 ton has similar style lug studs, albeit smaller ones. Popping those out would probably be best done with a press cuz they're probably froze up with rust. A big hammer should be able to knock one out, but take care with the neighboring studs.

Another suggestion, remove a lug from a different hub...that way you'll have at least four in each hub.