Oshkosh P-4 Fire Crashtruck Preservation

[jvandal]

We always filled them with 30 at when warm and 10wt when cold, while water is not unusual in there, it does say that the primer pump may need help. Of course you only have to worry if you plan on filling it up from a body of water.

 

[m1010plowboy]

30wt when warm and 10wt when cold, 

Well there you go! I didn't think this was gear oil so maybe there was a change made which I don't see in the TM.

Really appreciate that, was worried I was losing my sense of smell but 30wt or 10wt is what it looks like, groovy.

 

[marchplumber]

Thanks for the photos!! Be an amazin experience to hear her yawn, then roar back to life! Quite the endeavor ahead of ya!! Glad your mechanic skills pertain to the antifreeze lid, what else?

God bless,
Tony

 

[lost in the bush]

Hi great truck I think I may have one.. I purchased a 1977 Oshkosh.. I will have to look at the title later today when I go into the office. All equipment is in great shape with the exception of the engine. The dept. I purchased from thought that the head was bad of one of the jug liners were cracked.

 

[lost in the bush]

I am trying to decide if I should fix or strip for scrap.


I have another larger 4x4 Oshkosh I think I will sell than I drive the thing and change my mind
.

 

[Another Ahab]

I am trying to decide if I should fix or strip for scrap.


I have another larger 4x4 Oshkosh I think I will sell than I drive the thing and change my mind
.View attachment 484189

Of course, you got to do what you got to do, but...

Strip? For scrap?!!

 

[m1010plowboy]

Those are shiny. Somebody already loved those trucks so I bet they're begging to be driven like a truck. If I was you.......I'd get in there and get Steel Soldiers some pictures in the mud first.

I hear the 1693 Cat was a fine engine with 425hp and lots of million mile stories.
There's a gent on You tube that did a fun re-build video of the big Cat but it's about the same cost as buying a house.

Thanks for the pics,,,,,, sets the bar very high for a paint job, any more detail pics are most welcome also.

View attachment 484184View attachment 484187


.

 

[lost in the bush]

We are already converting a hush one pumper to a Zombie hunter truck. and a 932 to a Chevy Sil. dually. I may just sell it for scrap. the entire body is made of aluminum

 

[m1010plowboy]

It hit the freezing mark today so with some SuperDave motivation we got at the big red truck again.
Thank God for great mechanics.

Trying to do as much as needed but as little as poSSible to give the big Cat the best chance to fire....and fire she did.
After installing the new heat/start switch and hooking up the interstate 1000cca batteries to check electrical systems, SuperDave turned the old engine shut-down switch to the on position and the light show was awesome. 24 volt bright. Kinda funny seeing both of us buried in the TM's making sure we didn't do it.

Appears that the old stop switch shorted internally and gave SuperD a close up light show which only made him giggle a little.

After some trouble-shooting and leaving the stop switch alone, in the on position, Super hit the master switch and Bzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz was the second sound she made. The low air pressure buzzer can be annoying after some time but that first Bzzz is sweet.

Part of the pre-start checklist is to be sure we knew what the fuel looked like so I crawled under to start removing the inspection panel for the diesel drain valve. SuperD managed to find the drain-valve that was just above my head and with Cat like reflexes I avoided being part of April Fuels Day. We both took a little diesel bath today but found what may be a full tank of dyed, clean diesel.
With air intake, fuel, anti-freeze, spotless trani fluid, engine oil and electrical all checked out it was time to prime........and where we got hung up.

The 1693 Cat has a very simple plunger style priming system but it just didn't feel like it was drawing properly. If anyone has stroked the Cat primer before could you tell me how it felt and did it go phfffffftt T phfffffftt T or was it more like a shhhhh cuk shhhhh cuk sound????

Instead we opened the first injector and only had to hit the starter for a few seconds before fluid showed up.

By the time we started to get smoke out of the exhaust the batteries started to complain and the starter began to kick out after only a few revolutions so for now it was time to eat hot dogs, pole dance in the truck and pretend the horn works. On to warmer days.

A few pics

 

[tbar123]

I have a great memory from what I believe is this truck, but it may be the 4x4 pictured above, to young to remember how many tires she had. My father was in the local ANG, actually 178th ANG to be exact, and was good friends with the fire captain. He ( the captain) had set up a day where my brother and I could spend a day with him on base. What a day that was, We got to go up in the flight tower, actually ride from the tarmac into the hangers in an A-7D corsair( my favorite plane...Wonder why),look around the whole base, and to top it off. We got to ride down the runway ( which is long enough for the big daddy C-5) in the back seat of one of these beautiful machines. I can still smell the interior of that truck, I love it. This would've been around-82'-83'.

 

[m1010plowboy]

My father was in the local ANG, actually 178th ANG to be exact, and was good friends with the fire captain. He ( the captain) had set up a day where my brother and I could spend a day with him on base.

That sounds like a cool way to spend the day. There is a private airstrip not far from us. If I can get the truck running you come on up here and we'll recreate that day, except the Corsair may need to RC.

Did your folks keep any old photos around of those days? That would be something finding an old black and white or polaroid photo of the trucks that day. Interesting how the smell "truck" stays with us.

 

[tbar123]

I only wish they did, My mother was working at the NCO club across the street, and my father had to go to his day job at the local hospital(mercy). So there are no pictures that I'm aware of. I do wish that there were. I would spend a ton of money( not literally,but to me) to come and just sit in that truck for 5 minutes. I can't tell you how much that truck influenced my life.

 

[m1010plowboy]

Throttle Linear Actuating Cylinder Assembly

I'm not exactly sure how these things work so can we talk "Throttle Linear Actuating Cylinder Assembly"?


It's think out loud mode so we've got this throttle that doesn't work unless it's got air. The truck won't start without throttle control (maybe)so I'm thinking the truck needs an external air source before it starts. It just isn't logical to 'air up' a fire-truck prior to turning the key so me hopes me missing more than just me mind.

I devoted another hour of toilet time to tantalize the TM's and have this verbatim directly from the manual:


The air system consists of an engine-driven compressor and four air pressure storage reservoirs, together with the necessary plumbing, to supply and control the various air operated devices on the vehicle. Air, under pressure from the compressor, flows first through a safety valve and air dryer, to one small reservoir, where pressure builds up to a level sufficient for safe operation of the brake system. Once this level is reached, a pressure regulator in the system opens to allow the remaining reservoirs to be pressurized. All air operated components operate from the air supply in these two larger reservoirs until the pressure drops to a predetermined level; then, the brake system has priority. The reason for this "two stage" type of system is to allow a rapid build-up of pressure for safe operation of the brake system, since the truck cannot be moved until this pressure is adequate.



.......and that brings us to the unsuccessful event I had trying to "pressurize" the easiest accessible air-tank. Adapted the fitting on the lower tank and managed to fill it but it would not register on the dash gauge so I'm back to the books and looking for input.

- I know it'll be funny when I figure it out but where would one introduce external air to the air system if I need to? (by-pass safety switch and air-dryer, fill first tank?)

- ....what am I missing about a functional 'Throttle Linear Actuating Cylinder Assembly' working before the truck has air? Did they park the trucks and plug in an airline?

We've got the engine rolling, fuel, air, rad and most of the electrical wrapped up so I focused on what I'm good at......and started cleaning.


The temps are going back to freezing so if anyone needs me, I'll be in the can, reading.

 

[marchplumber]

What a great thread! You've made good progress. I know absolutely NOTHING about fire engines or Oshkosh trucks. So, I am learning along with you. (not as rapidly, but still,,,,,,,,,,,,,,,,,,LOL) Thanks for sharing the pics and the stories!! Best of luck!!!

God bless,
Tony

 

[jeepsguy]

That model deuce-based fire truck with the turret nozzle is the 530C.

 

[tbar123]

I love that fire truck, but I'm SOOOOOOO very happy that you have to deal with it. Way to much technical stuff for me to get into. But she sure does clean up nice!!!! I would imagine for a crash truck, that the fire crew would be notified in advance of aircraft coming in, so the truck would be started before hand to get the air tanks full or close enough to full, so that they would be completely full by the time they reached any accident. In case of an absolute unforeseen tragedy, that might hinder the trucks response time, but I really don't have a clue. Considering bypassing the air dryer would give you the air needed to fill the tanks, but then it would also add water vapor into your tanks. One or two times shouldn't hurt just to check the system out. I would suppose that you could also turn the ignition system on ,disconnect the outlet line from the air dryer and use an air compressor to also check the system, but I would limit your compressor to 90 psi.I hope this helps, but I doubt it.

 

[m1010plowboy]

Right now anything helps and the systems are technical. I'm still not seeing how the 'throttle treadle' pushes required air into the 'throttle cylinder', then to a lever on the governor when there is no air in the system.....but we're close to comprehension. I can now see how the engineers solved the problem of controlling several systems off of a few controllers by using several valves and actuators mostly controlled by air.

One little blurb on page 5-4 says: Throttle Pedal: Controls engine speed WHEN THE AGENT SELECTOR IS IN THE OFF POSITION. Controls the modulating clutch when the agent selector is in the WATER or FOAM position.

The start-up procedure does not say "ensure Agent selector is in the off position" prior to starting engine so reading the entire manual does help and we've got a possible solution by checking a few settings.

In the Air System Diagram, the Inversion Valve, Double Check Valve, Three Way Control Valve and the air reservoir all get air together before heading to the Throttle Threadle Valve. When the air gets there, depending on the which way the levers are pointing the air goes to the Limiting Valve and Modulating Valve or another Inversion Valve. If heading to the Throttle Cylinder it goes through another Double Check Valve before hitting the Throttle Cylinder which pushes it off to the STRUCT. Throttle on the top right of the page and onto the cable which, I'm guessing moves the governor to give her fuel.

If the guy had the Agent Selector in the on position, well just that's a whole other story now isn't it.

It's a little chilly here but we're heading back tomorrow to check out the switch location so until then the best I can do is a little song from Conway Twitty. http://www.youtube.com/watch?v=d2aeRg_yMSE

and some P-4 time
http://www.youtube.com/watch?v=4rhkfDV0QC8




This may be as simple as flipping a switch

 

[tbar123]

You Sir are a master at not only MV, but music!

 

[m1010plowboy]

,disconnect the outlet line from the air dryer

I just read this again and that makes a lot of sense for plugging in external air. That outlet goes to the RH Rear Reservoir....puzzled look on my face slightly reduced, thank you.

 

[m1010plowboy]

P-4 Pre-Start

Somebody must remember doing the painting on our IndianTown Gap PA ARFF OSHKOSH 1975 P-4....Unit 2. Had some new eyes around the truck today and we found this mouth painted inside the front cannon. Whoever did it knew the truck well.




Found an interesting symptom today in the short time we had to roll the motor. I only put in 5 gallons of anti-freeze to keep it cool for a few minutes and if she fired we'd think more about the cooling system.

I do not have a cap on the over-flow tank and while cranking her over we noticed that smoke was coming out of the radiator over-flow tank.

The same sweet blackish/blue waffs of smoke that were now happily coming out of the exhaust, also appeared to be coming from the tank. I'm no mechanic but if a guy climbed through that cooling system into the water-jacket of the engine I'm thinking something would need to be broke to see smoke.

Any thoughts on a symptom like that?



The switch makes a bzzz and now we know that airing up the rear tank operates the brakes and makes things go hssss so a quick fix on the airline and we're ready for longer days.


Here's a shot of the air valve systems and compressor tucked in behind the motor. I'm sure that one leaky O Ring is in the middle there somewhere.


We may not need to worry about it and I'm running out of reasons to keep Patracy off my rear-ends.

If my suspicions are correct the rad in these pictures possibly caused the over-heat problem mentioned by the PO and the result is exhaust smoke sneaking into the cooling system through a cooked and broken gasket somewhere in de motor, off the top of my head.

CLEAN YOUR RADS