The Stovebolt Site Forums The Parking Lot Big Bolts 1954 450 fire truck. Slow speed rearend

I’m new here on Stovebolt. I see a lot of fascinating articles, and can’t wait to take it all in.
I just bought a 54 3 ton fire pumper. 5000 miles on it! Beautiful condition, but I plan to take all the fire equipment off of it.
The differential ratio on this thing is 6.80 ! I drove it home, about sixty miles, and she really revs out at 45 miles an hour, as you can imagine. There are a few issues to deal with and I’m sure some I haven’t imagined yet, but I am excited to be building a dream housetruck on it! I’m looking forward to getting some direction on changing out the differential to a low number, hopefully 2 speed rear end. So, there it is, and I hope to hear from others if there is any advice. Thanks for reading my post !

Start with your existing wheel bolt pattern, it would be best to match the front. If it has split rims of some sort, 22.5's tubeless are easy to get changed everywhere, can mount larger OD tires.

It might have info on the inside of glovebox such as engine, trans, rear axle and ratio. What engine does it have? Does it have juice brakes? Rubber brake lines, two on the front, one in the rear are easy to replace.

Ed

Thanks, Ed. Yes the glovebox info is there. 302 engine, runs great. 6.80 ratio, rear axle is Timken
8.25- 20 tires on split rims. Wonder if I could get a differential that bolts on the same axle.
I see you have a 52, though bigger. Bet it’s nice.

So, do you have 6 bolt Budd wheels or 5/10 on 7.25" wheels? Perhaps you have Dayton wheels?

Anyway, another option would be to put a 'brownie' aux. trans in the driveline. Relatively easy to do, 5500 or 5800 series would be the right size, although a 6000 series would also work, just a little bit larger. Watson aux. boxes are a little bit fragile. I put a 5831 in my '53 GMC with a 302 which had 6.6 single axle, would cruise at 70 if the load wasn't too heavy.

You probably have a park brake on the back of your existing trans., so it would be best to find a 'brownie' with attached park brake, although intact ones are rare. Tru-stop brake pads are available.

Ed

Just to add my two cents, usually if it's a fire truck, pumper, it will most likely not have the parking brake on the drive shaft since the pump is driving by the drive shaft. On a 4 speed, most likely put the trany in 3rd, activate the transfer case (Wich uncouple the rear diff from the drive shaft) and pump water. If parking brake would have been installed behind the transmission, pumping water would have be impossible, and or parking brake totally inoperative when pump is engaged. Mounted on the front of the diff would work, but never seen it before. All this unless it is a front engine crank drive pump

Here in Canada, if it was ordered to be a fire truck it would have been most likely a maple leaf 3 ton, a rebadged GMC.... With the 6 bolts rims.

J. F.

Santerre, yes, the six bolt rims with the spokes. In the case of this Howe pumper, the trans has normal band brake drum on the back .
A short driveshaft to the transfer case drives the pump, which disengages the rear end at the same time , as you say.
This results in the odometer clocking miles while pumping, so there are actually a lot less than the indicated 5620 miles showing!
I would think this truck, if sold for over the road use, would have had a two speed rear end pretty much standard equipment?

Are you talking about Dayton type wheels when you say "spoke"???
As for the parking brake arrangement, the transmission might not be the original. I very doubt the builder would have use a setup like this one for a fire truck. The chance of forgetting the parking brake activated while engaging the pump causing the truck to stall and not restarting or smoking the park brake is too great, plus the fact that you are loosing park brake with the pump engaged. Do you have an other park brake system at the rear wheels?
I've seen fire truck with both, single or two speed rear end.
It safe to say about half of the milage is actual road miles, maybe less.

J. F.

Several fire trucks I have had put the park brake on the rear of the trans. Removing the water pump transfer case makes a perfect location for a 'brownie' aux. trans, only have to shorten one driveshaft.

Ed

Santerre, there is a brake lock system that locks the brake fluid pressure. This is for fire pumping work.
With the vacuum brakes(hydrovac) it is quite effective.
Yes, I agree, the fire truck designers were careful about safety, and potential accidents.
Ed, the brownie sounds interesting. I’m not a trucker, but the extra choice of gears could come in handy with the vintage 302 power I plan to keep in the truck. I believe these trucks ( the 3 ton GMC),were used over the road way back when and were considered competent at the time.
Does the brownie include an overdrive gear? I’d be inclined to think it backwards to gear up and then back down, so to speak, at the differential. Can you educate me on that? My main concern is to get a higher highway gear , and still keep this low range for hills.
Why I thought of a simple 2 speed.
Thanks for your input. This old girl really runs good, and I’m excited about the project!

Brownies typically have a low gear, direct and OD gear, some have 2 lower gears which is OK, not have to use lowest gear, when you find one, just enter the MN to get the ratios, I. E. 5831 box, ratios available. Most only care about the OD ratio.

When with a load, best go to high direct, then OD, back down to high direct. Then lower, keep big loads off OD ratio to save ear on cluster gear. These are not weak trans'.

There is not a 'simple two speed' 'brownies' only to use direct and OD without a load.

Mico Loc type park brake units are not legal, although many use them. Best to use a real park brake, even if only on main trans.

Ed

Most of the pumpers I've seen, even current ones, are equipped with a big set of wheel chocks which are used while pumping water. It's just one more safety feature to assure the truck doesn't "go walkabout" while it's on the job!

The only downside to a Brownie trans is the need for a second shift lever, and since most of them aren't synchronized, you'll need to get good at split-shifting without using the clutch. It's an acquired skill, but once you get the hang of it, it's actually faster than shifting with the clutch in the mix. A 5-speed becomes a 15-speed with the Brownie involved, and you'll also have 3 ratios to choose from in reverse.
Jerry

Thanks again , Ed. I’ll not be using the mico locks, just to note that the fire truck has them. Yes, the band on drum parking brake is pretty good. I’ll be looking int the brownie more. Thanks for the tips!

Most Brownies are somewhat hard to find, most yards have no clue, get in the yard somehow, then look for 2shift levers, two shift rods going to unit high in middle of frame, if bed still on, look just behind cab, might have to cut shift rails with saw if bed still on, make sure to get shift mechanism from cab, get both driveshafts, too. Many have Tru-stop brake still attached, better score, new pads are available here in Denver. MN on brass or Al tag on left side.

Ed

That sounds like a great truck, welcome to the gang! My 52 3 ton Chevy fire truck, Canadian built, has the sm420, and the vacuum two speed. She also revs pretty good, closer to 50mph, but it's got a 78 292 power plant.
To the point though, since mine does use the main drive shaft to pump in 4th gear, the drum style with mechanical inner and outer shoes parking brake is located on the rear of the pumps gearbox. This way it holds the truck's rear drive shaft thus the wheels, steady while pumping.

Ok, thanks, this all make sense. Now that you mention it, I remember seeing this on a way older truck. I guess it might have depends on the manufacturer and "popular practice" for the area at the time. What brand is the fire body and the pump?

J. F.

Thanks for the response, 52 vff, and santerre. Yes, that Seagrave has the more sensible hand brake location.So, the 52, the fire truck is certainly great looking. Is it owned by a fire company?
I’m feeling a little ashamed of dismantling the fire equipment, but have thought it through, and as no one has, after many years , been interested in restoring it, I don’t think it will happen. Very expensive proposition, to restore all that antiquated pumping machinery etc.
The fact the truck itself is in such good shape was the clincher for me, after watching it for sale for some time. I went in person last winter to see if it was in the shape it looked like. It was. I’ve washed the cab inside and it really looks practically brand new!
I hate to sit on the seat!
It is, by the way, a Howe, with a Waterous pump.

One of my "one of these days" projects is a 1961 American LaFrance pumper on a GMC pug nose chassis. It's got a 401 V6 engine and a Clark 5 speed trans with direct drive in 5th. gear. I'm planning to remove the fire bed since it's been stripped of a lot of the valves and plumbing and the onboard water tank has a big hole in it. The driveshaft-mounted pump will be replaced with a 3-speed Brownie I got in a horsetrade a while back. That will give me 15 forward gears and 3 in reverse. I'll mount a commercial 5th. wheel and a goose neck hitch, and I should be able to tow anything I can back up to!
Jerry

Sounds nice, Hotrod. With that Brownie overdrive, you oughta back up pretty fast!
Just wondering what ratio that rearend has?

Steelonsteel, my 52 is owned by me personally due to some family history of a similar truck, and due to the craziness of liabilities it gets more use than any parade truck in mine and neighboring fire departments trucks.
Don't fret about changing its use, but before you do make some pictorial and written documentation of what you've got, just in case someone does come a looking later, not to mention for your own posterity. Document casting numbers etc. You could even try to track down the Howe records so you could find original owners and maybe even pictures.
I'd love to have shop big enough to hoist off the fire body to make it a fifth wheel sometimes, but then I remember it's a pig on gas and slow so I wouldn't go too far anyway....

Thanks for the advice, 52, and I will endeavor to document the equipment on it.