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Converting an OTR truck to a dump...need ideas on where to get some parts.

Dieselcrazy

New Member
Joined
Jan 25, 2013
Messages
1
Location
Minnesota, USA
Occupation
Ready Mix Driver/Mechanic
My friend and I are converting his old road tractor to a dump truck. He knows it would be cheaper to just buy a new one, but he's more doing it for sentimental purposes, and because he can. The truck is a 1985 Pete 359 with the corvette dash, a 425 Cat 3406B, 6/4 overdrive trans. 282 or 285" wheelbase. It currently has some huge 150 gal tanks that were mounted below the sleeper but those will need to go. Which is the 1st question, he wants to run dual tanks still, where can I get a fuel tank with steps on it so they can be mounted below the cab. If I could get one that would be half fuel/half hyd fluid to run the wet kit that would be even better. 2nd question is where can I get a wet kit for a 6/4 transmission and is it any different than the ones for the other transmissions....guessing a PTO is a PTO but best to ask. He is also looking to run 2 pusher axles in front of the duals so any info on the best ones to run would be awesome. Was thinking Hendrickson but dont know. Also a good place to get rims for all axles, have to be aluminum, including super singles for the fronts. Also I'm not sure where to get the hydraulic ram and all that fun stuff for the box, and while Im at it the box too. He'll use the truck primarily for dirt work and pulling his D5 Dozer. Just need a little direction as I've never taken on a project of this size. And since I'm in the material transportation business myself I know that the best people to ask are the ones who drive and work on them every day. Thanks in advance for any help.
 

51kw

Well-Known Member
Joined
Dec 7, 2007
Messages
239
Location
Minnesota
My best advise is to leave that as a tractor and buy one set up as a dump. I have loaded many of those big conversions and they are worthless offroad. You also forgot that the steer axle and springs need to be changed to heavier specs. I would go with at least an 18000lb axle set up. There is ALOT of weight on that steer axle when you lift the 2 pushers! You will end up breaking springs and bending the axle. At the very least you will eat king pins quickly. Also I would double frame it. By the time you set it up correctly it will be so heavy you cant get any payload in it. I loaded a set up like this on a job this fall. He was hauling less in the box than the quads. Plus he was stuck all the time and it took 40 acres to turn it around. Im not trying to be a party pooper. Just stating facts.
 

DiamondLTruckin

Well-Known Member
Joined
Mar 22, 2010
Messages
107
Location
Wyoming
Occupation
Truck Driver / Mexican Dragline Operator / Mechani
You can convert a tractor to a dump truck, but it'll be just that a converted dump truck, main thing is that it's probably got air ride.. Not sure what rear supsension your 359's got, but Pete AirTrac is IMHO the best air ride dump truck suspension but it's still an air ride dump truck, have fun off road. I'd keep 2 or 3 ride height rods in stock at your shop, and keep one in your truck. As far as fuel tank steps, on the Pete style brackets, there should be 2 holes on the top saddle, any truck wrecking yard should be able to get you steps, you may need to have em shortened, way easier to shorten em up than lengthen em and make it look good. I pretty much re-did most of this stuff when I sortened the wheelbase on my 96 Pete 378. I run a 90 gallon fuel tank under passanger door and run 2-3 days easy on fuel. I'd really try to talk him into that type of a setup and also STRONGLY recomend a 23" diameter fuel tank over the 26" diameter fuel tanks that your Pete likely has. Poking a rock through the fuel tank on a rough jobsite just leads to a bad day in general. I know and that's why mine's a 23". Next project for me is adding a drop axle as well, going to look for a set of air tanks like you find on mixers, to save frame space, also will be able to move the battery box up for ground clearance. Finding parts best bet is to call around to salvage yards near you, or get on line and search if you're willing to pay shipping and potentially wait for their yard guys to pull parts off. Jealous of your 6 and 4 trans, always wanted one of em!
 

tireman

Senior Member
Joined
Apr 19, 2011
Messages
264
Location
St.Louis,Mo.
That is a classic truck - why ruin it trying to make a dump truck that'll be worthless as an ashtray on a motorcycle? Single frame, air ride, etc. Find another project and leave the classic alone. Sell it or admire it - don't ruin it. 51kw nailed it.
 

DGODGR

Senior Member
Joined
Dec 18, 2009
Messages
1,060
Location
S/W CO
Split fuel tanks are available from Peterbuilt. I don't see why you would want one though. You will have plenty of oil in a "between the frame rails" tank that can reside just aft of the lift cylinder. I converted a OTR truck to a dump truck. I used a Western bed (rock tub) but I was on the West coast at the time. If I were you I would look into Crysteel for the bed and the cylinder (I think they are in MN). FWIW, you will never have a truck that is as good of a dump truck as a spec'd out unit. At least not for a reasonable cost. Since you are determined to do it anyway there are a few things that you should know. The tractor must be changed to a truck (different TP valve, adding another set of maxis, etc). I would not try to employ a double frame. If you want more strength one could order the bed with a sub-frame. The converted trucks that get around best off-road are those that have only the single frame. The problem with the on-road suspension is the lack of articulation. Making the frame stiffer reduces the ability to twist. Add that to a rear suspension that doesn't articulate and the truck will get stuck easily when not loaded. If the rear ends were equipped with full lockers this would not be as big of an issue. If you are running air ride I would also suggest installing a hi-speed dump valve to reduce the stress on the air bags when dumping. The brake can are not in the same location when comparing an OTR tractor with a dump truck. The OTR brake cans are clocked differently on the axle and this makes them hang lower. They will get ripped off if the driver is not careful. The longer wheel base the more it will put the tanks at risk, even if they are the smaller diameter. The gearing will be wrong too, though the 6/4 may fix this (I've got no experience with the 6/4). I bet you could find 20k# axles for a 359. I'm pretty sure that I have seen concrete mixers built on that platform. I converted a 377. I put and 18k# axle under it and it required customizing. They don't make HD axles for the 377 so I had to use one from a 379. The 377 & 379 have different spring lengths. I had to use a set of KW springs and customize the bushings to work on the 377. That brings a very important point to light. You may not know what, exactly you are up against until you are done with the project. Who knows what road blocks you may encounter. Best of luck if you go ahead with this project. When I buy my next dump truck I hope to find one that was spec'd out from the factory. I doubt I would convert one again, unless I just could not locate one that is already set up.
 

JDR62

Active Member
Joined
Mar 28, 2008
Messages
39
Location
sw wi
Converted many 359 & 379s road tractors, when it's that long you need to double frame it from motor mounts back,add a used 20,000 lbs front axle , new springs, asst. Power steering ram on right side, fuel tanks cut to size rewelded ,PTO mounts on the aux trans. 280 inch wheel base needs a big box , weakest link will be your driveline with a box that big you use all the space sooner or later.If I were you doing my own dirt work, shorten to fit a 14 ft box and pull a pup or transfer dump. You' ll save a lot of $$$$$$, alot easier to get around (280 in. Wheel base quad needs lots of room),plus you will have a cool looking ride that will add a lot of $$$ value to a classic 359. If your heart is set to build a quad not a problem i have proven ones working on the grade all summer around here
 
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JDR62

Active Member
Joined
Mar 28, 2008
Messages
39
Location
sw wi
They get stuck easier you learn real fast were you can't go or stop especially empty
They not heavy usual lighter
The only problem w/ a double frame is corrosion inside. Use to be a factory option single or double
As far as a value lots of 359 s all over cheap, unless it's a show truck w/ exhd
Lighter driveline,axles, rearend but they last if your good driver
Steering is really hard going slow, especially trying to do a. Y. Turn . ( need daul steering gears )
I built & drove them many years, easy to sale If there cool looking , tandems w/15' boxes sell best around here
 
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