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Dump truck controls

Rickyb1968

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Joined
Dec 13, 2021
Messages
108
Location
Arkansas
I’m looking at a dump truck and have a few questions. It’s a Mack truck with a ox body dump bed on it. The control panel inside the truck has in/out pto switch and beside it is a shifter style handle that you move to down or up to raise and lower the bed. Behind that is push button for tailgate air gate latch.

First question::::: the control to raise/lower bed is backwards. To raise bed you move shifter to lower and vice versa. How would I correct this?

second question…… there is no cylinder for air gate latch. Don’t know what happened to it. How do I go about finding cylinder that will work with my setup.
 

crane operator

Senior Member
Joined
Mar 27, 2009
Messages
8,275
Location
sw missouri
First question::::: the control to raise/lower bed is backwards. To raise bed you move shifter to lower and vice versa. How would I correct this?

Depends on what the handle does. If its a cable operated push pull control, its going to take a little fabrication to swap. You may have to change around some brackets so the cable pushes the spool the other direction. The cable likely goes right to the control spool on the pump.

If the lever controls air lines, you probably just need to swap the lines on the control valve.

If its a lever on a hydraulic valve(rare, but on some county or state surplus trucks), then you may have to swap some hydraulic lines around.

If you're just missing the cylinder, you just need a closed dimension and a open dimension (length) to size the cylinder, And a big enough diameter to have enough push, any good truck parts place can get you the right stuff. A fleet pride or Inland truck parts etc.
 

Rickyb1968

Well-Known Member
Joined
Dec 13, 2021
Messages
108
Location
Arkansas
Thanks crane operator. I’m looking at buying the truck Monday. I will be able to post some photos and get a little more information. I know it’s not cables. More than likely air. Thanks for the response.
 

Dave Neubert

Senior Member
Joined
Jul 18, 2018
Messages
1,649
Location
Monroe NC
You could just turn the control 180 or you will have to ab a bracket for the cable to come from other direction i its air operated just swap lines
 

Rickyb1968

Well-Known Member
Joined
Dec 13, 2021
Messages
108
Location
Arkansas
Another question on this dump truck and being able to tailgate a load out of it. With this truck I have to put truck in neutral and engage pto while moving shifter to raise bed. Release clutch and bed comes up. With this information how would I tailgate a load of gravel?
 

Labparamour

Senior Member
Joined
Sep 6, 2013
Messages
732
Location
Washington
Set gate chains, engage and leave pto engaged (you can drive with it engaged), raise box a bit while in neutral ( you can often hear material start to move), select appropriate gear to maintain good spread and start forward, trip gate and continue to raise box incrementally to keep material moving.

How I do it...
Others may have better ways
 

1466IH

Senior Member
Joined
Feb 4, 2014
Messages
613
Location
prairie du rocher, il
Set gate chains, engage and leave pto engaged (you can drive with it engaged), raise box a bit while in neutral ( you can often hear material start to move), select appropriate gear to maintain good spread and start forward, trip gate and continue to raise box incrementally to keep material moving.

How I do it...
Others may have better ways
To clarify you can Not drive down the highway with pto engaged. You can run at low speeds and low rpm though. If it is the same hoist control that I am thinking of (which is on every air operated valve I have seen in dump truck or tractor with dump trailer in the last 25 or so years) you will have to remove control from bracket and reinstall in opposite direction because they automatically kick out pto when lever is moved to "lower" position. Swapping lines around will just kick out pto as you try to raise body.
 

Labparamour

Senior Member
Joined
Sep 6, 2013
Messages
732
Location
Washington
Yeah, should have said- pto engaged only while dumping.
Yes, will be trial and error for proper gear and chain setting based on material size.
I like to be moving before tripping the gate so you don’t have a “lump” of material at the start of spread.
 

Labparamour

Senior Member
Joined
Sep 6, 2013
Messages
732
Location
Washington
Also need to add:
Better to chain gate wider than too little...load will bind up and you can’t close gate to loosen chains. Have to rake/scrape out from between gate and box until gate closes enough to re-adjust chains. (Had that happen when I went from crunched aggregate to soil and forgot to remove chains!)
I chain so gate has about 3-4” for 1 1/4” crushed. Also probably better to be moving too fast than too slow..you can always lower box, back up and make another pass rather than not having material go as far as you wanted.
 

Rickyb1968

Well-Known Member
Joined
Dec 13, 2021
Messages
108
Location
Arkansas
So just to clarify I can keep the pto engaged while tailgating? You would have to if your raise your bed a little as you do it?
 

Labparamour

Senior Member
Joined
Sep 6, 2013
Messages
732
Location
Washington
Correct: clutch must be out to operate hydraulic pump and/or move truck.
While not healthy, I’ve mistakenly started down the road again w pto still engaged...caught quickly.
Not good but not fatal (when stationary, lots of drivers will run up engine speed,1200rpm or so, to raise box quicker)
 

skyking1

Senior Member
Joined
Nov 3, 2020
Messages
7,465
Location
washington
If you float your gears the PTO will let you know you left it in :)
All that above is good stuff, start fat on the chains, get a roll going before popping the gate, WATCH FOR OVERHEAD WIRES!!
I tend to raise it almost enough to overtop the tailgate with gravel, and then only have to do a little lifting to get it clear.
If the sidehill is too much for that, it is probably too much to be tailgating.
If you are doing partial stripes, lower the bed as you slow down. Set the brakes and grab the shovel off the rack, and pry the gate open with it and let it slam until you can set the gate latch for round two.
Don't get your precious fingers anywhere near that gate. Ask me how I know :mad:
 
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