Cat DD9H Push Dozers And More

Bumpus,
Thanks for sharing the photos. I worked on a road job at Ft Benning Ga. while I was in Grad school. Started out on a 2U D8 with one steering clutch and no pony motor. Finally moved up to A D9G push Cat. Outfit had 3 hydraulic pans and 6 cable rigs. The manifold on the
D9 was our "Lunch Warmer" 1972

.

In this video it looks like he has the controls hook up backwards.
The brakes are locking on the right hand track,
while he is doing a left hand turn.


http://www.youtube.com/watch?v=LOo26HGshVE
.

[quote="Bumpus"].

In this video it looks like he has the controls hook up backwards.
The brakes are locking on the right hand track,
while he is doing a left hand turn.


http://www.youtube.com/watch?v=LOo26HGshVE
.[/quote]


I posted this remark about the video on another sight
and a member there post the reason why he felt this was happening.


HIS REPLY
[quote]
If you stop and think about it for a minute, if the controls on the rear tractor were the other way around, then when he turned left with the lead tractor, the rear would also try and turn left. That would push the rear of the lead tractor to the left as well, negating any advantage gained. By having the rear tractor steer to the right, it turns the articulation joint so the whole tractor assembly is now turning left..
[/quote]

.

Firstly Bumpus thanks for puting up all the posts that you do, now down to the Quad Track, the 2 pilots I find a bit strange as the area the driver station ocupies on the back tractor is a bit full of air jacks plus air compressor pipe fittings also air tanks, the fuel tank is often re-located to aid rear vision, the load monitor cylinder from the hard nose down to the hitch??? , so I tend to think this is 2 D9's having a bit of fun, the steering is reversed onto the rear tractor controls

tctractors

Hi, TCTractors.
You are mistaken, M8. I have seen the beast 'in the flesh', so to speak, last year at the Powerland Museum in Brooks, Oregon, on the day that that video clip was shot. That is a genuine DD9H. In fact, I have been told that it was the last set made and that it used to belong to Peter Kiewit and Sons. The reason that the right track is dragging on the back tractor is, I believe, simply that the operator doesn't have enough 'loud' pedal on the back tractor. In a later video clip from the same show, you can see both tracks behaving normally.

When starting or finishing a turn, diagonally opposite tracks drive to get the unit 'bent' or 'straightened out'. During the turn, both outside tracks drive to get the outside around faster than the inside. How-wevver, You do need to be careful just how much hay you feed to the horses in the back tractor or you may end up pushing the rear of the front tractor sideways. There are two separate accelerators in the front operator station to assist with this.

There is a single steering control on the front machine which has six positions and which takes care of all the 'working detail'.

Hope this helps.

Hi, Folks.
Some of you might like to check out this thread over at SoCal Earthmovers.

http://socalearthmovers.com/forum/index.php?topic=1246.0

It appears to me the rear machine is along just for the ride,as the rain cap shows no action.

Deas, I dont want to pull your pants down on this 1, but it "dont look right" in my head,

hello everybody ,there is nothing wrong ,😆,if you watch the video the back cat they were pulling to start ? .back cat is not running , back cat is turning behind the front cat with the rigth track stopped because the man sitting on the back cat pushed the brake on the the back cat .if the front cat is turning left and he needs to turn quicker he gets the back cat man to stop the back cats rigth track pulling the two cats straigth like deas says.if they had the 2 cats runing it only wate fuel ,so being safe they would have a man on the back cat to help with the turns ,quote - d9 hydraulic steering clutch and brake booster .👍,bruce oz

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sorry in the second video they have the second man to help without the back dozer when its not running ,
http://www.youtube.com/watch?v=LOo26HGshVE