Dozer blade tilt question

[Rickyb1968]

I have a CAT D5M with 10’ blade. A friend of mine that has operated dozers a lot was making some observations. He basically said the dozer should be able to lift one side off the ground with the tilt function. He placed blade flat on the ground and tilted the blade down to right. He says the dozer should pick the right side of itself up. It doesn’t do it if you tilt down to left either. He is saying because mine want do this there is a problem.

If you have blade flat on ground and push blade straight down it lifts front of dozer up. I understand this is using two different cylinders. Can anybody shed any light on if dozer should or shouldn’t be able to lift itself with just tilt cylinder? That may be a lot to ask with a 10’ blade.

I did ask why that was important because with blade up the tilt works just fine. He said it needed to do this to cut in the ground. Thanks for your input.

 

[Dave Neubert]

I don't see why it would have to maybe on a small 450 it might does it cut

 

[Rickyb1968]

I personally don’t know if it cuts. I’m thinking he is saying because if it want pick itself up that it will not cut.

 

[DMiller]

Raise the blade, Tilt it while UP, then move to the grade and see if retains that tilt. Repeat for opposite side. Not ever ran one to cut ditch but watched a few skinners do this to start a cut then adjusting depth and angle as move into cut.

 

[Tinkerer]

The tilt cylinder force has nothing to do with being able to start cutting a ditch or a slope.
Tilting the blade and then applying down pressure with the entire blade is what will force the corner bit into the cut.
If the dozer has an angle blade it makes it easier to get the corner bit to cut.

 

[Rickyb1968]

Yesterday I took the dozer to a pile of top soil and I don’t think it’s cutting either. It like it’s lost it’s down pressure. What ways can I use to test if it’s getting full fluid to that cylinder? Thanks Ricky

 

[Dave Neubert]

pressure test put a gauge on it

 

[Rickyb1968]

Ok where do I put the gauge? On the pressure side where it connects to cylinder?

Could the packing in that cylinder be failing? Even though it’s not leaking.

 

[DMiller]

Was just going to suggest checking the Down pressure to see if either of the cylinders get warm to the touch in short order, bypass of hyd fluid will cause heat QUICKLY. First can T into down side fitting at any point and find the pressure value, then dead head pressure check the main Down Line with cylinders not in circuit to see what that is.

 

[Dave Neubert]

Should be a pressure tap on the valve body or pump Nige could help you with location and pressure setting

 

[Tinkerer]

Has the hydraulic oil filter been changed or inspected lately ?

 

[Willie B]

Mine is 7 ton Dresser, after refreshing the friction surfaces a few years ago, I couldn't tilt while pushing a full blade. It loosened up & now will. I'm certain it won't lift the track off the ground with the tilt.
Why do you want to? Mine (not Cat) will hold if it is already tilted & I push down.
Likely you have port relief. Inflow might be relief limited at typically 3500 PSIG, but closed valve might have port relief at 4500. Holding is more powerful than tilting & it doesn't have to overcome a lot of friction.

 

[iowahill]

Yesterday I took the dozer to a pile of top soil and I don’t think it’s cutting either. It like it’s lost it’s down pressure. What ways can I use to test if it’s getting full fluid to that cylinder? Thanks Ricky

If all other hydraulic actions are working normal then I'd say that the tilt cylinder is by-passing from a bad seal on the rod. Make sure you have full travel on the valve though.

 

[Welder Dave]

Go on flat ground, tilt the blade when lifted and then drive forward and lower the blade at the same time. If the tilt cylinder seals are bad the tilt won't maintain the preset angle. There's a chance it could be the valve but cylinder seals are usually the problem. I suppose you could tilt the blade, then lower it with the lift cylinders trying to pick the machine up and leaving it like that. If the blade starts leveling out with down pressure on it is another way of checking the cylinder seals.

 

[Rickyb1968]

Thank you for all your reply’s. I have a lot to digest. Tinkerer to answer your question. Yes the fluids and filter have been changed less than 5 manchineel hours ago.

Welder Dave I’m really thinking the inner seals are bypassing fluid. So your saying to raise blade and tilt all the way to one side. Lower the blade while moving forward. If seals are bad will the blade flatten out when the lower angle makes contact with ground.

 

[Tinkerer]

You could extend or retract the cylinder (dead end it).
Remove the hose from that end.
Then apply pressure to it, as if you were going to extend or retract it further.
If oil comes out of the port on the cylinder, the piston seals are leaking.

 

[skyking1]

with track frame oscillation it's not going to dramatically lift the down track off the ground. Tilt the blade all the way and take a tape measure and measure the rod that is out. press the blade down a bit, go have a cup of coffee and come back and measure again. If things are tight then that cylinder won't move. If not, then get a gauge or whatever, start looking into it. It should not bleed down at all.
Just don't forget about track frame oscillation. It is there to keep that track engaged over a wide range and measuring anything by how far that track lifts is not helpful. For total down pressure yes, you can see that when both tracks lift and it holds that on flat ground.

 

[Welder Dave]

Tilt the blade and apply down pressure without moving. Then measure how far out the rod is extended like skyking1 suggested. You could put a mark on the rod with a felt pen or something too. Leave the down pressure on for 1/2 an hour and come back and measure how much the rod is extended or notice if your mark is no longer visible because it's inside the cylinder now. Slight movement might be normal but if the cylinder retracts 1/2 an inch or more, leave it for another 1/2 an hour. If it retracts even more then cylinder seals would be suspect.

 

[Rickyb1968]

Sorry guys been working and not had time to look at the dozer. So to understand what your saying welderdave. Raise the blade and tilt it let’s say down on right side. Lower the blade until that lower right side rest on the ground. Turn off dozer and come back later to see if blade has moved. I get putting a mark on the rod. This correct?

 

[Welder Dave]

Don't just put it on the ground, put some down pressure on it with the lift cylinders and shut it off. The lift cylinders may creep but you want to see if the tilt cylinder creeps. The more I think about it, I don't think the tilt cylinder should lift the front end up. The lift cylinders put a lot more down force on the blade than the single tilt cylinder.