D5m priority valve pressure loss

[Northpoint]

If I got it correctly , u had the brake/clutch valve assy off the tractor and found no evidence of a problem? and still the right and left side of this dual valve system behaves diff and sound to be the problem in your dozer?

This weekend i plan to look a my dozer, and the idea was to remove the TXM pump and send it for testing and repair if needed, but in this case i´ll also look at the priority valve pressures and the Brake clutch Valve system to see if it mimics your finding.
As i mentioned before, i´ve seen people complaining of this very same problem in this era machines here and other forums, with apparently no solution.

I noticed a post on here of a guy just changing everything and still had the same problem after parts changing.
Then he either still hasn't fixed it or he fixed it and didn't post what his findings were. Which we all would be curious.
The main thing to do before anything is check pressure on the priority vavle at operating temp low and hi idle, and that will direct you to where to start looking as I stated in my post above.
As Mobiltech mentioned above it's probably the steer clutch's, and he had that answer after I mentioned my priority pressure went up when I pulled either of the steer levers. Well that wasn't hard to figure out after I mentioned that.
But I like to be sure myself and found a way to test which steer clutch side it is, maybe somebody knew how to test it but nobody posted how to. So my answer is Your Welcome!
Good luck finding your problem.

 

[Mquinista]

I noticed a post on here of a guy just changing everything and still had the same problem after parts changing.
Then he either still hasn't fixed it or he fixed it and didn't post what his findings were. Which we all would be curious.
The main thing to do before anything is check pressure on the priority vavle at operating temp low and hi idle, and that will direct you to where to start looking as I stated in my post above.
As Mobiltech mentioned above it's probably the steer clutch's, and he had that answer after I mentioned my priority pressure went up when I pulled either of the steer levers. Well that wasn't hard to figure out after I mentioned that.
But I like to be sure myself and found a way to test which steer clutch side it is, maybe somebody knew how to test it but nobody posted how to. So my answer is Your Welcome!
Good luck finding your problem.

Yep after some time dealing with several types of machinery including airborne machinery, i can conclude that books and manuals do not speak with us... and certain procedures are hid, or they are too obvious if one know the system by heart.
Lot of people in forums search answers for their problems, but once they fix theirs forget about it. Personally I like to share my solutions and or findings.

Experience also tell´s me that a tired oil pump is never the root cause of this type of problems, unless its too obvious due to catastrophic failures.

About your testing... maybe i did not got it well, u have done static testing on the Brake/steer clutches too? i mean bypassing the valve? cause i understood the problem was on the valve? is this correct?
If u did test the steer/brake clutches how have u done it?

Thanks.

 

[Northpoint]

Yep after some time dealing with several types of machinery including airborne machinery, i can conclude that books and manuals do not speak with us... and certain procedures are hid, or they are too obvious if one know the system by heart.
Lot of people in forums search answers for their problems, but once they fix theirs forget about it. Personally I like to share my solutions and or findings.

Experience also tell´s me that a tired oil pump is never the root cause of this type of problems, unless its too obvious due to catastrophic failures.

About your testing... maybe i did not got it well, u have done static testing on the Brake/steer clutches too? i mean bypassing the valve? cause i understood the problem was on the valve? is this correct?
If u did test the steer/brake clutches how have u done it?

Thanks.

If your 5h is the same as a 5m and you have lever steer with powershift transmission, this is how you test the steer clutches.
The steer/brake valve has 4 test ports on it, made for PD242 quick coupler (amazon.com). The right and left outside ports are for the steer clutches. (You may have to remove the left side male quick coupler and put on a 90 degree -6 ORB male x -6 ORB female and then put the straight male coupler back on because there are hoses in the way.) I had to remove the emergency brake 4 bolt cover to install the -6orb 90.

With the engine off, put a bungee cord around both lever steers and pull them both back as far as you can. This will make each steer clutch independent for testing.
Connect the PD242 coupler (amazon.com) with just an open hose (no gauge on it) so you can inject shop air one at a time to those outside test ports and see it pressures up. (You may need to remove the trans fill tube cap for the test to let the air escape if one of the clutches leaks air) (You can also try a leak down tester to be more accurate for the test)
They should hold pressure.

You can also test the other inside test ports for the brakes but you need to remove the bungee cord from the lever steer controls and allow them back to there normal postion.

 

[Northpoint]

I should say that you can just remove the test port male fittings and put the air hose right on the valve to test so you don't have to buy anything.

 

[Mquinista]

So, there´s no problem in your Steer/brake valve... problem is upstream in the cluch pack... i understood reverse.
5m same weight as 5h diff engine and other gadgets available like finguer tip control...
TXM with lever control seems to be much alike. including same problems...
thanks

 

[Northpoint]

Yes, I believe the problem will always be in the clutch pak on all machines. Probably will never be the valve.. My problem is the clutch pak, the left side does not pressure up.

 

[Northpoint]

Yes, I believe the problem will always be in the clutch pak on all machines. Probably will never be the valve.. My problem is the clutch pak, the left side does not pressure up.

The reason. I thought it was my valve is because my filter collapsed and may have let debris into the valve. But that was not it.

 

[Mquinista]

Yes, I believe the problem will always be in the clutch pak on all machines. Probably will never be the valve.. My problem is the clutch pak, the left side does not pressure up.

Ok, Got the point
But did u find any problems steering or braking with the levers when operating the machine?
Anyway , do u have steering/braking system operation explanation in your Manual? could u share this part? Or someone in the forum...
Maybe i´m missing something , cause i understood the system operates by releasing the brake clutch pack from spring action for service brake, and by adding/removing pressure to the piston for active braking, either by foot pedal or lever action. And Steering is achieved by releasing spring action by adding pressure to the pack.
would apreciate an explanation

 

[Northpoint]

The problem I had with my machine is I would loose priority pressure after an hour of operation which got worse as I used the machine and it would only effect the ability of it not going into gear unless I increased it to high idle where as it would then get 400psi and then it would go into gear. Watching the priority pressure gauge, the pressure would drop to around 200 psi at low idle after an hour or so which is why it would not shift into gear because the priority pressure needs to be around at least 400psi for the spool to shift over in the priority valve for the transmission to get oil to shift. I did explain this at the beginning of this thread.

I think you need to read the system operation section in the Cat manual for your machine so you can understand how it works. The steer clutch gets 325 psi + -20psi as soon as you start the machine and remains under pressure until you pull back the steer lever which then reduces it to 0 psi. Both steer clutch's are co-mingled from pump pressure when they are not pulled.
When you pull both steer levers back and hold them there, they are separated from each other and separated from the pump to were they can be tested with the machine off as I directed you in the above post.

 

[Mquinista]

That is exactly what mine does, i start it and it run perfect for an hour hour and half or two hrs then starts to have problems to shutle when cuting gas, keeping the ability to shutle at WOT, if one continues it starts to act funny in geting off gear and in gear.

I don´t have the manual thats why i asked if someone could share it.
Nevertheless , probably we can conclude something weird happens in the cluch packs, or in some O rings in piping, wich is much easier to fix than if it was inside the TXM.
In 2 or 3 days i´ll post my findings.
Regards

 

[Northpoint]

In this thread Nige posted the operation section of the manual that you can download. Maybe a page or 2 back.
Nige is very helpful with posting parts of the manuals.

 

[Mquinista]

Hy gentleman...
Looks like my dozer(d5H) experiences the same fault as this one (D5M) ... when i operate the steer brake levers P1 acts funy ... it goes up and drops... left handle more than right...
sorting out where F%$#" PV port is located

 

[Northpoint]

Hy gentleman...
Looks like my dozer(d5H) experiences the same fault as this one (D5M) ... when i operate the steer brake levers P1 acts funy ... it goes up and drops... left handle more than right...
sorting out where F%$#" PV port is located

It's under your feet when sitting in the seat. Remove the plate under your feet.

 

[Mquinista]

Buh... did not found the PV test port @ valve assy(behind filter)
I wonder where is that thing, picture in manual is a bit blured to understand where that thing is located.
A good picture would be apreciated.

Anyways , found some interesting repairs in that thing... the most interesting was that at some point someone replaced the oil intake hose to the TXM pump, this gipsys used a silicone hose and clamps like those used in auto tunning.
Thing is the hose has evidence of colapsing , i could not test it, cause i was alone and nobody to help in throtling... ( i'm pretty convinced this is not an issue) nevertheless i going to replace this hose.

Meanwhyle, despite i couldn't measure PV pressure, i could get an idea on how much the levers movement afect P1.
Left handle rises about 500 kpa, right some 350.

Other interesting thing is the P1 with the parking brake aplied comes down to 750Kpa, and when released P1 goes up to 1500. This testing was done @ 1000RPM after 2.5 hours working, when the shifting problem is really evident.

Apreciate comments, pls have patience first time diging into this mechanics.

 

[Northpoint]

Because I don't have the same machine I can't tell you how to find the PV test port, but I believe in your year machine it is made as 1 casting with the filter housing and the test port ( if it has one) should be on that filter/PV valve ( the filer is part of the PV valve) .
Like I pointed out before, the order of testing always starts with a gauge on the priority valve pressure.
When you have the required pressure at the priority valve 420psi at operating temperature or after running the machine for an hour is when you want to test the PV pressure. If it stays up around 420psi after an hour or so running or so only then can you test p1 pressure.
You keep testing p1 a d that's not how you do it.
You will not figure it out if you keep trying to test p1 pressure. That is only for the transmission, You have a steer clutch problem and you only test that by way of PV pressure test..

 

[Mquinista]

Yes thats true, the PV is in the filter assy, belive it or not there´s no port on the PV body, nevertheless there is a port over the Filter cover labeled Pump Press, could that be the port? The manual show a test point , no way it resembles the filter cover... and they say its on right side of Steer/brake valve.... no way i see those ports there...

i understand your machine is not same as mine... its just the next model ahead...

Tested P1 just cause i couldn´t find the PV test port , nevertheless it show some interaction when moving the levers... as u mentioned yours had...

BTW understood by reading manual that the steer clutches are opened by Lubrication fluid pressure and not spring actuated like the brakes, what didn´t made sense to me was: in absense of oil press they would disengage, and they do but that is not a problem as the brake clutch pack is dwn stream of driving power and will always secure the track hub in the absense of oil pressure.

thanks again for your time.

 

[Northpoint]

I believe that port on the filter is what they mow call priority pressure, it is the first thing the pump goes to which is the priority valve.