I've been working off & on this winter trying to solve the low pressure problem I have with the steering clutches on my D6c. It's kind of turned into a quest to solve what appears to be a combination of problems.
A couple of years ago I redid the steering clutch seals so I checked out as many other potential causes as I could before removing the clutches again, but found I was losing aprox. 100 psi between the steering clutch valve and the clutches (by comparing pressures with clutches blocked off or not)
To be sure it is all good I replaced the seals (with Cat parts) and both the bearing cages and clutch hubs (aftermarket). The seals, which are a split ring type, had a fairly large end gap (nearly 1/8") which I didn't care much for.
After reassembly I checked the pressures and leakage again. I did get some improvement but not as much as I was hoping for. I realize it's designed to be somewhat sloppy but would like to get a little better pressure readings.
Here are results after the new seals are in:
Video of leakage at clutch seals at low idle w/warm oil: http://ift.tt/1D8ytiN No doubt the piston seals have similar bypass leaks but aren't visible.
2nd video: Lt & Rt clutch pressures (low idle, warm oil) http://ift.tt/19ZdXHN Note sluggish pressure rise. Manual spec. is 315 psi min. pressure
3rd video: pressures @ high idle http://ift.tt/19ZdW6C First gauge is supply pressure to steering valve, then the two clutches.
4th video: bevel gear case showing oil flow from valve as clutch is operated: http://ift.tt/19ZdXHU
Stream at far side is overflow lube oil for bevel gear bearings
Near stream is dump from steering clutch pistons
5th video showing sluggish pressure rise even with clutches blocked off at the bevel gear case (low idle, cold oil) http://ift.tt/19ZdXHX
The slow pressure rise here makes me suspect a secondary problem....perhaps bypass at clutch valve or in trans relief valve (see my other youtube videos of trans valve)
I real temped to pull the clutches again and make my own seals that don't have such a wide ring gap. They appear to be made of Delrin and wouldn't be difficult to make since I have a lathe & mill.
First I wan't to eliminate the clutch valve as a problem. I have located a used valve that I may be able to try out temporarily to see it it makes a difference.
Basically, I think it's a build up of leaks from wear on several different parts that's reducing the flow of oil. I did tear down the gear pump and found it to be in good condition and checks within manual specs. I can get an aftermarket pump for about $150
Anyway, thought I'd post these videos to get other opinions about what I'm seeing.
A couple of years ago I redid the steering clutch seals so I checked out as many other potential causes as I could before removing the clutches again, but found I was losing aprox. 100 psi between the steering clutch valve and the clutches (by comparing pressures with clutches blocked off or not)
To be sure it is all good I replaced the seals (with Cat parts) and both the bearing cages and clutch hubs (aftermarket). The seals, which are a split ring type, had a fairly large end gap (nearly 1/8") which I didn't care much for.
After reassembly I checked the pressures and leakage again. I did get some improvement but not as much as I was hoping for. I realize it's designed to be somewhat sloppy but would like to get a little better pressure readings.
Here are results after the new seals are in:
Video of leakage at clutch seals at low idle w/warm oil: http://ift.tt/1D8ytiN No doubt the piston seals have similar bypass leaks but aren't visible.
2nd video: Lt & Rt clutch pressures (low idle, warm oil) http://ift.tt/19ZdXHN Note sluggish pressure rise. Manual spec. is 315 psi min. pressure
3rd video: pressures @ high idle http://ift.tt/19ZdW6C First gauge is supply pressure to steering valve, then the two clutches.
4th video: bevel gear case showing oil flow from valve as clutch is operated: http://ift.tt/19ZdXHU
Stream at far side is overflow lube oil for bevel gear bearings
Near stream is dump from steering clutch pistons
5th video showing sluggish pressure rise even with clutches blocked off at the bevel gear case (low idle, cold oil) http://ift.tt/19ZdXHX
The slow pressure rise here makes me suspect a secondary problem....perhaps bypass at clutch valve or in trans relief valve (see my other youtube videos of trans valve)
I real temped to pull the clutches again and make my own seals that don't have such a wide ring gap. They appear to be made of Delrin and wouldn't be difficult to make since I have a lathe & mill.
First I wan't to eliminate the clutch valve as a problem. I have located a used valve that I may be able to try out temporarily to see it it makes a difference.
Basically, I think it's a build up of leaks from wear on several different parts that's reducing the flow of oil. I did tear down the gear pump and found it to be in good condition and checks within manual specs. I can get an aftermarket pump for about $150
Anyway, thought I'd post these videos to get other opinions about what I'm seeing.
D6c Steering clutch pressure (again)
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