Volvo EC15B weak track performance

[Muz]

Thought of continuing with this topic as it is hydraulics related.

the story is as follows:
-slow drive works ok and both final drives seem to be doing fine. The machine runs straight.
-rabbit drive is partially ok. Right hand final drive slows down the engine rpm, not stalling, but clearly there is something that resist oil flow. It appears clearly when using that drive only.

should I take the drive for inspection and perhaps replace some seals or should I suspect the feedthrough between upper and lower parts of the doug?

Merry Xmas to all

br. Mattir

As far as I know, the block is fed by a main gear pump and the output is not variable,but a constant flow., so when you select double speed travel, an extra solenoid kicks in to supply extra flow to the drives to increase the drive speed, but as a rule of thumb, this will reduce the power available at the drives, and the engine will appear to be under extra load, as if you had pulled on 2 services at once, and your tracking power will be reduced, but the speed increased, does that make sense ? The last one I had that had double speed tracking, had the solenoid fail a long time ago so I havent checked it but I expect with high speed travel engaged, virtually no other service will be available ?

FYI the boom offset solenoid is the same type as the one that controls the hi speed travel and also the dead mans circuit .. got to a stranded machine one time at night which wouldnt move, as the dead mans circuit one got fried, and I used one of the other solenoids to get it going

[Matt_EC15]

Thought of continuing with this topic as it is hydraulics related.

the story is as follows:
-slow drive works ok and both final drives seem to be doing fine. The machine runs straight.
-rabbit drive is partially ok. Right hand final drive slows down the engine rpm, not stalling, but clearly there is something that resist oil flow. It appears clearly when using that drive only.

should I take the drive for inspection and perhaps replace some seals or should I suspect the feedthrough between upper and lower parts of the doug?

Merry Xmas to all

br. Mattir

[gardenshed]

Top tip, thanks Muz!

[Muz]

As these machines age, they all gradually suffer from progressively weaker tracking performance, to the point they wont slew they machine on a grippy surface like a dry road, this is clearly not good.

The solution usually is that the main valve block pressure has dropped to around 160/165 Bar when it should be 175. The main bank inlet P3 needs adjusted to correct the problem as in the picture. 10 Bar doesn't seem a lot, but it will drastically improve tracking performance once set correctly. The locking nut is a 19mm and you'll need a small hex key to screw the valve in to increase the pressure, not even half a turn will be enough but you will need a guage to set it , using the test point on the other side of the valve

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