Fixing a tiny hydraulic oil pump.

[Ulma Doctor]

Nice save!

I have worked on lotsa different equipment and vehicles.
That’s the first electric hydraulic clutch pump that I have seen.
Usually the hydraulic pump is manually operated.
Leave it to the Germans to overcomplicate simple things!
I love their precision but I often think they take it way too far, in unnecessary over engineering

 

[Flynth]

I wondered if the commutator grooves were worn in by the springs that pushed the original brushes.
Perhaps the entire brushes were "consumed" in those 18 years and all that debris was the brush remnants.

Brian

It is very likely. The springs were an unusual kind too. Unfortunately I haven't taken any photos of them when clean, but here one can be seen.

It has an arm that pushes the brush. I never saw this kind of spring in a vertical arrangement (coaxial to main shaft).

I am having trouble understanding the design concept involved with your clutch system. Many years ago, I had an Isuzu pickup, the predecessor to the Chevy S10, that had a dry clutch that was activated by a hydraulic system similar to an automotive brake system rather than a mechanical linkage but no pump was involved there.

My experience with wet clutches was with 1960's era automatic transmissions where the clutch plates ran in a transmission oil bath. Operation was achieved by means of a piston working against springs and powered by pressurized hydraulic fluid provided by an internal pump and control valve system. I am having difficulty understanding how your little pump works. Is it simply circulating the fluid internal to the clutch or is it actually creating the pressure to operate the piston to engage the clutch? It seems rather small for the latter.

German engineering has a reputation for being top shelf but in this case, it seems to be lacking. Come to think of it, my wife used to have an Audi and I recall of number of experiences where I questioned the wisdom of their engineering.

A video was posted, but let me add few words Sorry for a wall of text.

First about its purpose, then how it works. It is important to note (if not already known) this is not the main clutch that sits between the engine and the gearbox. This car in its default configuration is front wheel drive only. The one I have is 4x4 (all wheel drive) and this clutch "system" sits in front of the rear differential. It's job is to engage power to the rear wheels in the amount controlled by its controller. On road it is supposed to improve handling, off road it works together with automatic breaking of slipping wheels so one can get out of trouble when both one front and one back wheel slips.

Then it's function. I have a motorbike with a wet clutch submerged in gearbox oil like one you described. Imagine a driveshaft coming from the front has a wet clutch right in front of the rear differential. The clutch is hydraulic operated. It has two valves (one to close, one to open) a hydraulic accumulator and this little pump.

that is a very impressive fix, well done! When you slit the new brass commutator did you slit it all the way through into the old insulation?

Thanks . I was aiming to slit it 0.2mm (8 thou) below the surface of brass. I think this barely scratched the original isolator if at all.

Nice save!

I have worked on lotsa different equipment and vehicles.
That’s the first electric hydraulic clutch pump that I have seen.
Usually the hydraulic pump is manually operated.
Leave it to the Germans to overcomplicate simple things!
I love their precision but I often think they take it way too far, in unnecessary over engineering

Me too I often wonder why VW went to great lengths to advertise this clutch system under another company's name (haldex). It went to a lot of their cars, but they still emphasise it is a third party product. Perhaps they were expecting it to fail pretty soon too and they wanted to limit their brand damage?