No drive to rear wheels (4x4 off road)

[Frenchtone]

You should visite Nth West finistere, Lanidult, a local beer is brewed from kelp, and, its actually not too bad!!

[voxmagna]

Put the glass in a freezer and see which layer freezes first. If either layer freezes above -10 deg C, it won't me much good inside the clutch.

[Yety]

On ‎26‎/‎01‎/‎2017 at 13:43, voxmagna said:

Put the glass in a freezer and see which layer freezes first. If either layer freezes above -10 deg C, it won't me much good inside the clutch.

 

Wrapped the stuff in cling film, because of the smell, and popped in the freezer at -18*C.

 

Still both parts fluid over the weekend. I fished a bit of the "stuff" out and it looks suspiciously like the "blobby" stuff blocking the filters. It is soft and squishes up the same way as the blobs which drain out with an oil  change.

 

I'll try and put some pics on tonight. My chemist's mind is thinking of precipitation of some sort, chemical breakdown, or something else

Hot or cold it has the same appearance, water doesn't seem to mix or form an emulsion, and the two container's content, one new, one two years old look dissimilar.

I need an oil expert.   

[Urrell]

That sounds like the orange gunge that precipitates out when DOT4 brake fluid is mixed with DOT5.
2 different oils that are not compatible.

[Yety]

Thinking about this while lying under my Suzuki, it might be that the whole matter of pump malfunction is due to increased workload/ filter blockage is due to the oil "degradation".

Why are the two container's contents so different in appearance, what are the blobs, why do they appear, and more?

There doesn't appear to be any mechanical wear debris when draining the oil.

[voxmagna]

Thinking about it some more....... The pump is a gear pump as far as I know? I posted that it runs at around 1 amp when not pumping. I didn't measure what it did with its fluid input blocked, but I suggest the pump would run just as though it was offload. It would be a different story if the output was blocked, then the blockage would push up the motor current. Since ithe motor is running normally at around 3 Amps and the 5 amp fuse also powers the cockpit display, an increase in pump current should take out the fuse. Whilst the sludge is very visible and if containing hard metal particles, could affect the pump mechanics, I put my bet on most pump failures being electrical caused by the motor, but aggravated by the momentary diagnostic self check not getting the correct current. Once the fault is latched your 4WD is no more and you won't know until you need it - Fit the led.

 

How many dealerships are going to mess around taking pump motors apart? Realistically they will scan the car, get the fault code, call in a replacement pump and send the customer off with a repaired car and a big bill.

[felicia16v]

me I took one apart, its a sliding piston pump with a wobble plate quite similar to an ac pump, what my findings are is that water gets into the wiring, the + wire mainly and corrodes it where its soldered to the motor causing the controller to see a higher resistance and shut down, replacing this wire and sealing it properly seems to cured the 4 I've done so far this year. 

The controller measuring blocks show the hydraulic pressure and as the only connection it has to the rear diff is the pump, no other sensors etc it must calculate the pressure from the load on the pump, I think it does a simple resting resistance check on startup and if its wrong just shuts the pump down until its happy again.

[voxmagna]

...it must calculate the pressure from the load on the pump.....

 

I don't think so. Look at the graphs I posted showing motor current and pressure. The motor current is either near zero or 3.5 Amps and fairly constant. Pressure is controlled by the positioning motor V184 which is a stepper motor controlling the valve. It's connections are via the two contacts you have to be careful with when you lift the Haldex controller off the main body. One question is where does the feedback come from to control it? I think this is coming from torque sensors or other sensors elewhere.

 

I would summarize replies to the problem of failed Haldex Gen 4 pumps as follows:

 

1. The Haldex motor has bad internal connections from the wires connected to terminal points inside the motor.

2. The Haldex motor has poor brush contact due to sticking brushes, brush wear or dirt.

3. The Haldex controller does a short motor burst 'current good' check at key on and permanently latches a motor fault if the test current is too low. Thereafter, there is no 4WD and you don't know until the car is scanned or you are in an off road situation with wheel spin.

4. A good motor should measure a resistance of around 2.5 ohms.

 

I'm intrigued by the discussion on globby Haldex oil, but I think Haldex pump motor failures are down to the Haldex design. Fortunately most can be easily fixed saving a lot of money. Even brushes might be sourced. Somebody needs to confirm brush length on a low mileage pump - mine were 9mm.

 

 

[felicia16v]

Oh yeah forgot about the valve for the clutch pack.. I'll try and remember to measure the brush length on the next low mileage one I do and update this with the data 

[voxmagna]

I just finished fitting a green 5mm led and bezel to the lift off interior panel nearside rear. With  some patience you can remove the rear lock cover trim and get a wire down the side, without removing the lining. The led is not over conspicuous and annoying (at night) and can 'disappear' with a slight shift of the interior mirror to the offside. I used a green led and 560 ohm resistor. A 12V led would work fine, but you can't control the brightness if it is too bright. Anybody who tries this needs to know that +12V is on the yellow pump wire and 0V is on the black wire. I can see the pump come on for low speed acceleration, stay on longer when in off road mode, go out when on the flat cruise and come on when decelerating and when cornering which all sounds normal behaviour. It also goes off a couple of seconds after using the hand brake.

 

What they got wrong is the wire entry point into the motor: The wire entry is high up on the end and as everybody knows, water runs downhill! If they had brought the wire into the bottom of the motor housing with a slight drip loop, it would have sealed better. If I need to get the pump out again I'll have a look at that.  Apart from getting a good seal, if the motor lead was longer it could loop downwards a little before it goes up and locks in the first cable clip. But for off road running through streams etc the motor wire sealing needs a second look.

Edited 2 February, 2017 by voxmagna

[dasower]

Just what Skoda should have fitted in the dash display ! Any chance of a couple of photo's on the LED installed ?

 

Was the LED a 5v with the 560 ohm or a 12v with 560 ohm.

 

Will have to get one fitted.

[Yety]

Good stuff here. A lot has been explained about the Haldex coupling clutch. Bearing in mind the Haldex advice is oil and filter must be changed every 20k miles - VAG/Skoda say sealed for life - simply clever. Perhaps the "blobs" are oil degradation/polymerisation caused by heat after extended mileages, the pump seems to be busy.

I was going to lengthen the power supply lead to the pump, but changed my mind. It has a silicon sleeve which if you're careful can be inserted into both connectors, as the sleeve is extra long and bunched up under tension, which might help to proof the wire entry into plug joint. A bit of silicon grease at both ends might be useful. If the lead was longer, might it be possible to turn the pump through 180* and have the pump/cable grommet pointing down as suggested.

 

Is there such a thing as say a wifi "switch" to save looking for a route into the cabin?

[voxmagna]

Ordinary leds (diodes) need a series resistor. I don't run green more than about 15mA otherwise you get short life. Therefore 5mm green led + 560 Ohm is about right and not too bright. If you want it in your face, or rather the rear mirror, go for high bright clear red and a 470 ohm resistor. Otherwise use a 12 volt led which has a resistor built in. If you don't want to drill a 6mm hole in the rear corner trim cover, you could just poke the led out from the edge of the cover. It comes off easy, unlike the long cover over the lock keep which is a pain in the but to get back without breaking the 5 spring clips along the top underside.

 

To get this simple led up in the cockpit with wiring would need a lot of messing about. I could have used a cheap Fleabay wireless single channel garage door opener, but you need to do some work on the fob to permanently enable the button and provide a step down voltage from the pump.  Then you mount the receiver 'module' up front under the console to activate your led. These things are only about £4 and I've used them before.

 

Simplest was to remove the rear top plastic cover, run a wire down behind the left lining, down through a bung in the boot floor then across the back side of the heat shield to the Haldex unit. The back side of the heat shield shouldn't get too hot being cooled by the air space above, but I did use some silicone wire. Glass fibre sheathed cooker wire would be high temperature also. I'm sure 105 deg C would be o.k, but I already had the silicone wire. I fitted a 2 pin faston connector on the end and its female spliced to a a pair of wires soldered to the Haldex motor wire. I did extend the motor wire my about 100mm which makes it easier to remove the connectors on the controller. I'm not sure you can turn the motor around, the pump section has to stay aligned for its filter to align with the port in the body(?).

 

Attaching my 2 pin faston connector to the pump wires now means I would have to cut and solder splice the connector and wires on to a new pump if it was replaced.  The really smart mod. would be to identify the Skoda OE 2 pin connector and wire up a break out adaptor using a male and female plug/socket.  Will post up a photo.  Seeing the led come on, go off, or dim whilst driving gives some insight into what the 4WD is doing and when it is most active.

[voxmagna]

Photos uploaded. Sorry, Yeti off the ramps now so no wiring photo, but everything is neat and tidy, soldered splices with heatshrink sleeve over. resistor and solder junctions all fit inside the moulded space for the cover retaining clip.

[Yety]

Looks good, a led closer to normal view would be time consuming, but not impossible - well done.

 

I've just ordered two http://www.ebay.co.uk/itm/VW-AUDI-2-PIN-PLUG-1J0-973-702-CONNECTOR-1J0973702-FREEPOST-/171094209519?hash=item27d60273ef:g:0sQAAOxybetR~ODr  to fiddle with. I thought, taking your lead  that the led wires could be included in the new plug onto the Haldex controller, together with an extension with adhesive heat shrink tubing.

Possibly my link is wonky, but you'll still find the item!

 

 

[voxmagna]

Ideally, you also need the matching other half as a wireable connector. I've always found it hard to get those to make 'breakout' leads for testing because the other half is always a module mounting version and only techis wanting to do other things would need them.

[dasower]

Making a breakout lead sounds brilliant, is this

 

http://www.ebay.co.uk/itm/VW-AUDI-2-PIN-PLUG-1J0-973-802-CONNECTOR-1J0973802-FREEPOST/181418503944?_trksid=p2047675.c100010.m2109&_trkparms=aid%3D333008%26algo%3DRIC.MBE%26ao%3D1%26asc%3D41398%26meid%3D5a1d8094a8764535b3880ddfceb863fb%26pid%3D100010%26rk%3D3%26rkt%3D6%26sd%3D171094209519

 

the mating part of the connector no 1J0 973 702

[dasower]

or there is a kit of the 2 connectors  VW AUDI 2 PIN PLUGS 1J0 973 702 & 1J0 973 802 CONNECTORS from the same seller.

[voxmagna]

That looks like it with a similar series part number. So you need the following connectors:

 

1 off 1J0 973 702

1 off 1J0 973 802

 

Bridge them with longer wires and 'T' splice and sleeve for the led. Then no interference with the stock wiring if the pump needs replacing in future and you solve the problem of their short wire making it harder to access the plug to pull out of the controller.

 

Found these cheaper: http://www.ebay.co.uk/itm/Audi-VW-Skoda-2-Pin-Plug-Waterproof-Connector-Kit-1J0-973-802-1J0973702-JPT-/191707222602?hash=item2ca2a4124a:g:UvEAAOSw9r1WD-Cc

Edited 3 February, 2017 by voxmagna

[dasower]

Will get them ordered, I made some similar break out leads ones when I fitted LEDs to my DRL so I could just unplug the ballast resistors.