S3 8l Haldex problem

Bullseye

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Hi Everyone,

New here,my 2nd post is a problem already!

Getting wheel spin so no 4wd!.So far I've checked,

the haldex fuse,earth strap underneath car from differential to body,
handbrake switch working correctly
.7 amp draw on VCDS measuring blocks to the controller,
cleaned the connection at the controller,
scanned with no faults and is communicating with the haldex controller,
in output tests pump is making noise,

I didnt hear any noise for the test to engage clutch but not sure should this make noise anyway? When the car is on a lift the 4 wheels are spinning but defintely not working when on the road?

The haldex oil and filter were last changed about 18months ago or 10k.
Everything looks ok to me and no funny noises either?

Im not sure where to go from here so I would be greatful if anyone had some more suggestions!
Also Ive searched through other threads with the same problem too,

Thanks
Dave
 
If you've got access to ramps it'll only cost £15 to drop the oil and put some new stuff in so that can't be a bad place to start, at least then you'll know 100% it has the right amount in.

If the precharge pump is a little bit fubar, will it still make a noise? might not be making enough pressure to engage the haldex clutch for power delivery on the road?

Take the precharge pump out and inspect it?

EDIT: I forgot to say, pull the Haldex fuse and see if it handles/responds in the same way. Also have you tried driving it with the ESP off?
 
Thanks for the reply,

Yes changing the oil would be a good place to start,at least it can be ruled out!
I never tried driving the car with the fuse out,If I turn off traction control the front wheels only spin,I had my girlfriend doing fast take off's on the grass just to make sure!

Pump not making enough pressure could be a cause alright,I'll have a look at it tonight,

Cheers will report back with more news

Dave
 
Its been awhile since i have tried to sort this out!
I have since changed oil and filter in haldex but the problem still persists.I was reading on another thread about 5% going to the rear but not too sure what this means!

Im thinking now maybe the pump is not making enough pressure like vfr800 said to engage the clutch? Ive since had the car remapped so I need to sort this out now!

Any suggestions greatly appreciated.
 
Im thinking now maybe the pump is not making enough pressure like vfr800 said to engage the clutch? Ive since had the car remapped so I need to sort this out now!

I've been thinking about this. If the pump isn't make enough/consistent pressure then it might be slipping the haldex clutch - more than it's designed to be - which might be a cause of the plates burning out/seizing.

You mean 50%? When the haldex clutch is fully engaged it will transfer all the energy sent down the prop shaft to the rear diff. So when it's fully engaged you'll be getting a 50/50 split of power between the front and rear. I don't know if the haldex is designed to reduce the power to the rear by slipping the haldex intentionally - any way not for sustained periods I'd have thought.

(btw these are my assumptions/thoughts so I could be entirely wrong)

Liam
 
I've been thinking about this. If the pump isn't make enough/consistent pressure then it might be slipping the haldex clutch - more than it's designed to be - which might be a cause of the plates burning out/seizing.

You mean 50%? When the haldex clutch is fully engaged it will transfer all the energy sent down the prop shaft to the rear diff. So when it's fully engaged you'll be getting a 50/50 split of power between the front and rear. I don't know if the haldex is designed to reduce the power to the rear by slipping the haldex intentionally - any way not for sustained periods I'd have thought.

(btw these are my assumptions/thoughts so I could be entirely wrong)

Liam
Thanks for your reply Liam,

I think I might take the pump off and get it reconditioned to rule that out but as you said the harm could be already done to the clutch plates.Is it possible to repair/replace these?,the local dealer is 1500 euro for new haldex with my one part exchange.I have been looking for second hand one but Im in ireland and not that many in the breakers at all!Its puzzling me because when i have it on the lift I tried stopping the rear wheels when I had the car going but there was fair pressure on them and they were still spinning,but on wet grass they still wouldnt spin!
 
Thanks for your reply Liam,

I think I might take the pump off and get it reconditioned to rule that out but as you said the harm could be already done to the clutch plates.Is it possible to repair/replace these?,the local dealer is 1500 euro for new haldex with my one part exchange.I have been looking for second hand one but Im in ireland and not that many in the breakers at all!Its puzzling me because when i have it on the lift I tried stopping the rear wheels when I had the car going but there was fair pressure on them and they were still spinning,but on wet grass they still wouldnt spin!

Yeah you can get new haldex clutch plates - but it'd probably be cheaper to drive over here and get an old one from from a scrappie. Loads of different VAG models use the same Haldex clutch.

I guess a new(er) haldex pump is your best bet for the moment. A new one will be warrantied for two years as well. I bet a recon one won't.

When you change your haldex oil - look to see how much debris/gold coloured flakes - that's your friction surface on the clutch plates I believe.

Liam
 
Thanks for your help!
I seen this on ebay motor for haldex pre charge pump gen1 | eBay

When I changed the oil it was clean but on the filter there was half a teaspoon of grey slime but no flakes of any description!Im constantly checking for fault codes too but none so far.Ichange that pump and report back with news hopefully good!

Cheers
 
Thread resurrection ! !

I had put this on the back burner for awhile as I got married last year so funds had to go elsewhere!

Anyway as Liam suggested I bought a second hand haldex/diff unit of ebay. Unfortunately the pump or controller didnt come with it but I changed it anyway today. So another haldex oil change for the newer unit but problem is still there. Four wheels spinning on the ramp but only two on the dry road.it has me thinking it must be the pump now just not making enough pressure? I started the car and put it in gear on the ramp and it took about ten seconds before the rear wheels started to spin. Nextup is a new pre charge pump. I will change that and report back here.

Also if driving with esp on (light off on the dash) the cars power dies when wheel spin occurs and the esp light is flashing.then when it gets a grip it takes off again.if the haldex did work would the power not die and four wheel drive cut in then? And if driving with esp off what happens then when wheel spin happens?

A little bit confused!
 
Maybe the controller is duff? Try another controller and see what happens.
 
When the esp is on, the car will cut the power if itv thinks the wheels are slipping. When it's off, it'll spin if traction breaks.
 
There may be worn Haldex-discs but it is unlikely. There are several other options, one of which is clogged strainer on the pump and it can not make enough pressure.
 
I had a look at the pump strainer when i changed over the haldex. It was spotless clean no dirt at all as was the haldex oil. I might the pump next and then the controller.if i change both together i wont know what was at fault if i manage to get it working!

Thanks for replies.

@ sham 101 is the pump working ok?
 
Thanks rupe

Cheers sham 101

I will go with the new one for the sake of a few extra bob and see how i get on!

Fingers crossed!
 
just to help you out i will lend you the pump at £20 and if i dont sort out your prob you can send it back that is fair
 
I bet £20 that is not the pump! Just a week ago I had the same problem and know what was the reason for me. Guess what's in the case.
 
Whats in the case??!!

How did you solve your problem,haldex controller?
 
One option is to blocked rotor of the electric motor. The other is to have a worn gear teeth.
 
So just to update this thread with 4wd fixed!

I agreed to pay sham 101 for a loan of a working pump.never turned up or a refund. I then bought a new pump but that still didn't get the 4wd working. Next was to change the controller so I bought a used working controller and after changing that everything works as it should ! Happy days ! Thanks to all who posted with advice,cheers!
 
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Fixed after nearly 3 years, now that's dedication!

i think mine was fixed after about 6 years. mine too turned out to be the controller - I went for that first. I was just waited until a new one popped up for second hand price...and yes one did eventually in America.
 
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