allroad V6 TDI slow build

[Greg Roles]

Nice to hear you are leaving the cat in, that's the way forward, responsible performance!

[Ryeman]

Do you mean play you exhaust sound on your stereo? Not sure I would want that. Perhaps noise cancelling though, that might be better.

Yeah,
it'd play on a frequency which you could tune in and select whenever.

[gldgti]

Got 870 off km off the first full tank after the new exhaust, which speaks well for the benefits indeed (previously getting 770-800).

[gldgti]

Having some other issues with the air suspension now, looks like the compressor needs some TLC. I have ordered at compressor repair kit (£29) so will see how that goes. Towed my my 600kg trailer with about 800kg of scaffolding in it on the weekend and the car didn't even seem to notice the load. Even better for reversing said load up my steel driveway. Gotta love quattro auto for that!

[gldgti]

Pulled the compressor last night and dismantled it. A bit of piston ring wear but it all looked pretty good considering 240,000km - certainly a new ring will help though. My main concern is that it appears the compressor motor might be the real problem, I suspect worn brushes as I couldnt measure any continuity across the terminals for the motor (at times). I put it all back together and got it to work with some jumper leads, blew plenty of air which was good but its definitely a bit hit and miss with the current as once it was back in the car and working again it stopped a couple of times and started again when I gave it a whack with my hand.... so im even more certain about it being brushes now. Good news is that its not the airbags, no leaks I can find anywhere and the valving is working exactly as designed.

took about 10min to remove the compressor, 10min to disassemble and 15 min to put it all back, so its not a pain regardless.

[anthony--t]

Possible to upgrade the comp to a viair model? I'm really interested in the air setups on these, I'll have to have a google about the setup when I get a chance.

[gldgti]

Welcome to come and take a look man

[anthony--t]

We'll have to tee something up. Keen to come see your exhaust too and I think I still have your oil catch tub thing haha

[gldgti]

maybe you should come and give me a hand when I put the resonators in? I'm gonna do that at home cost its not too much welding.

[anthony--t]

Yeah man, flick me a message beforehand and so long as I'm not working would love to!

[gldgti]

So we were going away for the weekend until the car wouldnt raise up. Limped home thinking it was either the compressor, a bag gone or both. Got home and checked all the bags and definitely no leaks. So, pulled the compressor again and started troubleshooting...
After a few tries experimenting beach testing, I realised the compressor would run bit not start when voltage was applied when it was stopped in a particular position. So, after adjusting the preload on the brushes, polishing the commutators and still no real improvement, I finally noticed that 2 wires going to the armature were cracked just near where they looped around the connection to 2 of the commutator bars. This meant that spots on the commutator were basically dead and hence the compressor would start sometimes but once it stopped in a dead spot that was it.
So, I soldered the windings back onto the commutator and boom, the damned thing runs like NEW.
Makes me wonder how many compressors get replaced for this relatively simple problem, not even hard to fix once you realise what it is!

[Ryeman]

So we were going away for the weekend until the car wouldnt raise up. Limped home thinking it was either the compressor, a bag gone or both. Got home and checked all the bags and definitely no leaks. So, pulled the compressor again and started troubleshooting...
After a few tries experimenting beach testing, I realised the compressor would run bit not start when voltage was applied when it was stopped in a particular position. So, after adjusting the preload on the brushes, polishing the commutators and still no real improvement, I finally noticed that 2 wires going to the armature were cracked just near where they looped around the connection to 2 of the commutator bars. This meant that spots on the commutator were basically dead and hence the compressor would start sometimes but once it stopped in a dead spot that was it.
So, I soldered the windings back onto the commutator and boom, the damned thing runs like NEW.
Makes me wonder how many compressors get replaced for this relatively simple problem, not even hard to fix once you realise what it is!

Cars with 'air' suspensions, as far as I'm concerned, are are ok if a business expense but from my budgetary position are a complete no-no/nightmare of added complexity and unreliability.
Is there a vehicle with such that has a good reputation?
It'd be nice to think that you've found the weak link and will never fail again.
If there is a top-of-the-range model that has it it's ruled out as AFAIC.

[gldgti]

Well, I think its a bit of an overreaction to say its a nightmare of added complexity and unreliability. Its another system that can go wrong - its more that the system forms part of the suspension and so if it does go wrong, there could be 'no drive home with it broken' results - same as any other part of the drivetrain.

I was dissappointed with the car for the 5-6 hours before I finally fixed it, at which point I fell back in love with it again for all its awesomeness. I find it hard to imagine ever going back to a car without air suspension after this (talking family car sized - its not a requirement for me on a hatchback).

There are nearly no factory air suspension vehicles with a good reputation, and interestingly, nearly every factory air ride car in the world seems to use this same WABCO compressor.... to name a few:

> All VAG air ride cars inc Porsche
> All Volvo air ride cars
> All BMW air ride cars
> All merc air ride cars
> All modern Range Rover/Landy with air ride

And I'm sure others that I dont know about.

Heres a pic of the commutator - this is before I'd done any work on it, but you can see ehre the armature windings attached to the commutator bars - in 2 places it had simply cracked.

[gldgti]

big thanks to anthony--t for giving me a hand today adding resonators to the exhaust. Took us about 2.5 hours but got the job done right and now the tips are sitting pretty, sound is sweet and the droning has gone - no more baffles at all - WIN!

[anthony--t]

Woohooo!!