Hello All,
I tried closing the hood one day and it did not want to budge. After closing it manually and a bit of trouble shooting I found it was the electric motor which drives the hydraulic pump which was faulty.
Symptoms: Roof unlatches but does not open, storage compartment unlatches but does not close, no noise from hydraulic unit (in RHS in boot), unit starts working after a few light taps with a soft mallet.
All the above can be due to poor conduction between the motor commutator and motor brushes.
The cause of this is that the brushes get stuck in the brush carriers and do not make good contact with the communicator, this in turn leads to arcing and poor contact. The issue is resolved by cleaning the commutator and prevented by prying open the brush carriers (gently) to allow the brushes to move freely again.
Here is what I did to get my motor working again

(As you would expect please do so at your own risk I accept no responsibility)
So I started off by removing the boot rubber channel then the rear cross panel trim,
http://dl.dropbox.com/u/38150502/A4...ving and installing rear cross panel trim.pdf
http://dl.dropbox.com/u/38150502/A4...ving and installing rear cross panel trim.pdf
Removing the right side trim
http://dl.dropbox.com/u/38150502/A4...ing and installing side trim (right-side).pdf
but before this panel can be removed the hinge for the hood storage compartment has to be removed, be careful not to drop the washer between the hinge and the bodywork
Unclip at the back
The trim should then slide out towards the rear of the car (slide past the hood storage compartment)
You should then be somewhere here, then remove the wiring plug to the 12v power socket and the boot light
Once this panel is removed, remove the three bolts holding the amplifier
Move the amplifier to the side for easy access to the hydraulic pump
You should now have access to the hydraulic pump, proceed to removing the three nuts holding the pump down
Now before you let loose at dismantling the motor housing do something I did not do (and learnt the hard way), MARK the position of the motor casing with a black marker
Unclip the relays from the relay carrier
Now you are ready to remove the motor cover, open the 7mm bolts (make sure you have marked the position of the housing)
Pull the housing, bear in mind that the magnets will provide some resistance
So now you can see the problem, dirty commutator
So I got some 800 wet and dry paper, held it in place with a screw driver and turned the motor by hand until it cleaned up
Once the surface is clean, use a stanley blade to clean any debris in the slots on the commutator
And there you have it, a nice clean commutator
Reassemble with a touch of grease on the end bearing not forgetting to line up the markings you did earlier and you should be all sorted !!
The next step is to stop the problem reoccurring by prying open the brush carriers, insert a small screwdriver between the small slot in the brush carriers and gently pry them open, then pull the brushes back and confirm they spring back freely towards the commutator. See picture below
View attachment 14986
I have attached some other files which I pulled of Elsa on A4 Cabriolet roofs, these are below:
General Information on Hydraulic System
http://dl.dropbox.com/u/38150502/A4...r/General Information on hydraulic system.pdf
Exploded View of Convertible Top
http://dl.dropbox.com/u/38150502/A4 Cab Roof Motor Repair/Exploded View of Convertible Top.pdf
Exploded View of Hydraulic System
http://dl.dropbox.com/u/38150502/A4 Cab Roof Motor Repair/exploded view of hydraulic system.pdf
Block Diagram of Hydraulic System (This is in case you want to know how it really works !!)
http://dl.dropbox.com/u/38150502/A4 Cab Roof Motor Repair/Block diagram of hydraulic system.pdf
Wiring Diagrams for Electric Hood
2003 Onwards
http://dl.dropbox.com/u/38150502/A4 Cab Roof Motor Repair/Electric Hood Wiring Diagram 2003 on.pdf
2005 Onwards
http://dl.dropbox.com/u/38150502/A4 Cab Roof Motor Repair/Electric Hood Wiring Diagram 2005 on.pdf
Good luck ! In case of any queries, or if you would like any more information of the workshop manual drop me an email
khurrumsattar@hotmail.com
facebook.com\VProUK
I have recently had a number of emails and requests for other roof related issues and for carrying out the procedure above. Although I work full time as an Engineer I can assist for a small fee (to cover my time). So please do not hesitate to contact me !!