questions about improved ('08-up) trunk motor
#1
AudiWorld Senior Member
Thread Starter
questions about improved ('08-up) trunk motor
I put a used '08 lift motor on a friends '06 A8 today, but it neeeds a slight upwards touch of the lid or it wont open. Question #1 : has anyone ever known of a failure with the re-designed motor ? I am thinking that's an unlikely failure.
So what could be preventing even the powerful improved motor from being able to open the trunk ? The struts on that car are weak...when closing, the lid gets to a point it just free falls and slams shut much faster than my A8. Question #2: good struts give a more controlled drop when closing, but do they also play a part in helping the motor lift the lid by supplying a bit of upward force ? Since the gas wants to extend them straight I would think they help the lift at some point as the struts get partially extended and more vertical, but when the struts are horizontal (as at the moment when the lid is unlatched) are they contributing to the lift ? When I put an '08 motor in my A8 I had fresh struts because I had changed them as an attempt (futile) to improve the performance of my original lift motor. Adnd in my case the revised motor solved all performanced issues at all temps.
However, I have a 2004 and the '04s had the spring loaded plungers on the edge of the lid that the '06s do not. And the performance of my lid opening is improved by leaving the plunger on the motor side retracted, and the pop from the plunger on the non-driven side helps the lid stay level as it starts to rise, reducing binding.
I oiled the hinges on the '06 and when manually moving the lid through its travel there doesnt seem to be any binding or stiffness from the hinges...which is easy to guage do to the lack of resistance from the struts.
So what could be preventing even the powerful improved motor from being able to open the trunk ? The struts on that car are weak...when closing, the lid gets to a point it just free falls and slams shut much faster than my A8. Question #2: good struts give a more controlled drop when closing, but do they also play a part in helping the motor lift the lid by supplying a bit of upward force ? Since the gas wants to extend them straight I would think they help the lift at some point as the struts get partially extended and more vertical, but when the struts are horizontal (as at the moment when the lid is unlatched) are they contributing to the lift ? When I put an '08 motor in my A8 I had fresh struts because I had changed them as an attempt (futile) to improve the performance of my original lift motor. Adnd in my case the revised motor solved all performanced issues at all temps.
However, I have a 2004 and the '04s had the spring loaded plungers on the edge of the lid that the '06s do not. And the performance of my lid opening is improved by leaving the plunger on the motor side retracted, and the pop from the plunger on the non-driven side helps the lid stay level as it starts to rise, reducing binding.
I oiled the hinges on the '06 and when manually moving the lid through its travel there doesnt seem to be any binding or stiffness from the hinges...which is easy to guage do to the lack of resistance from the struts.
Last edited by awdinut; 09-14-2015 at 10:35 PM.
#2
AudiWorld Super User
Have you looked at the whole TSB on the trunk issue? The struts sounds like it's fine. The trunk should close without resistance from 12 or so inches from the bottom.
I am of the opinion that the motor and hinges should be replaced together for long term reliability. Even with that the trunk motor system is a bad design. My 09 has all the improved design components and it works 95% of the time.
I am of the opinion that the motor and hinges should be replaced together for long term reliability. Even with that the trunk motor system is a bad design. My 09 has all the improved design components and it works 95% of the time.
#3
AudiWorld Senior Member
I lube the hinges every six months
I put a used '08 lift motor on a friends '06 A8 today, but it neeeds a slight upwards touch of the lid or it wont open. Question #1 : has anyone ever known of a failure with the re-designed motor ? I am thinking that's an unlikely failure.
So what could be preventing even the powerful improved motor from being able to open the trunk ? The struts on that car are weak...when closing, the lid gets to a point it just free falls and slams shut. Question #2: good struts give a more controlled drop when closing, but do they also play a part in helping the motor lift the lid by supplying a bit of upward force ? Since the gas wants to extend them straight I would think they help the lift at some point as the struts get partially extended and more vertical, but when the struts are horizontal (as at the moment when the lid is unlatched) are they contributing to the lift ? When I put an '08 motor in my A8 I had fresh struts because I had changed them as an attempt (futile) to improve the performance of my original lift motor. Adnd in my case the revised motor solved all performanced issues at all temps.
However, I have a 2004 and the '04s had the spring loaded plungers on the edge of the lid that the '06s do not. And the performance of my lid opening is improved by leaving the plunger on the motor side retracted, and the pop from the plunger on the non-driven side helps the lid stay level as it starts to rise, reducing binding.
I oiled the hinges on the '06 and when manually moving the lid through its travel there doesnt seem to be any binding or stiffness from the hinges...which is easy to guage do to the lack of resistance from the struts.
So what could be preventing even the powerful improved motor from being able to open the trunk ? The struts on that car are weak...when closing, the lid gets to a point it just free falls and slams shut. Question #2: good struts give a more controlled drop when closing, but do they also play a part in helping the motor lift the lid by supplying a bit of upward force ? Since the gas wants to extend them straight I would think they help the lift at some point as the struts get partially extended and more vertical, but when the struts are horizontal (as at the moment when the lid is unlatched) are they contributing to the lift ? When I put an '08 motor in my A8 I had fresh struts because I had changed them as an attempt (futile) to improve the performance of my original lift motor. Adnd in my case the revised motor solved all performanced issues at all temps.
However, I have a 2004 and the '04s had the spring loaded plungers on the edge of the lid that the '06s do not. And the performance of my lid opening is improved by leaving the plunger on the motor side retracted, and the pop from the plunger on the non-driven side helps the lid stay level as it starts to rise, reducing binding.
I oiled the hinges on the '06 and when manually moving the lid through its travel there doesnt seem to be any binding or stiffness from the hinges...which is easy to guage do to the lack of resistance from the struts.
For the last year the trunk has been 100% functional. I think lubrication on all hinges and other parts makes a big difference. Plus good struts.
#4
AudiWorld Senior Member
I put the improved motor on my 06. I tried lubricating the hinges, etc with the original motor and that did not solve the issue. The new motor fixed all the issues and has been 100% reliable.
I tried the spring loaded plunger/bumper. That was a waste of time and money.
If it were mine I would replace the gas struts and lube the hinges. Those struts really do offset the weight of the trunk lid.
I tried the spring loaded plunger/bumper. That was a waste of time and money.
If it were mine I would replace the gas struts and lube the hinges. Those struts really do offset the weight of the trunk lid.
Last edited by richard-tx; 09-14-2015 at 11:10 PM.
#5
AudiWorld Member
#6
AudiWorld Super User
I sell you my brand new gas struts that I bought...
There is no fixing this problem except for my solution or may be weld a bar across the trunk lid to stop the lid from flexing when the motor engaged, but then, the hinges will give... the initial 2 sec lift the the critical - if the power is weak, the motor clutch is slipping - it's over.
Cheers,
Louis
#7
AudiWorld Super User
This is just another over engineered Art's BS design inline with front upper control arms, MMI screen mechanism and so on. Struts have no leverage at the lower end, so thay can't help. Fixing bent (!) hinges and lubricating may be a bit. Lid flexing is irrelevant.
Riding 10 years old E class Mercedes taxi on a 50 years old Greek island pavement makes me think. Not a sound.
Riding 10 years old E class Mercedes taxi on a 50 years old Greek island pavement makes me think. Not a sound.
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#8
Which surprises me - I would expect the gas struts to get *stronger* when it's hot, but something else clearly fails then.
Once car cools down (or moved to shade - BOOM - it works 100% again.
#9
AudiWorld Member
Well, for me it worked. Lubed the hing points with white litium grease and new struts makes it work 99% of the time. Except when it's really warm and car (black) has been parked in the sun.
Which surprises me - I would expect the gas struts to get *stronger* when it's hot, but something else clearly fails then.
Once car cools down (or moved to shade - BOOM - it works 100% again.
Which surprises me - I would expect the gas struts to get *stronger* when it's hot, but something else clearly fails then.
Once car cools down (or moved to shade - BOOM - it works 100% again.
#10
AudiWorld Member
Take all the tools out of the tool kit and see how it goes.
Also, I have found that the motors are not created equal. My current H series is 221NM rated but I have seen some with under 200. The old black motor that was in the car was 162NM
Mike
Also, I have found that the motors are not created equal. My current H series is 221NM rated but I have seen some with under 200. The old black motor that was in the car was 162NM
Mike