Audi A8 D3 Trunk / boot motor fix - sanding disc
10-28-2014, 10:10 AM
#21
AudiWorld Wiseguy
Thread Starter
you not fixing anything.
all you are doing is altering the original design removing the biggest safety feature out of it.
so now it works up/down open/close.
that was not the original simple purpose of this device.
what if something is in the way of the trunk lid while closing?
all you are doing is altering the original design removing the biggest safety feature out of it.
so now it works up/down open/close.
that was not the original simple purpose of this device.
what if something is in the way of the trunk lid while closing?
Joking aside, I did consider this and in testing this safety feature is unaffected. The safety mechanism doesn't work by allowing clutch slip, rather by actually disengaging the clutch itself. The system monitors motor current draw, and if it exceeds a certain threshold as would be caused by the lid binding on an obstruction it automatically de-energizes the clutch coil and shuts down the motor therefore releasing all the force in the mechanism. Its important to note that the lid can still be manually operated in exactly the same way as before. This modification doesn't alter that in any way.
10-28-2014, 03:39 PM
#22
fix
Aw, Shucks....that'd be why I lost my arm to the trunk lid just yesterday!
Joking aside, I did consider this and in testing this safety feature is unaffected. The safety mechanism doesn't work by allowing clutch slip, rather by actually disengaging the clutch itself. The system monitors motor current draw, and if it exceeds a certain threshold as would be caused by the lid binding on an obstruction it automatically de-energizes the clutch coil and shuts down the motor therefore releasing all the force in the mechanism. Its important to note that the lid can still be manually operated in exactly the same way as before. This modification doesn't alter that in any way.
Joking aside, I did consider this and in testing this safety feature is unaffected. The safety mechanism doesn't work by allowing clutch slip, rather by actually disengaging the clutch itself. The system monitors motor current draw, and if it exceeds a certain threshold as would be caused by the lid binding on an obstruction it automatically de-energizes the clutch coil and shuts down the motor therefore releasing all the force in the mechanism. Its important to note that the lid can still be manually operated in exactly the same way as before. This modification doesn't alter that in any way.
congratulations on keeping safety in mind when working on it.
11-10-2014, 07:29 PM
#23
AudiWorld Super User
I think Mishar is correct about the trunk lift motor...
The Summer project is finally done - 3 steps deck. I had sometime to start working on my weak trunk motor. I checked the Magnet clutch, extremely strong, it's practically impossible to slip. The motor does draw lots of current to turn the clutch - gears and trunk linkages. It's the combination of the weak motor and the hinges, the design does need a very high torque motor. It will time out after so many seconds of time if the trunk is not lifted.
- I took out the motor, put some pine rosin on the surface of the clutch - doesn't work.
- I bought the non slip strip for stairs, the clutch and the plate stuck tight, can't even close the trunk manually.
- I cleaned everything, all the film caused by the glue, the old solder paste, the new glue from the non-slip strip - Make all the contacts clean and shiny and put it back.
Yes, I could close the trunk but not lifting the trunk. Adjust the hinges - charge up the battery - lifted the left stopper a little higher - There it is, it lifts the trunk again.
If the hinges and and the trunk is aligned perfectly, I'm sure the motor can lift it up every single time, but our trunks are getting old - USED - hinges are not well aligned - therefore the lifted stopper with the spring helps the trunk to lift. The closing part is easy.
Now, if <a href="http://www.ebay.com/itm/like/171122644473?lpid=82" target="_blank">I boost the power on the motor dc input</a>, it may work - Only need the first few seconds with tons of torque to lift the old hinges up and away it lifts.
NO more voodoo stuff on this motor.
Cheers,
Louis
- I took out the motor, put some pine rosin on the surface of the clutch - doesn't work.
- I bought the non slip strip for stairs, the clutch and the plate stuck tight, can't even close the trunk manually.
- I cleaned everything, all the film caused by the glue, the old solder paste, the new glue from the non-slip strip - Make all the contacts clean and shiny and put it back.
Yes, I could close the trunk but not lifting the trunk. Adjust the hinges - charge up the battery - lifted the left stopper a little higher - There it is, it lifts the trunk again.
If the hinges and and the trunk is aligned perfectly, I'm sure the motor can lift it up every single time, but our trunks are getting old - USED - hinges are not well aligned - therefore the lifted stopper with the spring helps the trunk to lift. The closing part is easy.
Now, if <a href="http://www.ebay.com/itm/like/171122644473?lpid=82" target="_blank">I boost the power on the motor dc input</a>, it may work - Only need the first few seconds with tons of torque to lift the old hinges up and away it lifts.
NO more voodoo stuff on this motor.
Cheers,
Louis
11-10-2014, 08:30 PM
#24
AudiWorld Wiseguy
Thread Starter
Looks like the non slip tape you put in is too thick so doesn't allow any clearance so jams it up. Try it with the thinner sticky back Sanding disc like I did. Still going strong by the way
04-05-2017, 08:31 PM
#25
AudiWorld Member
dvs_dave, how is your trunk working now. I am contemplating my trunk which has a new hinge, new struts and is lubed all around, but still can't lift from closed position, or close from the open position. Once started, it works fine...it just can't get started. Before I shell out $500+ on an H motor, it might be worth it to give your clutch solution a try...
04-05-2017, 08:44 PM
#26
AudiWorld Super User
Why people keep wasting money on struts and hinges, there are only 2 ways, buy a new motor or use the springs like mine. It's been working for 4 years now and still working.
My struts still the old ones. The new ones experts up here recommended are still in the garage, collecting dust for 4 years.
Cheers,
Louis
My struts still the old ones. The new ones experts up here recommended are still in the garage, collecting dust for 4 years.
Cheers,
Louis
04-05-2017, 08:50 PM
#27
AudiWorld Senior Member
I have the same issue with my wife's 08 A8L. I am going to experiment with a few ideas. For now, I believe the self stick sandpaper idea is a good one.
I am not going to add springs to my cars for a few reasons. Crude and gauche are but two.
If I have to, I will buy a new motor but since I have one to experiment with, I will try a few things to improve/repair the original motor. Based on my observations, it seems that the friction material is worn. More to come.....
My wife's trunk lift struts were wrong. Someone installed two left struts. Installing the correct one on the right improved matters tremendously. Once I find a solution for the slipping clutch, then her trunk will work properly.
rich
I am not going to add springs to my cars for a few reasons. Crude and gauche are but two.
If I have to, I will buy a new motor but since I have one to experiment with, I will try a few things to improve/repair the original motor. Based on my observations, it seems that the friction material is worn. More to come.....
My wife's trunk lift struts were wrong. Someone installed two left struts. Installing the correct one on the right improved matters tremendously. Once I find a solution for the slipping clutch, then her trunk will work properly.
rich
Last edited by richard-tx; 04-05-2017 at 09:01 PM.
04-05-2017, 11:22 PM
#28
AudiWorld Super User
The full cure in my opinion is a new motor and struts. After experimenting with new motor only on my 05W12 and now my 09W12 that came with the updated motor runs perfectly only after the strut replacement.
04-06-2017, 05:50 AM
#29
AudiWorld Wiseguy
Thread Starter
I snapped up a killer deal on a used H motor ($175) off eBay. But my old motor was still working with the sanding disc fix at the time, so its worth a go.
I took both motors apart to compare them and aside from the bigger motor and alloy case, the clutch and gearing in both versions were seemingly identical.
I think perhaps that flexing of the plastic gear case is a contributary factor in the clutch clamping force and its consequent ability to transfer torque once the clutch wears down to a certain point.
Switching the whole case assembly from injection moulded plastic to cast alloy is an expensive and major change to implement for the supplier, so it must have been determined to be a root cause after the numerous prior revisions. I think the bigger motor is a belt and braces measure whilst they were at it.
I took both motors apart to compare them and aside from the bigger motor and alloy case, the clutch and gearing in both versions were seemingly identical.
I think perhaps that flexing of the plastic gear case is a contributary factor in the clutch clamping force and its consequent ability to transfer torque once the clutch wears down to a certain point.
Switching the whole case assembly from injection moulded plastic to cast alloy is an expensive and major change to implement for the supplier, so it must have been determined to be a root cause after the numerous prior revisions. I think the bigger motor is a belt and braces measure whilst they were at it.
04-08-2017, 12:20 AM
#30
AudiWorld Senior Member
The clutch works by virtue of the electromagnet (coil) so case flexing has nothing to do with clutch clamping force. The friction material is really hard so it has less friction than a softer material. The friction material is glued in place so replacement is possible. Replace it with what is the big question. More to come....