Thanks to @RobbiZ4 for all his work on the E89 hydraulic top system. I suspect this may also apply, in some way to the E90 hydraulics? @RobbiZ4? I am reposting this information from E89 Post, and ultimately one wants to go look at the German Zroadster forum, where the work is laid out in further detail.
From RobbiZ4 at https://e89.zpost.com/forums/showthread.php?t=1522435
Hi guys,
In the German zroadster.com forum we currently had several cars with damaged hydraulic pumps. Today I got one damaged pump as well as the 2 pink relais from one of the forum members for further analysis.
All the following links will direct into my German threads. I'm pretty sure you will be able to understand the basics, the pictures as well as my conclusions. -
If not, you can open those links with Google translate and you will get a nearly perfect translation.
Weeks ago I already made an analysis of the electrical environment of the hydraulic pump and relais. My retractable hardtop diagnostic tool was re-used to plot another EKG diagram of the hydraulic activities of the roof:
The following link is not required to read! It will lead you to the backgrund story and the "why" did we discuss and analyze this topic.
http://www.zroadster.com/forum/index...raulik.133304/
By trying to understand the electrical support of the hydraulic pump I've identified a massive weakness of this construction:
The pump is directly connected to the plus and minus terminals of the battery. There is only a 50A fuse in the line as well as those 2 pink relais. No additional switch to remove the battery power from the pump. The 2 relais are conducted by the Cabrio Top Module (CTM) the way, that always 1 relais has to be activated and the other has to be deactivated and vice versa. If both relais are deactivated (without any currency), the pump is switched off. So far so good, that's the intended function.
With every opening and closing cycle the contacts of the 2 relais will abraded a little bit (hope this is the correct word in English) due to the high amouunt of currency to be switched (up to 50 ampere).
Depending on the age and the number of roof opening cycles, the 2 relais will fail after some years.
The pump will continue to run even if you lock your car and leave it. It might be stopped by an empty battery. But our current experience is, it will run until all wires will be melted! Just have a look on the linked diagnostic of the burned pump.
The most worse thing is, that BMW has arised the price of this pump from 600€ up to 2.700 € in this year! In total you will have to pay much more than 3.000€ to get it repaired by your dealer., caused by a simple cheap relais for only 15€, that was used beyond it's lifecycle.
Based on these analysis results we placed a recommendation in the German forum to replace both relais every 2 years to avoid a burning hydraulic pump.
Feel free to think about it as well.
Hydraulic damage analysis part 1 (Relais ~ 15€)
http://www.zroadster.com/forum/index...2#post-2763037
Hydraulic damage analysis part 2 (Hydraulic pump ~ 2.700€)
http://www.zroadster.com/forum/index...2#post-2763122
My recommendation in the German forum:
http://www.zroadster.com/forum/index...-jahre.133521/
Source of damage:
Result:
Attached Images
From RobbiZ4 at https://e89.zpost.com/forums/showthread.php?t=1522435
Hi guys,
In the German zroadster.com forum we currently had several cars with damaged hydraulic pumps. Today I got one damaged pump as well as the 2 pink relais from one of the forum members for further analysis.
All the following links will direct into my German threads. I'm pretty sure you will be able to understand the basics, the pictures as well as my conclusions. -
If not, you can open those links with Google translate and you will get a nearly perfect translation.
Weeks ago I already made an analysis of the electrical environment of the hydraulic pump and relais. My retractable hardtop diagnostic tool was re-used to plot another EKG diagram of the hydraulic activities of the roof:
The following link is not required to read! It will lead you to the backgrund story and the "why" did we discuss and analyze this topic.
http://www.zroadster.com/forum/index...raulik.133304/
By trying to understand the electrical support of the hydraulic pump I've identified a massive weakness of this construction:
The pump is directly connected to the plus and minus terminals of the battery. There is only a 50A fuse in the line as well as those 2 pink relais. No additional switch to remove the battery power from the pump. The 2 relais are conducted by the Cabrio Top Module (CTM) the way, that always 1 relais has to be activated and the other has to be deactivated and vice versa. If both relais are deactivated (without any currency), the pump is switched off. So far so good, that's the intended function.
With every opening and closing cycle the contacts of the 2 relais will abraded a little bit (hope this is the correct word in English) due to the high amouunt of currency to be switched (up to 50 ampere).
Depending on the age and the number of roof opening cycles, the 2 relais will fail after some years.
- Failing in this special situation means NOT, the roof doesn't work anymore (this was our assumption up to now).
- Failing of one of these 2 relais means, the contact will stay closed even if the relais power supply has been removed.
The pump will continue to run even if you lock your car and leave it. It might be stopped by an empty battery. But our current experience is, it will run until all wires will be melted! Just have a look on the linked diagnostic of the burned pump.
The most worse thing is, that BMW has arised the price of this pump from 600€ up to 2.700 € in this year! In total you will have to pay much more than 3.000€ to get it repaired by your dealer., caused by a simple cheap relais for only 15€, that was used beyond it's lifecycle.
Based on these analysis results we placed a recommendation in the German forum to replace both relais every 2 years to avoid a burning hydraulic pump.
Feel free to think about it as well.
Hydraulic damage analysis part 1 (Relais ~ 15€)
http://www.zroadster.com/forum/index...2#post-2763037
Hydraulic damage analysis part 2 (Hydraulic pump ~ 2.700€)
http://www.zroadster.com/forum/index...2#post-2763122
My recommendation in the German forum:
http://www.zroadster.com/forum/index...-jahre.133521/
Source of damage:
Result:
Attached Images
Last edited: