ESA Preload

[Bobra]

Hi all

The ESA preload on my 2007 RT has decided to stop working - the GS-911 returns an error message indicating a rear ESA short circuit.  There is 0 resistance across the motor and nothing happens if I apply 12V directly to the motor connector (in either polarity).  I’ve done a search here and this seems to be a relatively common and terminal problem 🙁. There is reference in this forum to a detailed BMW Service document on testing the ESA but the link (to Dropbox) is now broken.  Can anyone provide me with a current link please?  Any other comments, ideas would be most welcome.

 

cheers

 

Rob

[dirtrider]

8 minutes ago, Bobra said:

Hi all

The ESA preload on my 2007 RT has decided to stop working - the GS-911 returns an error message indicating a rear ESA short circuit.  There is 0 resistance across the motor and nothing happens if I apply 12V directly to the motor connector (in either polarity).  I’ve done a search here and this seems to be a relatively common and terminal problem 🙁. There is reference in this forum to a detailed BMW Service document on testing the ESA but the link (to Dropbox) is now broken.  Can anyone provide me with a current link please?  Any other comments, ideas would be most welcome.

 

cheers

 

Rob

Evening Rob

 

There is 0 resistance across the motor and nothing happens if I apply 12V directly to the motor connector (in either polarity)-- This pretty well tells you that it can't be tested or repaired while it's on the motorcycle. (with an open it is dead so unless you can get some continuity across the motors leads  (bumping strut, beating on, shaking, turning upside down & slamming down on a piece of wood, etc) then there really isn't much to test as you NEED MOVEMENT to test it.

 

BMW testing procedure____ 

 

Get a couple of  wires (one red & one black) preferably with alligator clips on each end.  

Find the blue motor connector with the orange wire  black wire going to it.  (obviously on the strut side not the bike side) 

 

Connect the red jumper wire to the orange wire at the blue connector, 

 Connect the black jumper wire to the black wire at the blue connector, 

 

If the spring base adjuster is at the bottom limit stop (all the way up), proceed as follows: Connect the red-cable crocodile clip to the positive terminal of the battery.

Touch the black-cable crocodile clip to the negative terminal ONLY for as long as the spring base adjuster needs to move to approximately the midway point of its range of travel. 

 

If the spring base adjuster is at its top limit stop - (all the way down)      then polarity has to be reversed and the cables and crocodile clips connected as follows:
Connect the red-cable crocodile clip to the negative terminal of the battery.
Touch the black-cable crocodile clip to the positive terminal ONLY for as long as the spring base adjuster needs to move to approximately the midway point of its range of travel.

 

If the spring-strut adjuster fails to move when power from an external source is applied in this way, then the spring strut will have to be replaced. (my addition, or try to get it working by removing & hitting it while powering it in both directions) 

[Bobra]

Thank you DR - I'll try the "brut force" method and see if I can get it working.  When I tried applying direct voltage all I got was sparks at the battery and some very hot jumper wires but I didn't try beating on it.  Can I do that without removing it from the bike?

 

 

 

 

 

[dirtrider]

8 hours ago, Bobra said:

Thank you DR - I'll try the "brut force" method and see if I can get it working.  When it tried applying direct voltage all I got was sparks at the battery and some very hot jumper wires but I didn't try beating on it.  Can I do that without removing it from the bike?

 

 

 

 

 

Morning  Rob

 

With all those sparks it sounds like the upper (movable)  spring seat is stuck-- so lubricate it with penetrating oil, then see where the spring seat is at now, then power it in the direction (per my post above) that it needs to go to move to center position. (try lightly beating on the upper spring seat while trying to power it up in the correct direction)

[Dave Glen]

G'day Rob, I had this problem with the strut unit on my bike (2005 R1200RT) a few years ago. BMW wouldn't  help except to sell me a new strut or the electronic module.

I decided to strip it down and found that the preload was mechanically stuck  fully up.

Once unstuck I was able to cycle it up and down just using a battery but when installed back in the bike it wouldn't  work using the handlebar switch so I fitted a switch under the seat directly powered from the battery. It works fine now and the damper adjustment still works off the handlebar switch.

I took some photos of the disassembly and assemble process but I think they have been lost  in the changeover of computers over the years.

All the best with yours

Dave THE bastard

Australia

2005 R1200RT (226000 klms)

 

[Bobra]

5 hours ago, Dave Glen said:

G'day Rob, I had this problem with the strut unit on my bike (2005 R1200RT) a few years ago. BMW wouldn't  help except to sell me a new strut or the electronic module.

I decided to strip it down and found that the preload was mechanically stuck  fully up.

Once unstuck I was able to cycle it up and down just using a battery but when installed back in the bike it wouldn't  work using the handlebar switch so I fitted a switch under the seat directly powered from the battery. It works fine now and the damper adjustment still works off the handlebar switch.

I took some photos of the disassembly and assemble process but I think they have been lost  in the changeover of computers over the years.

All the best with yours

Dave THE bastard

Australia

2005 R1200RT (226000 klms)

 

 

Thanks Dave.  The preload is stuck on single rider/no luggage which, in these COVID times, is just about all I'm doing (even in South Aus)  so I'll wait for a rainy weekend and strip it down.  I'm no spanner man but there seems to be lots of guidance here and there.  I'll report back.

 

Cheers

Rob

[Dave Glen]

Have a crack at it, you will need a press to dismantle and mantle because of the spring tension.

I will check to see if I can find those photos.

Dave THE bastard

Australia

2005 R1200RT 

[Dave Glen]

G'day Rob, found the photos, not as many as I thought.

The bosch motor drives a threaded shaft which then pushes a a hydraulic ram which pushes oil against the larger ram raising and lowering the strut. 

The threaded shaft jammed at full stroke, it was quite hard to loosen but once

 loosened it cycled easily by hand. The threaded section was cleaned and regreased and the whole lot assembled with new oil.

Hope this helps

Dave THE bastard

Australia 

[Bobra]

2 hours ago, Dave Glen said:

G'day Rob, found the photos, not as many as I thought.

The bosch motor drives a threaded shaft which then pushes a a hydraulic ram which pushes oil against the larger ram raising and lowering the strut. 

The threaded shaft jammed at full stroke, it was quite hard to loosen but once

 loosened it cycled easily by hand. The threaded section was cleaned and regreased and the whole lot assembled with new oil.

Hope this helps

Dave THE bastard

Australia 

 

 

 

Cheers Dave.  It will be an adventure

 

[alexvtr]

Hi Dave!

Extremely interesting post; it's the first time I see someone "reviving" a first generation ESA preload.

I have the exact same problem (preload stuck, damping ok).

 

Would you be kind enough to provide a bit more info on how you got access the preload system?

What's procedure did you used to remove the coil spring from the strut?

And when you mention that the threaded shaft was hard to loosen, exactly which part are you referring to?

Thanks in advance for your wisdom! ;-)

[Dave Glen]

G'day  Alex, sorry I haven't  replied earlier,  I have been checking for photos and also trying to remember the breakdown sequence of the rear strut. No photos and memories dim. Check out Ted Porters utube videos particularly the r1200gs breakdown. The press I used was a typical workshop press with the hydraulic ram on the top. I compressed the spring enough (with the strut upside down) and removed the clip securing the spring and then removed the preload unit. You will have to work out the various bits and bobs to fit around a spring coil ( I think I used a bearing 2 part thingamebob and steel blocks ) and push down on the bottom eye of the strut. Screenshot of a thingamebob. 

Dismantle the rebound unit after draining the oil, the motor drives a hexagonal shaft with a male thread at the opposite end,  the male thread engages in a hydraulic piston (lefthand end of photo), it is this thread which was locked on my strut. If that is your problem ( hopefully not a burnt out motor) unlock the thread,  regrease the thread,  clean every thing, reassemble and fill up with hydraulic oil with the unit in the fully down position. ie rider only position. 

You will have to work out exactly how everything  pulls apart but this is actually a very simple mechanical/hydraulic device so no rocket science required. 

I hope this is  some help, all the best with it.

Dave THE bastard

Australia

2005 R1200RT

[alexvtr]

Hi Dave!

 

Thanks so much for taking the time to add all those details!!!

I've saved this entire post to make sure I can access it when I'll start working on this little project, most probably next fall.

[Gary RT]

Hi David,

I am attempting to resurrect the seized preload adjuster on my '06 R1200RT.  I am not having as much luck as you did in the above post but still have some digging to do I believe.  My question is do you have to remove one or both of the plates with the 2 pin wrench holes in them, as shown in the attached picture?