1988 BMW 750Li front passenger seat

Tiny
HUSKERBORN
  • MEMBER
  • 1988 BMW 750LI
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 90,000 MILES
The seat back was reclined (electric). When attempting to bring the seat back up to 90 degrees,
the left side of the seat back raised but the right side (closest to the door) did not. As I continued to play with the recline switch, it finally raised equally on both sides into the upright position. BUT. When I sat in it, the right side moved back as if the motor slipped, now the entire seat back is down and dead. At least the left side is dead. Help. Thanks.
Friday, June 20th, 2008 AT 8:37 PM

6 Replies

Tiny
TJEGZ
  • MEMBER
  • 10 POSTS
Haha, 1988 BMW 750Li. I have one
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Friday, June 20th, 2008 AT 8:59 PM
Tiny
DOCHAGERTY
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This is a problem I have a lot of experience with. The motor that controls the seat back is attached to two cables that go to the actuators and what is happening is the internal parts that turn to move the actuators has come out of the actuator and to restore this to working condition you will need to unbolt the seat(I don't take the seats out to do this repair but you may wish to) and isolate the motor that operates the seat back, remove the 8mm screws that locate the motor and pull the drive cables from the motor. Then, pull the internal cables out(careful, they're greasy) and put them aside for now. Then the ends of the black plastic tubes have metal ends, with a heat gun or a Bic lighter CAREFULLY heat the metal and when the plastic gets hot enough the ends will come off. Then what you do is cut about 1/4" of the plastic off. Then heat the metal end and push it onto the plastic tube. Then push the greasy cable back in and repeat the procedure for the other side, reassemble after you have raised BOTH sides of the seat back so that they are "timed" the same. Reassemble and that will be that my friend.
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Friday, June 20th, 2008 AT 9:11 PM
Tiny
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My original question was logged for a 750Li but I own a 735Li. I'm not sure if there is a difference with the seats, but I took out the passenger seat as you said, located the motor. It appears to be two motors side by side toward the front of the seat slightly left of center that has two cables running to the two actuators at the back and base of the seat bottom. What I'm confused about is the actuator... each has two cables connected to them. The forward most motor runs it's cables to the forward most part of the actuators. The second motor runs it's cables to the lower and further back position on both actuators. Which is which? Also, am I supposed to just pull the cable out (with silver ends attached) then heat or heat then pull? Do I also pull the cable from the actuators as well?
Hope I'm not making this too difficult. I think I understand, but I want to be sure. This vehicle is mint and I love working on my '88 325ic as well. Thanks, Doc.


https://www.2carpros.com/forum/automotive_pictures/204278_DSCN3088_1.jpg



https://www.2carpros.com/forum/automotive_pictures/204278_DSCN3089_1.jpg



https://www.2carpros.com/forum/automotive_pictures/204278_DSCN3086_1.jpg

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Sunday, June 22nd, 2008 AT 12:43 AM
Tiny
DOCHAGERTY
  • MECHANIC
  • 9,601 POSTS
I understand your question. The distinction between the motors is one is for the seat back and the other is the seat base. The way to tell them apart is to plug the electrics back in(this is why I do not take the seats out of the car) and operate the seat back and observe which of the motors is running, I believe the motor towards the front is the one but my memory isn't what it used to be. As to the cable question, the inside cables need to come out completely because you are going to shorten the black plastic that houses the cables by about 1/4" and to do this you are going to warm up the metal ends just enough to get the plastic to start to melt and let the metal ends pull off, do not get them too hot, just enough to start to get the ends loose, do that and then shorten the plastic tubes, heat the metal ends enough to let them push back on to the plastic tubes, once again, not too hot. This may require a little trial and error so lets keep the errors to a minimum, don't use too much heat!
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Sunday, June 22nd, 2008 AT 11:06 AM
Tiny
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WOW! That was actually a piece of cake. Next time I won't have to take out the seat. Thanks Doc! Next paycheck, donation for the cat.

Thanks again,

"Husker Born"

by the way, how much money did you just save me?
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Monday, June 23rd, 2008 AT 12:05 PM
Tiny
DOCHAGERTY
  • MECHANIC
  • 9,601 POSTS
If you would have taken your car to an honest and trustworthy technician for these repairs it might have been an hour or an hour and a half of labor at the posted labor rate of the shop. If replacement was the suggestion of the repairing facility then a salvage yard or facility would need to be be sourced for a replacement and the labor to R&R the seat from the car, so I would say the information we exchanged was worth at least one hundred dollars. Please remember that this is my humble opinion and might also depend on outside factors that may be beyond my control such as availability and condition of exchanged goods. If you find that you would like to go the extra mile, please feel free to contact the site management of 2carpros and let them know what you feel. My cat is glad for you!
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Monday, June 23rd, 2008 AT 1:06 PM

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