M4 Seats

[freddyb]

I have 4 series convertible seats in my Chevelle. Absolutely love them and very easy to fit.
There are many threads about the electrical and what works/doesn’t.
So far I am unable to get the memory to work but have no problems with the seat adjustments including bolsters.
The issue that you will face (as have anyone else that has done this swap) is that the seats don’t stay “awake” for very long. You can get in, start the car and adjust. The moment you stop the seats will sleep until power is cut and re-sent.

Etc Attachment 174198

310chevelle,

The M4 Convertible seats look great in your car, which is why I bought a set. I noticed when I sat them in my car they are a little off center of the steering wheel. Did you notice the same thing, if so how did you correct this? Do you have any pictures of how you mounted the seats you can share?

I finally figure how to get the seats to constantly work from watching several youtube videos and browsing the bmw forums. Now I just need to get them mounted some way. Any additional info and pictures on mounting them will be great.

Thanks,

Fred

[freddyb]

I purchased a set of BMW 4 series convertible front seats for my 71 Cutlass Convertible. I have found a couple of issues already.
1st- Seats are about a inch to 1-1/2" off the center of the steering wheel.
2nd- Passenger seat moves in reverse when prssing the switch up/down or forward/back
Has anyone had this issue? I added a clip of the seat operation as well.

[TLeeLaguna]

I purchased a set of BMW 4 series convertible front seats for my 71 Cutlass Convertible. I have found a couple of issues already.
1st- Seats are about a inch to 1-1/2" off the center of the steering wheel.
2nd- Passenger seat moves in reverse when prssing the switch up/down or forward/back
Has anyone had this issue? I added a clip of the seat operation as well.

@freddyb do you have any wiring diagrams for the M4 seats? I'd like to power mine up like you do in the video, but can't find a diagram to show me where to apply 12v power.

[AB69Z]

310chevelle,

The M4 Convertible seats look great in your car, which is why I bought a set. I noticed when I sat them in my car they are a little off center of the steering wheel. Did you notice the same thing, if so how did you correct this? Do you have any pictures of how you mounted the seats you can share?

I finally figure how to get the seats to constantly work from watching several youtube videos and browsing the bmw forums. Now I just need to get them mounted some way. Any additional info and pictures on mounting them will be great.

Thanks,

Fred

Can you clarify why the seats are off Center from the steering wheel. Is it because of the mounts to the floor pan? Can this be adjusted by building some adapters to move the seat to Center? Is this a problem on both drivers and passenger side?
Im looking at installing the M4 seats in a 69 Camaro Convertible because of the integrated seat belt. Did you solve the wiring issue?

[chuckd71]

The seats are off because of the way the floor is shaped. To get the seats low enough to be useful for anyone over 5 feet tall you have to either cut into the car and then reweld a space for the seat frame or simply leave them off center. You can use planted or similar brackets, but you'll end up with higher seats. BMW seats are great, but without cutting the floor the slight compromises in position, and lack of a really good way to mount them in a truly secure fashion, were enough to make me sell them. I had them in a convertible chevelle

[cdrod]

Can you clarify why the seats are off Center from the steering wheel. Is it because of the mounts to the floor pan? Can this be adjusted by building some adapters to move the seat to Center? Is this a problem on both drivers and passenger side?
Im looking at installing the M4 seats in a 69 Camaro Convertible because of the integrated seat belt. Did you solve the wiring issue?

AB69Z:
The offset is the result of 2 issues; the floorpan on the A-body car is not flat like the F-bodies because it needs to clear the frame rails, so the A-body seats have the mounting tracks closer inboard to clear the rising curve in the floorpan at the door jambs. The outside seat rail on the BMW seats is much closer to outer edge of the seat; this is where it interferes with the A-body floorpan and gets pushed off-center.

Look back at post #37 where I installed a pair of e46 seats from a 2001 M3 into a '72 Olds 442 convertible. I welded up some brackets out of 1-1/2" flat steel to raise the BMW seat high enough to overcome the floorpan curve. This allowed me to shift them to the outside enough to be centered on the steering wheel. The BMW seats are rather tall and I was concerned about the overall height if I raised them higher. Fortunately, the bottom seat cushion of the A-body seat sits taller than the BMW seat so a 1" tall bracket puts the BMW seat cushion at about the same height as the factory bucket seat and the headrest is only a little higher than the factory seat would be.

Passenger restraint is significantly different between these two options. The original mounting points for the factory bucket seats are only strong enough to hold the seats. In a serious accident, the passenger is restrained by the SEAT BELT mounts. Look closely and you'll see the seat belt mounting points have heavy gauge steel plates welded to the sheetmetal floor pan and use a 1/2" bolt whereas the mounting points for the factory seats only use a 5/16" bolt. In a crash, the BMW seat must restrain the passenger as well as the seat so there are 6 14mm bolt holes in the seat rails to secure them firmly to the car body. When retrofitting these into an older car, you MUST reinforce the floorpan at the mounting points otherwise you're likely to imitate an ejecting fighter jet pilot in a serious collision; flying through the air still strapped to your BMW seat only without the parachute landing!

Rodney

[Camaro LT4]

Does anyone have a printed copy of the M4 wiring diagram, the link to the website provided was shutdown by BMW

[Camaro LT4]

I just reversed/switched the positive and negative wire on the motors

[Camaro LT4]

Can you tell me what connections you made to power up the seat, I can’t get the lumbar or bolsters to work

[joeko23]

The M4 seats need to have a timing/pulse circuit otherwise they go to sleep. Check out this video. It’s what I did. I used the timing/pulse generator and everything works. I had to play around with that screw on the pulse generator to get the seat to always be awake but it works. I bought the timing/pulse generator from Amazon and it came in a 5 pack so I have 4 left over. If you want you can have one for free. Just pay for shipping. Send me a PM if you want it or have other questions on how to make the seat work.

https://youtu.be/Y1lOHxfewRA

[Camaro LT4]

Can anyone share how they wired up there seats and got them to work continuously with going to sleep.

Peter

[AB69Z]

Can anyone share how they wired up there seats and got them to work continuously with going to sleep.

Peter

I'm waiting on my seats to arrive for my 69 Camaro convertible project.
That would be great info to have.

[AB69Z]

I'm waiting on my seats to arrive for my 69 Camaro convertible project.
That would be great info to have.

Anyone have any more info on the wiring