Lowering Birkin seats

[KiwiBirkin]

Hi guys my car needs to go back to the work shop for a small issue with the rebuild of my car (nothing serious) and the center consol is coming out again, i promised my self that when the center consol was ever removed again that I would look at lowering my seats in my Birkin and now is the time to do it.

 

So has any one done this in their Birkins and if so do you have pictures at all you could share ?.

 

My thoughts are to cut the 2x 25mm box sections that the seat slider is bolted to out and weld in some 5mm flat bar along the same lines and then bolt the seat slider to that instead, it looks like I could lower the seat about 35mm lower this way.

 

Cheers Kiwibirkin

[slomove]

I cut out the slide rails altogether, made a hole in the floor, welded 2 bent steel strips 1/8" x 1" as seat carriers and riveted a 1" lowered aluminum pan under the hole. The seat is bolted through the pan to the steel strips. Overall that dropped the seat over 2".

[KiwiBirkin]

I cut out the slide rails altogether, made a hole in the floor, welded 2 bent steel strips 1/8" x 1" as seat carriers and riveted a 1" lowered aluminum pan under the hole. The seat is bolted through the pan to the steel strips. Overall that dropped the seat over 2".

 

Do you have any pics Slomove, I understand what you have done but pics spell a 1000 words. Mind you I still have to make the drivers side adjustable for those rare days my 5 ft 7" wife wants to drive which means i maybe cant drop that much. But as they say another 1" is some time all you need :rofl:

[snookwheel]

I also would love to see some pictures so I can get a better read on your solution! My wife is 5'7" too and having the slider really does raise the seat.

 

Scott

[Automoda]

What I did was cut 3 wedges of wood (from a 2x4) and screwed them to the bottom of the seat. They'd rest on the floor skin, which is weak and not something you'd want to put weight on... So I welded up some metal brackets that attach to the front of the wedges which allow you to bolt into the factory mounting points (front). Of course that leaves the back side of the wedges, being very thin, with nothing to sit on. So I made some more brackets and put a piece of 2x4 across the back panel at the right position and bolted it to the back seat-bracket mounts. That let me sink some big nasty screws through the seat into the wood to hold up the back side of the seat. Perfecto. It has a bit more recline and it is mounted firmly and is reinforced with the wedges so that you can stand on it (plus a little protection from below). It is as low as you're going to go without dropping the pan, since the back-bottom corner of the seat is touching the floor. Its light too (mostly wood and some metal brackets). Yes, I know-- wood is not a material you use in cars. But it is very difficult to line everything up in the back and just being able to sink some screws anywhere in the area is a lot easier. The wood is painted black anyhow, so it doesnt show-- and it adds lightness and strengthens the bottom of the seat.

 

The down side is it took days of tinkering and welding and filing. And those seat bracket bolts that go in from the sides in back are a pain to thread due to crowding. Slowed me way down. I'd take pictures but I dont feel like removing the seats. Here's a sketch:

 

http://herb.linkrealms.com/seat%20sketch.jpg

[slomove]

Do you have any pics Slomove, I understand what you have done but pics spell a 1000 words. Mind you I still have to make the drivers side adjustable for those rare days my 5 ft 7" wife wants to drive which means i maybe cant drop that much. But as they say another 1" is some time all you need :rofl:

 

I did not take a pic specifically for the lowered seat but here is one I took for the propshaft cage and you can see some of the lowered driver seat floor behind it. While that drops the floor over 2" (compared to stock with sliders), the net gain is actually smaller because my Cobra seats are taller at the bottom than the stock Birkin seats.

 

The height is perfect for me, looking through the top 1/3 of the screen. But even my 5'2" tall wife can drive with no height problem whatsoever. However, having shorter legs and arms she needs a special 4" thick rigid foam seat back spacer/cushion for her and a 2" block for the clutch to get the right position for the pedals and steering. She does not use it very often but has been driving with that a full day on some of our long tours. No complaints.

 

If I had to do this again, I would probably avoid the additional floor pan and riveting and just hammer planish the floor sheet to create an integrated pan.

 

http://lh5.ggpht.com/_242PlvPtVpE/SyVWauzVHUI/AAAAAAAAA6U/nIrDeF7FuDM/s1024/P1000845.JPG

Edited September 3, 2010 by slomove

[KiwiBirkin]

Great pictue Slomove it helps alot with my ideas.

[gjslutz]

I used 1" X .063 square tubes and bolted it to the bottom of the Birkin. They were spaced far enough apart for me to drop my slim Ultrashield seat down in between. I cut out the floor between them and then added .032 T3 aluminum on the bottom side of the tubes for an 1" drop.

 

If another person that was shorter was to drive the car, I would just add padding in the seat to fit them.

 

 

I had removed the tracks prior, but it was not enough for me.

[KiwiBirkin]

I also would love to see some pictures so I can get a better read on your solution! My wife is 5'7" too and having the slider really does raise the seat.

 

Scott

 

Hi Scott I have managed to lower my seat today and keep the slider I have lowered it around 1 1/2" inches and it has made a huge difference to me sitting in the drivers side. im 5ft 11 and instead of looking through the windscreen 2" from the top of the windscreen frame im now looking through it just above center.

 

All up it took about 5 hours and I have taken pictures and will put them in this forum thread as soon as I can get them of my mates camera.

 

It involved cutting out the seat rails so it looked like Slowmoves picture of the passenger side and then mig welding 5mm x 50mm flat bar across the bottom and then using the flat bar from the bit I cut out with the nuts in that held the seat slider in place, this was then welded across between the 2 bits of 5mmx50mm flat bar after I grinded the nuts of and opened the holes to 8mm which was also drilled through the floor pan. I then re bolted the sliders back in and had to bend the slider handle up a bit as it now fowled on the front bracing box section as it was sitting lower

 

I then re-bolted the seat rails back in, because I used the flat bar they were mounted to they lined back up fine and I then put the seats back in place.

 

I hope you can understand what I did and if I have made it clear enough.

 

Opps there is one thing I did do while doing this and that was move the flat bar that the seat rails were mounted to aft a bit from the orignal position as I noticed I was at the 2nd to last notch of the slider when sitting in the car and when you do all this you have to remember that you are moving the seat to a more upright position from its angled position and therefor will end up with a gap at the back of the seat if you keep it all in the same place so move those bits back about 10mm and you will have about 2 more notches for your seat to go back on.

 

Pics soon .

Edited September 6, 2010 by KiwiBirkin

[Kitcat]

No one's worried about their butts hanging down below the floor pan? I know its not a lot and your do have the seat "cushion". In my case that consists of about 1/8" carbon fiber Tillet seat. Just curious.

 

Mike

[KiwiBirkin]

Managed to lower my drivers seat another 1" today by taking out the seat rails and bolting the seat directly to the floor via the new 50x5mm flat bar bits I put in the other day. While this is great for me as I drive the car 99% of the time I will put the seat rails back in when I go on longer trips in case Marg wants to have a go at driving some of the time, it will only take about 20 mins to swap this around when I come to do it.

 

Out of all the mods I have done to my car lowering the seat is the best one yet and im now in sitting position like I was in a my mates Caterham, I cant not for any reason think why Birkin mount their seats so high up ???.

[snookwheel]

Kiwi, Thanks for the description of what you did to lower the seat. I am looking forward to seeing the pictures! We do have to keep the slider in since both my wife and I drive it a fair bit.

 

Scott

[KiwiBirkin]

I really didn't need to lower my seat anymore as I had accomplished what i wanted too with the seat rails in place but the little bit extra was there for the taking

 

I tried to get the photos off my mates camera today but he had a mini sd card and I didn't have a reader capable of reading it, I will have photos up by at least the beginning of next week though for you Scott.

Edited September 7, 2010 by KiwiBirkin

[KiwiBirkin]

Ok here are the pictures as promised.

 

Old seat rails cut out

 

http://i660.photobucket.com/albums/uu326/Hotdognz/bits%20and%20pieces/Seatrail1.jpg

 

New flat bar tacked in flat bar is 50mm x 5mm and sitting as low as possible so its on the floor as to say.

 

http://i660.photobucket.com/albums/uu326/Hotdognz/bits%20and%20pieces/Seatrail2.jpg

 

Flat bar cross section that the rails bolted down too from the old cut out section, I used these bits as it allready had the correct spacing for the bolt holes in my seats.

 

http://i660.photobucket.com/albums/uu326/Hotdognz/bits%20and%20pieces/Seatrail3.jpg

[KiwiBirkin]

Another picture but from a angle this time.

 

http://i660.photobucket.com/albums/uu326/Hotdognz/bits%20and%20pieces/Seatrail4.jpg

 

Seat rails bolted in place

http://i660.photobucket.com/albums/uu326/Hotdognz/bits%20and%20pieces/Seatrail5.jpg

 

Hope all this makes sense too you and helps you out, after I was happy I painted all the new metal with Black Galv paint.

 

Cheers Kiwibirkin

[Automoda]

Hm. Mine is a 2003 and it had no seat rails welded in. The whole seating track was bolted to the cross-piece at the front of the seat and the harness tabs on the floor in both back corners. Welded in rails would be a bit tougher to work with.

 

You know, I just thought about it and another solution would be to hold the seats from the sides rather than trying to support from the bottom. Depending on your seats of course.

 

My solution had the seat tipping back a bit, too. I *really* like the position now. (but you have to be careful not to tip back too much or you'll find your knees hitting the underside of the scuttle's framework). But if you're tipping the seat back, then much of the metal (*added weight*) in the flat bar-stock solution people are using is not really supporting the driver's weight because the front of the seat would be sitting on a spacer on top of the cross-piece in order to tip it up. So in that case I think just a short tab of metal that catches the back of the seat, with perhaps a small 90 degree angle cut to a slope (for strength) would work at the back (especially since everyone is welding it, which would make it extremely secure). So I guess my thinking is that if the seat is just being held up at a few points, just make sure those points are strong. I added the wedges to actually help stiffen the bottom of the seat since I am using the fiberglass ones that came with the car (plenty strong to step on).

 

It seems regardless of the method, its a fair bit of work and tinkering. Someone should make a kit ;o)

[MHKflyer52]

My solution had the seat tipping back a bit, too. I *really* like the position now. (but you have to be careful not to tip back too much or you'll find your knees hitting the underside of the scuttle's framework). But if you're tipping the seat back, then much of the metal (*added weight*) in the flat bar-stock solution people are using is not really supporting the driver's weight because the front of the seat would be sitting on a spacer on top of the cross-piece in order to tip it up. So in that case I think just a short tab of metal that catches the back of the seat, with perhaps a small 90 degree angle cut to a slope (for strength) would work at the back (especially since everyone is welding it, which would make it extremely secure). So I guess my thinking is that if the seat is just being held up at a few points, just make sure those points are strong. I added the wedges to actually help stiffen the bottom of the seat since I am using the fiberglass ones that came with the car (plenty strong to step on).

 

Here is a photo of how I mounted the seats in my 7 and it is like the way you described I think.

http://picasaweb.google.com/MHKflyer52/ALotus7Replica#5217898795526478770

 

http://picasaweb.google.com/MHKflyer52/ALotus7Replica#5217899304071487618

 

:driving: :auto: