E39 Sport seat discomfort

[Sprun24]

About a month and a half ago I bought a 540i m sport that needed the seat twist repaired. While it was broken I managed to get the seat into a good enough position for me to drive for 3 hours completely comfortably. After I took it out and fixed the twist issue, I can't sit in it for more than 10 minutes without back and neck pain. I am fairly sure I got the seat even, it looks and measures even when in in the car. I've tried all manner of seating positions with no improvement, everything from old lady bolt upright to basically laying down.

I can't figure out what the problem is. It feels comfortable when I first get in, but after a little while it starts to hurt. The seat doesn't have good lumbar support but putting a towel behind my back only makes it hurt more. I'm going to take the seat out tonight and see if anything looks wrong. I have had other people drive the car (for a short distance but enough that it would make my back hurt) and they had no complaints.

Writing all of this out it really sounds like the issue is unrelated to the car. I have an office job and sit for most of my day. My desk chair doesn't cause me any discomfort. Nothing else does actually, it only ever hurts when I'm in the car or for a few hours after getting out. Right now this is easily the worst seat I have ever sat in, not even limited to car seats. Stadium bleachers are better than this.

Is there any way this isn't caused by the car seat? If it is caused by the seat, do you have any ideas on how to fix it? I'm confused because it was comfortable at some point. Its possible that I put something together wrong, which is what I hope for tonight's investigation to reveal. I love the car but I'll have to at least buy new seats if I can't sort this out. I bought the car mostly for its luxury aspects so swapping to the comfort seats would be nice, but they are hard to find locally(pa) and not cheap.

Thanks!

[kallekula]

I got the sport seats too and yes they are not comfortable. Maybe the foam ages with time and becomes harder. Check the dealer (or if aftermarket exists).

[Sprun24]

The bottom cushion is definitely squished down on the drivers side. Replacing it seems to be quite the chore but I will get to it eventually if I keep these seats.

I tried out a smaller towel for lumbar today when I went to grab lunch and it seemed to make a major difference. I also adjusted the seat after placing the towel, which I didn't try before. I'm going to see if I can add some foam between the metal bars and the seat back foam to give it a bit of natural lumbar support. The seat being hard is definitely part of the problem, but I think that just means it needs to fit me correctly, which it doesn't currently do. I test drove another e39 before this one and the seats felt similarly firm.

[haolibird]

When I do seat twist repair, I power up the seat in the garage, sit in it, adjust it, and finish the repair.

If you apply power to the red and brown wires, you should be good.

Curious, how did you go about fixing the twist?
Opinions vary.

As an aside, I am going to experiment with taking the stuffing out of a passenger seat, and installing it on the drivers side.


Tom

[MotorMouth93]

You can retrofit lumbar support parts from the comfort seats.

The bottom cushions are the same on both sides, and you can buy brand new foam from BMW for $150ish and its softer than the old 20+ year old foam. Swapping the foam and installing lumbar support parts was the first thing I did when I traded my comfort seats for sport seats.

[Sprun24]

Tom - I repaired the seat twist by pulling off the metal ends, and then pushing them back on after heating them up. I put some glue filled heat shrink on after, it seems sturdy. When I put the seat back together I left one of each of the cable disconnected and put it in the car. I positioned it perfectly sitting in it then put the cables back in the motors. It was a fairly easy project short of actually getting the seat out of the car.

MotorMouth93 - I do like the idea of adding the oem lumbar system to my sport seats. If my hokey/free fix improves things I will go that route. I want to make sure I'm at least heading in the right direction if I'm going to start spending money on these seats. Good to know that the new foam is softer, I would have thought the worn out foam would be softer. E38 16 way comfort seats seem like the most practical option if I replace them. They are affordable and were standard on the lwb model so they are plentiful. I believe they are the same as the e39 comfort seats but most e39s being parted out around me have sport or basic seats.

[SW530]

Odd.. when we picked up our 2003 540i/6 in Texas we drove back in a 14 hour day and it was the most comfortable seat I've ever experienced. I had a head on, on my Harley when I was 32yo.. the guy was drunk and hit me at a 135mph closing speed. My pelvis was broke in 8 pieces cleanly, my back broke in 4 places, hips were broke, femurs, about the only thing not broke was my right arm. (needed that for.. well.. you know..) I was also split open and disemboweled from below the sternum to the bottom on my back. I was inpatient for nearly 3 years. Today I walk around with a limp and my back is a constant issue mostly because the best repairs they could do didn't result in the pieces lining back up as they should.

So when my son and I went to get the car we were planning on six driving hours a day at most with plenty of breaks.. I know it aggravates him like it did me when my father would have to stop every 45m to smoke for 15m.. He never complains though.. but imagine his surprise when our only stops in a 14h day were for gas or food. I love my sport seats.

When I repaired the seat twist on both front seats I rigged up a small push mower starting battery I hadn't thrown out yet.. ran two wires with spade lugs to the appropriate spade connectors on the seats connector and ran the seats through their adjustments at least ten times each. I also measured how they seats don't sit flat in the car, but you can measure this and then run appropriate sized strips of wood on your bench, screw them down, and then lag the seat to the bench, one side on the strip. As far as I can tell or measure they're level when in the car.

I don't know if the seat foam has been replaced, but my seat pad seems thicker than others I've seen by maybe 3/8".. I wish I could find new foam and replace it anyway..

StateFarmClassic-31.jpg

[MotorMouth93]

https://www.ecstuning.com/b-genuine-...h/52108162329/

$175

I hope you like hog rings.

[kallekula]

Hmm i thought i had a motor for lumbard support, guess not. Gotta google on how to do that. Nothing I been thinking about though and my back is shot.
I did all my wires when I fixed the up down functionality. Inside there are gearboxes and some gears are made of plastic. They were completely worn down. Must have been a really heave PO right now I’m doing the frontend and I think I’m done with the car after that though so I think I’ll skip the foam replacement.

- - - Updated - - -

https://www.ecstuning.com/b-genuine-...h/52108162329/

$175

I hope you like hog rings.

I don’t but I’ve removed and replaced hundreds of them redressing volvo car seats. Everything comes down to the right tools

-l

[Sprun24]

I had a go at adding some foam to the back for lumbar support. First impressions are good but we'll see how it is after I go to work tomorrow. I used some 1/4" craft foam and masking tape to build up lumbar support on the front of the seat to the point where it felt like just a bit too much. I then covered it in duct tape so it would hold its shape and slid it between the metal bars and the factory foam. Its a very significant difference. It feels much better but I'm not going anywhere tonight so I'll have to withhold judgement for tomorrow morning.

SW530 - I read a number of reports just like yours from people who think they're the absolute best, which is why I was suspecting something else initially. I'm 22 with no long term back injuries, I wouldn't have thought a bad seat alone could cause this. I'm pretty sure it was cumulative over a few weeks, which is why it didn't hurt in the beginning. But an hour and a half of not enough support a day adds up I guess.

[kallekula]

Take care of your back. I’ve had lumbard problems most of my life on/off and it’s not fun. If you have an office job try getting a desk you can height adjust.

[MotorMouth93]

For lumbar support retrofit you need the air pump assembly, valve assembly, bladder, switch, a hose to connect the pump to the valve, and wire harness. The air pump has a plastic housing that clips onto the bottom of the seat. All E39 power seats have a little plastic cover over where the switch goes you just have to pop it out and snap the switch in, they also all have the mount point for the valve assembly inside the seat back. All the parts are pretty cheap on Ebay, I almost bought the stuff at my local junk yard before looking up the prices and balking. 3x the cost of Ebay and I have to stomp around a scrap yard and pull the parts myself, no thanks. I bought brand new OEM valves and bladders though trying to avoid leaky old parts, and ended up with leaky new parts.

I fabricated my own harnesses but if you had access to a donor seat you could probably extract the wiring. I also found that ALL of the new valve assemblies available were leaky pieces of crap after sending a few back and having them all leak down. Maybe there was just a bad run of valves, it was early COVID and manufacturing was suffering.

I find that moderate weight (mid 200s) deadlifts and squats do a nice job of keeping my back feeling good despite an office job.

[kallekula]

You have some pictures of that lumbard foam work?

[SW530]

https://www.ecstuning.com/b-genuine-...h/52108162329/

$175

I hope you like hog rings.

Thank you! Ordered.

[Jason5driver]

Yeah , my standard comfort seats are not doing so hot ….
The driver’s seat foam and heating element is pushed way over , and burns the left part of your back and butt . lol

[Sprun24]

kallekula - I didn't take any before I put it in, but here's the seat after installing and the back of the seat where I put the foam. From the front it doesn't really look any different. I think it squished down a bit over last night, I might see about adding some plastic or something hard between the foam and the wires.

20230130_185733.jpg
20230131_073150.jpg

Motormouth93 - I normally never have issues with it, this car is the first thing to really give me any trouble. The foam was definitely an improvement. It was slightly uncomfortable on my drive to work but nothing like it was before. Really just feels like it needs to be a bit taller and it'd be perfect. I suspect the past month of back pain contributed to todays discomfort, if I was 100% it would probably be great as is. The lumbar support addition seems pretty easy, where did you end up getting a leak free valve? Even if I buy a seat harness to disassemble on ebay I'd be into this for less than $150 so its definitely an appealing option.

[sleuth255]

https://www.ecstuning.com/b-genuine-...h/52108162329/

$175

I hope you like hog rings.

I've heard that using zip ties instead of hog rings is the hot tip here. Makes sense to me but I've not tried it.

[kallekula]

I've heard that using zip ties instead of hog rings is the hot tip here. Makes sense to me but I've not tried it.

Using zip ties just makes the job harder. They’re also plastic and might break after a while. A good pair of pliers and a bag of hog rings is not expensive.

[Sprun24]

I'm pretty pleased with the foam solution. I might order one of those hand pump inflatable lumbar supports and put it in instead of the foam, having some adjustment would be nice. Regardless, I think I'm going to replace the seats with the 16 way seats, either with or with the intention of installing the active function. My goal with this car is pretty much exclusively comfort on long trips. The only 'performance' mod I'm going to do is a lsd, which should be standard in rwd cars anyway. At least now I can put off replacing the seats for a little while, I'd like to get my e36 working first.

Thanks for the help ya'll

[MotorMouth93]

The OEM bladder has an upper and lower bag, it would be a pretty good solution to hook up hand pump bulbs to these instead of the pump and valve assembly, and you'd have the up and down adjustability.

I never found working valve assemblies I gave up since I didn't really need the lumbar support and was tired of taking the seat apart. Now that I'm thinking about it again I might mess with it though.

[haolibird]

I hate hog rings...

Looks like it's TJ upholstery for me...

My covers are shot as well.

Sprun, I have done that repair the same way, until I came across something I thought was easier.
By cutting a section out of the outer sheath in a convenient location, pushing the 2 parts together, then using fuel line and zip ties to keep it all together.
Glad to hear you got it sussed.

[kallekula]

About the hog rings, sometimes they sit in awkward places and you need to press the tool in between the foam to get them to the right place. A good pair of pliers holds the rings firmly until you crimp them. Much harder to do with zippies where you have to use both hands and really struggle to get em in there. To get the old ones off use a heavy duty side cutter or open them up with a pair of lock ring pliers. Just my 2c.
Think this was the pliers I bought. HF sells/sold them but they didn’t hold the ring properly. Never tried them but I could tell by the design they wouldn’t work properly. Might have changed design now I dunno.
https://a.co/d/5rzdp9m

[philly98540]

I ended up using good quality zip ties when I replaced my driver side foam many years ago. Working fine. I guess either method works good. Hog rings seemed more effort at the time but likely not such a big deal.

[Sprun24]

I hate hog rings...

Looks like it's TJ upholstery for me...

My covers are shot as well.

Sprun, I have done that repair the same way, until I came across something I thought was easier.
By cutting a section out of the outer sheath in a convenient location, pushing the 2 parts together, then using fuel line and zip ties to keep it all together.
Glad to hear you got it sussed.

I saw someone do something similar with fuel line and hose clamps, I think I'm going to do this when I get to the passengers side(and whatever new seats I buy, probably should do it before I put them in). Seems easier. I might try to get some of those metal zip ties like you use for steering rack boots, would be a little lower profile than hose clamps and sturdier than zip ties.

[SW530]

About the hog rings, sometimes they sit in awkward places and you need to press the tool in between the foam to get them to the right place. A good pair of pliers holds the rings firmly until you crimp them. Much harder to do with zippies where you have to use both hands and really struggle to get em in there. To get the old ones off use a heavy duty side cutter or open them up with a pair of lock ring pliers. Just my 2c.
Think this was the pliers I bought. HF sells/sold them but they didn’t hold the ring properly. Never tried them but I could tell by the design they wouldn’t work properly. Might have changed design now I dunno.
https://a.co/d/5rzdp9m

Agree about hog rings. Many people don't know they exist, but a set of "compound" wire cutters makes cutting off old hog rings really easy.