Lowering the seat bases

We installed seats with air suspension and swivels. That combination made the seats too high for the van. So we swapped out the seat bases for lower versions.

We love the Knoedler air suspension seats we bought. It’s also really helpful to be able to swivel the passenger seat to face backwards when we are camping. To make this setup work, we needed lower seat bases.

Mercedes makes shorter seat bases. They are used with the factory swivel option and with the factory suspension seat option. We should have had factory suspension seats in our van, only the dishonest dealer sold the van we custom ordered to someone else.

Lower seat base next to original base

The bases are about 3-1/4″ lower than stock. The handbrake moves down with the lower base, but not by the full 3-1/4″ so it might still interfere with a swivel on the driver’s side. There’s no need to re-tension the cable, because the cable/housing length doesn’t change. You just push a little more of it down through the floor grommet. We had to trim about 1/4″ of plastic off the base of the handbrake cover, but that could also be because we took the opportunity to add some sound damping under the rubber floor in the driver and passenger footwells at the same time as changing out the bases.

The seat bases come in beautiful primer black. We decided not to bother painting them, and they actually blend in better than the originals.

Installing lower seat bases

To swap the bases out, you start by removing the seats (and the swivels in our case). Do NOT put the key in the ignition while you have the seat wiring unclipped. You’ll end up with SRS warnings which may or may not need a scan tool to reset. I also unhooked the battery disconnect next to the accelerator pedal and also undid the cable from the auxiliary battery terminal under the hood.

Stock height seat base with swivel

The whole job is much easier if you remove the rubber floor mats from the van. First you have to take out the plastic panel at the top of the door step (Torx 20 screws) and the tool cover in the footwell, then you can just pull the floor mat out. The pieces behind the seats just slot in place. Give them a little tug and they will come free.

Inside the passenger seat base you’ll probably find at least one mystery box with wires coming out of it. Remove the screws attaching it to the seat base (Torx 20 or Torx 25 screw heads) but leave it wired. It can just rest on the floor while you change out the bases.

Each seat base is held in place with four bolts. The bolts have Male Torx (E type) heads, which need a special socket set. If you don’t have it already, it’s worth getting for all the other bolts on the van. The bolts are tightened down well and they have a nice coating of rubber undercoat holding them in place from below. You’ll need to give them some persuasion to work them loose.

Once all four bolts are out, you can carefully lift up the seat base and remove it.

Passenger seat base removed

My seat base had a couple of extra pieces inside it because I’d already run an air hose and some wires from the driver’s seat base across under the plastic raceway. If you were planning on adding wires, this is an ideal time to do it because with both seat bases removed you can actually undo the plastic raceway and fish around inside it – something that is impossible with the seat bases in place. I took the opportunity to add more cables for a subwoofer install later.

Now it’s time to install the new lower seat base. Use the same four bolts that you removed. Place it carefully over the mystery electrical box and any other wires you ran, and then bolt it down. Check carefully that you haven’t trapped anything under the perimeter of the base before you tighten it fully. I added some sound dampener and foil faced foam insulation inside the original base, and I had to make sure it didn’t get squashed under the new base as I installed it.

The driver’s side base is pretty much the same, only you have a lot more wires to contend with. Use a voltmeter to check that absolutely nothing inside the seat base has any voltage flowing to it before you start. If it does, you will most likely short it out which could mean troubleshooting either burnt-out fuses or burnt-out cables. Save yourself the hassle. Disconnect all of your power sources first.

Driver seat base, lower plinth

In this picture you can see the mess you are left with after you’ve removed each component, removed the base, then carefully placed the new base over all the cables, relay bars, and fuse panels. We worked on this together to avoid trapping anything.

Our original seat base had a 12v outlet in it. We were under a time crunch and didn’t have the patience to work out how the outlet disconnected from the base. We should have spent the time figuring it out, because now we have to drill a 1-1/4″ hole in the new base while it is in place. It would have been much easier and cleaner to do this before we bolted it down. By the way – we got the outlet out of the old base by bending some of the metal that forms the shield inside the socket, so that the plastic clips that push against the opening could move back away from the opening.

Buying the right parts for the lower seat bases

Buying the seat bases aftermarket isn’t too hard. They cost around $200 each from online stores. The part numbers are A9069107300 (passenger) and A9069107900 (driver, with handbrake mount). You might need to remove the leading “A” if you’re searching online.

If you order from an online source, do NOT enter your VIN number – they’ll substitute the correct seat bases for your van without telling you (ask us how we know). Instead, just read and ignore all the stuff about how they won’t do a refund if the parts turn out to be wrong if you haven’t entered your VIN.

Also, do not expect any customer service from the online merchants. Even though they are actually Mercedes dealers (genuinemercedesparts.com is a dealership in Georgia, for instance) they have very slim margins on their online sales and their level of service reflects this.

If you are in Europe, FASP make a different replacement seat base. It’s slightly taller than the lower OEM base.

If you are thinking of adding a driver side swivel, you can buy a folding brake lever that kind of flops down after you’ve pulled it up/on. The parts you need are: 906-420-03-12 (Brake lever); 906-427-06-34 (Brake lever cover); 906-427-01-20 (Brake lever handle); 906-420-54-85 (Brake cable, 144″ wheelbase); 906-420-55-85 (Brake cable, 170″ wheelbase). Alternatively, you can leave the handbrake off while you rotate the driver seat, then put it back on when you’re done scooting it around.

25 Replies to “Lowering the seat bases”

  1. Hey there! So I just did the exact same install for my 2016 sprinter, but the arm rest keeps the door from closing, unless I over rotate by at least 15 degrees. Do you have arm rests?

    It looks like I might have been okay if I stayed with the taller seat base, but I wasn’t happy with the 2″ increase. Really too bad Mercedes stopped doing these as an add on.

    1. Our knoedler seats have both arm rests. They clear the door on our 2015, but we did mount the CTA swivel “sideways” with the red catch facing the door. That gives us a couple of inches of extra clearance when the seat is swiveled.

      If you were using the stock seat or if you didn’t install the swivel the exact same way as we did, then I can see why you might have problems. It is a tight fit.

  2. Hi,
    I posted an early comment that didn’t go through, but now I see you have the measurement, 3-1/4″ that I was looking for. Using your part numbers, I checked with the dealer where we purchased our van (2016) and they have both pedestals available for about $400/pair. With my factory seats and the shorter pedestals I will actually end up about 1-1/4″ lower then where I started. Any idea if that will work for the hand brake with the stock seat? Maybe your seats affected the parking brake interference about the same? My alternative is to just cut down the pedestals by the CTA swivel height and have the same height as where i started. Though, it seems most people would benefit by having seat height adjustment DOWN, rather than UP and using the lower pedestal would be better. Any thoughts?

    Thanks for all the great information and your response to my other question on the LowE.

    1. $400/pair from the dealer is a good price. I think you’ll have interference with the handbrake on the lowered seat base if you are using the CTA swivel. It’s the swivel height that makes the difference, not what seat you use. The part of the CTA swivel that turns is likely to interfere with the handbrake cover.

      The problem is, if you cut down your stock bases you might end up with the same issue. For $200 is it really worth the hassle of cutting the bases down? The bases would probably be a pain to re-weld after you’d cut them down.

      A better solution, if you can weld, would be to remove the handbrake bracket from the base (either stock or lowered base) and re-weld it slightly lower. It’s only about 1/4″ or 1/2″ clearance issue.

      I do know that one of the swivel companies made/makes a metal plate that bolts on to the handbrake bracket and has threaded holes that the handbrake connects to. This lowers the handbrake height by the required amount. It shouldn’t be too hard to make if you have the correct tools.

      1. Thanks. Welding any of these parts is not a problem, so I might just experiment cutting mine down and lowering the hand brake bracket. CTA is out until December. Did you have a chance to look at, and compare, the CTA swivel with others such as Sportscraft?

        1. I didn’t get a chance to directly compare the action of the Sportscraft to the CTA. I’ve seen both in person and I’ve read several reviews of the Sportscraft by forum members. I think both bases have pros and cons. The sideways offset of the Sportscraft is a big pro, unless you’re prepared to mount the CTA sideways like we did.

          December isn’t that far away, so don’t let that sway your decision too much.

          Moving the handbrake bracket would be the biggest issue. I wish I had the skills to do that type of welding. If worst comes to worst and you really mess up your seat base after you’ve cut and welded it, I have some leftover full height bases I’d sell you cheap!

      2. Diesel Fumes… I have been searching all over and cannot find a place to order the shorter base… could you share which dealer you used?
        Thanks!

        1. Mike, we used genuinemercedesparts.com and it looks like they’ve changed their web site since we ordered. Now their search engine doesn’t work.

          Because most of these online dealers use the same third party for their web site hosting, I imagine that’s the reason you’re having trouble finding the parts. If the search engine is broken for one of them, it’ll be broken for all of them.

          Try https://mercedespartscenter.com/parts/index.cfm?searchText=9069107300&make=Mercedes-Benz&action=oePartSearch&siteid=215720 – we haven’t used them, they just came up in Google Search.

          It’s also worth asking your dealer. Their parts department might not be much more expensive, and you’ll get the parts in just a couple of days.

        2. I used https://mercedespartscenter.com and ours arrived today (passenger side only). $217 with shipping to CO. It looks to be 16 5/8” square bolt pattern but I have not actually mounted the new console to test it. Can anyone confirm that the Sportcrafters brand of swivels will fit on this console? We have stock 2016 seats with heating option. And yes, Dieselfumes is right about this parts site; no images, measurements, and they will tell you that it does not work on your VIN # of Sprinter. No returns either.

          1. Any brand of swivel made for the regular height console will fit on the lower console. If they don’t, it is either because the console is out of square, or more likely it’s because the swivel holes aren’t accurately drilled. Several people have had to re-drill or add clearance to the swivel mounting holes.

            Two tips:
            1) Don’t completely tighten down the mounting bolts for the console before you add the swivel. This gives it more opportunity to flex. That only works for the passenger side one, because you can’t reach inside the driver side one to finish tightening the base bolts once the swivel is in place.

            2) Measure the diagonals across the top of the seat base/console. If they aren’t the same length, the console is out of true. Put bolts in the threaded holes and use a ratchet strap to pull the diagonal corners with the longer measurement toward each other. It won’t take much force.

  3. Cloude and Dieselfumes,
    Given my location, I’m not able to look at either CTA or Sportscraft swivel bases. I can get the CTA swivels now from a European supplier for a good price and the Sportscraft are readily available in US. The Sportscraft swivel weighs 43# (which seems substantial to me), has an offset swivel that sounds like it allows it to clear the door and the pillar just fine, and I”m being told by the supplier that they mount them regularly on new vans with no interference with the parking brake. Dealing with swivelrus is a bit of a pain and they can’t seem to tell me how much the swivel weighs. I take it that the CTA is not an offset swivel? Can you confirm this? I don’t plan on buying the lower bases, but instead cutting mine down by the 1.5″-2″ that the swivel raises the overall height. Cloude, would you use CTA again if you had it to do over? The forum complaints about the nylon rollers on the Sportscraft may be a moot point. They changed and upgraded the rollers in 2007 and claim to not have any problems since than. Also, Sportscraft claims that they are crash tested to all European standards and certification is included. I can’t seem to get anything in writing from Swivelsrus/CTA about testing.

    Any advice would be appreciated, thanks in advance.

    1. Chris,

      The CTA swivel weighs about 20lbs. You can see some more details about them in this earlier post. It is offset. However, the offset is from front to back rather than from side to side. I mounted my CTA swivels sideways so that the offset is side to side.

      The parking brake will most likely interfere with the swivel if it is in the raised (“on”) position with either the Sportscraft or the CTA swivel. You will probably have to release the parking brake to rotate the seat.

      SwivelsRUs have terrible customer support and a horrible web site. If you aren’t getting answers from them, don’t buy from them. They need to up their game.

      1. OK, thanks. I called EuroCampers to confirm the weight of the Sportscraft swivels, and they are 43# net. That is a significant difference.

  4. ….Buying the seat bases aftermarket isn’t too hard. They cost around $200 each from online stores. The part numbers are A9069107300 (passenger) and A9069107900 (driver, with handbrake mount). You might need to remove the leading “A” if you’re searching online….

    Searched online for the shorter seat bases (genuinemercedsparts.com). No luck. Could you include a URL of where you purchased them?

    1. Genuinemercedesparts (where we bought the bases) have changed their site recently and their search no longer seems to work for part numbers. Oh well, their loss. You can call them, or use a different company.

      There are plenty of other online sites that will take your money. Try https://mercedespartscenter.com/parts/index.cfm?searchText=9069107300&make=Mercedes-Benz&action=oePartSearch&siteid=215720 – we haven’t used them, they just came up in Google Search.

  5. 10-4. I have found MB supplier with your URL. The description “seat console” threw me. I hope it is a seat base or seat pedestal. Seems like no images on that site makes it difficult to confirm.

    1. You won’t find a site showing an image of that part. Most auto parts don’t have images. Unfortunately you just have to trust that the part numbers are indeed the right thing for what you need. Good luck with your order.

  6. Thank you for this wonderful write up. I just ordered a passenger side short seat base from the link provided. I continue to buy from the links provided from you and I urge fellow diy’ers to do the same to support people like you.
    Best regards,
    PJ

  7. Interesting regarding mounting the CTA swivel facing “sideways” toward the door. Its a pain in the butt to rotate all the way around 90 degrees jacking the seat up to get the armrest over the side door and then down to get it to more normal height. I’ll need to try your “sideways” mount method.

    Thanks!

    1. We’ve just started having problems with the CTA swivel rocking from side to side while it’s in the closed position. I don’t think it’s got anything to do with the sideways mounting, but just be aware of that.

      I haven’t investigated fully yet, but it feels like the chair and top half of the swivel are just turning on the bottom half of the swivel, only being stopped by the catch. I’m hoping that some tightening up will do the trick.

      1. Dammit. Thanks for being the person who tried this out. Looks like the swivel catch interferes with the seat rails.

        We had to do a little grinding for our aftermarket seats, but that was only through the base plate and not through any functional components.

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