The not-so-definitive guide to Sienna seats

mgmetalworks

Explorer
So putting these seats in the front is a pain if you're building everything from scratch. I've bled for this modification for sure. A word of caution when you're working on the internals of these seats... be careful about the sharp edges!

The driver side is mounted and basically done. I'm going to pull it out again and have everything powdercoated when I'm done with the other set I'm working on.

Here are a couple of learnings:

1). Installing the seatbelt pre-tensioner is not a big deal at all. You have to remove the factory bolt from the bracket which requires spinning a small keeper off the bolt. Then you have to drill one 1/2" hole in the seat at about the 7 o'clock position relative to the seat belt mounting hole (for the driver side... the passenger side is opposite of that, ~5 o'clock). If you hold up the pre-tensioner bracket to the side of the seat, you can easily mark where the hole needs to be drilled for the tab on the bracket that keeps the pre-tensioner from rotating. When the hole is drilled find yourself a longer bolt that fits the threads in the seat and about a 3/8" thick spacer (or stack of washers). The bolt I used was a 2" long, grade 8, 7/16-20. Yeah... a standard bolt on a pretty much all metric seat, that makes complete sense. I'll take some more pictures when I do the other side. Here is what it looks like assembled.
20130818_105839 (600x800).jpg
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2). Once you get the Ford seat belt receiver on, the Toyota seat belt won't latch into it. I'm just going to use the Ford seat belts anyways. Someone might choose to leave the Toyota seat belt in place but I chose to remove it. You have to remove the upholstery on the back of the seat to do this. More opportunities to bleed profusely so be careful if you're going to do this. :)

3). I designed in a 2 degree lift to the rear of the seat and I'm glad I did. It doesn't feel like you're falling into a deep hole like the back seats. This seat has a much different feel than the stock seat. The sienna is not mushy like the Ford seat and you feel like you're "in" the seat, not "on" the seat. I like it and I'm looking forward to putting some miles on the van with this configuration.

4). No problems with clearance around the module under the driver's seat. Didn't even have to touch it.

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Passenger side with swivel is next... The mock up last night highlighted a couple minor clearance issues but I have a solution already figured out. By the end of all this when I've updated the CAD and every little bug is worked out, I should have a pretty close to bolt-in solution for mounting these seats in the front. You'll still have to risk some bleeding and cussing to do a few mods to the Sienna seat before install though. ;)
 
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mgmetalworks

Explorer
I spent the last couple hours getting all of the mods done on the passenger side seat. Here are a few pics.

Once the side panels are removed and the seat belt is unbolted, I drilled the hole for the seat belt pre-tensioner from the Ford seat. You can see the tab that needs to fit in the hole at the bottom right of the bracket

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before the hole is drilled....
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After the hole is drilled.... I guess its more like 4:30 than 5 o'clock (for passenger side.. driver side would be ~7:30).
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Then pre-tensioner installed.
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I also took the seat belt out of this seat (sorry, no pictures). There are a couple of tricks to getting the side panels off but unfortunately it doesn't photograph well. There are a few screws on each panel but there are some clips that hold the side panel to the another piece of plastic near the seat belt anchors on both sides (you can see the two snap locations on the piece of plastic just above the pre-tensioner in the above picture). You have to pop the plastic clips apart to get the side panel off. The best tool is a long screwdriver to push the snap through its mating clip. Remove the screws, maneuver the panel as far away from the seat as you can and then reach in from the bottom side to pop the snaps out. It isn't too difficult once you see them.
 

mgmetalworks

Explorer
Hey MG, is there a way to disable the footrest and still keep the tilting back? Thanks.

They are independent of each other. You can disable the foot rest by disconnecting the cable from the release lever if you want. The foot rest mechanism can come off of the seat in one piece as well, held by only 4 bolts and the cable.
 

bknudtsen

Expedition Leader
Does it make for a comfortable front seat? It seems like the seat bottom would lean too far back.


See below...

3). I designed in a 2 degree lift to the rear of the seat and I'm glad I did. It doesn't feel like you're falling into a deep hole like the back seats. This seat has a much different feel than the stock seat. The sienna is not mushy like the Ford seat and you feel like you're "in" the seat, not "on" the seat. I like it and I'm looking forward to putting some miles on the van with this configuration.
 

Bluvan

Member
Slides for the front Siena seat option

For all those following this with plans to do the swap you will need to know what sliders your van seats have. The MG base is designed around the slides from the current model year. My van a 2003 has a different style slide which does not work with the seat base. I have been working with Michael to verify his base will work with the earlier model years before he goes into production and this is the only issue. I was able to grab late model slides from Warehouse Salvage, the same place the seats came from. MG may be buying up the rest of their stock to have available for the folks who are interested.

Photos of my original slides (2003 model year) if your slides look like these you will need the newer ones.
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Late model slides. The slide needs to have the locking mechanism on the side of the slide not the bottom
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Finally the driver side in place. There is room for my small amp under the seat. As others have said these are very comfortable seats. The foam is firm vs the stock seats which were just too mushy for me. One lesson learned, paint the slide black before you install.
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You might want to plan 10 - 12 hours for this project.
 

Cole

Expedition Leader
Maybe I missed it somewhere but what year Siennas are these seats from?

I may have a Sprinter cargo son and it would need a bunch of seats! (Replace front two and create a second row) These would be perfect. Especially since there was never an original second row with seat belts before.
 

mgmetalworks

Explorer
Maybe I missed it somewhere but what year Siennas are these seats from?

I may have a Sprinter cargo son and it would need a bunch of seats! (Replace front two and create a second row) These would be perfect. Especially since there was never an original second row with seat belts before.

2011
 

Bluvan

Member
Maybe I missed it somewhere but what year Siennas are these seats from?

I may have a Sprinter cargo son and it would need a bunch of seats! (Replace front two and create a second row) These would be perfect. Especially since there was never an original second row with seat belts before.

The floor in the front of the ford vans is sloped forward where the seats mount so keep in mind these brackets are designed with the ford floor, seat ht, and Siena seat position in mind.
 

mgmetalworks

Explorer
The floor in the front of the ford vans is sloped forward where the seats mount so keep in mind these brackets are designed with the ford floor, seat ht, and Siena seat position in mind.

For mounting the seats in the rear of a van, just use the mounts Ujoint sells. They're simple and can fit many applications. If you wanted a solution for the front of a sprinter, you may have some problems with how tall the base of the Sienna seat is. From what I've seen of the sprinters, the front seats are mounted on platforms (not to the floor). I don't know if that can come out or not but if it can't that would put the seat up way higher than you'd want it. If you aren't concerned about having the recliner in the front, you may be able to find a Sienna seat that will sit lower but those come with their own set of challenges... I can provide you with dimensions of the seat if you tell me what you're looking for.
 

Bluvan

Member
Finally posting photos of the finished product.
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Small amount of filing needed at the slide lever to work with the base.
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Amazing upgrade!
 

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