How to fix stuck rear middle seat belt mechanism.
Posted: Sat May 21, 2022 3:24 am
I folded the rear seats down and the belt in the middle got stuck and would not unlock and was very tense when I returned the seat back.
After fiddling with it for a few minutes I got it even worse and I was not even able to lift the rear seat anymore. So here is how I fixed it:
First I removed the rear seat by unbolting the hinges, 1 nut on the outside side and 2 nuts on inside under the boot carpet to get the folded rear seat out. Unbolt the seat belt end as well and you can take it away from the car.
There is already a guide how to open a seat and remove the belt mechanism but it does not attempt to fix the seat belt mechanism itself: https://www.406oc.co.uk/viewtopic.php?f=10&t=14926
Here is my broken seat out, the belt is really short and completely stuck, no matter how much I pull, it won't go out.
Once I got the seat out I opened it up on the side by unclipping the plastic piece with a flat head screwdriver and pliers.
Here you can see how does the plastic edge that is holding it together looks like.
Seatbelt mechanism is held in place with one 16mm bolt and once that is out, you can just pull the thing out completely.
I read somewhere on internet that you should not attempt to open the mechanism as it is spring loaded and the spring tend to shoot out at you. With that in mind I decided to go for it, since it's already broken anyway so I picked one side (the wrong one with the spring) and started to opening it, it's held together with 2 plastic pins which needs to be pushed out first and then you can simple unclip the rest of the plastic and this was the side with spring and it was extremely aggressive and it shoot out at me and got tangled almost instantly
When fully opened, I did not find anything broken on this side.. so proceeded to open the other side.
The other side had a lot more stuff in it. I was completely baffled at how this thing even work so had to spend some time on youtube studing how seat belts even work to understand it. As it turns out there is more than one mechanism in there that causing the belt to lock at different situations and that's why it was looking so overwhelming at first, but once you understand which part is doing what and when, it's not that complicated.
I forgot to take the picture of the other side, but in my case, it was the little ball mechanism that broke and had a 2 little chips that snapped. I think it's these 2 chips that threw the ball mechanism out of it's fine balance and it would not unlock when the seat was in it's normal position and it was in locked mode constantly.
I have good experience fixing broken ABS plastic with soldering iron, which tends to be very strong afterwards, instead of using superglue which snaps almost instantly.. The idea is to melt the plastic to fuse the broken parts together which restores almost all of the original strength of the part if you do melt it properly.
First I just melt a little bit to make it stick together at the correct position, then once it's attached I work along the broken seam to melt and join the plastic. Even scraping some melted additional plastic from surrounding areas if I need more material to fill in.
I have worked a bit more than these 2 pictures show to make it more better fused together but again forgot to take the final picture, but it was looking a little bit more fused together as I molded it into shape.
Once the part was sorted and I was happy with the shape and strength of the tip, it was time to wind the spring back into shape. I decided to remove the belt first as I would be doing a lot of spinning of the part when winding the spring so it would not get tangled. To remove the belt, you have to push it out first with something like flat head screwdriver or other flat tool then remove the plastic pin and then just pull it out.
I have first untangled the spring and winded it in the direction it naturally wanted to be winded... that is however not the way it needs to be winded in the mechanism and everything pointed out that you have to wind it in the opposite direction than it naturally bends. That is also why it tends to shoot out so aggressively when opened as it is winded in opposite way which gives it even more energy. So I put the center piece in place, hook up the spring in it and start going in opposite direction than it bends... Also don't forget to lock your center piece by sticking something inside like you can see on the picture below, this is to prevent it to rotate as you would wind the spring.
You have to constantly keep your finger on the spring as it naturally wants to get out and flip to it's other side. It almost got out on me and started tangling twice, but I've managed to push it back.. if that happens, and you are unable to put it back, you would have to start again from scratch. I slowly rotated the belt mechanism and putting more and more spring in place while constantly pressing with my fingers on top of the already winded parts.
Once I got all in, there is a hook at the end that need to be placed over the plastic edge. Again, flat head screwdriver helped with this and the final challenge is to put the cover back in without the whole thing shooting out. I found success by starting with the corner where the end hook is resting and then placing the rest in place and pushing it down as I quickly remove my fingers to snap it in place before it gets out.
After you have secured the spring, the rest is just to put everything together, starting with the belt which is going to be a bit harder now as the thing is now loaded and try to rotate. I have used a set of bits to hold the center piece stuck while I was trying to feed the belt back in. Once the belt was in I tested if it unlocks when in correct position and it worked just fine this time!
Rest is just to reinstall the part inside the seat.
Close the seat by pushing the white plastic edge with the other side together in until it clips back in with some flat tool.
And we are done!
No need to buy a new seat belt (not that I could find any.. which is why this repair was attempted )
After fiddling with it for a few minutes I got it even worse and I was not even able to lift the rear seat anymore. So here is how I fixed it:
First I removed the rear seat by unbolting the hinges, 1 nut on the outside side and 2 nuts on inside under the boot carpet to get the folded rear seat out. Unbolt the seat belt end as well and you can take it away from the car.
There is already a guide how to open a seat and remove the belt mechanism but it does not attempt to fix the seat belt mechanism itself: https://www.406oc.co.uk/viewtopic.php?f=10&t=14926
Here is my broken seat out, the belt is really short and completely stuck, no matter how much I pull, it won't go out.
Once I got the seat out I opened it up on the side by unclipping the plastic piece with a flat head screwdriver and pliers.
Here you can see how does the plastic edge that is holding it together looks like.
Seatbelt mechanism is held in place with one 16mm bolt and once that is out, you can just pull the thing out completely.
I read somewhere on internet that you should not attempt to open the mechanism as it is spring loaded and the spring tend to shoot out at you. With that in mind I decided to go for it, since it's already broken anyway so I picked one side (the wrong one with the spring) and started to opening it, it's held together with 2 plastic pins which needs to be pushed out first and then you can simple unclip the rest of the plastic and this was the side with spring and it was extremely aggressive and it shoot out at me and got tangled almost instantly
When fully opened, I did not find anything broken on this side.. so proceeded to open the other side.
The other side had a lot more stuff in it. I was completely baffled at how this thing even work so had to spend some time on youtube studing how seat belts even work to understand it. As it turns out there is more than one mechanism in there that causing the belt to lock at different situations and that's why it was looking so overwhelming at first, but once you understand which part is doing what and when, it's not that complicated.
I forgot to take the picture of the other side, but in my case, it was the little ball mechanism that broke and had a 2 little chips that snapped. I think it's these 2 chips that threw the ball mechanism out of it's fine balance and it would not unlock when the seat was in it's normal position and it was in locked mode constantly.
I have good experience fixing broken ABS plastic with soldering iron, which tends to be very strong afterwards, instead of using superglue which snaps almost instantly.. The idea is to melt the plastic to fuse the broken parts together which restores almost all of the original strength of the part if you do melt it properly.
First I just melt a little bit to make it stick together at the correct position, then once it's attached I work along the broken seam to melt and join the plastic. Even scraping some melted additional plastic from surrounding areas if I need more material to fill in.
I have worked a bit more than these 2 pictures show to make it more better fused together but again forgot to take the final picture, but it was looking a little bit more fused together as I molded it into shape.
Once the part was sorted and I was happy with the shape and strength of the tip, it was time to wind the spring back into shape. I decided to remove the belt first as I would be doing a lot of spinning of the part when winding the spring so it would not get tangled. To remove the belt, you have to push it out first with something like flat head screwdriver or other flat tool then remove the plastic pin and then just pull it out.
I have first untangled the spring and winded it in the direction it naturally wanted to be winded... that is however not the way it needs to be winded in the mechanism and everything pointed out that you have to wind it in the opposite direction than it naturally bends. That is also why it tends to shoot out so aggressively when opened as it is winded in opposite way which gives it even more energy. So I put the center piece in place, hook up the spring in it and start going in opposite direction than it bends... Also don't forget to lock your center piece by sticking something inside like you can see on the picture below, this is to prevent it to rotate as you would wind the spring.
You have to constantly keep your finger on the spring as it naturally wants to get out and flip to it's other side. It almost got out on me and started tangling twice, but I've managed to push it back.. if that happens, and you are unable to put it back, you would have to start again from scratch. I slowly rotated the belt mechanism and putting more and more spring in place while constantly pressing with my fingers on top of the already winded parts.
Once I got all in, there is a hook at the end that need to be placed over the plastic edge. Again, flat head screwdriver helped with this and the final challenge is to put the cover back in without the whole thing shooting out. I found success by starting with the corner where the end hook is resting and then placing the rest in place and pushing it down as I quickly remove my fingers to snap it in place before it gets out.
After you have secured the spring, the rest is just to put everything together, starting with the belt which is going to be a bit harder now as the thing is now loaded and try to rotate. I have used a set of bits to hold the center piece stuck while I was trying to feed the belt back in. Once the belt was in I tested if it unlocks when in correct position and it worked just fine this time!
Rest is just to reinstall the part inside the seat.
Close the seat by pushing the white plastic edge with the other side together in until it clips back in with some flat tool.
And we are done!
No need to buy a new seat belt (not that I could find any.. which is why this repair was attempted )
. I would bet I double checked and was sure it's the correct way.. hmm.