Sedan seat belt hack: tilt sensor delete

[Buzz Skyline]

No matter how I fiddled with them, I couldn't get my sedan donor seat belt reels oriented so the tilt sensors wouldn't lock up. So I removed the sensors. Now the belts work great. The lock up feature due to sudden jerks on the belt is unchanged.

I took the driver's side reel off the car to delete the sensor, but I did it on the passenger side with the reel still attached.

To open the the reel, pop the three plastic pins that secure the transparent cover

20141116_113918.jpg

The cover should pop off, I pried it gently with a flat head screw driver. Don't turn it over or the gears will fall out. They're easy enough to drop back in though.

20141116_112958.jpg

20141116_113009.jpg

The tilt sensor is the orange part in this pic, although it's green on the 818 passenger side (formerly WRX driver side) belt

20141116_113029.jpg 20141116_113114.jpg

It easily slips out.

Make sure the gear is in the right position . . .

20141116_114323.jpg20141116_114811.jpg

. . . before you replace the cover.

20141116_115545.jpg

Test the belt a few times to make sure everything is replaced properly, then pop the plastic pins back in and you're done. Now the belt will work with the reel in any orientation

[Bob_n_Cincy]

I don't think I would have done that.
The tilt sensor locks the belt before driver movement is detected by sensing g force on the frame.
I originally had stock wagon belts in my 818 and they worked fine.
If it works in the donor, it should work in the 818.
Bob

[Buzz Skyline]

There are three types of seat belt tensioners that I know of (not counting the explosive tensioners in front seats, of course): centrifugal clutch(feed out sensor), g-sensing (aka tilt sensors), and dual centrifugal clutch/g-sensing. Subarus use the dual technology, but centrifugal clutch should be good enough. I'd prefer both, but deleting one so that the belts can be used at all is a reasonable solution, considering many cars over the years have used only centrifugal clutch designs. Would quicker lock up be better? Maybe, but the centrifugal clutch system locks up with less than an inch of belt fed out. I can't see that it would help much to be even quicker.

Besides, I use a lap belt pretensioner for autocross, and would probably use one all the time in this car. And there's nothing faster than a pretensioner.

[Buzz Skyline]

BTW, you can spend a lot for a latch to pretension your lap belt http://www.amazon.com/CG-Lock-CG001-.../dp/B004NY1DHS

Or you can spend a little http://www.ebay.com/itm/New-Help-Car...-/201017366115

I spend a little.

[Bob_n_Cincy]

Hi Buzz,
Are you using the rear seat belts?
Do you know why the OEM belts are not working?

I have all the belts out of my 2 donors. (both wagons). I'll play with them to see if I can figure out why yours aren't working. Wish I had sedan belts like you to test.
Bob

[Buzz Skyline]

Hi Bob,

Yep. I'm using the rear sedan belts from my donor (2002 WRX). I believe they didn't work because the orientation of the reel when mounted on the 818S is off enough that the tilt sensor was tripped. When I removed the driver side one, I could find an orientation that worked, but every time I mounted it on the frame the tilt was in the wrong orientation and kept the belt locked. That's why deleting the tilt sensor works.

It's easy enough to pop back in, and I may tinker with it more on the passenger side. But I will probably leave the driver side as is and rely on the centrifugal clutch, along with a locking clip to keep the belt tight on my lap. I wouldn't expect most passengers to want to use the clip, so a tilt sensor is more important there as a redundant safety measure.

I believe the wagon belts have a white tilt sensor in them that lets the belt feed out provided the reel is level. The ones for the tilted sedan reels are orange (WRX passenger side) and green (WRX driver side), at least for the 2002. Potentially, you could use the sedan belts in the wagon position if you swapped in some white sensors. I may do that because I have a pair of ugly and worn beige wagon belts that I would rather not put in my 818.

-Buzz

[freds]

The rear seat belts are designed to lock solidly when installing a child safety seat. When used for that purpose obviously the belt should not unlatch like the normal inertia reel

That device is able to be released by allowing the belt to retract "a certain amount" and then pulling it out rapidly. Its an iffy thing to get to work and I had a lot of trouble achieving that on mine, so I too removed that locking device. It does not interfere with the normal inertia reel function.

There is a a page of SUBARU instructions for locking/unlocking that safety seat securing function...should be in the owners manual, but certainly available from Subaru. I'm sorry, but I cant find the copy I had when I was facing exactly this problem. If I find it I will post it.

[freds]

"ALR" is the always locked condition. "ELR" is the normal condition.

MSA5M1313ASTIS_8_Page_1.jpgMSA5M1313ASTIS_8_Page_2.jpg

[Buzz Skyline]

That's it! Thanks, Freds.

The problem must be that in installing the reels I pulled the strap all the way out, putting it in the always locked position. I'm guessing that because of the location of the reel, I could not let the strap retract all the way, so there was no way to get out of the always locked condition.

Of course that may also mean that I will have the problem again, if anyone ever pulls the belt all the way out. I'll check the next time I'm home.

If that's the case, then the sedan location of the reel is just plain unworkable - eventually someone is going to put it in the always locked condition.

Not good news, but good to know before I commit to the sedan location. I may have to drill out all those rivets - again. Sigh.

Thanks again, Freds.

[Buzz Skyline]

You can see in this diagram that the stock location of the reels on a WRX sedan allows the belt to retract much farther than for the 818.

http://parts.subaru.com/a/Subaru_200...11-646-01.html

If you need to let the belt fully retract to get out of the always locked condition, it would never be possible in the 818. Dang it.

So the message seems to be that you simply can't use sedan belts in the 818 unless you're willing to unbolt your belt (which would require me removing my seat) every time it gets pulled all the way out.

On the bright side, now that I know how to delete or swap tilt sensors, I can mount my sedan belts to the wagon reel mount locations.

[RPGs818SNA]

Thanks for your posts, Buzz and Fred! Over 7 years later, I ran into the same sedan seat belt problem where, once fully extended, the rear belts will only retract until fully retracted. But once the belt end is attached to the frame near the floor, it can’t retract far enough to release the mechanism that lets it extend again. As Fred noted, this is so child seats can be held securely in the back seat.

Taking Buzz’s lead, I decided to try to remove that unneeded feature while keeping the others. Fortunately, the reel mechanism cover is transparent, so I was able to see how it worked.

Seatbelt Reel 1.jpg

The white lever in the bottom left corner remains out of the way until the belt is fully extended, after which it prevents any extension until it is pushed back out of the way upon full retraction.

To remove that lever and its function, starting on the passenger side, just pry off the very top transparent cover with a small screwdriver. The following photos are of the same process on the driver’s side.

Seatbelt Reel 2.jpg

Note where the notch in the top gear is positioned near the top.

Seatbelt Reel 3.jpg
Seatbelt Reel 4.jpg

Turn the gear until its notch is over the lever and pull the lever and its tiny spring out.

Seatbelt Reel 5.jpg

Turn the gear notch back where it was and replace the cover. Repeat on the driver’s side.

Now the inertia function still works, and maybe the tilt, but otherwise the belt moves in and out freely.

I suspect many other builders have discovered this procedure over the last 7 years and documented it in their build threads or elsewhere, but this was the only thread I could find using a google search.

RPG