From digest.v6.n871 Fri Jul 11 10:00:42 1997
Date: Thu, 10 Jul 97 16:23:55 -0500
Subject: <E36 M3> Schroth Harness-Part 2 of 3
(Part 1 gave an overview and some conclusions. Parts 2 and 3
cover installation in considerable detail. Thanks again to
the several people, and especially Duane Collie, whose input
enabled me to do the installation and put together these
Tools & Supplies
- - Schroth Rallye 4 Harnesses, left and right sides
- - E36 Harness adaptors
- - Schroth shoulder pads (optional)
- - Schroth grips (optional)
- - 3/8" drive 16 mm socket
- - 3/8" drive extensions
- - 3/8" drive wobble extensions (optional but helpful)
- - 3/8" drive ratchet handle
- - 3/8" drive T40 and T50 Torx sockets
- - Heavy-duty vise, sturdy enough to hammer on (essential!)
- - Hammer
- - Channel-Lock type pliers and/or Vise-Grips
- - 5/16" washers, qty 4, for spacers
- - Needle nose pliers
- - Sharpie fine point permanent ink marker
- - Eye protection (I'll explain why...)
- - Towel
- - Flashlight
Rear - Standard Method
Slide both seats forward and then release them to the rear seat
entry position. Get in the back facing rearward, grasp the seat
bottom at its front edge with both hands, about a foot inward
from each side of the car. Tug sharply upward to unsnap the seat
bottom; remove it from the car. Notice the airbag controller box
and some other wiring under the seat: make sure you don't
disturb any of it. With a ratchet handle, extension, and 16 mm
socket, remove the inboard seat belt anchor bolts.
Pull back the grey foam rubber stuffing at the rear outer edge
of the seat pan. The outer seat belt receptacle anchor bolts are
partially or fully recessed under the outside trim panel edge,
however this panel does not have to be removed. Instead, push
the bottom edge of the trim panel hard outward to expose the
bolt head, then push a 16 mm socket with a long extension over
the bolt. Because these bolts are slightly angled outward you
may find it useful to use a wobble extension. Unscrew the anchor
bolt and remove the receptacle stalk. All the seat belt anchor
belts are hard to turn and have a very fine thread. This will be
important to remember when you replace them.
Lay out the tailstraps of the Schroth harness, make sure they
are the right way up and not twisted. Both mounting brackets
will have to be bent.
The outboard harness bracket will be mounted on top of the
standard receptacle stalk bracket base, extending forward and
then bent up at a right angle. Mark the inside of the bend line
with a Sharpie, fairly close to the small end mounting hole. The
bend position isn't very critical here, just leave room for the
bolt head and drive socket. Clamp the small end of the harness
bracket in a vise, grasp the other end and bend. Make sure the
bend is in the right direction first. Use a hammer to tighten
the bend if it curves too broadly.
The inboard harness bracket goes under the original seatbelt
anchor bracket. It will point backward, then bend up at a right
angle. Because it has to bend around the outside of the original
bracket, the location of the bend you make is more important. It
must be closer to the large end in order to clear the factory
part. Mark the bracket with a Sharpie, clamp the small end in a
vise, and bend. The bend will probably be more rounded than you
want, use a hammer on the vise to make more of a right angle.
Now you are ready to bolt down the harness brackets. At the
outboard side thread the bolt through the harness bracket first,
then the receptacle base. Note that the receptacle base has a
locating tab which goes into a hole in the car to orient it.
Because of the angle of the bolt it can be difficult to start
without cross-threading. And because these bolts are hard to
turn anyway, it's also hard to tell if they are cross-threaded.
Using the extension, try to hold the bolt orientation so that it
is true to the hole as you start it in the threads, and fasten
Make sure the tailstrap isn't twisted, and fasten down its
inboard leg. This time the harness bracket goes under the
factory anchor bracket. Repeat for the other side of the car.
Replace the rear seat bottom after threading the harnesses over
it. Push the rear edge of the seat all the way back, then snap
down the front.
Rear - Alternate Methods
This normal installation results in a semi-permanent setup.
However there is a rear crossmember under the parcel shelf which
is already designed to withstand seat belt accident forces (the
stock shoulder belts are in the folding seatbacks, which latch
to this crossmember). There are three threaded bushings preinstalled
in the crossmember. These are normally concealed under
the parcel shelf covering, and are intended to secure child
safety-seat retaining straps. It's not clear to me if these 8 mm
bushings are sufficient for harness anchors. It would be
possible to improvise some other form of attachment to the
I have seen installations where eyebolts are bolted through
holes made in the trunk floor. I've also heard of, but not seen,
custom machined adaptors which connect a single harness
tailstrap to each rear seat latch once the seats are folded.
I've envisaged adapting the harness tailstraps with stock
seatbelt buckle tongues to snap into the rear seatbelt
receptacles (the centre receptacle would carry two tailstraps).
This would be quite easy to do, but requires resewing the
harness ends, with potentially disturbing safety implications.
Installation of the front harnesses continues in a separate
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