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Rear seat 3-pt belts

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I'm on a mission to fit 3pt belts in the back, but I'd like to avoid a retractor located on the parcel shelf or below it (cutting and vapro tank relo involved).

The option I was exploring with Al is to leave retractor in existing location, but increase the belt length and instead of the belt ending in the buckle as on the stock lap belt, make the buckle free floating like on the front belts and bolt the free end up on the c-pillar location. Problem is that the retractor (per Al) needs to be in a vertical position instead of the 45deg position it is in now and the retractor can't be installed vertically in that location -- interferes with the rear wall.

While looking at the belts today, I noticed another seat belt mount location under the seat. What was this for? Seems redundant...

IMG_2601_zpsdcb93d67.jpg

So a second option emerging is to use this location and mount a retractor like this:

IMG_2603_zpsdd579f0c.jpg

The belt would then go up parallel to the edge of the rear seat back up to the c-pillar where a loop would be mounted, and the free end mounted in the rear original retractor location.

This pic shows the rough angle that belt would take (the lap belt was not long enough to reach the c-pillar.

IMG_2604_zps0107b4b7.jpg

There seems to be enoug space between the side of the seat bottom and the side panel to allow free movement of the belt into the retractor.

IMG_2605_zps2ebd25f6.jpg

Has anyone tried this?

Al, will a front retractor work (if the locating pin is cut off) or will the front retractor only work when vertical?

Byas

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Front retractor may not work at that angle. I believe repa will work +/-10 degrees off vertical but that angle seems too much. There are other retractors (e.g., Autoflug with some mods), however, that will work. Also installing a retractor at that location will put the lower part of the (lap part) webbing too front ahead, so may not be safe. That location is an alternative mounting point (I think 74-76 only) for the front belts where the left retractor installs on the right and right on the left location. Unfortunately, there is not much room at the back to install proper 3 point belts without modifications, or installing on the parcel shelf (easier solution I believe). The most professional approach would be to install a retractor under the parcel shelf by welding some brackets (like in an E30, E21 or other late model cars) and cutting holes on the parcel shelf to lace the webbing, but most owners won't do that due to cost and to keep originality. A simplest approach would be to install 3-point manual belts with locking plates on the webbing, you won't need any retractor, and no cutting/welding will be needed.

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A simplest approach would be to install 3-point manual belts with locking plates on the webbing, you won't need any retractor, and no cutting/welding will be needed.

Al, have you made a kit like this before?

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A simplest approach would be to install 3-point manual belts with locking plates on the webbing, you won't need any retractor, and no cutting/welding will be needed.

Al, have you made a kit like this before?

yes, many sets using Autoflug or other German/US parts. You can use the c-pillar mounting or parcel shelf mounting, and the bottom mounting where the OE rear retractors are installed.

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Al,

I was thinking that the lower part of the belt would be mounted where the stock rear retractor is mounted today at the back corner of the seat bottom) -- so the lap portion should still fit well.

Some more investigation showed that yes, the belts are limited to a narrow vertical angle. I opened up the retractor and found that the mechanism that limits the vertical orientation can be disabled easily (and reversibly if needed).

IMG_2606_zps957175de.jpg

The white plastic nub can be turned up to disable the vertical limiting mechanism.

Disabling should enable it to work at an angle from the forward mount. Ofcourse, the locating pin on the back of the retractor would have to be cut off or another hole drilled, or I get a retractor without the pin.

Al, will call you next week about the other idea you have. If these don't work, I'll go with a manual 3 pt.

Byas

PS: I am getting better at rewinding the retracting spring to tighten up the retracting mechanism - not fun, but do-able.

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Al,

I was thinking that the lower part of the belt would be mounted where the stock rear retractor is mounted today at the back corner of the seat bottom) -- so the lap portion should still fit well.

Some more investigation showed that yes, the belts are limited to a narrow vertical angle. I opened up the retractor and found that the mechanism that limits the vertical orientation can be disabled easily (and reversibly if needed).

IMG_2606_zps957175de.jpg

The white plastic nub can be turned up to disable the vertical limiting mechanism.

Disabling should enable it to work at an angle from the forward mount. Ofcourse, the locating pin on the back of the retractor would have to be cut off or another hole drilled, or I get a retractor without the pin.

Al, will call you next week about the other idea you have. If these don't work, I'll go with a manual 3 pt.

Byas

PS: I am getting better at rewinding the retracting spring to tighten up the retracting mechanism - not fun, but do-able.

I wouldn't mess with original retractors, removing the plastic cap will make it work funky, believe me, especially those old Repas. Once removed it cannot be put back together, it is press fitted. If you really need to do that, remove the entire locking/balance level from inside the retractor, it is riveted at two spots. This will make the retractor effectively a webbing sensitive retractor only and will work better. The locating pin is screwed, just unscrew it, use correct metric socket (5 or 6mm if I remember).

I have many small profile retractors that work at several angels so please don't mess again with those old retractors. You also need a webbing neck, or sleeve ( I have some) to prevent webbing from rubbing between the seat and quarter (door) panel trim. You can wind as much as you want but once the spring lost sensitivity it will never work 100%, I am just saying (do not attempt to remove the spring from the retractor!) Call me later.

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Turns out the mechanism unscrews out pretty easily -- but not where I thought it would. The Pendulum actually is 3 parts: Once the plastic cap on the pendulum is removed, the pendulum top and bottom.

IMG_2607_zpsbdc027fa.jpg

IMG_2608_zps68149236.jpg

IMG_2609_zps3c9af6bb.jpg

With this pendulum removed, the reel works well in any position. Of course, the inertial lock on this particular reel does not work well -- and that's the most critical element, so I would not want to use this reel. But, good for mocking up the fit etc.

Byas

PS: I'm sure all of what I've posted so far is not news to Al, but I thought it would be good to record it for others who want to experiment.

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Fixing the Inertial Locking Mechanism:

Inertial mechanism on my old passenger side retractor did not work properly (as posted above), but the driver side one worked, plus I had 2 new units to compare it to.

So, this morning I thought I'd try to understand why it did not work. I had read thru umpteen patent filings from the 60s and 70s last night on intertial locking retractors to understand that the basic mechanism is pretty straight forward.

In this REPA unit, it consists of 2 toothed wheels. The outer one is connected to reel axle, while the inner wheel rotates loosely coaxially to the outer wheel. A circular spring acts between the reel body and the inner wheel pushing it out towards the outer wheel and locking it.

When the reel unwinds quickly, the outer wheel turns faster than the inner wheel -- and ramps in the tooth push the inner wheel towards the reel body (after overcoming the spring resistance). The inner wheel then locks against cogs on the reel body preventing further reel rotation.

The spring in my non-working unit seemed to have similar tension as the good ones so that did not seem to be the problem. Cleaning with various spray cleaners and compressed air did no help either.

It turned out the problem was that there was just s little bit of sticky greaselike residue in the valleys of the teeth of the outer wheel, that caused the inner wheel to stick to it. Was not much stickiness, but enough to prevent the lock from consistently engaging.

Here's a picture of the locking mech in normal position -- unengaged. You can see the silver inner wheel and the brass colored outer.

IMG_2614_zps6887b7db.jpg

Here's what it looks like in the locked position:

IMG_2611_zps1ef494e5.jpg

I used a tiny screwdriver to loosen the deposits and used q-tips soacked in isopropyl alchohol to clean the valleys while holding the mechanism in the locked position.

That did it -- it now locks easily.

This is easy enough to do and the results were quite dramatic. It seems like this should be a preventive maintenance feature for those running older belts to ensure the locking works well.

Byas

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Mounting the belt

The c-pillar location is 3 1/4" above the latch (at least for a '74).

IMG_2615_zpsfc72fdbe.jpg

I mounted the upper loop first, and the mounted the retractor so that it was in line with the upper mount. Here's what it looked like mounted.

IMG_2618_zps348c7d3d.jpg

The belt operates very freely and does not rub against the seat or the side panel.

Here's a pic of the space around the belt. A sleeve as Al mentions would be a plus, but there seems to be enough space as is (at least on this car).

IMG_2619_zps07a296f0.jpg

So far, so good. Then the disappointment -- the buckle from the front seat belt will not fit in the rear seat belt receiver. It's the same shape, but just a hair thicker. Back to the drawing board.

At least the concept of the location works. And, I've figured out how to make an oler belt work better. Will see if I can adapt the front receiver to the back.

Byas

Go Packers (me)

Go Redskins (wife)[/i]

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You need to use the thinner rear male latch plate (buckle) which requires removing the thick one and installing the rear one on the webbing, not sure if you can do it without removing and cutting the webbing, and restitching at the retractor side, the slut on the male buckle is to thin for the stitched end of the webbing to go through, end loop inside the spool is too thick, although some elbow grease might solve the problem.

FYI, the end of the webbing goes through a slot inside the spool and secured with a pin that goes through the loop on the other side of the webbing (Repa only, Autoflugs are different). If you try, make sure you to secure the spool with a flat object that goes through the slut to lock it, if you let it wind too fast you will damage the spring. You need to be very careful as you will need to use both hands while installing the webbing again.

However, your design concept opens new possibilities for a 3-point rear belt conversion using factory parts that need no modifications for 74-76 model cars, cosmetics aside. For earlier cars, a threaded nut plate or hole needs to be fabricated on the inner rocker to adopt your solution. Nicely done.

Also, many repa retractors have rivet looking screws (oval head) instead of phillps type screws like your repa has. So the plastic cover cannot be removed without using a special tool, or drilling out oval head screws.

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Thanks to Al -- I've now got 3pt shoulder belts for the rear seat, along with a lap center belt.

IMG_2665_zpsc2fdd71b.jpg

IMG_2666_zps4cafb3ad.jpg

Byas

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Nicely done! Thanks to you and Al for the in-depth seat belt information.

As many folks here have said, having a set of properly operating seat belts adds to the safety and driving enjoyment of our old cars.

Those rear belts sure beat the spaghetti Klippan set up that I removed from my 69 and the D-ring and chrome center bar on the 71.

1969BMW2002021.jpg

IMG_7001.jpg

IMG_8013_zps508a3fe2.jpg

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Jim;

what are your plans with the ti clone? Roll bar? rear seat delete? Harness?

I'm keeping the rear seat, but installing a newer set of belts. Will upgrade to 3 point retractables in the front.

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