Question - Adapting Rear 3-Point Seat Belts to an Older Car... - NJFBOA - Home of New Jersey's Camaros and Firebirds

The Fixer · 05-30-2010, 03:14 PM

Hey guys,
In order for me to put both my kids in the Monte, I need to have rear 3-point seat belts. So, after some searching online, I ordered a set of new belts and hardware from Beam's Industries, and have one side mocked up.

I have one problem though - the upper mount has to go into the rear shelf behind the upper seat cushion, and needs to mount near the edge in order for the retractor to work properly.

This leaves me with an issue - the washer that is supposed to spread the load underneath won't clear the shelf, so can I cut some of it away so it'll clear? For reference, the washer is 2 1/2" in diameter, and the section I need to cut off is 3/4" at its widest point. That side would then go underneath and be flush with the package shelf.

Or can one of you guys give me a better solution?

//<86TA>\\ · 05-30-2010, 03:54 PM

can you bend it instead of cutting?

Mark42 · 05-30-2010, 04:15 PM

Quote:

Originally Posted by //<86TA>\\

can you bend it instead of cutting?

My thought too. Bending it to an L shape will actually make it stronger than cutting off that much.

BonzoHansen · 05-30-2010, 05:07 PM

go get a piece of steel and cut to fit. it's all about spreading the load across the package tray. that is what I did in the Z. I'd guess I used a 1/8" thick plate of steel that is ~2"x6"

The Fixer · 05-31-2010, 09:39 AM

Thanks for the suggestions guys! I think I'm going to bend the washer for now - my brother-in-law has a bench vise, so I'll put the wide side in and bend the short side. Eventually I may add an extra plate underneath it too Scott - I like that idea, but there's not a lot of space back there to work, and the shelf has a funny contour to it.

BonzoHansen · 05-31-2010, 11:25 AM

Quote:

Originally Posted by TPI Monte SS

...Eventually I may add an extra plate underneath it too Scott - I like that idea, but there's not a lot of space back there to work, and the shelf has a funny contour to it.

Look under your car, that is how your OE belts are anchored

The Fixer · 05-31-2010, 12:39 PM

Quote:

Originally Posted by BonzoHansen

Look under your car, that is how your OE belts are anchored

Indeed, I noticed that the other day. Looks like that plate is the same gauge as the floor, with the nut welded on it. And I discovered my plan has run afoul for now - the trunk hinge bracketry is in the way on the inside. FML. I need to come up with another solution - gonna climb in the trunk later and see what other locations will work after my wife gets home.

BonzoHansen · 05-31-2010, 12:45 PM

You picked a nice cool day to be in a trunk.

The Fixer · 05-31-2010, 01:00 PM

Quote:

Originally Posted by BonzoHansen

You picked a nice cool day to be in a trunk.

LOL, I know! Well, I can't get started until after 4, because that's when the boss gets in.

Hopefully it'll have cooled off a bit by then!

BonzoHansen · 05-31-2010, 01:47 PM

Hint: get a fan.

I was doing that Friday night. New package tray this weekend, added the LH rear belt and changed the mounting on the RH one. I need to reinforce under the tray still, I ran out of time & sweat. Right now I just have gr8 washer, lock washer, nut under there.

Did you know 3 point rears were an option 70-~72? See the mount pads? They never changes the tray stamping. Belts are very rare, not sure if I ever met anyone that has seen a set in person.

The RH one was anchored like this. If we get in an accident and that pulls through I got way bigger problems than belt stretch.

Fox body belts (trunk cars, not hatchback). I figure Ford did the heavy R&D lifting, I just mounted them like they did. I will snatch these up at any swap meet I see. When I bought these the guy had 3 black sets, $20 each. I should have gotten them all. Last time all he had was blue & red.

While I'm copying & pasting..my 4th gen front seats & belts

The Fixer · 05-31-2010, 02:26 PM

Those look really sharp Scott! They look like they were always there - very cool. I dig the mount bracket you made also - I wish I could fit something like that under my rear deck. You're lucky that the belts in your car are black - I got kinda screwed because the OEM burgundy is a tough color to match. I thought about adapting a set from a W-body Regal but the retractor mechanism is through the rear deck and that spot is really short on a Monte. So, my setup has the retractor mounted on the floor in the original spot, then up behind the seat cushion to the upper mount, and then down to the floor to the outside of the cushion. Here's how the floor part is anchored -

Beam's belts are certified and pass MVS standards, so I assume their hardware is all part of the testing process.

The Fixer · 05-31-2010, 09:48 PM

Arg, I climbed into the trunk after dinner, and discovered that the X-braces behind the rear seat and the box that surrounds the trunk hinges are interfering with my plan. Check out the pic -

The bolt that goes through the upper seat belt mount is the one you see in the middle of the pic. Even if I bend that washer, it doesn't fit, because the seat brace pops out. Any other suggestions guys?

BonzoHansen · 06-01-2010, 07:36 AM

I don’t have a sense of how much room you have between that bolt and where the metal comes down (yellow arrow), but can you just get a piece of steel in there? (red), or maybe a 90* pice of steel? You may need to move that back a bit (blue), which I don’t see and a big issue.

The Fixer · 06-01-2010, 09:01 AM

Quote:

Originally Posted by BonzoHansen

I don’t have a sense of how much room you have between that bolt and where the metal comes down (yellow arrow), but can you just get a piece of steel in there? (red), or maybe a 90* pice of steel? You may need to move that back a bit (blue), which I don’t see and a big issue.

Scott, there's probably 1/4" between the upper part of the deck where the bolt comes through and then when it turns to go down to the seat bracing (the arrowed area). I could probably do a piece of steel plate there, since there is about 1/8" or so between the rear deck and the part of the brace that flares out. I should be able to get a plate of 1/16" steel in there and then just drill the hole near the one corner for the bolt.

As for moving the bolt, I tried the other hole you can see just behind where the bolt is right now, but the belt gets hung up on the rear deck and the retractor doesn't work properly. Where the bolt is now is probably the best location and gives the smoothest operation for the belt.

Now I gotta find somewhere that sells plate steel - maybe Home Depot or Lowes?

BonzoHansen · 06-01-2010, 10:06 AM

Either of those places have steel. Maybe you can get some 90 to make up for the hole so close to the edge. What about a hole between those two holes? With a good backing plate I don't think there would be an issue with another hole.

The Fixer · 06-01-2010, 12:17 PM

Quote:

Originally Posted by BonzoHansen

Either of those places have steel. Maybe you can get some 90 to make up for the hole so close to the edge. What about a hole between those two holes? With a good backing plate I don't think there would be an issue with another hole.

After looking at your pic of the plate under the rear deck, I think I'm going to make a 3"x4" plate of either 1/16" or 1/8" steel (whatever will fit), and drill a hole at both ends - the side closer to the seat will have the bolt for the shoulder strap, and then I'll add another bolt through the other end. Take a look at the 2nd pic in my first post and you'll see the hole I'm talking about. The bolt will be covered by the package tray so that'll be good, and I think will reinforce the whole setup.

The Fixer · 06-01-2010, 04:02 PM

Quote:

Originally Posted by BonzoHansen

What about a hole between those two holes? With a good backing plate I don't think there would be an issue with another hole.

Well, after further review (again!), I'm going to have to do this. I tried to get the nut to thread on the bolt in it's current location, and it's right against the flange on the seat brace, so the nut won't thread. I'm going to drill a new hole slightly back and offset from the current location, and put a 3"x4" plate of 1/8" steel behind it. Hopefully that'll work nice.

V · 06-02-2010, 06:51 AM

how about this...
steel plate, bend to a sharp 90 degree, trim/bend to fit up in that corner
then cut out a section on the side to recess the nut into. just enough that the upper hole and the hole in plate and hole in nut all line up.
then have the nut welded in place onto the steel plate
the pics are the best i can do i think to explain the idea, with the red lines being the final weld lines.
with the nut itself still being flush up against the metal tray/seat back brace, you should have enough clearance since you said you cant thread the nut as it is now, but did you try holding the nut then threading the bolt into it. That way the hexagon bolt wouldn't need to turn, which reduces side clearance.
...its an idea...lol

The Fixer · 06-02-2010, 11:24 AM

Quote:

Originally Posted by V

how about this...
steel plate, bend to a sharp 90 degree, trim/bend to fit up in that corner
then cut out a section on the side to recess the nut into. just enough that the upper hole and the hole in plate and hole in nut all line up.
then have the nut welded in place onto the steel plate
the pics are the best i can do i think to explain the idea, with the red lines being the final weld lines.
with the nut itself still being flush up against the metal tray/seat back brace, you should have enough clearance since you said you cant thread the nut as it is now, but did you try holding the nut then threading the bolt into it. That way the hexagon bolt wouldn't need to turn, which reduces side clearance.
...its an idea...lol

I really like this idea - not sure how easy it would be for me to do though, since I don't have access to a welder.

I'm gonna check at HD later to see if I can find the steel first, then climb into the trunk again and monkey around with it some more. I'll keep you posted!

79T/A · 06-02-2010, 12:47 PM

How old are the kids?

The Fixer · 06-02-2010, 04:44 PM

Quote:

Originally Posted by 79T/A

How old are the kids?

7 & 4 - my son is older. Right now he rides in the front passenger seat because that's the only 3-point belt, and with no airbags, it's perfectly safe. I know my daughter is itching to go to cruise nights and stuff though too, so I have to make something legal for her.

79T/A · 06-02-2010, 08:41 PM

I like V's idea the best so far. I have a tendency to go overkill on stuff like roll cages and seat belts, so I'd take it one step further and sandwich the sheetmetal between two pieces of 3/16 or 1/4 steel plate. I'm assuming that the top plate could be hidden by the rear deck's cover.

And I don't trust Home Depot for steel or Grade 8 hardware. I've heard that the stuff they sell is cheaply forged and therefore not as strong. I don't know where in the north you are, but I go to Tractor Supply Co for the Grade 8 and RS Phillips in Vernon for the steel. They've got a fantastic short rack full of cut offs and what not that's sold for about fifty cents a pound. Bring cash and walk out with a bunch of good steel.

And the reason I asked about the age: Depending on her weight and height, the four year old could probably still be in a car seat with a harness, which would temporarily solve the problem. Most of the newer seats are rated up to 65 pounds with the harness.

The Fixer · 06-02-2010, 09:23 PM

Quote:

Originally Posted by 79T/A

I like V's idea the best so far. I have a tendency to go overkill on stuff like roll cages and seat belts, so I'd take it one step further and sandwich the sheetmetal between two pieces of 3/16 or 1/4 steel plate. I'm assuming that the top plate could be hidden by the rear deck's cover.

And I don't trust Home Depot for steel or Grade 8 hardware. I've heard that the stuff they sell is cheaply forged and therefore not as strong. I don't know where in the north you are, but I go to Tractor Supply Co for the Grade 8 and RS Phillips in Vernon for the steel. They've got a fantastic short rack full of cut offs and what not that's sold for about fifty cents a pound. Bring cash and walk out with a bunch of good steel.

And the reason I asked about the age: Depending on her weight and height, the four year old could probably still be in a car seat with a harness, which would temporarily solve the problem. Most of the newer seats are rated up to 65 pounds with the harness.

I'm in Bergen County - Vernon is about 1 hour away, but there are a few steel suppliers that are more local. I'll give them a ring and see what I can find from them -thanks for the tip on the HD stuff. I like your idea about putting a plate on top as well, so after I find out what's available in the area I'll make some changes.

I also thought about keeping the other car seats, but they were 6 years old and the belts were starting to get a little worn, so we just picked up Graco flat booster seats for her too. I'm sure this will work eventually - just gotta find time to get them done.

Thanks for all the ideas guys, you've all been a big help!

BonzoHansen · 06-02-2010, 09:26 PM

What is a plate on top going to do? Forces are only going to pull it one way, it;s not getting pulled into the trunk. Automakers just reinforce under the metal for a reason.

LTb1ow · 06-02-2010, 09:36 PM

Quote:

Originally Posted by BonzoHansen

What is a plate on top going to do? Forces are only going to pull it one way, it;s not getting pulled into the trunk. Automakers just reinforce under the metal for a reason.

Well if you can tie the top plate to the bottom plate it will only add to the area the force is distributed over, but that would be tough to do, be either a lot of bolts or a serious weld.