Seat belt bolt threads?

[ghunt81]

Does anyone know what thread size the seat belt bolts are? Mine got majorly boogered up due to rust and I definitely need to fix the threads on both the bolts and inserts.

Anyway, they look like M12 and are fine pitch, but are they 1.25 or 1.5?

 

[PlumCrazy]

If the insert treads are boogered up, then I would drill them trough and replace with 1/2" grade 8, use a lock nut and a decent sized washer on the bottom side to be sure it wont come loose or pull through in the unfortunate event of an accident.

 

[Mark_88]

+1

I'm about to do the same with my seat bracket bolts and just went out and bought some GR8 bolts and nuts and washers. The seat belt bolts are usually surrounded by reinforced metal but it's always a good idea to go over that area with a fine toothed comb (not too many of these around anymore) to make sure the metal is sound.

 

[ghunt81]

I suppose that's probably not a bad idea. The threads on both bolts are rusty and pretty much ruined, so I imagine the inserts are the same way.

Never understood why they use these super-fine thread bolts for the seat belts, then make them protrude through the floorpan where they get all rusty, and ruin everything when you have to take them out.

 

[Mark_88]

That's what I was saying about body grounds. If the grounds are all good then there is much less corrosion...something to do with static electricity and poor grounds causing different metal connections to corrode.

My seat brackets have already rusted out so bad that one broke...not that my fat ass and shifting weight around like a dancing Pillsbury Dough Boy helped matters...but I replaced both seat brackets on my driver seat only few years ago...and they corrode up with battery like corrosion so bad that I need to clean them off every year or they will disintegrate.

I will say that to this point I only have one or two body grounds and only just went out and bought a few more to be installed...will have to see if this makes things better on the hot seat...

 

[Mazda]

Never understood why they use these super-fine thread bolts for the seat belts, then make them protrude through the floorpan where they get all rusty, and ruin everything when you have to take them out.

Because Car/Truck companies really don't want you still driving around a 9 year old truck let alone a 20 or older like I have and want you to buy a new one every 4 years or so. LOL!!!!!

They are M12 1.25 but are grade 10 bolts.

 

[PlumCrazy]

Not grade 10....they are 10.9 which is the metric equivalent to grade 8.

I deal with this kind of stuff on a daily basis (automotive crash testing lab)

Sent from XT1030 using Crapatalk

 

[Mazda]

Not grade 10....they are 10.9 which is the metric equivalent to grade 8.

I deal with this kind of stuff on a daily basis (automotive crash testing lab)

Sent from XT1030 using Crapatalk

Thanks PlumCrazy. I guess I bought metric bolts. just thought they were a higher grade. Hate doing SAE-Metric conversion. Should have gooooogled.

 

[1992redranger]

Does anyone know the thread size, thread pitch, etc. for the bolts that hold the seatbelt height adjuster onto the b pillar? Just cross-threaded and messed one of mine up, so I'll probably have to tap the hole it goes into, too.

2002 Mazda B3000 regular cab

 

[racsan]

Ive snapped many torx bits trying to remove them, its a bit rediculous as a grade 2 , 1/2x13 would easily be enough bolt for the job.

 

[PlumCrazy]

All seatbelt attachments are 7/16-20 thread per FMVSS regulation

 

[SenorNoob]

Ya learn something new every day. Is there a metric equivalent or all standard?

 

[pjtoledo]

7/16" = .4375"
11mm = .433

20 tpi would equal 1.27mm thread pitch
so,, it's close but will bind more than I care for.

available tap pitches for 11mm are .5, .75, 1, 1.25, and 1.5

 

[PlumCrazy]

Ya learn something new every day. Is there a metric equivalent or all standard?

All standard. I work for a Japanese OEM seat supplier and even our stuff is all SAE thread for belt attachments

 

[1992redranger]

Interesting. To confirm, I attached a couple images of the bolts I'm talking about. I found some 3/8" - 16 x 1" bolts (Dorman part 960-710D) at Advanced Auto that seemed to thread well when installing. Are these ones not correct?