sen2two

iTrader: (10)

I started on a rear sub-frame swap about a month ago, got it about 90% done then life got in the way, and havnt touched it since. I finally have time to finish the install, and I cant find the big nuts that goes to the front of the sub frame.

Anyone now what size they are so I can go buy some at a local auto/hardware store.

RockLobster

iTrader: (7)

I forget what pitch it is but is an ultra-fine thread. Not typically available at your local hardware store. You may have to order from Mazda or go grab a couple from a junkyard.

sen2two

iTrader: (10)

Not sure were talking about the same nut, these two nuts are not fine thread at all. I have a standard thread and pitch gauge, but it's obviously a metric thread.

Diameter looks to be around half inch, and the threads per inch is closest to 18 in standard. But dosnt really fit.

These are the two nuts that bolt the subframe to the body, one on each side.

eage8

iTrader: (9)

they're 21mm nuts either that or 17mm... I might be getting the diff nuts and subframe nuts confused.

part # B037-28-091
they're like $3.50 each

I would imagine they're probably M12s

RockLobster

iTrader: (7)

They require a 21 mm wrench/socket but that's not what size nut they are.

All i can recall for sure is in the rear of the car there are two different nuts that are the same inside diameter and require 21mm tools. They have a different thread pitch which is not typical for Japanese manufacturers.

IIRC the nuts holding the front diff mount to the subframe are the same size but a different thread pitch.

The ones holding the diff to the body are the same pitch and size as the ones holding the subframe to the body, and it is a finer thread pitch than the diff to sub frame ones.

sen2two

iTrader: (10)

I had a spare nut that bolts the front of the diff to the subframe, tried it. to small. I guess its off to the junk yard for me... ehhh...

sen2two

iTrader: (10)

I don't know the thread and pitch still, but i did go down to the junk yard to pull one off another FC. Luck would have it, they didn't have any there...

So I started checking random Mazdas figuring that there would be the same bolt somewhere. Yupp, found them on a Miata for the front suspension and the 929 rear subframe mounts front and rear. Probley a few other cars too...