521 Lug nuts

[fiveNdime]

I have no idea what size of lug nut is on my 521. I have already tried

12mm 1.50 and 12mm 1.25 Both do not work well the tread pitch on the trucks wheel studs are a 1.25 pitch I checked that with my guage. The lug nuts that are on it are a 1.25 pitch but fit way better. All I can think is that the wheel studs are an 11mm instead of the 12mm. Thanks for the help!!!

[pl521sss]

ahhh, you ran into same problems I had.

If you try metrics, it won't work.

 

It should be 716, last I noted what they are before I went with spacers with 1.5 studs.

[DanielC]

On the 521 pickup, the engine bolts are metric, and the body bolts are in fractions of an inch. Pipe fittings on the engine are BSP (British Standard Pipe)

I am not sure what the brake line fittings are, I am going to find out soon,

[datsunfish]

I have owned 2 521s and they both had different lug threads.One was standard and the other metric.Not sure if they had been changed out.

[dat521gatherer]

most people dont believe me when i tell them my datsun is half sae. they just look at me funny and say o.k.

[irsa76]

I've had 3 cars like that, all GMs. Drove me nuts! My 720 is sort of like that as well. So far most bolts etc are metric, except for the ones on the flatbed! And half of them are different sized! Not to mention most of the wheel nuts are different sized. New nuts are coming, new wheels would be nice as well.

[DanielC]

We are dealing with cars and trucks that are 30 years old, and more. Probably not many of them are totally stock.

[Steroid]

I had wondered about that. I have "acquired" two 1972 1/2 620s, since scrapped, and noticed the lug thread difference. I removed one lug and noticed the totally different lug it had than any other 620 I own. Yes, it was smaller. Also, where the other 620 lugs are splined, this one was a tad bit smaller but had an area on the very back removed and no splines. Where the removed area was, it fits inside a different axle with a part of the casting that as the lug is placed, it lines up to keep the lug from turning as it is installed. I hope My discription makes sence. Both of those lugs are different as well as the lugnut threads.

[71-521]

On the 521 pickup,

I am not sure what the brake line fittings are, I am going to find out soon,

SAE...that is what makes the brake upgrade so had for some...

[fiveNdime]

Well i figured out that the original wheel stud was a 12mm with a 1.25 thread pitch. Thats going back in the books a long ways. All I can think of is they have been used and abused for 30 plus years and so they have worn down. All those "Nuts" that though a 12mm 1.50pitch nut would work were wrong and not knowing this messed the threads up. I would also imagine that some have also used SAE lug nuts as well which is also wrong. Hence the loose fitting "correct" lug nuts. This is now settled. All I have to do now is replace all the wheel studs with new ones which sucks cause its a bit of work, but is also not too bad cause I can get longer ones for the thicker aluminum wheels which could go on my truck if I were rich:lol:

 

Brake line fittings are standard 7/16 Flare Wrench

[Socalman]

Just for future reference, on my 521, the lugs were 7/16"-20. in case someone else runs into this issue. my studs are stock.