520/521/620 Seat differences

[69dime]

I saw a 620 in a junkyard and the seat looked like it would almost bolt into a 521. I don't have the stock seat for my 521 but I bought a frame from someone that I was told was from a 521. The seat in the 620 had a catch on the back so it wouldn't fold forward without releasing it. Is the 521 seat supposed to have that?

 

Would a 620 seat bolt into a 521 with no mods?

 

What are the differences in the seats from a 520, 521, and a 620? Since most of these have been replaced, it's hard to find pictures of them. The seat in the 620 was a rectangle seat - no cutout for the shifter area.

 

Does anyone have pictures on what these stock seats are supposed to look like?

[datsunaholic]

The mounting rails are completely different, and the 620 seat is wider.

 

The 520/521 cabs have a longitudinal rail welded to the floor (front to back) that the seat rail bolts to. On the 620, the rail runs transverse, across the cab, and only the front bolts to that. The rear bolt goes through the floor itself to a nut welded to the underside of the floor. Plus the 620 floors changed in 1976 to allow use of stock buckets, the earlier 620 floors were flatter and didn't have provisions for extra seat rails next to the tunnel.

[69dime]

The mounting rails are completely different, and the 620 seat is wider.

 

The 520/521 cabs have a longitudinal rail welded to the floor (front to back) that the seat rail bolts to. On the 620, the rail runs transverse, across the cab, and only the front bolts to that. The rear bolt goes through the floor itself to a nut welded to the underside of the floor. Plus the 620 floors changed in 1976 to allow use of stock buckets, the earlier 620 floors were flatter and didn't have provisions for extra seat rails next to the tunnel.

 

They look pretty close. The 620 also has a locking mechanism to keep the seat back from moving forward.