New 521 build/restoration

[GCF]

Just picked up this '70 521.

 

No long term plan yet, I just want to go through and fix a few things so I can start driving it. Previous owner essentially rebuilt the engine so mechanically it runs fine. There are a few things I need to do first...

 

Gas tank leaks. 1/4" hole on the back someone tried to patch with JB Weld and it also leaks around the seam. A little rust inside but it's not bad. Guy at a radiator shop told me it cannot be repaired and then quoted me $350 and i said nope. I think i would like to buy a new universal tank but keep it in the same location and use the existing fill cap if possible. Anyone done this? I dont really want it where the spare is.

 

 

 

[datzenmike]

There are two part epoxy pour in tank liners complete with cleaner and etching wash to prepare the metal. Pour in and tumble the tank to coal it and let set. You get to keep the original rank.

[Stoffregen Motorsports]

A universal tank will require hours for mounting and plumbing. And you probably won't find one with a filler neck anywhere near where it needs to be, so fabrication time too.

 

Find someone here on Ratsun that will sell you one and ship it. Money better spent.

[mrbigtanker]

I have a gas tank but shipping will be expensive. But would sell it for 125.00 plus shipping.

[GCF]

Maybe I'll try restoring my tank first to see how it goes. Like I said the inside really isnt that bad other than a couple holes! 😂

 

How hard is it to find a bench seat that'll fit the 521?

Previous owner threw out the bench seat because it "was shot" and put in some buckets from who knows what that puts the steering wheel under your chin. I assume most bench seats are going to be too wide. Any ideas on what to look for? 

 

 

[datzenmike]

If getting buckets make sure they are thin. Buckets came in only the 620 king cab where there was room.

[NC85ST]

Where are you in Tennessee? I live a little east of Asheville, NC. I might have what you need.

[Stoffregen Motorsports]

240Z seats (or 260, 280) are thin, low and have built in headrests. Later 280Z seats are still easy to find. Toyota Supra seats are also thin and low and easy to find.

 

I have a pair of MG Midget seats that are perfect for fitment in a tight cab pickup (and retro cool too), but they don't have headrests. For what it's worth, I would rather have buckets without headrests in the tight confines of a mini truck. That said, maybe a pair of stock 510 buckets would work...?

[GCF]

20 hours ago, NC85ST said:

Where are you in Tennessee? I live a little east of Asheville, NC. I might have what you need.

 

Im just south of Knoxville. Asheville is about 3 hours from me. What do you have?

 

 

 

Are there any bench seats known to fit? 

[yenpit]

20 hours ago, GCF said:

 

Im just south of Knoxville. Asheville is about 3 hours from me. What do you have?

 

 

 

Are there any bench seats known to fit? 

 

I modified a 720 bench seat.  The seat back is too wide, so we cut 3inches out of the middle, pie cut the corners, drew the side in to the center, welded all back up & custom upholstery.  My truck already had the original seat rails cut off of the floor..................have not installed yet, but all looks good!  The 620 seat is also too wide at the seat back.  The 521 B pillar has a "squiggle" at halfway point, that rolls in & out.........that is where the 620 & 720 seats hit, thus you lose about 3++ inches cuz they won't slide all he way back!  Find a 521 seat or modify!

[GCF]

Well I found a bench seat locally from a 95 D21. Took the chance and it seems to fit great. Will have to do a little bit of work to get it bolted in the right position but fitment wise I think it'll work. Maybe a little long in the legs but Im not going to complain.

 

 

[mrbigtanker]

3 hours ago, GCF said:

Well I found a bench seat locally from a 95 D21. Took the chance and it seems to fit great. Will have to do a little bit of work to get it bolted in the right position but fitment wise I think it'll work. Maybe a little long in the legs but Im not going to complain.

 

It will fit in the cab ? Or is it pressing the doors out on each side. 

[bilzbobaggins]

 

 

Not my thread but guy put a hardbody seat in his 521.  He shows how he mounted his as well 

[GCF]

Sorry still trying to find the best way to post images.

 

 

[yenpit]

Wow that looks like it fits nicely! 😎

[BrothersGarage]

Awesome little truck

 

Edited February 17, 2021 by BrothersGarage

[GCF]

Really want to get this truck drivable but the brake lines are pretty corroded. If I go through the trouble of replacing the brake lines I would also like to swap out the master cylinder with a dual reservoir. Im fine keeping the drums all around, is there a dual master cylinder that would work without too much headache?

or should I just keep the original master cylinder for now? I will probably do discs up front in the future.

[mainer311]

You can swap to a dual master, and then just change the residual valve so that it’s setup for drum-drum. And then later on, you can put the original valve back in to go back to disc-drum. I believe a late-70’s 620 master is what you want.

 

Cardone 131839 or equivalent is what I bought.

Edited April 10, 2021 by mainer311

[datzenmike]

That would be a 13/16" up from a 7/8" or 3/4". You can't move more fluid with the same effort as the 3/4" master (conservation of energy aka you can't expect something for nothing) so get the vacuum booster with it or the pedal is not only stiffer to push but comes in higher up. 

[GCF]

14 hours ago, datzenmike said:

That would be a 13/16" up from a 7/8" or 3/4". You can't move more fluid with the same effort as the 3/4" master (conservation of energy aka you can't expect something for nothing) so get the vacuum booster with it or the pedal is not only stiffer to push but comes in higher up. 

 

Is the stock MC a 3/4? If so would something like THIS work without the booster? Thanks for the help.

[mainer311]

14 hours ago, datzenmike said:

That would be a 13/16" up from a 7/8" or 3/4". You can't move more fluid with the same effort as the 3/4" master (conservation of energy aka you can't expect something for nothing) so get the vacuum booster with it or the pedal is not only stiffer to push but comes in higher up. 

13/16” is less than 7/8”. And who cares if the pedal is slightly stiffer? People put boosters in because they want more braking power, not because they have weak ass legs.

Edited April 11, 2021 by mainer311

[datzenmike]

Guess it was 9/16". 

 

 

 

Anything that makes braking easier is a plus. Same with steering. At the end of the day when you're tired it makes a difference. Early Datsuns were light and didn't need it as much but there isn't a vehicle made today that doesn't have it. A booster increases line pressure by about 50%. Tires traction and brakes have improved in the last 50 years and you can brake harder. Increasing the master diameter increases the effort to get the same line pressure. No matter how strong you think you are you can't compete with a booster. Yes... why wouldn't you want more braking power????