Looking for help on My 521 Truck

[SunBitches]

I purchased a 1971 Datsun 521 truck. Wasn't running for 20 + years but after a few days of working on it, now it is.  I need parts for the fuel tank . The fuel sending unit, lock ring, and gasket ring so i can hook up the fuel system and be ready to run. I see a lot of parts online but they aren't just right to match the parts I have and I don't have the measurements for the lock ring it didn't come with the truck. So if anyone have a link for the correct parts, lease help me with that. I'm up to buying new or used to get the correct parts. Thanks for the help

[datzenmike]

No idea where you would buy obscure parts for a 50+ year old gas tank.  Wrecking yard? or .... https://ratsun.net/classifieds/category/9-datsun-parts/

 

Lock ring is............ 17343-14801 Used on all Datsuns from '68 to mid '80s

gasket is................ 17342-14800 Unique to 521. All other Datsuns used an O ring (17342-18000 might work)

sending unit is...... 25060-15200 Unique to 521. Top mount so 620/720/610/710 and others would theoretically fit and bend the arm to suit.

[Stoffregen Motorsports]

Good luck finding them new. You could probably get a whole tank for $40 from a Datsun guy.

[SunBitches]

So are there any Datsun guys that may have extra parts? where can i find help? 

 

[datzenmike]

https://ratsun.net/classifieds/category/9-datsun-parts/

[Slow Loris]

I’ve got no clue if this site is legit, never bought from them but they do sell a lock ring for the fuel sender that looks just like what’s in my 521.

 

http://www.new-datsun-parts.com/datsun-pickup-parts.html
 

Also they sell the gasket. 

[thisismatt]

They are legit

[Crashtd420]

Just watch out for Ebay and the things they claim fit the 521... often the 620 parts are sold saying they fit or work and they do not....

 

Minus the vent tube this looks exactly like the sender in my 521....

https://www.ebay.com/itm/185475804257?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=48NR-j7dQ_q&sssrc=2349624&ssuid=&var=&widget_ver=artemis&media=COPY

 

Those $30 ones you see have the wrong arm for our tanks.... they will work but the level will be inaccurate.. I even tried bending the arm to match the arch of the original but ended up using my old sender instead...

 

[thisismatt]

That sender is correct for the early, non-evap tanks.

[KELMO]

On 12/29/2022 at 9:20 AM, datzenmike said:

No idea where you would buy obscure parts for a 50+ year old gas tank.  Wrecking yard? or .... https://ratsun.net/classifieds/category/9-datsun-parts/

 

Lock ring is............ 17343-14801 Used on all Datsuns from '68 to mid '80s

gasket is................ 17342-14800 Unique to 521. All other Datsuns used an O ring (17342-18000 might work)

sending unit is...... 25060-15200 Unique to 521. Top mount so 620/720/610/710 and others would theoretically fit and bend the arm to suit.

I will have to check but that lock ring may have been available as late as last year. I also think that if the lock ring is used on all Datsuns as stated, the O-ring should theoretically fit as will. I will check the lock ring part # later today when I am in the shop.

[datzenmike]

Vehicles in production in '82 had the ring and O ring in them till the end of their run (720, 810/, A10 S10 210 and Stanza)  the 280zx, Maxima did not, maybe because EFI?

 

I imagine the O ring is thicker than the 'gasket' used on the 521. Worth seeing if it will work. I used a brass drift to tap them loose or tight. O rings can get crusty with rust. I scratched it off with fingernail and cleaned thoroughly with WD-40... worked just fine.

 

As to the 620 sender as long as it reaches the bottom of the tank you'll know accurately enough to not run out. Reading full at 3/4   isn't the end of the world. There are other senders that mount on the top of the tank like the 521 that might work better than the 620.

[Crashtd420]

32 minutes ago, datzenmike said:

 

As to the 620 sender as long as it reaches the bottom of the tank you'll know accurately enough to not run out. Reading full at 3/4   isn't the end of the world. There are other senders that mount on the top of the tank like the 521 that might work better than the 620.

The one I got claiming it worked for the 521 and the 620 had too much reach.. with no gas it was reading over 1/4 tank or so... way to long of an arm.. bending helped but I was never satisfied.... 

 

 

[Stoffregen Motorsports]

Yes, an accurate empty reading is far more important than a full reading.

 

You can ix and match parts from senders. If the arm is too long or too short, you can cut it off and weld one with a correct shape onto it.  I do this often enough for the 40 gallon tanks I install in Land Cruisers. The new tanks are much deeper and I add five inches to the length of the float.