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1971 Datsun 521


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31 minutes ago, Charlie69 said:

Change to a 620/720 ebrake cable setup and do away with the all the bellcrank on the frame.

720 ebrake cable and handle assembly.png

I didn’t know that was a thing. I had the exact problem with the down pipe and the bellcrank also. I used a cable from a 510. Works great. I also had to shrink my battery mount to clear the intake. I really want to keep a battery in the stock location, but it will have to be a smaller frame size. 
Looking good!

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Buy complete trucks for parts.  If I remember correctly I had to use part of the 720 ebrake bracket and handle to manage the cable through the firewall.  I ended up putting a 720 chassis under my 66 which solved many small issues and got me away from king pins.


By the way Mike Klotz has 50 plus king pin kits hit him up before they are sold out.

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I used a 1980 720 chassis from a truck I bought for $50.  The front mounts under the radiator line up .  The middle and back cab mounts do not line up.  Wayno drills new holes I believe in the the floor of the cab.  My brother and I cut the mounts off off the 520 chassis and used the ends of them to extend the 720 mounts out to match the holes in the cab.


This is with the cab mounted on the 720 chassis

I cut all the 720 bed mounts off and ground of the residual metal from the frame.  I then blocked up the bed on the frame where I wanted it to line up the body lines wanted it.  I measured each mount height to the the mount on the bed and marked the the 720 2 sets of front mounts.  I the bolted the 720 frame mounts to the bed using the 720 rubber isolators.  With these 4 mounts positioned my brother welded the to the frame.  On the rear of the bed I made a 3/4" solid block of steel about 4" long that I drilled and tapped  for the rear bed mount.  Bolted these to the bed with a rubber pad and positioned them on the top of the frame rails.  My brother then welded them to the bed frame.  after doing this I realized the 3/4" rasied the back of the bed too high so I need to cut these out and refigure them and the second back set of frame mounts also.  Do the front and rear mounts first on the cab and be and the do the mounts in between as thi will establish the height of the mounts in between the front and the rear mounts.


Great care need to be taken to squre the cab and the bed up on the frame.  I also started by leveling my frame front to back and side to side before starting any fitting of the cab and bed.


Wayno has done several 720 chassis swaps he is the guru for this.  He guide me through my swap. 


This is all in my 520 build thread.

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So far the shorted thermostat housing is really close to the tps sensors. I have two extra connections towards the distributor I assume one was for the ac compressor the other maybe for the cooling fan? That one is a blue and black wires. Also have to switch the couplings to 2 inch ones the 3in one don’t even fit at all. And I tried flipping the e. Brake bracket in many ways and it still hits gonna wait Ans see what I can do about it later

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6 hours ago, Zonargx said:

Another thing I need help is finding the differential oil seal by the drive shaft when I removed the drive shaft I notice it had some oil leak all over the upper part of the bed? And down the housing

That should be a readily available seal... I see 2 listed on rockauto... I can check what part number I used when I get home from work today...

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Rock auto is weird they sometimes don’t have thing and sometimes they do. Anyways does the stock 521 clutch slave flex hose the same as the stock brake like. I just checked my hose and it’s has a very small leak. Rock auto doesn’t have them listed I only see brake likes

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2 hours ago, Zonargx said:

Rock auto is weird they sometimes don’t have thing and sometimes they do. Anyways does the stock 521 clutch slave flex hose the same as the stock brake like. I just checked my hose and it’s has a very small leak. Rock auto doesn’t have them listed I only see brake likes

Not sure on that one.... 

I tried looking around but didnt find one available either.... 

You could always have one made, I a have a local hose shop that can replicate what I bring them....


Careful because I see some listed in ebay for the 521 but also the 620....

I believe 521 is sae

But the 620 is metric.... 


On rockauto you can get the hydraulic line for the 620 but you would have to get a 620 slave cylinder to match.... and change the fitting on the hardline....


I did that before with my rear brakes... I needed those wierd y fittings.... 

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This is what I used for my differential pinion seal.... 

I think I got it from oriellys....


I think the timken 1167s seems correct but the skf that was also listed on rockauto seemed wrong....


It might be best to remove the flange from the differential and double check the measurements...


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