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My Ratsun Datsun 521, now with L-20-B and a five speed

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EMT-Electrical Metallic Tubing, or conduit.

Or maybe just throw a olive green tarp over it, and put a red cross on the doors.

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there's something about that rack that is kinda sweet. maybe it's the rust.:P I don't need one but if i did it would be something like it.

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When I quit working on the truck electrical last night, I had this happening.



If you look really close, you will notice the reverse light glowing dimly.

Here is a better picture of that.


This is a classic symptom of a ground problem. What is happening, is the taillight frame is not grounding to the frame of the truck, and the brake light is using the reverse lamp to try to ground.


I attached this extra yellow wire to the taillight frame. The scrap piece of yellow wire was not long enough, so it is attached to a blue piece of wire, to reach the front of the truck.


I did this so I can measure the voltage between the taillight frame, that should be grounded, and the negative battery terminal.

I did exactly that in this picture.



I removed the taillight assembly, and added this additional wire on the frame of the taillight.

that is my finger pointing at the extra wire.



The other end of this wire was attached to the frame of the truck. there was already a small hole at the end of the frame, that I put a 10-32 screw through, and I also put a "star" lockwasher between the lug on the wire, and the frame of the truck. The "star" washer bites into the metal of the frame, and the lug, and makes really good electrical contact.


Here is a picture of the additional wire on the frame of the truck.



After doing that, this is what I had for brake lights



And this is now the voltage drop between the taillight frame, and the negative of the battery.



But the fun continues. the reverse light do not work. I do have power at the reverse light switch, on the transmission, and have already used a test wire to jump the switch connections. Still no reverse lights. I am now tracing through the wire to see where I am losing the electrical connection.

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glad this thing finally got sold and not parted out, and wow that is one clean motor inside, you got lucky there :D

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I finally got all the lights on the rear of the truck to light up, to full brightness. I took the rear part of the harness apart, and had to use a jumper for a ground. I also jumped the brake light switch, and the reverse switch connections on the wiring harness. So, all then lights work, just not the normal switches for the light. I even have a license plate light. It had no bulb in it.

Part of the problem with the lights is the ground connection on the right side frame rail. Even though it was secure, it apparently was not making an electrical connection.


This truck has the hydraulic pressure brake light switch. It probably will get changed to one that works off the brake pedal. I also need to confirm that the reverse light switch on the transmission works, and repair the electrical connections on it.

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This is a post to send some props to Tdaaj. I bought some parts from him in 2008?


These were the front tires and wheels that were on this truck when MicroMachinery brought it here.

Left front.


Right front.



One of the parts I bought from Tdaaj was a rear axle. To move it around, he had these wheel and tires on it, a nice matched pair.




Does anybody recognize these wheels, and what they came off of? Is it possible to get hub caps for them?


Another wheel option is to use these wheels. They are stock 521 wheels, cleaned up, sandblasted, and painted white. A really bright white. If this truck was just about any other color than the Datsun 502 off white, the bright white wheels would work.


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More Tdaaj parts.


This is the hood that came with the truck. three of the four bolts are broken off in the hinge mount. It also has the struts not glued to the skin of the hood very well.

Hood top.


Hood bottom.


and here is another picture of the struts on the bottom of the hood.



This is one of the hoods I got from Tdaaj.


And the bottom.


Some of the struts are separated from the hood.


But this hood does have a few problems in the hinge area

Left hinge mount.


Right hinge mount.


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The bright white wheel and the rusted one like it are actually 320 or early 520 rims. I think the 320's were a bit narrower than the 520, but I'm not sure. The "tell" is in the shape of the reinforcement rib that point toward the hub. The 521's are rounder.

Great work!!!

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Wayno, and Mklotz,

Thanks for the info on the wheels


The first Datsun pickup I got was an early two headlight 520. Then that was traded in on a 1971 521. After having that as a "nice" truck, we got a beat up 320 for farm work. The 320 was sold, and then we got two more 521 trucks. And finally, the project that this thread is about.

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On this page.

Reverse light switch repair.

Access to nuts holding front parking lights.

First drive into pasture.

Holes in floor.

Wood blocks for seat.



I got the reverse lights working, by shifting the transmission into reverse. I had a bad switch. Good thing I had two other transmissions to pull the switches out of.
To start working on reverse lights, disconnect the ignition. Reverse lights only work with the key on.
To check the reverse lights, and the wiring you need to jump the reverse light switch connection.
You should have power on one of these wires with the key on.

This is one way of checking power in these connectors. You do not even have to take them apart. You go to a fabric store and get some of these "T" pins, that are used in sewing clothes together.
You then can take the "T" pin, and insert it from the back side of a connector, like this.
Now you have a handy place to hook up a test light.

Here is where the reverse light switch is on the transmission.
And this is what it looks like under the truck.

So I had some switches to work on.
The switch without wires was the good switch.
I had to solder these two wires on to the switch contacts.
and this is what it looks like with the wires soldered.
And finally, check the switch to make sure it works. The reverse light switch should have continuity when then plunger is out, and if you push in on the plunger, the switch should not have continuity.

Put the checked repaired switch back in the transmission. Here is my truck in neutral.
and shifted into reverse.

If you have not read this whole thread, you may be curious about the yellow wire hanging over the tailgate, going into the bed. It is temporarily added to the left taillight frame, like this.
I put it on the taillight frame when I was checking out a problem with the left brake light, see post #53 for details. In post #53, I mentioned the yellow wire only reached part of the way to the front of the truck, so I added a piece of blue wire. It turned out that the yellow wire ended up under the truck, long enough to about where the transmission is, and I used the connection there for a known good ground for a test light.

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Awesome! You're doing a great job documenting and sharing this info!!! Keep it up! :)

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MY tail light assembles.

I had to drill a hole in bottom as water would fill up and start popping my bulbs and rusting in there. Now I put antiseize on the outer ground side of the bulb and they come out less corrored and also serves as a water disspersaint . BUT NOT ON WHOLE thing as antizeize is conductive.

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This is a picture of the gaskets in the 521 taillights.
On the bottom gasket, you see three pencils pointing at three notches in the taillight gasket.
These go down, to drain water out of the taillight assembly.
It looks like I have two left gaskets. Turn one gasket end for end, and you have a right.

I have given some thought to fabricating a roll pan of some type, to protect the taillights from road crap being thrown up from the rear tires.

This is my thread on 521 taillights.

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This is the temptress that has been keeping me busy the last two days. I brought it out of storage Saturday morning, and got it ready for the Summer.

Got some more cleaning to do in her, and a few obvious gelcoat repairs to buff out, and then back to Ratsun Datsun.


This is her engine, a fuel injected Ford 351.


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Today, I worked on the side marker lights. See this thread.



Last Friday, I worked on the stop lights, reverse lights, and turn signals on the back of the truck, and got them all working. this was with the wiring harness hanging loose in the back of the truck. I taped the harness back up, and secured it under the truck. and the taillights quit working.


i started to poke around the fuse box, and the taillights, and side marker light came back on. did a little more work cleaning the fuse box. Moving the light fuse causes the lights to flicker.


After all that, I removed the clutch master cylinder, and that is where I ended up tonight.

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Left side,



Right side. I am missing a welded on bolt on the right side of this base.



How did you get these off? I've noticed that there's a bit of a 'pocket' on the backside under the wheel-well that looks like it may lead to the back of this, but then you can also reach it (with a bit of work) through just below the front grill section, but I haven't decided which would be easier to attempt first. Thanks for any advice, and nice informative thread!

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You need to take the pocket off from inside the wheel well. It's there to protect the backside of the lamp assy. Spray with penetrating oil and let it sit for a bit. If you have a welder, just snap them off and weld in new ones :)

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For DatWifey.

Front marker light mounting nuts can be reached by removing the cover or "pocket". It is held with three Phillips pan head tap screws. Two at the top, each corner, and one in the bottom, in the middle. Inside the fenderwell, forward of the front tire. If you stick your head in there to get a good look, your hair will get dirty. You will have more room if you remove the front tire.

If your truck was undercoated, the heads of these will be filled up, or the screw may even be hidden under the undercoat.

I will try to remember to get a picture tomorrow. It is after midnight.

Mikes method seems a little destructive.


And now, today's update. No pictures, sorry. When I quit last night, I had just removed the clutch master cylinder. I decided to get a new one, and a new slave cylinder also. I ordered them Tuesday morning, May 3.

That morning, I spent working on another boat. Removing the heater, it had a leaky heater core, and then removing the steering cable, and some worn parts on the steering wheel itself. I then took those parts to a boat shop in Oregon City to order the parts I needed for the boat.

When I went to Oregon city, I took the radiator that came with this truck, that I have named Ratsun Datsun, to get repaired. Remember about four pages back, I found a leak in the radiator.

I picked up the ordered clutch hydraulic parts, and after some other errands, came home.

I also needed to mow some lawn today.


Finally, this evening, I put the new clutch master cylinder in the truck. I also hooked up the the two old slave cylinders I had, to see if I could get them apart. One came apart, and might be rebuildable, the other, probably not.


When I was working on the truck tonight, I found out I left my trouble light in the boat I was working on. I did not want to take the cover off the boat, so for a trouble light, I used one of the front marker lights, with two test leads. One lead to body sheet metal, for a ground, and the other lead to the hot wire on the four way (emergency) flasher.

Tomorrow, adjust the clutch, and remove a twist from the slave cylinder hose.

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destructive, but sometimes necessary. :( I forgot they were screws. I think I've typically been able to remove the screws holding the pocket/cover. I have had to grind/cut the screw heads off before, but that may have been on parts rigs when I was getting impatient :) If the heads strip out trying to remove them with a phillips, you might be able to get in there with a small, thin cutoff wheel on a dremel. Cut a slot across the top of the screw and use a flat blade screwdriver.


If you're missing studs on the lamp assy, you can weld new bolts back in on those.

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Thank you both again for your advice. We've got all the wheels off and the suspension all torn apart on the front, so this is the optimal time for me to pull these apart while the husband is doing the suspension and brakes :D


Mike, good call on the Dremel cut-off wheel. I hadn't thought of that. We've come across so many of these small screws completely stripped already, and have been drilling them out, but that's one way to ensure we don't mess up the threads.

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It's even easier if you have the cable attachment for it :)

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