DanielC

No, the seat is being used.

521 brake slave cylinders only have one port for fluid to go in, and any air to get out. When bleeding the slave cylinder, you have to let the pressure on the fluid push the shoes out against the retracting springs, and then wait for the springs to retract the shoes, and push the slave cylinder pistons back . This lets air in the slave cylinder back out the bleeder.

I thought the l18 had a longer stroke than the l16. If you can get the parts using the l16 rods on a l18 crank gives you a "long rod" l18

The horn relay grounds through the steering shaft. With a gap,no ground. The pins have to flip a cam on the turn signal switch to cancel the turn signal. With a gap, the pins do not reach far enough to flip the cam that cancels the switch.

This relay is for switching the second set of retarded points in the dual point distributor. If you have changed the distributor, transmission, or carburetor, the relay no longer functions.

I have been driving Dragon pretty much trouble free, but yesterday, I needed to get some gravel to fill a pothole in a driveway down to a barn. Dragon got put to work.

Go to a Nissan dealer and get a BSPT oil pressure switch. Ask for an oil pressure switch for a 1980 720 without oil pressure gauge.

The oil pick up tube used under the 521 oil pan. They are matched to each other.

The ground is supplied by the washer switch on the wiper wash knob, by twisting the knob clockwise. Remove the bag from the truck. Using a heat gun on the hoses will soften them up so they can be pulled off the connections easier. The motor pocket in the bottom of the bag is held closed by some brass clasps, like loose notebook paper pages in a theme paper binder you turned your homework in school, in about 1970. With the motor out of the bag pocket, if it is not rusted too bag, remove the pump cover off the pump, and try to turn the rotor by hand. If it turns, try applying 12 volts to the pump motor, and see if it turns. If it reliably runs, put it back together. If the motor does not work, look in a junkyard, for a washer motor in another car. You can also search Amazon for new washer pumps, look for the smallest one that will fit in the bag pocket. You probably will not find a new pump with a inlet and outlet port that will fit the port holes in the bag, but you might find a washer pump that will fit into one of the port holes on the bag, and have to run one hose through the same slot in the bottom of the bag pocket that you put the motor in. One of my 521 trucks did not have the kangaroo washer bag. I put a washer tank and pump from a 720 truck in the same location as the OEM bag and pump. A lot more pictures near the bottom of this page. https://ratsun.net/topic/30606-my-ratsun-datsun-521-now-with-l-20-b-and-a-five-speed/page/25/

I have a spare one. Actually, I have more than one, one is cleaned up and on a painted bracket. The bracket is painted Dragon Green, the round body of the motor is painted grey. I also have one that is not cleaned up or painted. i can take pictures later if you are interested. You are in southern California. "you don't need any stinking wiper motors"

Lets start with this. This diagram is not 100% accurate, but it is close. It does not have any of the of the wiring for the crude emission controls on USA trucks involving several switches on the transmission, carburetor, firewall, or gas and clutch pedals. Sometime between 1970 and 1971 model year 521 trucks the headlght wiring was changed. There was also a factory option fog light setup, but I do not think that made it into very many USA 521 trucks, but it may have been a dealer installed option. Earlier and later 521 trucks had a six fuse fuse box. The earlier truck has one solid red hot wire to the light switch, and had three fuses always hot, three fuses ignition on hot. Later 521 trucks split out the headlights from all the other lights, and had two always hot wires to the light switch. The fog light option had a third hot wire from the fuse box, with a additional in line fuse. The wiring diagram above shows the four hot fuse box, with the fog light option. A "normal" non fog light option light switch has a four pin connector. Two contacts are power from the fuse box through the switch, to the headlight relay. The other two contacts are for all the other lights. I think that the wiring harness between the fuse box to the light switch on the three hot fuse trucks has a "Y" in it to feed the two circuits to the light switch. The OEM 521 light switch has two positions. Pull out one click, everything except headlights come on. Pull out second click adds headlights to everything else. If you have the fog light option, when the light switch is pulled to first or second click, the switch will rotate clockwise, similar to the washer squirt switch on the wipers. About a third of the way down this page, http://www.new-datsun-parts.com/datsun-pickup-parts.html Is a headlight switch that I put in one of my 521 trucks, the six wire option. The four pin plug fits the dashboard wiring harness, and the lights work normally. The knob on the 52136 switch is not the OEM knob, but I was able to put the original knob on the six connector switch by tapping the hole in the switch shaft to fit the screw thread from the original 521 light switch. If you go to a hobby store, a company called Du-Bro sells a tap and drill set, 10-32, 8-32, 6-32, 4-40, and 2-56. All these tap sizes are used on a 521. While on the subject of thread sizes, 1/4-28, 5/16-24, 3/8-24, and 7/16-20 are also used on the body of the 521. Headlight wiring is pretty simple on a 521. A red wire from the fuse box goes to the light switch. Headlight power from the light switch to the headlight relay us a red wire with a yellow stripe. The headlight relay has four 1/4 spade terminals, power in, low beam out, high beam out, and relay coil ground. The relay coil is internally connected to the power in terminal. The low beam out terminal is normally closed to the power in terminal, the high beam out terminal is normally open. The relay coil is grounded by the dimmer switch on the turn signal. Wires from the headlight relay are red with a black stripe to the low beams, red with a white stripe for the high beams. The headlights are grounded by a black wire in the wiring harness, that goes back to a lug under one of the screws holding the voltage regulator to the inner fender. This wire MUST be still grounded to the inner fender, even if you are now running an internally regulated alternator. There MUST also be a ground wire from the inner fender back to the alternator frame, and a wire from the alternator frame to the battery ground connection on the cylinder head, just behind the fuel pump on a L-16. These ground connections between the body and engine are critical. If these grounds are removed, or go away, the cab will ground through the throttle cable, and that will melt the throttle cable. Now I hope you will understand why I did not want to type this on my cell phone. I have two threads on 521 trucks. https://ratsun.net/topic/49698-my-dragon-datsun-521/ https://ratsun.net/topic/30606-my-ratsun-datsun-521-now-with-l-20-b-and-a-five-speed/ lots of info, some boring, in those threads.

I can give you more info about 521 headlight switches, but right now I am on phone, and need to get to my computer.

I believe 510's are metric, so I would not think so. But if the steering box on a 510, and a 521 are thread the same, it could work. Datzenmike just replied. About the driveshaft.

My guess is the steering box fill plug is probably a standard imperial pipe plug. Second guess, British pipe.

I measured centerline of u joints, slip yoke pushed in, then pulled out, but still engaged, then go to about middle of the two positions, but slightly forward of middle. If you still have the driveshaft center bearing, the front driveshaft length does not change a lot, most slip is on the rear half of the driveshaft.