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My island turquoise 521


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today was the first day actually driving the truck much after getting new brake parts and flushing and filling coolant. After about 20 minutes on the highway at around 55 mph, the temperature gauge was getting up there, still in the gray band but starting to get close to the top of that, but then again I'm not sure how accurate the 45 year old gauge is! There was also some trouble starting the truck up again each time we returned from a store (so, shopping in a store, and coming back out in maybe 20 or 25 minutes). It took longer to start up, and wanted to stall unless I gave some gas for a bit until it evened out. After maybe half of minute of rough idle each time we came back to the truck and started up, it'd get sorted and run fine.

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Picked up an IR thermometer, and definitely getting hot when running. I pulled off the road this morning and checked. Temperature at the water neck was about 220 degrees. Rad is fairly recently rebuilt and seemed to flow well when I flushed it. Heater core also seems clean. I'll try flushing this weekend again including from the side drain bolt on the block.


I'm currently sitting waiting for the engine to get cold so that I can start it again. Had he same problem with difficulty starting on the weekend after engine was had been running for a while. I stuck a spare spark plug in the end of coil wire and spark from coil right now seems good although I am getting a backfire out the tailpipe if I try to pump too much gas when trying to start. Is heat soak a problem with stock l16 and carb? Or should I be looking for some other cause?

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May not be the case but if your gonna try flushing the coolant system anyhow try flushing it the opposite direction the coolant normally flows... I've heard some people say in one direction it was fine and when they flushed in the opposite direction a ton of shit came out.... can't hurt if your already doing that.

When I rebuild my motor I was amazed how much loose and flaky rust was actually inside my motor around the cylinders... you could be shaking stuff loose causing a clog ... and did you check the temp at both the inlet and the outlet of the radiator not sure which end is the water neck....

Only other thing I've read have been thermostat maybe stuck, but like I said not sure where you took your temp reading. Others claim if you have too much advance on your timing that can make things run hotter. Just my opinion on what to look at..

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Yeah I ran it both ways last weekend but only through the hose connections. The water coming through was quite clean so I skipped opening the drain plug. I'll have another go at it.


It's been a frigging symphony of problems this morning. The muffler fell down and put pressure on the parking brake. I tied it back up with a scrap hunk of wire until I can get home. Might have been a part of the overheating problem since wheels were not free spinning when driving. Then waited for the truck to cool down, and at the same time cleaned the points and distributor cap and rotor a bit with a piece of sandpaper (glad some of my tools are still sitting in the truck). It runs but a bit uneven; distributor contacts look like shit so I'll pop a new cap on shortly. And after getting the truck started and back underway, something gave way in the front end. There's a grinding feel if I slowly roll forward and it's pulling hard to the right ( when moving, not particularly when braking ). So, bearing? Wtf...how much stuff can be broken at once? Torsion control rods seem intact and steering tie rods also look ok relatively so not sure. I don't have a jack with me to pull the wheels off. Gonna see if I can find a tow home.

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Don't force the lever. If you twist it too hard the soldier joint on the core can split and you'll have to repair it. Which sucks. If it doesn't move try taking the core out and use heat or penetrating oil to break it loose

so, when you mentioned this, I guess you meant the little knob on the heater core and not the heat vent level that's attached to the dash? At the time I assumed you meant the lever under the dash, since I hadn't even figured out there's a brass heater knob on the core at that time! haha...shoulda paid more attention to your reply at the time, considering I did exactly what you warned about.

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Man that's a Ruff day. Might be able to pop the dust cover off and see if the spindle nut is loose at all, about all you could really do without a jack... FYI if it is a wheel bearing be careful. All the autopart websites have the inner bearing listed incorrect... the inner bearing is for the most part obsolete.. I saw a couple on ebay and a couple complete kits with the correct bearing size.... there is also a 620 bearing conversion out there.. Mike klotz I think it was... bluehands.com or something... I am sure someone will correct me or you have seen some of his posts...

And as far as how many things can be wrong I was amazed when I finally tore my truck apart how may systems were worn and shot and I was still driving it.... these old trucks just keep going... good luck getting her home....

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Too much advance may cause a engine to overheat, but you should hear bad detonation or ping before it can last long enough to over heat an engine.

Retarded timing, on the other hand will definitely cause over heating because the piston has travelled too far down the cylinder when the fuel burns, and that exposes a lot of the cylinder walls to the heat, and the heat goes into the cooling system instead of pushing the piston down.


This is how I flush the cooling system on a 521/L-16.  Remove the radiator, remove the thermostat.  Remove the block drain plug down by the starter.  Put the radiator hoses back on the engine, put a garden hose in to the lower radiator hose. Get an air nozzle ready to blow air into the block drain.  Turn on the water, let the block fill, with your thumb on the block drain hole.  When water comes out the top radiator hose, clear, blow air in the block drain hole.  Let the block fill with water again, and repeat the blowing of air into the block drain hole.  Repeat until blowing air into the bloke does not dislodge any more crud.  Flush the heater both ways.  Flush the radiator out, you can blow air into the radiator drain plug hole similar to flushing the block.


Refill the system with 50/50 antifreeze, and distilled water.

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I tried rolling down the road a bit and got another mile. I think it's the brakes in the front passenger wheel that gave out, maybe broken brake spring to start. I replaced everything on back brakes but didn't do anything to front brakes yet other than adjust them, so parts might be getting old. Same thing happened on one rear brake, broken return spring. I'm getting a tow and will take the wheels off when I get home.


I'll also check timing and see how off it is.


I sense another order from rock auto in my near future

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wheel hub feels smooth when rotating on drivers side, and on passenger side, the inner bearing doesn't feel perfect, but doesn't feel totally awful. Outer bearing feels lumpy when rotated. So for sure I'll order some outers. I'll have to see if mklotz is currently selling his bearing/hub spacers. given that the inner doesn't feel that bad, does it make sense to just do outers for the moment until I figure out a source for inner bearings, or should they be replaced as a pair?



the bigger problem today seems to be that the brake shoes decide to part ways with their linings. This is what came off when I pulled the drum:




Everything else (springs, shoes) was still in place, although the top return spring looked pushed a little out of position, probably due to brake shoe bits hitting it. So, new parts will be on the way to replace everything except adjusters.

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That will make the whole vehicle shake and vibrate, it can even make it go thunk, thunk, thunk, thunk, as I have had that happen recently, did you put it back together and spin the drum after removing the brake linings, that is what I would have done to see if the bearings felt right, if they ground or ticked, then and only then would I call them bad.

I have never had a wheel bearing go bad in a Datsun, front or rear, and I have hauled mass amounts of weight in my trucks, especially the work truck with a stock H190 rear axle, and with the C200 dually axle it has under it now, when ever I get a wheel vibration, it always has something to do with the brake pads/linings.

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After taking the tire and drum off, I rotated the hub by hand (without the tire or drum mounted), pulled the outer bearing and spun in my hand and pulled the hub off and rotated the inner bearing in my hand. The outer bearing when spun in my hand was certainly lumpy/clicky feeling, but the inner felt ok, and rotating the hub on the vehicle (without the tire on) felt a bit rough, but the spindle nut was on there fairly tight, and the grease was about the consistency of beef jerky. I could try repacking and reassembling, mount the tire and see how it feels. 


To clean up the driveway, I did put things back together tonight at dark, without regreasing and without brake shoes installed, and just zip-tyed the wheel cylinder in case I have a brain fart and touch the brakes before I replace stuff. I snugged the castle nut then backed off slightly; the wheel felt firmly seated, no wiggle, and the lumpy feel was quite reduced. so maybe you're right about the durability of datsun bearings?


I was thinking to just order that passenger side outer since it seemed like the primary offender, but I could do what you suggest and reassemble things to be sure.


And yeah, the truck started with a pull to the right and a bit of a rubbing. I tried to back off the adjusted a few clicks on that side and figured maybe I could slowly sneak home, but after about a mile, there was a thunk-thunk-thunk-bang! so I pulled over and called for a tow.

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The bearings have to feel good once the nut is on and at least finger tight, if it is not smooth, then you need to figure out why, more than likely you will need a bearing.

In general if I change a bearing, I will just change the bearing that needs to be changed, but when I did the front bearings in my Mini, I changed all of them, as my Mini is the most unreliable car I have ever owned in my life, and it wasn't easy getting in there, so I did all 4 front bearings.

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well for better or worse I got tired of looking at the rockauto site for the night, so added the one outer bearing to the list of stuff and submitted the order :) 


While that order's shipping, I've got a couple of trucker mirrors that I'll clean up and paint and scored a super cheap autometer monster tach that's bigger than my dash that I need to find a spot for.

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ok, question about reassembling the front wheel hub. For the inner bearing, I have the bearing and race, then a metal ring (spacer?) and then the grease seal. Looks like the ring/spacer is part #5 in the illustration 50 in the 521 parts manual. When I popped the bearing and seal out, I didn't see how the how the metal ring was situated before removal. Does it just sit between bearing and seal or is there anything special about installing it?

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Hum.. I am interested to see the response you get for this. I didn't have that spacer in my hub at all. Don't even remember a reference to it in my manuals.. from the pic it looks like its just as it states a spacer. Bearing first, spacer, then seal.... then install on spindle...

Was the spacer originally in the hub or with the new parts?

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It was installed in the hub. I only saw it when I drove out the bearing and seal. Looks like just the right fit to fill the gap between seal and bearing. It's the same diameter as the outer edge of the seal.. It's just a split metal ring.


I installed the new outer bearing, greased everything and installed the spacer between seal and inner bearing. It all seems to fit back together!

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