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Bruiser! 78 620 KC project


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Tired of looking at the rusty bed in this 620 so I plan to paint with POR15 (truck bed liner will have to wait for another day)


Good prep-work is the key to a good result so I grabbed a scrub brush, whetted the bed down with "Superclean" or something like that, and started scrubbing away.  The froth was turning orange and the metal underneath was turning, well, not orange.




By the time I was done going over it twice, most of the surface rust was actually gone!




Hopefully this will give me a good clean surface to adhere to.


Wish me luck!


Need to let it dry and warm up inside for a day or two.

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Looks good! Those arms gotta be sore!

Just a heads up, POR15 will fade in color after a couple of years. My green 521 has a POR15 bed that's now dark gray instead of black (previous owner did it).

I plan to eventually raptorline it anywho but it's protected for now. 

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Ya the Por 15 degrades under uv light.... they do sell a UV protection top coat..

Or you could coat it with a single stage uv protected paint... 

My entire 521 was done that way...

Por 15 rust prevention underneath,  por top coat on the frame , and a flat black single stage on the body....

No issues in 3 years.... just make sure you go through all the steps to clean, degrease and prep the surface... 

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Corey's truck still has a nasty habit of one of the chokes sticking open. 

I pulled off the carbs, cleaned them really well, and spent a long time tweaking the linkage arm to try to get the chokes to close reliably 100% of the time.








The linkage is free.

The return springs are in good shape.

The fuel lines are totally soft and pliable.

But still they occasionally stick.  You just have to tap them and they SNAP back closed.

I give up for now.  In a month it will be warm enough that the chokes are not required anyway.

Till then he can park in the garage.




I think there just must be something not 100% right between the nozzle and the bore they slide in.

That said - even lubing that with grease does not make it perfectly reliable...

Going to kick this one down the road.


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On 2/28/2021 at 2:41 PM, EDM620 said:

Maybe a slight build up of varnish in the bore?


Anything is possible - though light grease did not seem to make an improvement.  Maybe light oil instead?

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For years there has been a slow leak in the heater valve, the heater valve hoses, and/or the heater core itself.  Every time I fixed one part the next one would fail.  For the last couple of years the leak(s) have been so minimal I havn't worried about it.  But this weekend my wife and I got in the truck to go pull some parts for the 510 wagon and noticed that there was coolant on the driver's side floor (that's new) and the window started fogging on the way to our destination even though it was dry out.  Looks like I can't ignore this one any longer.




Fortunately, I have a complete 620 heater box assembly in the garage.  I'm pretty sure it was from the truck that donated all of it's panels to this cab and frame which means it should only have 3-4 years of use.  Some light exterior corrosion is from PO storage before I put it in the garage.




The heater valve is works like new!




So I drained the engine coolant and set out removing the old heater box assembly.  Not the easiest job in the world but not knowing the exact cause of the leak - I figured a wholesale replacement was the safest bet.




I replaced it with the "new" one.




Before putting the center console back in place and hooking the stereo back up (notice all the stray wires) I wanted to re-fill the engine coolant and take it for a test drive.


I didn't get that far.


Half way through filling the radiator, I heard the unmistakable sound of water running for freedom!  It was pouring out the bottom of the heater box as fast as I was putting it in the radiator.  : (






Looks like I'll be calling some radiator repair shops today to see if anyone can fix one of these units for me.  They don't appear to be available new anywhere on line.  Anyone happen to have a known good unit on their shelf?



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Posted (edited)

I was referred to Stan's Radiator Repair in Lake Stevens.  After looking at their reviews, I think I'll skip their lunch special (?) but look forward to their repair services.




He said most require a re-core, vs a repair.  And a re-core is approximately $300.  Ouch! 


To see which of the two are in better condition, and to possibly see what the issue is to begin with, I first pulled the heater core out of the old heater box we've been running through our entire ownership.


When I pulled the front cover off, what do I find?  Check out this nest!




It's amazing the heater/defroster worked at all in this thing!


Core has obvious signs of leak(s)








Then I pulled the heater core from the "new" box I just installed.


It looks brand new!




I filled it full of water and it gurgled out the hole in one of the ribs on the side of the core.  Why?  How?




No sign of leakage from before or during storage.  Something must have eaten a hole in there somewhere.  We'll see.


For now, I 'm just going to connect the hoses together and run without a core 'till we get this fixed.  Hopefully it will stay dry outside for a few days.



Edited by carterb
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8 hours ago, carterb said:


Anything is possible - though light grease did not seem to make an improvement.  Maybe light oil instead?

You should use a carb cleaner to cut through the varnish. High probability that is the cause of the sticking.


For your heater core leak, since the core is out & you have the dimensions, check out Spectra Radiators (spectrapremium.com) as they make new radiators & heater cores at a lower cost than getting a re-core done.

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Are those splits along all three ribs???? That would be from freezing I bet. If so, easy fix.


Sand away the paint. Use solder paste and tin the bare brass. Then solder it closed.

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Posted (edited)

I don't think they are splits.  Might just be the photo.  Those ribs are round.


For now, I installed a bypass hose and after a test drive, approve Bruiser for school commuting duty again while heater core repairs are executed.



Edited by carterb
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1 hour ago, EDM620 said:

You should use a carb cleaner to cut through the varnish. High probability that is the cause of the sticking.


For your heater core leak, since the core is out & you have the dimensions, check out Spectra Radiators (spectrapremium.com) as they make new radiators & heater cores at a lower cost than getting a re-core done.




I'll look at the chokes again and Spectra as well.


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  • 5 weeks later...

Couldn't make heads or tails of the Spectra website so I called Stan's who gave me a quote over the phone so Brenda drove up and dropped off the cores for me.  (thanks sweet pea)




I got a call a week later that they tried to repair the better looking of the two units and every time they would repair one channel, the next one would leak.  They finally gave up and ordered a replacement core.  I was thankful that they tried.  A repair was going to run about $150.  The re-core was going to be $300.  $319 in fact.  It was ready a week later.




Here it is - in all its glory




I asked about painting it and he said he doesn't recommend it.  Okay.  In it goes then...


I was a little surprised to find one of the lets was cracked (inlet or outlet?) but that shouldn't affect anything.




The old foam still fit around it - that was a good sign.




Now let's see if it fits in its home.




Like a glove!








I left off the center console for the first week to make sure there were no leaks before re-installation and everything looks great and Corey can defrost his windows again and the floors are dry once more!


Console and stereo are re-installed and now we wait to see what breaks next!  : )



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