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Bruiser! 78 620 KC project


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Before working on the brakes, I wanted Victoria to help me finish a couple other things that weren't completed after swapping over all the tan panels.  We needed to exchange the door lock cylinders so that her key worked, and we needed to mount a mirror on the passenger side door.


First, we removed the door panels.




I did one side to show her what to do and then Victoria did the other side.




After changing the lock cylinders, we addressed the missing mirror issue.  Judging by the missing hardware and dent in the door around the upper mount, I'm going to guess it was ripped off, not gently removed.




The mounting holes had pretty big volcanoes that I wanted to flatten out before mounting the replacement mirror so it would fit up tight against the body.


Upper holes - the fwd one was pulled out pretty far.




Lower holes:




Rather than bang on the door and make the situation worse than it already was, I made up a little press using a bolt and some fender washers.  I put the bolt through the hole with washers on both sides of the door panel.  Tightening the bolt and nut squishes the washers together and flattens out the volcanoes around the holes.  (shown in a shut line just to hold it for the photo)




Here are the upper holes, not flattened.




And the lower holes:




And the replacement mirror went on nice and tight against the door skin.



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Next we rolled the truck into the garage to fix the brakes.  There was nothing left!  Whatever was there allowing Brenda to get home was now gone.  I could only stop with the E-brake. 


I was going to start by filling up the master cylinder and bleeding the brakes to see if the fix was as simple as that or see what might be leaking in the process but once I got underneath and saw the condition of the soft lines - I decided I would replace them before starting anything else.  They are all cracked near the caliper and may be the source of the problem.



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  • 4 weeks later...

The new soft lines came in a while ago but I haven't had time to install them yet.






I was going to do it on Saturday but when I went to coast the truck into the garage, I found that along with no brakes, it also had no e-brake!  I was fortunate to discover that soon enough to steer across the driveway and into my lawn instead of into the garage, making a new hole in the back!  Anyway, I had to wait 'till later that night to retrieve the truck and lower it into the garage with a strap attached to my suburban.

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I made time tonight to get these installed so I could bleed the brakes and see where I'm at with the whole system.  I was curious though how Brenda made it home originally since when I checked, I found no brake fluid in the resevoir for the front brakes.  I figured she made it home on the rears (there was fluid in resevoir for the rear brakes)


But I pulled the caps tonight only to discover there was no fluid in either circuit!




Thinking about what Paul said above, I figured I'd better check out the master cylinder.  I disconnected the brake lines from the bottom of the cylinder and the line to the front brakes was still full!  Unsure about the rear...  Anyhow, I then removed the master cylinder from the booster and check this out...




Pretty grody eh?  Here's the back of the master cylinder.




I'm not 100% positive this is from a brake fluid leak but I'm not big on taking chances so I'll use this as a cue to change master cylinders.  The corrosion was pretty dry, so maybe it isn't from the fluid, but then the fluid may all be down in the base of the booster, if it is even coming out the back of the master cylinder to begin with.


So I went to the garage to grab the master cylinder from the tan parts truck, after all it only had three years of service on it.  It's probably in great shape right?!  Wrong...  :no:

It was corroded from sitting for so many years and the piston was stuck in the bore so badly I need a hammer to move it. 


Rockauto, here I come! 


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  • 3 weeks later...

Here is the new master cylinder in place




Left front brake line replaced.  So far so good!




Unfortunately, the right front brake line did not go so smoothly...




Rockauto sent the wrong brake line. 




It actually looked like it might work on the rear:






but it was wrong for that too.


The rear just takes one of these:




*sigh*  Looks like shopping trip #3 is in order.

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In the mean time, I figured I'd go ahead and install the new rear wheel cylinders - something I thought I was doing as a precaution.  That is, until I pulled off the left rear brake drum!






Grody to the max!!!




Gag me with a spoon!




So it would seem that this was the heart of the problem, and probably has been a problem for some time.  

The rear wheel cylinder was leaking, so that's where the fluid was going.  The master cylinder failed as well between the two circuits, so the front resevoir was re-filling the rear making it look like the problem was up front.  In the end, a massive seal burst left no fluid in master cylinder or anywhere in the rear circuit and since the brakes were coated with a slippery slimy concotion of brake fluid and brake dust, the emergency brake was no longer effective as well.  Kaput!


Bad wheel cylinder!  Bad!!!



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The PO had noticed something going on and just thought the rear shoes needed replacing, so he had purchased a set and included them with the truck.






So I disassembled and cleaned everything up and installed the new wheel cylinder and a pair of shoes.  That should do it!






The right side looked much better!




but I replaced all that as well



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On Monday the new lines came in (I just ordered from Napa this time)




rear (which I didn't need as it turns out, since Rock Auto did send me that one correct)




and front




now installed




and the rear installed too.




Now it's brake bleeding time!!!


I had Corey give me a hand (or a foot anyway) and we filled everything up and pumped out all the air and I took a short test drive and confirmed I had a good firm brake pedal and I could lock 'em up. 


Success!!!! :D

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The victory appears to have been short lived...


When I pulled out of the driveway this morning, my headlights illuminated the underside of the truck and I saw what looked like fluid leaking from the left rear wheel.


When I got home, sure enough, that's what I found. 




Now we have a really annoying neighbor dog that loves to come over and poop and pee on everything within reach but I don't think he's limber enough to actually climb under the truck and accomplish this feat. 


The backside of the wheel cylinder looks okay and there is no fluid at the brake line connection so it seems that the new wheel cylinder is faulty.




Every ask yourself why you didn't just take your car to the shop?  :(

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yep.  I'm sure they'll either take them back no problem or just refund and say keep it.  They've done it before.  I've gotten misboxed stuff from storefronts too.  No biggie.  The only thing I don't like is buying something brand new and having it fail upon first use.  Especially something safety related like a wheel cylinder.  Wasted time is one thing...

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Fortunatley, it looks like a false alarm.

I pulled the drum and everything is nice and clean and dry in there.

I'm wondering if maybe the backplate or maybe the channel around the perimeter of the drum was just full of cleaner from the rebuild - which pooled and ran down the side of the tire when parked.  After double checking everything I took it to the wood store and back today and there were no issues at all.  I'll check again tomorrow and see if there is any new sign of weeping.


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  • 1 month later...

We all know dogs love trucks right?




Well I guess cats do too.  Especially when the black tonneau cover is the warmest thing around on a 40 degree day.




I started daily driving the 620 a few weeks ago.  Salted icy roads, summer tires, and massive negative camber on the coupe do not mix well, so it's parked for a while.  This is the first time in years I have not daily driven a 510.  I usually have a wagon to drive through the winter.

Anyway, the truck still runs pretty good but it has an annoying (especially with slow stop/go traffic up a hill) issue between 800 and 1200 rpm (basically - coming off idle) where you press the gas pedal down farther and farther and it feels like power drops into a hole, then comes back more than you wanted.  It's an annoying dead spot making it very rubber-bandy once the revs catch.  Everything is still stock.  Is this an issue that can be adjusted away at the carb?  Or is the best "adjustment" just to replace the old carb with a weber and never look back? 

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