You see this all started the other day when I went out to Pull-a-Part and picked up a e-brake cable for my truck, as it has been broken for many months...

I came home and put it in and while I was in there, I adjusted the rear brakes to grab better...I took it around the block and boy howdy, was I impressed what a little adjustment could do....the master was still shot and I had to pump it up several times before it would grab, but it locked up the rear nicely!

I headed down to the end of the block and as I approached the turn, pumped the brakes to slow down....ah, hello....NOTHING! No brakes what so ever! I screamed around the corner as I downshifted into second and let the compression slow me down a bit (nice chirp!)...nursed it on home and used my newely installed e-brake to halt me in my driveway! Thank goodness I had just fixed that!

By this time it was getting dark and I just said I would deal with it in the morning....The next day I went out there and discovered that the master was empty...filled it up and pumped the brakes and heard a hissing sound of fluid escaping! I crawled under there and looked for a wheel cylinder to be leaking(heaven forbid as I had just replaced all of them with brand new one's a year or so ago!)...nothing!  WTF?? I added more fluid to the master and pumped again, standing outside as I did so...It sounded like it was right by the front of the drivers rear wheel...I crawled under just in time to see a drip from the frame...Bingo!

Here's the scary part:
Datsun ran the brake, fuel and vapor return lines on top of the frame right before the drivers rear tire...over the years, this place accumulated all sorts of road grime and water...rusting out the brake line! Bingo! there's my leak...what a place to be....hmm, better check the fuel line...it was rusty too but nothing to be concerned about...yet!

I SUGGEST EVERY 521 TRUCK OWNER CHECK THEIRS OUT!
SERIOUS SAFETY ISSUE!
THis could have happened while I was coming back on the freeway from Ryan's in traffic! Or it could have happened anywhere, and then if it had before I fixed my e-brake...who knows what or WHO I could have hit!

Now comes the fun part....I decide to replace my master with the dual circuit one that I bought off ebay a few months ago...I rounded out the mounting holes on the master to fit the exsisting bolts:

It didn't take much...then I spent over an hour filing the whole in the firewall to get it an 1/8" larger to allow the master to fit flush....finally my buddy came home, and returned my call and I went and picked up his dremmel and it took me less than 2 minutes to finish the job!

I mounted up the master and found that it was frozen up! Drats! I told the wife that I needed a new one and went down to AutoZone and forked out 35 bucks for the master and then a few more for new brake lines and some dot 4 synthetic fluid...60 bucks total...

So, for about 60 bucks I was able to get a dual circuit master installed and new brake lines all the way to the rear (going down the drivers side of the frame)
It is not set up with a proportioning valve or anything else yet but I will see how it feels and go from there...

I just had to take a break and write this up as I have only 1 more line to install before bleeding it and testing it out! (lines are bent already, just didn't want to lay under the truck in the rain!)

One thing I found was that I had to reroute the vapor return hose that comes thru wheel well right below the Master just so that the brake lines would have room:

Anyways, check your brake lines right on the frame before the drivers tire...there is a rubber isolator there for all 3 lines that caught all the road grime on mine and allowed it to rust....what do you expect after 35 years on the roads?
L8r

sorry...dual circuit master....and yes, they had to order it...paid for it at 10 am and had it in by 2pm....

I took out the 4 way splitter that was installed on the passenger firewall and put in a 3 way splitter I picked up at Pull-a-Part...one line to each of the front and the other the input...

I ran a new line to the rear along the frame...worked nice...pictures to follow L8r

My rear line also used to go down the passenger side from the 4 way splitter on the firewall...used to...changed that...it was the one that came straight out and then turned and went down...

I put in a 3 way splitter that I found at the Pull-a-part and hooked it all up...no problems on the threading...the master and the splitter were all the Japonese threaded 3/16" lines.....stock lines hooked right up...I haven't finished the rear lines...started pouring rain again and I came inside, then had other things to do...

I picked the master out of a 81 280zx just because it was the year I graduated in and it would be easy to remember...

after all this was discussed with the wife, she told me to either get it done or get rid of the truck....guess what I told her...

"ok, honey...one step at a time!"

Mike: I'm really concerned about the SAE/Jap threads issue...the old lines came apart with a LOT of effort...but these new ones went together really easy...I have only to connect the rear line to the flex hose at the rearend but I wanted to wait until I checked to see if I could find a new one as the old one is really cracked....heck, I want to replace all of them with braided stainless!

I'll keep ya posted if I find out the answer to that problem.

1979-83 280ZX are all 4-wheel disc brakes.

1970-78 240Z/280Z are front disc, rear drum.

Hainz: It was rebuilt with lifetime warranty...Fenco #M51837

I have a spare clutch master...just don't need it yet!

And the wife has actually been after me to get the disc conversion done so she doesn't have to hear about it any more!

nah..what I mean is the IRS swap I've been drooling over the last few years...then upgrade that to the 280zx discs...

521_510_swap.zip

I had to take the Master Cylinder back in to exchange it today...they used aluminum bleeder valves and when I went to bleed it, one snapped right off! Fricking bummer! I'll use the steel ones off the core before I send it back for my $4.00...

Icehouse: the 510 IRS is about 2 inches wider than the truck rear according to the article I posted... at one time you had said you had several rears not being used...want to part with one?