My 1971 521

[d.p]

Thanks mainer, I will either cut/flare new lines or just bend them as I ordered those jap hard lines with metric threads and inverted flares.   And charlie, it shouldn't matter because all the lines I am running are to new parts...calipers, rubber lines, tee and MC.  The only existing line is the rears which I extended directly to the new MC.  

[DanielC]

A funny thing happened to my 521 yesterday.  I live on a hill, and of four roads I can take away from my house, three pretty much go down, except one that goes up, before it goes down.  The one that goes up before it goes down has a 16% grade on the down hill part.

I went up and down the steep hill, bought some groceries, came back up the hill, bought more groceries, and visited my bank, and came home.  Then I went down the other side of the hill, to Ace Hardware, to buy a fan, it is hot here in Oregon.  

On the way down that not so steep hill, my brake pedal went all the way to the floor.  Near the bottom of the hill, i turned around, and drove Ratsun back home, checked the fluid in the master cylinder, it was still full. 

I drove my other car, a Ford Aerostar to Ace Hardware.

I ordered a new Centric master cylinder yesterday from a good auto parts store if you live in Portland, OR, Clackamas Auto parts.

 

So, DP, where in this thread do you describe your brake system?

I do need advise on brake system upgrades for my 521 trucks.

 

[d.p]

I didn't.

 

But I will and most of this stuff is way of Beebani and crash.  

 

 

Beebani brackets

88 4WD d21 calipers, rubber lines and pads

2002 Honda passport rotors

Dual res MC (need to elongate mounting holes) : https://www.amazon.com/Cardone-Select-13-1834-Master-Cylinder/dp/B008LD2V78/ref=au_as_r?_encoding=UTF8&Make=Nissan|67&Model=720|2778&Year=1985|1985&ie=UTF8&n=15684181&s=automotive&vehicleId=5&vehicleType=automotive

3 way inverted metric brake tee: https://www.ebay.com/itm/391840134518 

New metric inverted ni-copper hard lines for the fronts

 

Keep in mind my truck is still not put together.  Waiting on the right parts but hopefully will be able to report back that all of this shit worked without issue. 

 

Edited July 24, 2018 by d.p

[mainer311]

The biggest part of the conversion is swapping from single reservoir to dual reservoir, and splitting the front brake circuit from the rear. The late model 620 master cylinder already has residual valves setup for disc in the front and drums in the rear, so it’s an easy swap.

 

The factory “tee” can be reused for the front brakes, with the 4th hole plugged with a 3/8-24 plug, then just run a new line to the rear OR run a short line from the MC and use a 3/8-24 coupler from the existing line to the rear. I have a few photos on my thread that highlight some of the changes.

[wayno]

7 hours ago, DanielC said:

A funny thing happened to my 521 yesterday.  I live on a hill, and of four roads I can take away from my house, three pretty much go down, except one that goes up, before it goes down.  The one that goes up before it goes down has a 16% grade on the down hill part.

I went up and down the steep hill, bought some groceries, came back up the hill, bought more groceries, and visited my bank, and came home.  Then I went down the other side of the hill, to Ace Hardware, to buy a fan, it is hot here in Oregon.

On the way down that not so steep hill, my brake pedal went all the way to the floor.  Near the bottom of the hill, i turned around, and drove Ratsun back home, checked the fluid in the master cylinder, it was still full.

I drove my other car, a Ford Aerostar to Ace Hardware.

I ordered a new Centric master cylinder yesterday from a good auto parts store if you live in Portland, OR, Clackamas Auto parts.

 

So, DP, where in this thread do you describe your brake system?

I do need advise on brake system upgrades for my 521 trucks.

 

What do want to know Daniel, I know a few ways to put disc brakes on a 521, I sold my work truck 521 disc brake setup(lower and upper control arms and tension rods) to a guy at the Canby meet, that is not the best way, but it is the cheapest way, I used it for over 14 years, and I know how to do it the proper way, I also can show you how to make a power brake setup.

Is your brake master leaking a little on the inside of the cab?

[datzenmike]

I put a 510 dual master in my 521. You don't need to run a new line to the back just connect the rear line to the front of the dual master. This was in or around '75 and I knew nothing about residual valves or proportioning valves. It ran ok for a kid of 25. ?

 

 

(these emoji suck the big one)

[d.p]

Fuck this new site does some weird shit. 

I just ran new ni-copper lines and used that flare tool I linked above, waiting for the new tee and will report back if everything works or not.  

[Charlie69]

12 hours ago, d.p said:

Thanks mainer, I will either cut/flare new lines or just bend them as I ordered those jap hard lines with metric threads and inverted flares.   And charlie, it shouldn't matter because all the lines I am running are to new parts...calipers, rubber lines, tee and MC.  The only existing line is the rears which I extended directly to the new MC.  

 

It does if the new hydraulic hoses that your newly flared fittings connect to are 37 degree and your flares are 45 degrees.  Your wheel cylinders in the rear would be affected also if you ran new lines.  They will not seal. 

 

Mike Klotz might be able to verify what the degree of angle is used on the stock brake lines and is the angle different from the 3/16/ 24 lines on the 320, 520, & the 521 from the 10mm x1 onthe 620 and later trucks.

 

One way you can work with the different metric and american brake lines is leep the old 521 fittings on the one end of the line a flare the other end off the line using the metric fitting which can be purchased in most places.

[d.p]

Its all put back together but still slight leak at the tee and the calipers (rubber lines on the caliper side).  Not sure why I can't get them to seal with my fancy flaring tool and ni-copper lines.  Figure I will give it another go in a couple days and see if I can't get it all sealed.  Truck drove and stopped well and Mike K's push rod is a thing of beauty compared to that stock nonsense.  

[Charlie69]

37 degree inverted flares will fix leaks. 

 

Somewhere I saw that you have a bubble flare tee and this will not worke with Either 45 or37 degree inverted flares.  Different animals.

Edited July 25, 2018 by Charlie69

[d.p]

I did have a bubble flare tee but replaced it with an inverted one.  Just odd that it leaks in a couple places but not everywhere because I used the same flaring tool/fittings across the board.  Hard line to rubber line is air tight as well as the union between the stock hard line and new ni-copper section the new MC.  

 

I can't imagine I need to do 37 degree flaring, I read that shit is just for airplanes and you got to use special fittings for it.  Any truth to any of that?  I might have just muscled my flarings a little too much so I can just try and reflare them with what I got.  

Edited July 25, 2018 by d.p

[Charlie69]

Then cut your leaking flares off and re flare the lines.  You might just have a few not so good flares.  Inverted double flares are not easy to get correct every time.

 

The better hydraulic flaring tools do make it some what easier than the manual flaring tools.

[d.p]

Ha I have cut/reflared them a couple times and they are getting better.  Guess I just need more practice which means more cutting/flaring.  

 

[mainer311]

Just use a scrap piece of line and keep practicing. It took me a while to see what works best.

 

Did you say the rubber line is leaking on the caliper side? Do you have a copper washer on each side of the manifold? There should be one between the manifold and caliper, and another one between the head of the banjo bolt and the manifold.

[d.p]

Yeah practiced some more tonight.  Hopefully I can be done with this tomorrow.  

 

Yeah copper washers on both sides and using m10x1 banjo bolts.  Even doubled up the washers trying to get it to seal.  

 

 

[Charlie69]

Did you use new copper crush washers?

 

Is the banjo bolt the size of the hole in the bajo fitting?

 

Are you Deburring the cuts before you flre the lines?

 

Are the cuts square?

[d.p]

Yeah doing all that but apparently not very well. 

 

I assume the bolt is the size of the hole otherwise it would leak like crazy no?  Right now it just weeps if anything. 

 

One of the flares I made...crash said that little nick/burr on the inside is no good though.    Which I assume prevents it from seating?  

 

 

Edited July 26, 2018 by d.p

[datzenmike]

It's not the threads that do the sealing it's the metal to metal flair. Very much like an engine's valve. The threads just provide clamping pressure.

[DanielC]

Like Mike said, the seal is a metal to metal seal, similar to a intake valve.  Any small burrs in the sealing surface will cause leaks.  The few brake double flares I have got to seal not only did I cut and file the end of the tube flat and square, I deburred both the inside and outside of the tube a very small amount, trying to deburr equally all the way around the tube.

I use a tubing cutter that rolls around the tube.  I do not cut all the way through the tube, but only part way, maybe 2/3 or 3/4 of the way, then flex the tube, and break it at the cut.  This puts a smaller burr on the inside of the tube.

 

[d.p]

Ok what about on the caliper side, why would that leak?   Using dorman part 13912 which is 10x1mm banjo bolt which I assume is the same as the OEM nissan one?   Mike K says to use that bolt on his site but for different calipers (720).  Nissan part number is for the banjo bolt is 4635650Y0A.

 

Anyone know? 

 

And mainer I looked in your thread and the only pic I saw was of the one caliper you did, any idea what size banjo bolt you used?  

Edited July 26, 2018 by d.p

[d.p]

Well I think I figured out the caliper leak.  Calipers came from RockAuto with washers but I had already bought some other 10mm washers from Amazon.

 

Amazon on the top vs Raybestos on the bottom. 

 

RA ones seem to be too wide to seal the hose on the caliper, once I swapped them for the amazon ones the calipers stopped leaking.  

 

 

 

Edited July 26, 2018 by d.p

[mainer311]

The banjos that I used came with the calipers that I bought from RockAuto, but I know for sure they were M10x1.

[d.p]

Yeah mine didn’t come with any.  I think I am OK for now.  Couple little things but the truck is back on the road so I am happy. 

[mainer311]

The flare you posted above looks fine.

[Charlie69]

Mariner did you use a 45 degree flaring tool on your truck?

 

I also have had problems with Raybestos hardware not fitting.