Brake pipe size

[Limey57]

Hi folks.  Been installing brake pipes on the Ranchero this week, it's got an MP Brakes dual master cylinder (and servo) and their disc brakes (front).  There are two pipes from the M/C to the front brakes (one for each side), these are 3/16" diameter.  There is one outlet to the rear, this is supplied with two unions, one that accepts 3/16" pipe and one that accepts 5/16", you can use either.

Now, I'm running the stock rear end and drums, the pipe linking the rear wheel cylinders is 3/16" as stock and couples up to a stock (but new!!!!) flexi hose.  The question is, do I use 3/16" pipe from the master cylinder to the rear flexi, or should I go up to 5/16"?  I don't see the point of upping the size from the stock 3/16" as it feeds into the standard rear flexi.

Or am I wrong........

Thanks

[hiball3985]

On my disc/drum system I just used the standard 3/16". Everything works fine.

[Limey57]

Thanks Jim.

[RICH MUISE]

I used 3/16 all the way also. Don't know if they work yet...having a heck of a time getting them bled to a "hard" pedal.....I remembered today I think someone told me a hydroboost does not have a hard pedal. I'm setting it down on the wheels today and trying to decide if I want to drive it thru our muddy backyard to get it out where I can check it. Anyway...3/16 seems to be what most everyone is using.

[Limey57]

That's good news as I've got plenty of 3/16" pipe on the shelf!  Do any of you guys use silicone brake fluid?  I've heard it compresses more than the standard fluid so I'm undecided.

[djfordmanjack]

Gary, the original lines are 3/16 and what I am going to use also in the 57 (stainless kit from e-pay).
I have used Dot 5.0 silicone in some of my vehicles and along with Jay's 34 and it works great. I personally don't think it feels much harder or softer than Dot 3 or 4. been using all of them before.
be sure that ALL of your brake components are brandnew or thoroughly flushed with special fluid before you put in Dot5.0 ! It is a totally different thing from the usual Dot 3 and 4 and even 5.1 alcohol based brake fluid. I love how silicone doesn't etch the paint. But beware. try to paint something after Dot 5 drpped on....it's SILICONE ! 
I get my Dot 5.0 from the local Harley dealer. it is OEM in the 2000s bikes.

[Limey57]

Thanks, yes, all brake components are brand new, to be honest, it's the "being kind to the paint" thing that interests me most, I don't want the regular stuff stripping any of my new paint if I've forgotten to tighten something or spill any when filling up the master cylinder!

[lalessi1]

Back when I thought I knew something.... I seem to remember that silicone brake brake fluid was not hydroscopic like other brake fluids, it didn't absorb water. That meant that when it got hot there was no water boiling off into a gas making an incompressible liquid compressible... plus the benefit on the corrosion side. I do not really know.. just remembering random stuff?

[hiball3985]

One thing about Dot5 is it aireates, not good if you are doing lots of braking like road racing, pedal ends up very spongy.

From Master Power Brake
http://www.mpbrakes.com/techtalk/brake-fluid/can-i-use-dot-5

[SkylinerRon]

I put Silicon in my 57 back in 1984 when I did the whole system. Works perfectly.
No water absortion, no rust, no problems.
I don't road race though.

Goodluck,

Ron.

[djfordmanjack]

100% true, Lynn !

Back when I thought I knew something.... I seem to remember that silicone brake brake fluid was not hydroscopic like other brake fluids, it didn't absorb water. That meant that when it got hot there was no water boiling off into a gas making an incompressible liquid compressible... plus the benefit on the corrosion side. I do not really know.. just remembering random stuff?