new brake lines

[BlackWidow]

Hello all

 

I am in the process of building a rally car (using my 72 2 door 510) I have to redo the brake lines and I believe that this is a distribution block for the brakes. Do i need this or can i do away with it when i run new lines. and what is its overall purpose. Searches are not bringing up any good explanations of what this does. Any help or advice would be very helpful and appreciated.

 

Mike G

 

[MicroMachinery]

It's somewhat of a proportioning valve. It equalizes pressure between the front and back brakes. If one system fails, there's a spool inside that moves to one side or the other, causing your brake light to come on in your dash. Don't get rid of it.

[BlackWidow]

Cool thanks. So just to clarify since i have upgraded my brakes to 200sx discs in the rear and discs in the front do I still need to add a proportioning valve or will the stock unit be fine? Or if I get a new proportioning valve do i need to eliminate the stock unit. Thanks alot for the info on what it does.

 

Mike G

[mklotz70]

Maybe DatzenMike or Datsunaholic will see this and clarify....but if I remember right, they've said that it is not a proportioning valve. IIRC, it's simply a distribution block with a switch that lights up the brake light on the dash to let you know one of the circuits has lost pressure.

[datzenmike]

Better read this first. I clears up some of the mystery and misconceptions about this item including the residual valves that must be carefully matched for use of drums OR disc.

[BlackWidow]

Datzenmike Thanks for the link

 

Lots of reading and very informative. Honestly I am a little lost in most of the language but I am now confident that i will keep all of the stock components and just replace the lines that need to be replaced. Thanks again for the link.

 

Mike G

[MicroMachinery]

Interesting. So there is no proportioning valve in the system? The pressure differential(front to back) all occurs in the M/C? Am I reading this correctly?

[hang_510]

So there is no proportioning valve in the system?

 

The pressure differential(front to back) all occurs in the M/C? Am I reading this correctly?

correct.

 

 

not really, apparently there is a reduction in the line at the T on the firewall.

the pressure is equal, the volume is reduced (seach: fluid dynamics)

[CorAce]

Wow... that all made my head hurt :blink: . Lots of good info though. It would seem that any of us that have done the ZX front brakes and stock rears need to take a good look at are brake bias, especially if the 15/16 MC was used.

[qwik510]

Wow... that all made my head hurt :blink: . Lots of good info though. It would seem that any of us that have done the ZX front brakes and stock rears need to take a good look at are brake bias, especially if the 15/16 MC was used.

 

Yep.

 

You can change the brake bias by installing 11/16ths rear wheel cylinders from a Datsun 1200 in place of the stock 13/16ths 510 wheel cylinders.

 

I ran this setup on my old 510 with the ZX front brakes and it worked great.

 

I will be installing the same setup on my VG33 car.

[yellowdatsun]

Just get rid of that ugly distribution block. The guys are correct, there is NO proportioning valve on a stock 510, no idea why everyone thinks so. Plenty of 510's have been converted to get rid of that unsightly block, including mine. The car works just fine without it. There's 2 ports on the M/C, one for front brakes and one for rear. Just run a new line and split it with a T for the front brakes, and run a new single line to the rear, there's already a T back there.

[ppeters914]

Yep.

 

You can change the brake bias by installing 11/16ths rear wheel cylinders from a Datsun 1200 in place of the stock 13/16ths 510 wheel cylinders.

 

I ran this setup on my old 510 with the ZX front brakes and it worked great.

 

I will be installing the same setup on my VG33 car.

Dave, did you just do this, or actually calculate it first? Did you also upgrade the brake m/c? If so, to what?

[qwik510]

Dave, did you just do this, or actually calculate it first? Did you also upgrade the brake m/c? If so, to what?

 

I did not do the calculations on this. I had read about using the smaller wheel cylinders in one of the old 510 newsletters from years ago.

 

 

On my old 510, I ran this setup with a stock 3/4" 510 master cylinder. The pedal was very firm and a bit hard to push but this setup would stop the car great.

 

On the VG33 car I am building, I will be running the same setup but will be using the 15/16ths master cyl from the 280ZX and using a brake booster from a B210. I am hoping to get a pedal that is firm but easier to modulate for street driving.

 

Hopefully, I will be able to tell you more in a few months.

[Just Joel]

Just get rid of that ugly distribution block. The guys are correct, there is NO proportioning valve on a stock 510, no idea why everyone thinks so. Plenty of 510's have been converted to get rid of that unsightly block, including mine. The car works just fine without it. There's 2 ports on the M/C, one for front brakes and one for rear. Just run a new line and split it with a T for the front brakes, and run a new single line to the rear, there's already a T back there.

 

From the article, I gathered that it should be left alone... You have no ill effects as a result of removing it? Maybe I missed something...

 

Later

Joel

[yellowdatsun]

Nope, been this way for years now. Even going through different styles of masters and calipers, it's always been fine. Another local guy just finished converting his too, and he has no complaints either. Probably 4 510's around here in Phoenix did it, nobody has had any issues.

[Just Joel]

Interesting, mines leaking and corroded and I would LOVE to chuck it if I could. Do you have any pics of your finished setup post removal?

 

Thanks

Joel