bias valve plumbing q's

cnfabo Custom Title Time!

1,353 posts · joined Apr 2008 · 6 Apr 2011, 11:10 pm

#834490

hi guys, im just about to install a front brake kit similar to vwcools but want to try it with my t3 rear drums with competition linings..so im thinking im going to have too much front brakes now..so would it make sense to install my bias valve inline for the front brakes to back them off a bit....if so, i dont want the adjustment to be done under the hood,so could i plumb a line from the master to inside the the cab into the bias valve then back out to a t-peice then to the front left and right corners.....
ill be running the kombie m/c thats why ill need the t-peice for the front aswell......

cheers....

cnfabo Custom Title Time!

1,353 posts · joined Apr 2008 · 7 Apr 2011, 9:24 pm

#834594

any🥲one🥲

mactaylor Custom Title Time!

1,005 posts · joined Aug 2007 · 8 Apr 2011, 7:32 pm

#834699

not all that legal but its a great tuning tool especially for longer stages where heat and fuel loads change. It prob needs bias to be used with a gentle touch as most dub owners know to much brake in the arse is not want you want,however as things change more control is a great advantage. now the norm is to cut the front to rear line and tee in the bias valve all it does the is slow the flow to the rears so its not a real bias adjuster however if your keen you can tee in the fronts as well to some bias valves and have a real 50/50 setup but it makes a twin system a single and thats no good for rego, but id do it!

EVERLAST CONCRETE TANKS
1800 552 123

BiX Veteran Volks Folk

2,499 posts · joined Sep 2002 · 8 Apr 2011, 7:44 pm

#834703

by putting the adjuster in the front circuit, you are reducing your braking capacity..... so why do the upgrade to such a good system. Isn't better to not put it in/put in the rear for later?

Even if your front brakes lock earlier than the rears? maybe try the system with no adjuster and see how it feels, maybe play with pad materials for the rear and front to fine tune the balance?

I have no sympathy for my car, only the wallet that pays for it!
Go hard or go home!!!!

mactaylor Custom Title Time!

1,005 posts · joined Aug 2007 · 8 Apr 2011, 8:14 pm

#834710

yes and no the idea is parity not reduction of brake efectivness, pad changes is ok but what you are doing is accepting a flaw but if you put the best you can [read afford] and adjust on the go, then you can do no better.

EVERLAST CONCRETE TANKS
1800 552 123

cnfabo Custom Title Time!

1,353 posts · joined Apr 2008 · 8 Apr 2011, 9:06 pm

#834725

bix and mac, for now im going to try the std bendix pads with the competition linings rear....see how that goes...

as far as the bias goes i thought the fronts would be to much for the rears so id balance them up a bit with the bias valve....surely even if i had to back them off a tad they would still be better then the stock t1 setup...and when i went to the ford rears i could re-plum the bias into the rear line...

pete wood 23 Windows of Awesome

6,828 posts · joined Jan 2004 · 9 Apr 2011, 11:14 pm

#834915

I've done this. And it works. It's a regular setup on many competition cars to adjust brake bias. It's a good way to avoid putting a balance bar in.

I did it on a buggy to stop the front wheels locking on dirt. Intially I just installed the bias valve in the front circuit, but I found it didn't work. I asked some rally guys and they advised swapping the outlets round on the mastercylinder. Ie. swap the front circuit over to the outlet normally used for the back and vice versa. Once I did this it worked very well. It was setup so that on the road the bias valve had no effect, I'd just wind it out at an event.

Re legality; My engineer told me it was ok providing it couldn't be adjusted from the inside of the cabin. A lot of cars have factory bias valves under the bonnet apparently. I put it near the mastercyl which worked well enough. I think you'd need certification for it though.

Hope that helps.

"stoopid is stronger than axles"
http://drivingnotpolishing.blogspot.com.au/

cnfabo Custom Title Time!

1,353 posts · joined Apr 2008 · 10 Apr 2011, 9:40 am

#834960

what did swaping the front to rear outlets do??

pete wood 23 Windows of Awesome

6,828 posts · joined Jan 2004 · 10 Apr 2011, 9:48 pm

#835105

Allows the bias valve to do it's thing. I don't know why exactly, I mean I understand hydraulics and I've poured over diagrams of the mastercyl but I still don't get exactly why it does this. It just works. Crazy but true.

I've looked at it over and over, but it stumps me. But I know it works.

"stoopid is stronger than axles"
http://drivingnotpolishing.blogspot.com.au/

cnfabo Custom Title Time!

1,353 posts · joined Apr 2008 · 11 Apr 2011, 11:39 am

#835165

oky im a lil confused, so where did u plumb the bias into when u did the front to rear vise versa thing. me dahhhhh.......

Aussie Dubbin Fahrvergnugen

895 posts · joined Jul 2008 · 11 Apr 2011, 12:04 pm

#835168

From a chat i had with a brakes guy ages ago...
You could put an adjustable valve in both lines - front and rear. 2 adjusters.
That way when fully undone they work as normal with no resistance, then you can reduce front or rear to suit your driving style or race event.
He said many race cars have it adjustable from inside the cabin but that as illegal for street but its up to you. Alternatively you just set it up in an easy to find location under bonnet/fuel tank...

'68 BUG build(Racing)
http://forums.aussieveedubbers.com/viewtopic.php?tid=85509
69Baja
http://forums.aussieveedubbers.com/viewtopic.php?tid=88798
Manx(MaxFX)
http://forums.aussieveedubbers.com/viewtopic.php?tid=88799&page=1#pid826884

oldtub356 Seriously Crusin Dubber

139 posts · joined Dec 2009 · 12 Apr 2011, 3:14 am

#835294

Handy Hint:

Always Bleed brakes with Bias Valve FULLY OPEN - then adjust it back to your preferred spot.

cnfabo Custom Title Time!

1,353 posts · joined Apr 2008 · 12 Apr 2011, 10:56 am

#835315

thanks for that tip..would of sucked trying all day to bleed brakes...

pete wood 23 Windows of Awesome

6,828 posts · joined Jan 2004 · 18 Apr 2011, 1:03 pm

#836316

cnfabo wrote:oky im a lil confused, so where did u plumb the bias into when u did the front to rear vise versa thing. me dahhhhh.......

Look at your master cyl. You will see that the line closest to the firewall/pedals goes back through the firewall to the rear brakes. The line closest to the brake light switch goes to the front brakes. This is the normal configuration.

However, if you simply put the bias valve in the front line, it won't work. Trust me. I tried and no cigar.

So, put the bias valve in the front line BUT, connect the front line to the master cyl outlet closest to the firewall/pedal (which would normally be used for the rear line). Then connect the rear line into the mast cyl outlet nearest the brake light switch (which would normally be used for the front). OK?

If it's all to hard, I'll take a pic for you ok?

"stoopid is stronger than axles"
http://drivingnotpolishing.blogspot.com.au/

pete wood 23 Windows of Awesome

6,828 posts · joined Jan 2004 · 18 Apr 2011, 1:28 pm

#836318

OK, so I took some pics anyway...

The first pic shows where I put my Bias valve. Out of the cabin but easy to get to and close to the brakes for simple connections... but I won't pretend it's pretty...

The second shows the master cylinder.

You notice it has two red letters next to the outlets marked A and B. In normal configuration it is like this...
A = rear brake line
B = front brake line (2 outlets)

However, for the bias valve in the front line, you need to reverse the outlets like this...

A = front brake line (to bias valve then to T piece and brakes)
B = rear brake line (with 2nd outlet blocked off)

Hope that's clearer.

"stoopid is stronger than axles"
http://drivingnotpolishing.blogspot.com.au/

PAZZAN Wolfsburg Wizard

592 posts · joined Jan 2008 · 18 Apr 2011, 6:34 pm

#836346

seems like a lot of work I had stock beetle rotors on the front with late callipers and 914 dics and callipers on the rear using the same comp pads front and rear never had a problem ...stock bendix pads turn to charcoal after one race ...10 laps ..👍👍

cnfabo Custom Title Time!

1,353 posts · joined Apr 2008 · 18 Apr 2011, 8:57 pm

#836379

ill let u know how it goes...
first race is 8th may.but not ten laps, more like ten stages.....ill see how the bendix pads go....

bigrudi Wolfsburg Wizard

401 posts · joined Apr 2005 · 29 May 2011, 6:08 pm

#843486

EBC do a very good ceramic pad to suit beetles and is also real good value as well, i ran the same set up as pauls car i had no need for more brake power until i went turbo Cheers RUDI