Gutting Brake Bias

[newbien]

Hi,

i want to change my sprinter over from drum to disc...

i cant afford to have a Willwood Bias kit put in, but have heard somewhere about taking the spring out of the standard ADM bias block...

anyone have any ideas or know of a quick fix?

any help is massively appreciated

cheers,

Chris

[Billzilla]

Easily done.
Just pull it all apart and pull everything out of the insides, so all ports get full brake pressure.

[newbien]

and that should do the job that i want it to?

as in, i should be able to have a reasonable pedal to go with?

i have 4 piston FC3S calipers up front and putting in RT142 Caliper setup in the rear

cheers

[Billzilla]

I don't know how it'll be with those calipers, but I did the mod to mine many years ago and it helped a lot.

[newbien]

cool, thanks heaps for the help

ill just gut the spare one i have and see how it goes

+rep for you

[cannonball]

Gutting the bias wont help you get a better pedal with those calipers if your still using the stock M/C.

Dont skimp on brakes, you will need a bigger M/C, and Bias adjusters are pretty cheap for what they can do for you.

[newbien]

i have a bigger master sitting around to go in when i put the rear brake setup on...

i just cant afford to have all new lines made up at the moment to put in the adjuster...

i was told that to put in the Willwood bias adjuster that i need to remove the standard adjuster from the equation...which would require having new front lines made up along with a new line for the rear so that it will have full pressure before the Willwood adjuster...

but with what BillZilla has said fresh in mind, i was thinking...can i gut the bias adjuster, so that the pressure is split equally between all lines, then simply add the Willwood adjuster on the rear line after the now gutted standard bais block?

hope that makes sense

[cannonball]

With the ADM bias adjuster, it is basically 2 parts in one. One half is the splitter for the front brakes, and the other part is the rear bias control. When you gut the bias control part, you can leave the rear in/out lines disconnected, basically just using the top half of the body as a splitter, and run the original rear in/out lines into the Adjustable Bias Controller, no new brake lines needed (If you buy a bias adjuster with the correct threads) and mount the Adjustable unit on the side of the old unit.

I have done exactly as you have said, running the adjuster in front of the gutted unit, for whatever reasons I had at the time. That works fine. Others have pinched a splitter from a diff, and used that for the front brakes, removing the old bias/splitter block completely.

None of these changes will give you a better pedal though
Your stock master cylinder moves X cc's of fluid through 1cm of travel, and when you are running bigger, multipot RX7 calipers where the single pot calipers used to be, your stock MC will just not be able to supply the required amount of fluid in the pedal travel you want.

PS, new brake lines are pretty cheap, if you measure up and fit them yourself, just head to your local brake shop with your measurements, and a sample so they can match the threads, and they will make them up on the spot, you just need to bend them without kinking them, which is easy if you take your time and are carefull not to crimp the tubes at all.

[newbien]

so the top section doesnt flow through to the bottom section?

so this is the rear bias section? and i just leave the spring out?


so this is the layout that i have in my head from reading the above...


will i need to plug the rear in/out on the bias block?

cheers

[newbien]

this is an extract from another thread....

"First of all I had to use a 1" master cylinder to flow enough fluid, because the pedal was almost hitting the floor. Once that was fixed, the rears were locking up way before the fronts, so I bought a Wilwood proportioning valve, put it in the rear line and adjusted it up. Results were awesome!

However, what I wanted to point out was, don't take out the factory valve or you will be defeating the purpose of putting the adjustable item in. I made this mistake initially and replaced it with the adjustable Wilwood valve and it totally worsened the issue.

Note to self, leave factory valve and add in the adjustable proportioning valve"

now im just confused...

[bigmat]

just use the proprtioning valve its much easier. it is ilegal though unless you get it engineered but the results will be worth it

cheers mat

[newbien]

so leave the stock proportion block intact and mount the willwood item in the rear line afterwards?

[bigmat]

i would try the system with the original valve in it first with biger mc and then go from there. unless someone else has done it before.

then i would do one of these things

i would gut the original prop valve to make sure it cant screw anything up in the system and fit wilwood rear bias valve to the rear line. that would be the cheapest option.

best thing to do make new lines but that would cost $200 to $300 and fit bias valve

cheers mat

[newbien]

hmm...my head is starting to turn...

alright, ill give it a go with the stock block, then gut it and see if that helps, and then if needed fit up a willwood valve after the gutted block...

in the top pic i have put up, is that all that needs to be removed from the bias block?

[bigmat]

thats what i would do. you might be suprised it might work.

cheers mat