Brake balance bar, does this look right? (VIDEO)

[shark92651]

Update:

OK so now my brakes are filled and bled. I moved the MC for the rear brakes to the inboard side of the pedal box and the MC for the front is in the middle. I have the balance bar centered and I have about .2 to .25 spacing in total between both clevises. The MC for the rear brakes moves about 1" while the MC for the front moves only about 1/4" to 3/8". No matter how I adjust the balance bar I cannot seem to get both cylinders to move at the same time. At best I can get the rear to move about 1/4" before the front starts to move. Is this normal or do I seem to have a problem?

New Video:
https://youtu.be/MkJ0hIsZqR4


Original Message:
So I'm working on my pedal box now and trying to adjust the balance bar on the brakes, but I really am not sure what I am doing. Right now I have the front MC (.75) on the right and the rear MC (.625) on the left. When I depress the brake pedal the rear MC push rod goes almost completely in before the front MC moves. It appears that the front MC rod won't fully depress until the very end of the pedal movement. Is this normal? I could use some suggestions as to what I want it to look like and how to get there. I am also thinking of swapping the MC's so that the rear is on the right as I think that will make the routing of the brake lines a little easier, and not sure if that affects the balance bar or not.

[boat737]

Looks like your rod is way off center. Center up that threaded rod (the balance bar).

Here is Wilwood's data sheet. I had to read and re-read it several times to fully understand it, but I did what it says and mine seem to be perfect. https://www.wilwood.com/PDF/DataSheets/ds252.pdf

[2bking]

As stated, the bar is off center but the travel in the masters looks to be excessive maybe caused by air still in both systems. My pedal has about an inch or maybe inch and a half of travel before a solid bottom. The balance point will be adjusted once you get to the go-cart stage and can start locking up the wheels to set the balance. You'll want the fronts locking just before the rears.

[Boydster]

Yeah, I messed with this for a while too. Get that bar evened up, get some fluid in there and get it bled. Then you'll see how it works. Right now it's just like an elephant with 2 extra knees... it just doesnt work right.

[edwardb]

X3 or whatever -- as stated, get it centered, make sure you have the proper spacing per the Wilwood instructions, then forget about it until you have fluid and are fully bled. Not too much to be learned by seeing how it works right now in that state.

[CraigS]

I agree w/ all of the above. Additional thoughts; 1-It doesn't matter which side which MC is on as long as you know which is which. 2- Even after the system is bled, there will be a difference in MC travel. Generally the smaller (rear) MC will move further. 3- You will want to adjust the MC pushrod lengths so you have a minimum free play, but there must be some free play so the MCs can return fully to rest w/ your foot off the pedal.

[shark92651]

Yeah no fluid at this point so probably too early to worry about it. I did get the spacing between the two correct as a sum of about .20. So when I do it for real, do I pretty much want both pushing in at the same time and the same distance?

[CraigS]

You want them both to start moving at the same time but they will not move the same amount. How far the MC moves is determined by the ratio between the area of the MC piston vs the area of the caliper pistons. The wide variation between the front and rear bakes makes for different amount of travel.

[shark92651]

Bump. New video and info in first post. Any comments on how the brakes are operating?

[shark92651]

Does anybody have any input?

[Boydster]

I looked at mine, too, when it was filled and bled and wondered how this was all supposed to work. Although I gotta say, once filled and fully bled, my pedal only moves about an inch... a lot less than yours at the balance bar.

With that said, I never tried to work out the ratios and braking efficiency of the front vs the rear caliper size vs front and rear master cylinder size vs pressure applied to the cylinders through a balance bar. So I dont know what that movement should exactly look like, and I doubt many others have either (although I'm sure someone has... ;) ). Yes, it is supposed to work in an odd way.

Make sure you bar is centered. Make sure you have a high and firm pedal. Wait until you can brake-check the car to do any adjusting.

And in your spare time you can sit down and figure out the physics of the pressure on the master cylinders.
(That sounded a bit smart-***, didnt it. Didn't mean it that way at all.)

[Dthquazi]

Out of the box was the spacing between the center pivot and the clevises on or off. I am following in the directions and got everything installed. The next page talks about the spacing of course.

[shark92651]

Out of the box was the spacing between the center pivot and the clevises on or off. I am following in the directions and got everything installed. The next page talks about the spacing of course.

I can't recall, but I think I had to adjust it a bit. I just can't seem to get both to move at the same time and didn't know if a 4:1 ratio of overall movement between the rear and front brakes was normal. These master cylinders came with the 13" Wilwood kit I purchased from FFR. Maybe it is fine, I just don't have any experience with this to know if there is an issue or not.

[totem]

It does not matter if the initial travel to take out the slack does happen at the same time. It’s just slack. Once load is applied, force will be balanced. Then, travel will be minimal, pedal will be rock solid, more than anything you have driven.

Slack in the rear might be to improper bleeding or the pads beeing away from the disk. Try pulling the handbrake a few time to set the rear brake adjuster.