Brake balance bar adjustment

[Malibu46pt]

No mater how I adjust the balance bar the front master cylinder compresses more than the rear. Does this mean I still have air in the lines on the front brakes.

[RoadRacer]

Yes, it seems very likely. Or a failed MC seal.

If you haven't bench-bled your MC, you might want to try reverse bleeding; I always find it more successful.

[Higgybulin]

No mater how I adjust the balance bar the front master cylinder compresses more than the rear. Does this mean I still have air in the lines on the front brakes.
Are your masters the same size? If you have the smaller .675, make sure it is plumbed to the front.

[Malibu46pt]

Both mc are the same size. Unfortunately foot box is complete. It will be difficult to change MC. Any way to determine if MC seal is bad.

[RoadRacer]

Both mc are the same size. Unfortunately foot box is complete. It will be difficult to change MC. Any way to determine if MC seal is bad.

If bleeding doesn’t help.. but don’t use that as an excuse not to bleed both ways a lot. Then bleed again. Always seems to be the answer.

[FF33rod]

Are your masters the same size? If you have the smaller .675, make sure it is plumbed to the front.

Really? the hot rod manual suggests the opposite - .675 for the rear and .75 for front...

[Mike.Bray]

These cars have an advantage with the MC being higher than the calipers. In these applications I have found this method to work pretty much 100% whether the master cylinders have been bench bled or not.

Get two of these (https://www.amazon.com/gp/product/B000CMDP44/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&th=1) and use them to gravity bleed both rear calipers. Make sure the reservoir is full, reservoir cap is off, and open a bleed screw on each caliper.

Allow to bleed for several hours, refilling the reservoir as required.

Now this is very, very important, you must do the rear brakes first.

Next move and repeat with the front brakes.

After gravity bleeding, move onto pressure bleeding, first the rear and then the front. I used one of these (https://www.summitracing.com/parts/mvp-0107).

Motive says to add brake fluid to the pressure bleeder, I did it dry. You just have to be careful of the fluid level in the reservoir with this method. Anything between 10-15 PSI is sufficient for pressure bleeding.

With this method you are virtually guaranteed to remove all of the air from the system and have a rock hard pedal.


Oh, and BTW. I just made that bit up about bleeding the rear brakes first but congratulations on reading all of my post!

[CraigS]

The general rule of thumb is bleed wheels in the order of furthest from the MC to closest so Mike's system works. My question is how does your pedal feel? I'd put the balance bar in the middle (same amount sticking out of both sides) and forget it for now. Generally one MC will move more than the other. This used to be caused by different MC sizes. But, even w/ equal MCs you still have calipers w/ different sizes. Since it is normal on nearly all cars, FFRs included, for the front calipers to be larger, it would also be normal for the front MC to move further. I am assuming that your FFR is not driveable yet. If your pedal feels fairly firm, I'd not worry any more and move on to other build steps. As a car tech for most of my life, I can't tell you how many times I or coworkers were in a situation where we where bleeding brakes and the pedal seemed to still be too spongey. But then we drove the car and realized that, sitting in the shop, we were applying 2-3 times the amount of pressure when bleeding compared to what we applied when driving.