• From: Frisco, Texas
  • Registered: 2009-05-02
  • Posts: 1,430

Re: Removing Power Assisted Brakes

jimeditorial wrote:
ifb_mole wrote:

So there is a method to "reduce" the boost then?  A boost or assist reduction would definately work, Hmmm.

Use a master cylinder with a larger bore diameter....less mechanical advantage and a shorter pedal travel...

Shorter pedal travel=less modulation sensitivity, the reverse of what they are asking for though... Less aggressive initial bite on the pads will work a lot better than messing with the booster or Master cyl IMO.. Lord knows I've tried to prove myself wrong on that one over the years though.

"Don't mess with Lexas!" LS400. We survived another one! See website link for build details.
Maker of the "unofficial Lemons fish!" - If you ask nice, I'll likely give you one at the track.

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  • From: Toronto, Ontario
  • Registered: 2009-05-03
  • Posts: 1,114

Re: Removing Power Assisted Brakes

Spinnetti wrote:
jimeditorial wrote:
ifb_mole wrote:

So there is a method to "reduce" the boost then?  A boost or assist reduction would definately work, Hmmm.

Use a master cylinder with a larger bore diameter....less mechanical advantage and a shorter pedal travel...

Shorter pedal travel=less modulation sensitivity, the reverse of what they are asking for though... Less aggressive initial bite on the pads will work a lot better than messing with the booster or Master cyl IMO.. Lord knows I've tried to prove myself wrong on that one over the years though.

Sure, but modulation is an issue once the pads contact the disc, i.e. zero pedal travel....the bigger master will reduce the dead space travel while the pads clamp up... during the actual braking you're modulation pressure with a solid pedal... do you mean that the extra pedal force makes it hard to modulate? I'm assuming that the stock power assist is retained.., of course my idea of modulation is lock, release, repeat as necessary!

Jim "Endo" Anderton
30 years of racing and still not Brambilla.....

28 Reply by djcommie (edited by djcommie 2009-12-29 08:48 PM)

  • From: Santa Margarita, CA
  • Registered: 2009-06-03
  • Posts: 177

Re: Removing Power Assisted Brakes

The entirety of the brake system geometry is based on whatever assist the boost provides, the stroke/travel of the pedal, and internal volumes and surface areas of the pistons and pads, and plenty of other things that are complicated even to racecar engineers. Don't take the booster off unless you know what you are doing and increasing master cylinder size or other such things.

Upgrading stock brakes is one thing, removing advantage on them is foolhardy. A firm pedal with a short travel is NOT an effective pedal with all other constants intact. I can go from my 89 Charade Lemons car to my former project Fiat X1/9 without power brakes and no changes in how I use the brake pedal. The Fiat was designed for manual brakes, the Charade was not and is quite terrible with the assist removed.

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1989 Daihatsu Charade

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  • Registered: 2009-09-01
  • Posts: 405

Re: Removing Power Assisted Brakes

There is no friggen way I'm removing the power brakes now, I just gotta be less aggressive, thanks one and all