No More Spongy Brake Pedal

[240 2NR]

Wow!!!!

Ok so I had orignally posted a thread about the brake issues I was dealing with after installing a new MC. Turns out after writing a long *** post my dial up connection at work disconnected and my post was lost.

BEST LUCK EVER!!!!! Turns out that since I didn't have responses from you guys I actually went and read the instructions that came in the box and came across the exact issues I was having. I've installed a MC before but the install was a big improvement right out of the box so I didn't read on and my friend who was working on it with me didn't bother to explain how to trouble shoot problems that didn't exist.

To back up, since I bought the car my pedal has been firm, but with a long stroke before engagement, though the brake lights turn on within a few mm so I knew it wasn't the pedal free play. I changed the stock pads to KVR's which made a big difference when hot and improved fade resistance, but cold it was just as bad. I've bled the lines numorous times without a noticable change and the MC seemed like the last option besides SS lines. I had read the FSM about checking the brake booster, but the procedure requires compressed air so I ignored it.

So this weekend I changed the MC and while I felt like my braking force was improved (there was definitely some leaking past the seal), modulation was worse than ever, accompanied by a groaning noise. This wasn't going to do with a 1000 mile road trip ahead of me.

So I read the little instruction manual and right there was the procedure for curing just that series of problems.

Turns out the piston for the brake booster wasn't seating in the MC piston in the retracted position and now with the new MC the problem was worse. Pedal travel before engagement was long, even though the pedal was firm once the pistons engaged.


So an hour later, super stiff pedal with very short travel!!!!!


Here's how to do it. It should only take about an hour and really only requires a 12mm wrench, a 7mm wrench and a pair of needle nose locking pliers (non locking will work, but locking is much easier).

-Unbolt the two nuts securing the MC to the brake booster.

-Pull back the MC to reveal the BB piston

-There is a round piston with a 7mm fitting on a threaded pushrod

-The entire pusrod/ piston assembly freely rotates by itself so you will have to use the locking pliers to hold the pushrod (easier if the pushrod is deployed so have a friend press on the brake pedal or rig up a way to have the pedal depressed while you work on it, I used a jackstand and a pair of 20+mm wrenches)and the 7mm wrench to turn the piston counterclockwise (or clockwise if you have brake dragging to retract the piston). I used 1.5 full turns and it went from very spongey accompanied by a groaning noise to super firm (almost too much) while allowing the wheels to turn without dragging the brakes. My guess is if you are not getting a groaning noise with the brake pedal depressed at idle you should go less than a full turn.

Then just rebolt the MC and go for a test drive (you may want to check for brake drag by lifting a corner and spinning the wheel while it's off the ground).

Pic....