deputydog95

Has anyone found a way to take the pedal play out of the factory brake boost systems?

When you first step on the pedal, it dips about an inch or two with no engagement. Then it gets firm all the way to full lock. The master cylinder is brand new and the fluid is fresh.

It's not a deal breaker and I'm sure I'll get used to it, but feels a little weird have to press the pedal down for that couple inches before the brake actually engages.

Back to sebring tomorrow for more testing....

Speeds5

I don't think my 86 Carrera does this. I'll pay a bit more attention next time I'm out and report back but certainly haven't noticed. I have stock brake system except for stainless steel lines. Motul fluid.

MUSSBERGER

Plus your steering will be lighter and your tires will come up to temp quicker.

MUSSBERGER

Do you have stock brakes?

deputydog95

I do. Stock brakes, stock master cylinder, pagid pads, and I don't remember which fluid but it's a premium brand that the shop uses.

JCP911S

How's the pedal effort? Also once the brakes engage, are they firm and controllable?

A bit of compliance at initial braking is normal, but a small hydraulic leak could cause a loss of immediate fluid pressure, and a warped rotor can push the caliper pistons back. Also, the pads must be properly bedded... "green" pads can cause a "soft" brake pedal.

Also, there are different "Stock" master cylinders.

The original 911 had unassisted brakes and used a narrow diameter master cylinder to create leverage and reduce braking force.

When the boosted brakes were introduced, a larger diameter barrel was used to reduce pedal travel.... this is why you cannot "heel and toe" a stock SC/Carrara without a modified throttle pedal.

Maybe you just need to get used to them... this is 40-year old technology... but IMHO when properly set up, these brakes are very effective and dependable.

deputydog95

I took it out to a DE yesterday to see if we could check a few more things off on the list.

There's some overheating going on at full tilt (running around 225-230), but it is Florida and it's more or less summer here now. We suspect the mesh pattern over the cooler is too "tight" so I guess the next step to put a more open mesh over the cooler, and if that doesn't work then add another cooler. It was every bit of low 90's out.

We had a throttle stick as well. That was fun with the car holding 5k at idle Turns out is was binding on some sheet metal in the transmission tunnel. Cleared that up and lubed the cable, all good.

Back to the brakes. The new pads were already bedded in last weekend, and the rotors are fresh. When the car was delivered the master cylinder was blown and leaking, so we replaced it with whatever was in there originally.

Power off, no pedal pressure whatsoever. Normal with the booster off the way I understand it.

Power on and parked, pedal travels about 3 inches before you meet any significant pedal pressure.

Driving in the paddock, same as parked. Pedals travels about 3 inches or so before engaging any real firmness. When driving it in the paddock, the car was slowing ever so slightly in that first 3 inches, but doesn't begin to stop hard till you get past those 3 inches into hard pressure.

On track, same as above. It's consistent. Stops well and brakes fine. You just have get used to the pedal dropping so much to get pressure and then it works like a normal brake system.

I'm trying to figure out if this is just the way it is... Or if this is something we can make more "normal"?

Speeds5

That doesn't sound right at all on the brakes. I just went for a drive and I have pedal pressure right away, as soon as you press the pedal. Considering the switch in the master cylinder I'd guess that would have something to do with it, maybe a good bleeding. I'd check that first before doing anything else. Good luck fixing, it's not normal.

Eifeler

From what I've read, brakes can be a weakness in the D & E SC's.

My D car (83' SC) had a relatively soft initial brake bite. If it didn't have the travel length yours does, it certainly got there as soon as things heated up.

The part that bothered me more than the soft pedal was that it was VERY susceptible to knock back. Prior to any high speed or heavy braking zone, especially after hitting any rumple strips I would left foot pump to make sure the pedal was good.

The car (or driver if you want to look at it that way) chewed up pads. It helped when I added double cooling (AJUSA air duct plates to the hub and duck feet ducted to the caliper), switched to Kryo'ed, Slotted disks and mildly tweaked the bias by going Pagid Yellow up front and Pagid Black in the rear.

BTW - For shoes, that car ran BFG R1's in 235 and 255.

Gary R.

Never had any issue whatsoever with my SC brakes. Stock Zimmeraman rotors, no added cooling. Only time the rotors were an issue was when I tried slotted/drilled, frozen, or whatever was the flavor of the week. PFC 97 pads, Motul 660 (and others)..

deputydog95

Is it possible to just remove the booster? Is it really necessary for a race car?

Also, do the rules require that the ebrake remain in the car and be functional? I have no use for it and I'd like to get rid of it if possible.

Gary R.

Next you will want to remove your passenger seat!!

good hands

Isn't it time you transferred your membership to Ferrarichat.com ?

Gary R.

Been there since last July, sometimes I like to hob-*** with the common people so I come back here...

deputydog95

And what about that A pillar triangle door window while we're at it