Help me with Soft Brake Pedal after Upgrade

[GriffX]

Theoretically no. Larger volume but more fluid. Still can only compress a liquid so much with the spacing in the lines, etc. Good thought though

Than the brake caliper piston area must stay the same? So instead of 2 big, 4 small pistons?

 

[Aussie-Parnelli]

We learnt when I was serving my apprenticeship many years ago, that if we had problems bleeding brakes you pushed the pedal as hard as possible and wedged the pedal with something under the dash 'piece of wood or tube' leave it overnight and the next day it would be fine. Disconnect battery to stop brake lights staying on. I still do it today with success

 

[01yellerCobra]

We learnt when I was serving my apprenticeship many years ago, that if we had problems bleeding brakes you pushed the pedal as hard as possible and wedged the pedal with something under the dash 'piece of wood or tube' leave it overnight and the next day it would be fine. Disconnect battery to stop brake lights staying on. I still do it today with success

Where did the air go?

 

[Aussie-Parnelli]

That is a good question, don't know but it works.

 

[Norm Peterson]

Theoretically no. Larger volume but more fluid. Still can only compress a liquid so much with the spacing in the lines, etc. Good thought though

Be careful here. You still have to move those pistons enough to take up the running pad to rotor clearances and any pad compressibility, and a larger total piston area will need more fluid in order to do this. Ultimately, this means you get a slightly longer pedal using the same MC.


Norm

 

[Norm Peterson]

I just know the pedal is not near as touchy/sensitive as my daily driver (a 17 Fiesta ST). That might be a function of 2008 vs. 2017 technology though.

The obvious question here is "which Hawk pads?". The knee-jerk answer - if they're the "regular" HPS or Perf Ceramics, initial bite is nothing to be writing home about no matter what you do. If your Fiesta brakes throw even a little brake dust, chances are they're higher up the brake performance food chain than either of those Hawk compounds.

At one point I ran Hawk's HPS, and they didn't feel a bit better than OE, and not as good as HPS pads had felt on previous cars (formulation change?). According to Hawk, their ceramic pads don't even have the HPS-level stopping power.

These days it's either Carbotechs in Bobcat/1521 compound or G-locs in GS-1 for the Maxima and (as soon as I can get them there) the new WRX. The Mustang gets track pads (CT XP-series, G-loc R series).


Norm

 

[1950StangJump$]

They are the ceramics, so maybe that’s part of it.

However, in my experience, the difference in pad bite feels different than the pedal sensitivity that I am referring to ..... but I’m not an experienced racer either so I might be off here.

On a side note, the criticism of the drilled rotors is accurate. I can feel “grinding” in the pedal as it closes to a stop, and I’d swear I have a steering wheel vibration on heavy braking already .... and it’s only been a couple hundred miles.

 

[Norm Peterson]

They are the ceramics, so maybe that’s part of it.

Quite possibly, since initial contact doesn't start doing much right away.

There may also be something involving pad to rotor running clearances up front and the amount of fluid required to take that up that's delaying solid front brake engagement.


Norm

 

[Juice]

Does the pedal feel improve if you pump the breakes 2-3 times while stationary? If not, then you most likely got all the air out.

 

[1950StangJump$]

Nah, it stays the same. I’m confident now that the air is out.

 

[01yellerCobra]

I don't remember feeling any kind of grinding when I ran drilled/slotted rotors in the past. On either car. Did you bed the brakes?

 

[1950StangJump$]

I don't remember feeling any kind of grinding when I ran drilled/slotted rotors in the past. On either car. Did you bed the brakes?

Absolutely, I did. To the letter as instructed by Hawk.

It's a slight feel as you slow down under 20 MPH with your foot on the brake pedal with moderate pressure. Found a few posts were folks said that was typical of drilled rotors, especially during break-in. Beats me. They look fantastic though. I'll run them for a bit and change them out if they bother me too much. The calipers have been such a PITA, just changing out the rotors/pads feels like a snap of the fingers.

 

[bujeezus]

My slotted rotors initially felt that way but it eventually went away.

 

[1950StangJump$]

My slotted rotors initially felt that way but it eventually went away.

Do you recall how long it took?

 

[OX1]

Be careful here. You still have to move those pistons enough to take up the running pad to rotor clearances and any pad compressibility, and a larger total piston area will need more fluid in order to do this. Ultimately, this means you get a slightly longer pedal using the same MC.


Norm

The problem is the GT's (non-Brembos) start with long travel squishy brakes .
I took mine in the first month complaining, and they said this is how they are.

Now that I finally have a pedal (3 month nightmare of various types of bleeders
and $1100 bi-dir scan tool) after the front Brembos, it is significantly worse
in pedal travel. Not even really sure what I did right to get a pedal at all, finally.

Even when the brakes seem to work great, if you push hard enough when stopped,
pedal goes down and hits a hard stop. I drove an 18 PP that did the same thing. I
couldn't believe that Ford was OK with that, but yesterday I stumbled on a post from
6G board that said that "theirs" does the same thing (and others agreed it is normal).

I posted up on on trackmustangsonline about putting S550 PP MC in an S197.
https://trackmustangsonline.com/threads/s550-pp-master-on-s197.14230/
I couldn't get a pedal when I had that MC on (couldn't get a pedal with orig MC
either, for quite some time), so really can not comment on pedal feel with that MC.
But I do feel these cars need a larger MC to get a brake feel that won't make me
think there is something wrong with the brakes, every time I drive it. Go drive any new
Fusion and you will see what I am talking about. I had an AWD 4 cyl eco and now a Sport
and they both have brakes that work RIGHT NOW, which I highly prefer.

 

[ghunt81]

When I did my Brembo swap (only removing the front calipers) I had to bleed the brakes twice to get a good pedal feel. To me though it feels more like stock now. I didn't use a vac pump or anything.

I agree about newer vehicles having grabbier brakes, I don't know why that is. My F150 is like that, whereas my wife's 2011 Explorer has a lot more pedal travel before the brakes really start to grab. Always throws me off when I go from driving my truck to driving her Explorer as I forget how much pedal travel the Explorer has.

 

[OX1]

So I finally found a shop that has the Ford IDS and they were able to get pedal higher for initial braking.
Brakes work very good, but still very high travel (overall) and can still push brakes all the way down to some mechanical stop. Tempted to put PP S550 MC back on and have them re-bleed, but for now just going to enjoy it for the summer.

 

[Norm Peterson]

So I finally found a shop that has the Ford IDS and they were able to get pedal higher for initial braking.
Brakes work very good, but still very high travel (overall) and can still push brakes all the way down to some mechanical stop. Tempted to put PP S550 MC back on and have them re-bleed, but for now just going to enjoy it for the summer.

Do you get this long travel with the car just sitting there or is it after driving it a bit?

If driving it is involved, the problem could be with one or more wheel bearings. The play that happens will cause pad knock-back during driving (and especially during cornering or over rough roads).


Norm

 

[OX1]

Do you get this long travel with the car just sitting there or is it after driving it a bit?

If driving it is involved, the problem could be with one or more wheel bearings. The play that happens will cause pad knock-back during driving (and especially during cornering or over rough roads).


Norm

It actually gets a bit better driving, but I suspect that is just pads heating up some.
Only have 7600 miles and roads are very smooth around by me, doubt it is a wheel bearing issue.

The fact that brand PP GT's also do the same thing, of being able to push brake pedal down to some mechanical stop (or maybe bottoming something in booster or MC), just sitting in car with engine running, means to me that is the way ford designed it. It doesn't even mean the brakes don't work well, they just feel like they won't (to me).

Girl at work has a very low mileage 13 Boss and her section is moving back into my area at work. I sat in her car with engine running a while back to feel brakes, but hope to drive it even across a parking lot soon, to see how it compares.

 

[GriffX]

An other cause of a long brake pedal is the side play in the rear axle half shafts. I noticed this when I changed to a torsen diff an the left-right play was zero afterwards.