Tell me how your brake pedal feels please!

[Big White]

Today, I knocked out one more item on my punch list, power bled the brakes. I have a KD power ball bleeder, a tool I got years ago to solve a problem on a custom car I owned. Worth its weight in gold imho. Anyway, I got the old fluid out which looked like used motor oil. I was hoping I may blow out a bubble somewhere in the system, but did not see any that I noticed.

The pedal seems a little soft. I like a very firm, right now feeling to the pedal. The brakes actually work great with a progressive engagement, but I would rather have VERY LITTLE pedal movement, more of a pressure feeling than actual movement. I know I can change it a little bit with more aggressive pads, but whoever owned the car before me (or the dealership) put all new brakes on all four corners. I don't feel like chasing it that hard, but I want to know what the pedal feel is like that on other XP's.

 

[toms89]

This is very subjective but....

I would say the brake pedal feel on my expy is softer than other vehicles I have driven. It doesnt inspire as much confidence as our honda odyssey for instance. Much firmer brake pedal feel in it.

 

[Big White]

I wonder about doing something like this:
soft break pedal adjusted - F150online Forums
But that one fellows warning is pretty steep.

 

[toms89]

I wonder about doing something like this:
soft break pedal adjusted - F150online Forums
But that one fellows warning is pretty steep.

Interesting...

 

[Big White]

Here is more about it.
*** Soft Brake Pedal Resolved *** - F150online Forums

 

[GAINMOB]

mine is fine to me...no comparison to my wifes 2011 altima but its new and lighter...shes on stocks and i have 26'z...

 

[ELVATO]

Interesting. Might try this, though I'm pretty sure my issue is the air leaking I hear by the brake pedal near the firewall.

 

[Big White]

Interesting. Might try this, though I'm pretty sure my issue is the air leaking I hear by the brake pedal near the firewall.

I would definitely change out the booster first. That is an issue, the diaphragm ruptured.

 

[tsgrpr97]

Mine seems soft too. I'm glad to hear its not just my truck.

 

[alaskanexpy]

mines okay, i do want to flush the fluid and put decent rotors on it. but the pedal in my excursion feels much better. but i also have power slot rotors in it which made a HUGE difference!!!

 

[Big White]

I am quite sure the rotor's themselves made no difference. If you changed out rotors and noticed a difference, it was because either

1) the old rotors were slightly warped, which dimensionally pushes the pads farther away from the rotor, retracting the piston further in the bore. When you apply the brakes, the pistons in the caliper have that much farther to travel, and gives the impression of a softer pedal.

2) You installed new pads at the same time, and they had a more aggressive compound that grips with less pressure. This also can give the impression of a stiffer pedal.

There is nothing in rotors in and of themselves that can change friction qualities. The drilled rotors (and slotted to some degree) are pure marketing/looks sort of thing. I come from an engineering background, and as far as I am concerned form follows function. The drilled rotors are really a left over from the performance crowd running organic pads that had a tendency to outgas during heat up. During severe out-gassing, there would be enough to actually reduce the clamping force of the system. The drilled rotors would give a place for the gasses to go. I'll take the increased mass which adsorbs the energy. Drilled rotors also suffer from stress cracks as there is no way chamfer the inboard rotor face to relieve stress concentrations.

Back on topic, I think I may set my booster output rod a half turn out and see what's doing.

 

[GAINMOB]

i changed my booster and fixed this for me...but i have noticed that depending on how i set my tire diameter setting on my programmer...it would give/take away the sponge feel by making it soft or tighter

 

[Big White]

i changed my booster and fixed this for me...but i have noticed that depending on how i set my tire diameter setting on my programmer...it would give/take away the sponge feel by making it soft or tighter

That is very odd. For the life of me, I can not imagine what a programmer could adjust on a brake system. I can certainly see how changing the booster would though. Did the booster have explicit instructions on setting the stab depth of the output rod?

 

[splintrcel]

I rebuilt all my brakes and replaced the brake fluid and bled the brakes with a power bleeder. My pedal changes slightly every day. I am assuming its directly related to the brake booster. When I rev it a couple of times my pedal is really firm but under normal conditions its about medium.

 

[Big White]

Bummer. All set to take it apart, and found this post: F150online Forums - View Single Post - *** Soft Brake Pedal Resolved ***
Still may birddog it though.

 

[GAINMOB]

That is very odd. For the life of me, I can not imagine what a programmer could adjust on a brake system. I can certainly see how changing the booster would though. Did the booster have explicit instructions on setting the stab depth of the output rod?

depending on how big you set your tires if your programmer has that option...it will adjust your ABS...i can set my wheel diameter to 33.50 and brakes will be spongy...set it to 32.75...my speed is correct and my brakes a good when applying the brake...set it to 32.50 and they are touchy

 

[Big White]

I still have a hard time with that, but if you say so....

Brakes are purely a matter of geometry and physics. There are no variables that can be electronically controlled, variable orifices such as may be used in variable effort power steering systems. The ABS will modulate pressure by opening closing a respective valve, but to change the sensitivity (or more appropriately the reactivity) of the system, I have no idea how a programer can do that...The liability of the people making a programer must be very high.

Looking at the wiring diagrams, I dont see anything (electronically) that can change the sensitivity. A programmer will certainly get the speedo corrected within the ECM .

 

[Fila571]

Soft pedal is often caused by soft ,weak or damaged "rubber" flex lines, a common problem with these trucks.Not expensive, but you will have to bleed the system after.My two cents.

 

[alaskanexpy]

I am quite sure the rotor's themselves made no difference. If you changed out rotors and noticed a difference, it was because either

1) the old rotors were slightly warped, which dimensionally pushes the pads farther away from the rotor, retracting the piston further in the bore. When you apply the brakes, the pistons in the caliper have that much farther to travel, and gives the impression of a softer pedal.

2) You installed new pads at the same time, and they had a more aggressive compound that grips with less pressure. This also can give the impression of a stiffer pedal.

There is nothing in rotors in and of themselves that can change friction qualities. The drilled rotors (and slotted to some degree) are pure marketing/looks sort of thing. I come from an engineering background, and as far as I am concerned form follows function. The drilled rotors are really a left over from the performance crowd running organic pads that had a tendency to outgas during heat up. During severe out-gassing, there would be enough to actually reduce the clamping force of the system. The drilled rotors would give a place for the gasses to go. I'll take the increased mass which adsorbs the energy. Drilled rotors also suffer from stress cracks as there is no way chamfer the inboard rotor face to relieve stress concentrations.

Back on topic, I think I may set my booster output rod a half turn out and see what's doing.

same pads nothing else was changed, stock rotors had no issues. the cryo treated power slots(slotted..no drilling) have been known to give a better bite. say what you want but i drive the truck daily and the rotors made a large difference. i can lock them up now when before that was laughable.


http://www.tirerack.com/brakes/brak...+Slot+Rotor&group=Power+Slot+Rotor&cat=Rotors