Spongy brakes?!!

[eckerd_explorer]

I'll cut right to the chase. My brake pedal has this weird feel to it, the best that I can describe it is as follows;

1~ when pushing the brake pedal it feels as if you a slowly stepping on a very stale sponge.
2~ the movement of the pedal is not smooth like it should be, it almost feels like it's sticking as you apply pressure
3~ accompanied with the sponge analogy, it makes a slight chirping sound.

the truck stops, but the brake pedal just doesn't feel right. Also it seems to be off and on. Please help I'm driving from Oregon to Minnesota in 3 weeks...
any ideas???!

 

[je5]

Possible calipers and master cylinder failure. If you also get a whishing sound your brake booster maybe failing.

 

[BrooklynBay]

The booster will make the pedal feel stiff if it is bad. The booster has a check valve which lets it hold vacuum without leaking out. To test this, start the engine, then shut it off. Pull out the check valve. If there is vacuum inside of the booster, you will hear a swooshing sound when you pull out the check valve. Did you try to bleed the brakes?

 

[eckerd_explorer]

All are good suggestions, I'll look into this today. Not sure if it makes any difference, but it was 104 degrees in portland yesterday and it seemed to be worse with the heat...?

 

[Iggy flywheel]

I would also check the rear wheel brake shoe cylinders for leaks. Unless you got 4 wheel disk. My petal felt spongy too replaced the master. It was bad. finally felt good after replaced leaky rear cylinders.

 

[Majisto]

Put in fresh fluid. Trust me, brake fluid can absorb moisture and air can indeed get into the lines. Don't do a costly master cylinder replacement without doing the fluid. Switch to ceramic pads next time too. I just posted a response in stock 95-2001. My PFC ceramics from Autozone and fresh DOT 3 fluid has made my Explorer's brake pedal as responsive as my Contour.

 

[CDW6212R]

Ditto, bleed the brakes completely. Has any air gotten into the system at all. That's huge, because it cannot be bled out of the ABS pump(Ford only). Good luck,

 

[NightRock]

Sounds like we got the same problem.. I have changed all the 4 brake pads and disk.. but the pedal still the same. I have notice some slightly leak on my brake master.. is there any repair kit for that or I need to changed the whole thing

 

[BrooklynBay]

Where do you see a leak on the master cylinder? Is it coming from one of the fittings?

 

[eckerd_explorer]

I'll bleed them this weekend and see if that helps. Not sure if I got air in there or not, all of the sudden this started happening so I guess this'll be the best place to start. Thanks guys, it's a huge help.
T

Oh yeah, BTW, I started my Ex and turned it off and took the cap off of my brake fluid resivour/Booster/whatever it's called and I didn't hear any woosh or any sort of vacum sound at all...... Ideas???

 

[NightRock]

Where do you see a leak on the master cylinder? Is it coming from one of the fittings?

I saw some minor leaks on the fittings connected into hydroback?? is that correct name?

 

[BrooklynBay]

Tighten all of the leaking fittings, and then bleed the brakes.

 

[ironbandit]

How 'bout this?

1992 XLT w/300K and OEM Master Cylinder. I did a brake flush and refill the last time that I did a 4 wheel brake job on here, about 4-5 years ago. Brakes are also in the process of being retrofitted with ABS of 93-94 vintage. Looked into rear disc, boneyard wanted WAY too much for my wallet.:thumbdwn:

Anyway, the retrofit is waiting for the two wires coming into the cabin to be hooked up, and the old RWABS 'puter plus wiring to be removed. In the mean time, the brakes have been done once in the interim while the front end was overhauled and painted. And been solid as a rock until about 2 weeks ago. Thought it was low fluid, checked and no. Topped off the MC with DOT4, same as what I refilled it with in 2003-2004. Improved the behavior slightly, but can still take the pedal to the bottom stop if I lean on it hard. Brakes pump right up and hold with engine off, can't be pumped up when vacuum is engaged (running). No leaks anywhere that I can find. Haven't pulled the drums, so I may tackle that soon.

I may do another 4-wheel flush and refill to see if that does it. But I rue going thru the ABS pump. I was able to bleed it completely while fitting the lines from the MC and to the calipers/cylinders. Can't really afford to let the system drain completely, or I'll get air in the pump and a spongy pedal for the effort. :roll:

Shall I rebuild the MC, or replace it?