Spongy Brake Pads - (Calipers?)

[CyberFyber]

Hi there,

My '95 Suzuki Sidekick was driving mighty fine with no problems in braking 'cept for a faint meshing noise which started last week. I researched this and figured it was the pads. Okay.

So I took it to the mech down the block and he replaced the pads. Well, thereafter the brakes have been rather spongy. So I took it back now after several days of driving to see if the pads will adapt (they didn't).

I'm now being told that Hey! It might be the calipers or something else?

MY QUESTION? why isn't this something which would've been caught the first time around?

They tell me: "Well, how are we to know?"

Can someone please enlighten me regarding this?

[curtis73]

It sounds like there is air in there, but there shouldn't have been any introduced just from changing the pads. Its possible the brake fluid is really poor and is boiling. Brake fluid is very hydrophilic; it loves to absorb water. The fluid at the calipers is also subject to extreme temps. Absorbed water + high temps = boiling. Try bleeding the brakes with fresh fluid and see if that fixes it.

Its also possible that in the process, nasty fluid from the caliper was pushed back into the master cylinder and it has damaged the seals. Its also possible that the pad material is of a different composition making it brake differently.

It wouldn't be the calipers unless they're leaking or stuck. In answer to your question, the only real way to tell if something is wrong with your brakes is by your experience. The mechanic may test drive it and be able to tell obvious differences, but subtle before and after things he won't be able to tell since he doesn't drive it everyday. The only thing the mechanic can really tell is if the job was done incorrectly, in which case the pedal would go to the floor and not apply the brakes. If it was done correctly, the pedal will stop the car. The subtle differences in between are up to the driver to determine since you're the one who knows how it should feel. If its done wrong its incredibly obvious. Different is not obvious except to you.

[CyberFyber]

Originally Posted by curtis73

It sounds like there is air in there, but there shouldn't have been any introduced just from changing the pads. Its possible the brake fluid is really poor and is boiling. Brake fluid is very hydrophilic; it loves to absorb water. The fluid at the calipers is also subject to extreme temps. Absorbed water + high temps = boiling. Try bleeding the brakes with fresh fluid and see if that fixes it..

He's now claimed to have done that but it's just as bad as it was yesterday. 'and I Did mention how the only thing wrong with the braking beforehand was simply the noise. This guy's already lost my trust because of something else, thus I'll be heading to yet another mech in the near future.

Originally Posted by curtis73

It wouldn't be the calipers unless they're leaking or stuck. In answer to your question, the only real way to tell if something is wrong with your brakes is by your experience. The mechanic may test drive it and be able to tell obvious differences, but subtle before and after things he won't be able to tell since he doesn't drive it everyday. The only thing the mechanic can really tell is if the job was done incorrectly, in which case the pedal would go to the floor and not apply the brakes. If it was done correctly, the pedal will stop the car. The subtle differences in between are up to the driver to determine since you're the one who knows how it should feel. If its done wrong its incredibly obvious. Different is not obvious except to you.

So you're saying there's no black and white when it comes to Spongy Brakes? I mean, you're saying that it's not just about whether they're Springy or not but rather the degrees thereof?

From what I've read everywhere, having to press the pedal to the floor just to get the car to stop is a definition of spongy. (something I'm now going through which I didn't mention in my OP). Or am I misunderstanding what I've read?

Also, thanks Curtis for chiming in.

[GreyGoose006]

yeah, i'd say that pedal to the floor is spongy.
go to a differennt mechanic and just ask him if he could drive the thing around block and see if anything is wrong. dont tell him what was done or anything. he will probably say that there is air in the braking system.


for clarification:
is the brake feel fine at first, then get a lot worse the more you brake, or is it just as bad the first time you brake as half an hour later.

if it gets worse the more you brake but is fine at first, then the fluid needs to be changed.
if it is initially bad and stays bad then you just have an air bubble somewhere in there and it is compressing, which destroys the brake feel.

[CyberFyber]

Originally Posted by GreyGoose006

yeah, i'd say that pedal to the floor is spongy.
go to a differennt mechanic and just ask him if he could drive the thing around block and see if anything is wrong. dont tell him what was done or anything. he will probably say that there is air in the braking system.

....and THANK YOU Greygoose!

Might you say that I'm safe for the next week as long as I don't go high-speeding anywhere? Or, that's probably hard to say, huh?

[curtis73]

Too tough to say.

With brakes, if you've done them "right" the pedal will not go to the floor. If you've introduced air (or didn't bleed them properly) they will go to the floor. As long as the mechanic doesn't notice them going to the floor he might assume that they're fine.

Since every car is vastly different in how they "feel" when they're operating correctly, the mechanic wouldn't pick up on if it was just different, just if its "wrong".

But if you're getting your foot to the floor, assume its either a bad master cylinder or air in the system. If its the Master Cylinder, that wouldn't have been the mechanic's fault. It was just its time to go.

[alan &marge pepper]

ya curtis is right you either have air in the brake line or you need a master cylinder. my question would be do you have two wheel dis brake or four wheel. the parking brake cables can cause some of this if rear shoes are not set up be for the parking brake. this will cause cables to strech while brakes are being applied. hope this help from alan

[UncleBob]

not knowing exactly what the mechanic did during the brake job, or how it drives exactly, before and after, its all very subjective, mine you.

The sidekick has hub-mounted rotors. Do you know if they cut the rotors (which is much more labor intensive than on most cars/trucks)? I'm assuming its a 4x4

If they didn't cut the rotors, its very possible that you have very uneven rotors, which can cause a new pad to not seat well at all. This won't cause a "spongy" pedal, but it will require a LOT of foot pressure to get it to stop. With a vacuum booster, this very well could require the pedal to move a long ways before it stops quickly.

Does it make any difference if you pump the brakes? Does the pedal get harder/engage higher? This would be a sure sign of air in the system.

Another question, is whether or not the mechanic opened up the bleeders on the calipers when he compressed the pistons. THis is what is 'recommended", but some do and some don't. This does allow the chance for air to get into the system, if they do open the valves.

Its also possible that the calipers have problems, such as a sticking slider pin, and it can cause weird problems that may not seem intuitive. Such as the slider prevents the caliper from centering, leaving a large gap for the piston to fill before the pads are engaged. This will cause a lot of pedal travel.

And lastly, I've seen this happen from using the wrong pads. I have no great explanation on why, but some brake systems are very sensitive to material. Some aftermarket pads are too hard and don't have much bite.

I know this isn't very helpful, but just outlining that there are many feasible answers to your question. If the mechanic said he bled the system, then I assume he's not lieing. So it might be a less-than-obvious problem that no one has posted. The final answer IMO, is take it to another shop. Not because the original shop is lieing, necessarily. It might be the original shop simply isn't very knowledgable. But I wouldn't hide the fact about the work that was done. Always give the mechanic as much info as possible, otherwise you are wasting their time as they piece together what happened and it doesn't do you any favors, because that just pisses us off. We don't like wasting our time playing sleuth's for stuff you already know.

[CyberFyber]

hmmm, so many questions. I'm thankful this many folks have thought to check in and give their ideas.

I'll say what I know as fact. I DID try it all out on the highway last night at good speeds (above 50) and braking really isn't bad at all. It certainly gets the job done.

BUT, here's the real kicker. An important test I find aside from being stopped at the Red Light is being on a mild to steep incline. There I find myself pressing that darn pedal and hugging for dear life. You know?

So yes, I WILL be going to another mech this week and I'll let him know what's happened.

[Steel]

as unclebob was saying, and im saying too, if its not air in the system, its most likely a stuck caliper pin.

[UncleBob]

Originally Posted by CyberFyber

hmmm, so many questions. I'm thankful this many folks have thought to check in and give their ideas.

I'll say what I know as fact. I DID try it all out on the highway last night at good speeds (above 50) and braking really isn't bad at all. It certainly gets the job done.

BUT, here's the real kicker. An important test I find aside from being stopped at the Red Light is being on a mild to steep incline. There I find myself pressing that darn pedal and hugging for dear life. You know?

So yes, I WILL be going to another mech this week and I'll let him know what's happened.

from this discription, it sounds to me like they didn't cut the rotors.

If thats the case, the problem will go away in a while. You could speed it up by doing some aggressive braking (safely of course)....but I'm not confident enough about my suggestion that I wouldn't still recommend trying another shop

[bm2boats]

"Brake fluid is very hydrophilic; it loves to absorb water." WOW, I never knew that. I should bleed my brakes the next time I do a brake job. How much should I bleed out of them? 1 Pedal push to the floor? or more then that?

[UncleBob]

you really should replace the brake fluid at least once every couple years, or every 30K miles or so. The fluid will get discolored, so you keep bleeding it til its no longer discolored. I usually just recommend it every time you do front brakes. Makes it easy to remember.

Not only does it reduce the boiling point, it also accelerates failure of the calipers and master cylinder. Its one of many simple little maintanence jobs that can save you a lot of money in the long run.

[CyberFyber]

Originally Posted by UncleBob

you really should replace the brake fluid at least once every couple years, or every 30K miles or so. The fluid will get discolored, so you keep bleeding it til its no longer discolored. I usually just recommend it every time you do front brakes. Makes it easy to remember.

Not only does it reduce the boiling point, it also accelerates failure of the calipers and master cylinder. Its one of many simple little maintanence jobs that can save you a lot of money in the long run.

Good that you should bring this up. I'd been researching this (re: brake fluid) over the past few months. It was very hard finding anyone around here who even does it. Then I went to this mech whom I mentioned in this post and whom I'd been going to for over a year and he insisted on never doing it. ...and so, he talked me out of it.

I DO KNOW that the plastic container holding the brake fluid is brimming to the very top (past the Max level) after he'd gotten through with it. Plus I'm certain he did not change the fluid, AND, it's just as black as it's ever been. To reiterate what someone else here suggested, Maybe this guy just doesn't know what's he's doing in as far as brakes are concerned, ie: Brakes are NOT his Forte

[curtis73]

Originally Posted by bm2boats

"Brake fluid is very hydrophilic; it loves to absorb water." WOW, I never knew that. I should bleed my brakes the next time I do a brake job. How much should I bleed out of them? 1 Pedal push to the floor? or more then that?

I suck the old fluid out of the reservoir, or at least most of it. Replace it with fresh new fluid. Then I bleed until I get fresh fluid at the brakes. You'll be able to tell because the old fluid will be brown and cloudy and the new will be light and clear.