sqeaking from brake PEDAL

[97tbird]

Hi, and thanks for the advice so far...

My car: 1997 T-Bird(4.6L); 86,000 miles.

This worries me really: When I step on the brake pedal, there's a sqeaking noise coming from the pedal; NOT from the brakes on the outside...it's inside the car, comes from the pedal. When I take my foot off the pedal, it sqeaks again. At the same time, the pedal feels mushy/spongy, and also feels like it sinks lower than it used to do. This started about a month ago. (when the a/c is on, the noise is worse,and the mushiness). The bird stops okay, but feels weird...as if the pedal can go further...

[If it helps the diagnosis: a brake inspection at Sears a week ago revealed that my rear rotors have "excess lateral run-out"(what's that??)and that the car pulls to a side when braking...the mechanic thinks it's the run-out and "caliper grabbing" doing that. (turning/machining rotors was suggested, but I didn't get it done yet)
...could this be related to the pedal-sqeak-problem? I forgot to mention the sqeak at Sears. Also, as far as I know, the brakes were never bled, and probably still has factory fluid.]

Any suggestions/ideas/advice is thankfully welcome.

 

[Mike242GT]

T-Bird;

Could the squeaking actually be a whistling sound? Because it almost sounds like you ight have an issue with your vaccuum booster (like a leak somewhere).

Excessive lateral runout means your rotors are warped. If they're original at 86,000 miles, they're probably too thin to be turned and will have to be replaced. Probably not related to the sound your pedal is making.

 

[labman]

quote:

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Originally posted by Mike242GT:
T-Bird;

....

Excessive lateral runout means your rotors are warped. If they're original at 86,000 miles, they're probably too thin to be turned and will have to be replaced. Probably not related to the sound your pedal is making.

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I agree on the warping, but it could require more piston travel between where the disks push the rotors back to, and where the pads are in enough contact to stop the car. More piston travel means more pedal travel. Mushiness could come from the pistons being out to where they do not travel freely, or even the pedal hitting the carpet. Pulling to one side means one wheel is not fully in contact with the pads.

The brake pedal is hinged up in some hard to get to place. You could have metal to metal contact and a squeak either at the pivot, or something the brake pedal rubs. It sounds like you need the rear calipers rebuilt and rotors turned/replaced. I am not a fanatic about rebuilding the calipers every pad change, but you may have gone one too many without it. Even after a brake job, you may still need to get some lube into a spot in the never, never land under the dash.

Occasional rebuilds/replacement of the caliper eventually replaces the brake fluid. Usually there is little need to do more with the fluid.

 

[JohnBrowning]

The sqeaking is unrelated. Take a dab of grease and work it into the pivot of the break pedal. Lateral run-out= warped rotors.

I would simply check engine vaccum and the one way filter/check valve going to boster. If Vaccum reads low you know you are leaking someplace.

 

[Robbie Alexander]

quote:

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Originally posted by JohnBrowning:
The sqeaking is unrelated. Take a dab of grease and work it into the pivot ---snip

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Would silicon spray work or would you need too many frequent applications? Mine squeeks only once and awhile and I donlt see anything there but a hinge... Spray solicon there and it lasts about a year. Same on the door hinge (8mo-year).

As far as the brakes, is there any way to Treat them so you don't have to rebuild them. I change my fluid once a year or so, If I changed it more often would they last longer?

 

[labman]

quote:

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Originally posted by Robbie Alexander:

quote:

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Originally posted by JohnBrowning:
The sqeaking is unrelated. Take a dab of grease and work it into the pivot ---snip

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Would silicon spray work or would you need too many frequent applications? Mine squeeks only once and awhile and I donlt see anything there but a hinge... Spray solicon there and it lasts about a year. Same on the door hinge (8mo-year).

As far as the brakes, is there any way to Treat them so you don't have to rebuild them. I change my fluid once a year or so, If I changed it more often would they last longer?

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I am a great believer in spray silicone. It may be the easiest way to get anything up in there.

In your caliper, you have metal or plastic sliding in and out of a rubber ring. The rubber or plastic eventually wears away. Some of the plastic eventually swells a little with the heat and fluid. Moisture also works its way in through the boot corroding a metal piston. Water should stay in solution in the brake fluid, but cylinders and calipers always seem to pit at the bottom. When you change fluid and bleed the brakes, the bleeder is always at the top where the air goes. Therefore, the new fluid can go through and out the top, leaving old contaminated stuff in the bottom. There is no real alternative to rebuilding calipers occasionally, if not every pad change. Otherwise, change fluid or not, they eventually either freeze up or leak.

A generous coat of silicone grease on the bleed screw when you rebuild a caliper or cylinder is a good way to avoid frozen or twisted off bleed screws.