Noisy front brakes when standing.
03-19-2003, 10:39 PM
#1
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Noisy front brakes when standing.
When I press hard on my brakes when standing completely still, the front brakes make a strange screeching noise. Are my brake lines about to burst???
Regards,
Sab.
Regards,
Sab.
03-19-2003, 11:16 PM
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The noise is probably caused by the pistons moving in the calipers or by the lever mechanism that actuates the booster. I don't THINK brake lines will make a noise. Something needs lubrication.
03-20-2003, 01:00 PM
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Perhaps with a little more description we might be able to make a guess. ".. a strange schreeching noise .." doesn't tell me too much.
Does the noise ocurr:
Only as you push the pedal down?
As long as you hold the pedal down?
If you push the pedal down repeatedly without the engine running, does the noise continue or does it stop happening as the brake vacuum goes away?
Does the noise come from under the hood (i.e., from the brake booster) or from the front wheel area (i.e., from the brakes)?
My first guess, based on virtually no info, is that the noise is being made by air flow intot he vacuum booster system.
Get someone to help, and try to define when and where the noise happens.
Does the noise ocurr:
Only as you push the pedal down?
As long as you hold the pedal down?
If you push the pedal down repeatedly without the engine running, does the noise continue or does it stop happening as the brake vacuum goes away?
Does the noise come from under the hood (i.e., from the brake booster) or from the front wheel area (i.e., from the brakes)?
My first guess, based on virtually no info, is that the noise is being made by air flow intot he vacuum booster system.
Get someone to help, and try to define when and where the noise happens.
03-20-2003, 01:57 PM
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Hello Wally,
thanks for your input and sorry for my poor description.
The noise occurs only when I apply heavy pressure on the pedal, engine on or off, as many times as I press it.
No noise just holding the pedal down.
It seems to come from the front calipers.
Regards,
Sab.
thanks for your input and sorry for my poor description.
The noise occurs only when I apply heavy pressure on the pedal, engine on or off, as many times as I press it.
No noise just holding the pedal down.
It seems to come from the front calipers.
Regards,
Sab.
03-20-2003, 03:30 PM
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I can think of only two possibilities:
Fluid flow thru a restriction.
Mechanical movement.
The pistons on the calipers should move only a few thousandths when you press the pedal. The pistons should move only enough to distort the square-section O-rings that seal them to the bores. This doesn't seem to be enough movement to cause a noise - perhaps a short squeak, but nothing more.
Sound like fluid flow thru an obstruction. If I had to guess, I would guess that you have a front brake hose that is swelling shut on one side.
If it is making a noise, you might be able to feel the vibration. Hold each hose in turn as someone presses the brake pedal. If one of the hoses vibrates, that might help to define the location.
I would suggest that, if this seems to be the problem, you replace both front brake hoses. They are the same age, and have seent he same service. Since you will have to flush and bleed the system, this looks like a good time to do both.
The bad part about this is that the hoses are expensive - P/N 928.355.081.02, $73.36 each, plus shipping.
Check carefully and see if you can determine for sure that it is the hoses - you might have to take them off and blow thru them. Some work, but ...
Fluid flow thru a restriction.
Mechanical movement.
The pistons on the calipers should move only a few thousandths when you press the pedal. The pistons should move only enough to distort the square-section O-rings that seal them to the bores. This doesn't seem to be enough movement to cause a noise - perhaps a short squeak, but nothing more.
Sound like fluid flow thru an obstruction. If I had to guess, I would guess that you have a front brake hose that is swelling shut on one side.
If it is making a noise, you might be able to feel the vibration. Hold each hose in turn as someone presses the brake pedal. If one of the hoses vibrates, that might help to define the location.
I would suggest that, if this seems to be the problem, you replace both front brake hoses. They are the same age, and have seent he same service. Since you will have to flush and bleed the system, this looks like a good time to do both.
The bad part about this is that the hoses are expensive - P/N 928.355.081.02, $73.36 each, plus shipping.
Check carefully and see if you can determine for sure that it is the hoses - you might have to take them off and blow thru them. Some work, but ...
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03-20-2003, 09:50 PM
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OK, I had someone press on the brake while checking on each wheel. It's a mechanical noise, the noise is coming from the left front caliper. It sounds upon applying pressure and upon releasing pressure. It somewhat sounds like opening a large very tight screw or wheel nut, like metal on metal.
It's not the lines, I can feel a slight vibration on the caliper.
regards,
Sab.
It's not the lines, I can feel a slight vibration on the caliper.
regards,
Sab.
