brake booster noise

[cocoasranger]

When I apply the brakes there is a loud swooshing sound from the brake booster as the pedal goes down, but it stops as soon as the pedal stops moving. This happens when parked as well as when moving. The feel and effectiveness of the brakes are good.

Is it common to have some noise on older master vacs as the pedal moves, or is the booster bad. I never took notice of any noise till replacing the brake master cylinder recently and have noticed the noise since then. It does not take much effort on the pedal to stop, by the way, and the rpm's don't drop when the noise occurs. I searched the site and found little on this. Any thoughts on this appreciated.

 

[Earl43P]

Do three dramatic decelerations right in a row, 50-35, 35-20, 20-stop.

If the boost is still good for that third hard stop, don't worry about it.

If you get a hard pedal, booster is shot, explaining the new noise.

It might last a long time like that.

 

[Wicked_Sludge]

dont skimp on braking systems. your booster is failing and theres no way to know how long its going to last. just replace it now and save yourself a traffic accident.

 

[cocoasranger]

I did try three stops from 45 mph just short of locking up all four wheels and the truck stopped like RIGHT NOW with no increased pedal effort on the next stop. I plan on replacing the booster asap in light of your comments. Thanks both for your input.

 

[Mark_88]

Be careful when you replace the booster not to snap the brake lines...they will move out of the way enought to replace the booter but not much more...someone told me to spray them with lubricant before moving them if they are rusted...apparently helps loosen the metal a bit so it's not brittle...I ended up snapping one line anyways and had to bleed the brakes...

Also, there are different booters with and master combos so try to get one from the same or similar year...the depth that the booster pin enters the master is critical...measure them if possible to ensure that the pin is not going too deep or not deep enough...they are adjustable as you will soon find out...

 

[cocoasranger]

Mark_88,
Thanks for the heads up on the brake lines. When I replace the booster it will be with a new unit. A remanufactured one is only $60 exchange.

 

[Mark_88]

Mark_88,
Thanks for the heads up on the brake lines. When I replace the booster it will be with a new unit. A remanufactured one is only $60 exchange.

Hope it helps...I think I paid $60 for a used one...that's a good price on a reman though...not sure what they are now but I replaced mine about five years ago...prices seem to fluctuate depending on availability...and some parts are obsolete now...