Master Cylinder

[mnesbit]

I think my master cylinder on my '95 LS 400 may be starting to fail. When I apply the brakes there is a faint whinning sound all the time and the feeling transmitted to my foot through the brake pad seems wierd.

The car still brakes OK.

I have also noticed that the ABS is almost deadly in snowy or icey conditions.

Any thoughts?

Thanks, Mike

[python]

when u brake and u feel the pedal slowly go to the floor, thats a master cylinder problem...never heard of them making a whinning noise

[eatingupblacktop]

Sounds like either the vacuum line or one of the valves (air, control, vacuum) in the brake booster is starting to leak. Have someone apply the service brake while you listen under the hood to locate the sound. If you need to apply more pressure than usual to brake, it's not the master cylinder.

Here's how you can test the booster: With the engine off, depress the brake pedal normally, several times to remove the vacuum from the booster. On the final push, keep the pedal depressed, then start the engine. As you continue depressing the pedal, it should go down. If the pedal goes down slightly, the booster is functioning normally. If it doesn't move at all, either there's no vacuum reaching the booster or it's malfunctioning.