Master Cylinder is it Bad?

**ceyermann** · 08-11-2007, 09:48 AM

How can I tell if my master cylinder needs to be rebuilt or replaced? 2001 suburban 1500 4x4. On a recent road trip the red brake light and ABS light come on and stay on. Then the next day no red brake light or ABS light. the brakes are soft to the touch and have recently been replaced.

**Davandy** · 08-12-2007, 04:16 PM

Never take a change with brakes

, if you can't diagnose it yourself let a professional take a look at it.

**Dj Friction** · 08-12-2007, 07:01 PM

My 95' had a similar situation with the ABS Light and Brake light. The lights would flash on and off and sometimes stay on....long story short....2 problems One....an ABS wheels sensor was shortening out and two the ABS module had hard fault codes that could not be fixed. Anyway.....You need to have a scope that can read the code to really figure out what is going on...you can replace parts for a long time without a proper scope...Take it to someone that can diagnose the problem correctly.

Don't mess around....ABS goes out you may not have brakes . period.

**TrailLeadr** · 08-12-2007, 07:45 PM

Originally Posted by Dj Friction

Don't mess around....ABS goes out you may not have brakes . period.

You're absolutely right. This has become my new quest to make sure people know that the ABS light doesn't only mean they may not work when needed, but could activate when they're NOT needed. Making it impossible for you to stop in time to avoid a catastrophy.

Do the right thing, and take it to a qualified tech to diagnose.

**ceyermann** · 08-13-2007, 07:30 PM

thanks guys for your input. I just finished a 2000 mile trip and the brake and abs lights were on for the first half and not on for the second half of the trip. hopefully the dealer can diagnose without the lights on.