My sister said it happened suddenly, she went to hit the brakes and it just went almost all the way to the floor. The pedal goes maybe 3/4 inch to the floor and does nothing, the last 3/4" will give you a little brakes, but not much. Its about enough to stop you from going with the engine running in gear. I open the hood expecting fluid to be low, but its full. No sign of any leaks anywhere. It has newer pads on the front, and the shoes are adjusted properly on the rear, but it happened all the sudden so its pretty obvious thats not the problem. I am just not sure if its the master cylinder thats bad or if its the abs controller thing. Has someone had a similar situation, or have any idea what the problem is. Is there some way to test to see if its the master cylinder or the abs controller or what?

Any insight/suggestions/ideas are greatly appreciated.

Shawn

Also, to specify if you didn't gather it from the post its a 1993 Olds Eighty Eight Royale, L27 (I think thats the only engine available), w/ABS, front disc/rear drums.

The ABS is failsafe. MC, and make sure you bench bleed it.

I agree; sounds like the master cylinder. That same problem has happened to me on more than one vehicle that I've owned.

And yes, bench bleed it before installing it. The instructions and needed accessories will be included in the box.

It'* extremely dangerous to drive it while that problem is present, so If it happens again before the master cylinder has been replaced, note that when it happened to mine I was always able to immediately remove my foot from the brake and then apply it a second time, and the second time the pedal was pressed it was full and braking was normal.

It always does it, it doesn't just do it every once in a while. Every time I push the pedal it goes almost all the way to the floor before doing anything. The car has been parked for 3 weeks or so (since the problem started, it was only driven home), I just haven't had a chance to look at it until today. We have 7 cars, plus my sisters fiances car (which is a '94 Olds 88 oddly enough) so its not a huge problem to have a car sitting as there is something else to drive. I figured it was the master cylinder, I just didn't know if the abs controller could cause this type of problem as well. I just wanted to make sure thats what it was before buying one and having it end up not being the problem.

Thank you, thats what I wanted to hear.

Shawn

I've never had one that failed such that the pedal was low every time the pedal was pressed. When it'* happened to me, I've always replaced the master cyclinder within a few days because of the potential danger. Personally, I won't buy a rebuilt master cylinder anymore; only a new one for safety'* sake because I've had rebuild ones that failed that same way or leaked externally after a short period of time (1 or 2 years).

If the pedal is always low and the fluid level is low, there'* an external leak and air has entered the system, and you'll need to find the cause of the leak(*) and fix them and bleed the system. If the fluid level is normal, I'd suspect an internal failure in the master cylinder.

Its obviously an internal leak, I knew that already. Thats why I wasn't sure if it was in the ABS controller or the master cylinder. I didn't think it was the ABS controller, but I wanted to get a second opinion before replacing it. In fact, I was on my way out the door to get one after inspecting the brakes and then I thought about it for a minute and decided to post on here to make sure just in case.

Shawn

I hade a leak in my MC. new one was like 80$ took me like 30minutes to fix. wish i didnt have to spend the 80 but what can ya do.

A new one was like $52 (I pay wholesale ) but they didn't have one in stock. I am going to pick it up tommarrow morning and throw it on there.

Shawn

Got a '93 Bonneville with identical symptoms. Thanks for the info!

-MMM-