Pedal to the Floor

**Bill** · #1 (**permalink**) 02-23-2004, 09:27 AM

While driving back from an Alfa Club Tech. session in Houston Sat. afternoon (great bunch of folks!) I was approaching a toll booth on a pay road and downshifted to slow and tapped the brakes...WENT TO THE FLOOR!

Pumped a few times and they came back, but did it again for four or five repeats, then back to 'normal' and has not happened again.

Checked fluid level, fittings, hoses and MC...all look good, no leaks, bulges in the hoses, etc.

Could it be overheating the fluid in stop-and-go traffic for 15 minutes before? (Did notice a "squeeling" while braking from right rear, prior to losing pedal).

Any ideas on what happened and why?

Thanks

**John M** · #2 (**permalink**) 02-23-2004, 11:07 AM

Hey Bill:

Sounds either like a bad MC or leak in the system. If you cannot find fluid sprayed and dripping, my bet on the MC.

Best Regards,
John M

**tubut** · #3 (**permalink**) 02-23-2004, 01:41 PM

I agree that this sounds like a master cylinder problem.

**Roadtrip** · #4 (**permalink**) 02-23-2004, 01:59 PM

Master cylinder. Bill, what's the story? With all the problems lately, are you trying for a "restoration-by-parts-attrition?"

**Bill** · #5 (**permalink**) 02-23-2004, 02:23 PM

John, You mean this is not how a restoration is done???
Good one!

With 105K , 23K of those this past year, I guess its just wear and tear w/age thrown in for good measure. I'm putting 2K a month on her, in all driving conditions & weather and throwing in an AutoX once a month, so I expect things to "get out of Spec."

I can't complain too much. For a 'used' car she really hasn't been much of a problem, has served me well as a daily driver, and has put a smile back on my driving face.

I will check the MC. Whats the best way?

Thanks

**John M** · #6 (**permalink**) 02-23-2004, 03:29 PM

Hey Bill:

You can pull the booster hose fitting and peek inside the booster to see if its wet with brake fluid in the bottom. Most likely will be wet if the pedal is going to the floor. But unless you have a leak at a caliper or line.....its the MC. Any drips at any of the wheels? Brake fluid spray inside the fender wells?

Yank that puppy out. Get a new one or a rebuild kit and go at it. I think...if memory serves me and since yours is a 78......two bolts hold the MC to the booster. Disconnect the brake lines, three of them. Disconnect the low fluid brake light wire loom. MC just slides forward.

Best Regards,
John M

**Trav** · #7 (**permalink**) 02-26-2004, 07:18 AM

It does seem like the MC is the culprit, BUT having just been through a MC change without it fixing the problem I have a suggestion I think should work.

To be certain the MC is bad, remove the brake lines and put bolts in the MC (three 10MMx1). If the pedal still goes to the floor, its the MC. If not, it is elsewhere in the system. I did this to test my new MC and further to determine if the problem was in the front or rear circuit. My problem seems to be the pressure regulator for the rear circuit.

It should only take a few minutes to test before you remove the MC, and you will know if it was bad.

What do you all think? Is this a valid test?

TD