Quick question for those who store their Crossfires.

I live in the south where we can drive year around. I have had mine for one year now. I remember when I bought it the brake pedal felt a little soft to me but that went away after a while. Not sure if real or imaginary but they seemed to improve in my perspective. The previous owner did not drive the car much, maybe 1000 miles a year or so if that.

Fast forward. This past month or so I haven't been driving the Crossfire. I had bought a new to me truck and have been needing to use it at work to haul some stuff and then the weather has been bad, lots of rain etc so for the 1st time the crossfire has sat in the garage untouched with the exception of a coat of wax.

I decided to drive it today to maintain the battery and the fact that I have missed it.
When I got in it fired right up running like a sewing machine.

However, the Brake Pedal went to the floor!!!!!!

I've had power brakes do similar before, but they easily pumped up and maintained their pedal afterward.

The crossfire took quite a bit of pumping to bring it back up and it was never truly firm. I moved the car back and forth in the garage a few times and it stopped fine. I didn't drive it but ran my errand in the truck. When I came back it was low again. Not as low as before but still low.

I see no fluid leaks, the revivor was full. Not as clean as I would like but still as would be expected for similar mileage vehicles. I have bought fluid already as I had planned to flush the system just as PM.

Humidity here is very high year around so much so that the engine started to steam when it heated up after being stored inside a closed garage.

So, am I looking at a vacuum leak? or an "O" ring or seal?

Where should I start???


Is this an issue when stored?

 

Common issue when stored for a long time, you need to bleed the brakes then all will be normal again.

 

The only way I could see the pedal going to the floor like that is from a bad master cylinder if the fluid level isnt going down.

 

Thanks, do you know what the cause is?

 

Thanks, Do you know the root of the problem? What causes it?

 

That is a possibility I guess but I was taught that a master will leak down under pedal pressure slowly. This does not once it pumps up it is fairly stable. I was also thinking it may also be a frozen caliper by rusting due to the high humidity in the area. Things rust fast here.

 

Master cylinders go bad from the seals failing. But it can be caused by using the wrong brake fluid or other contaminants getting into the brake fluid.

Brake fluid sucks up moisture like no tomorrow and over time it can become very heavily contaminated with water. This can lead to rust and corrosion brake lines and such.

For the pedal to go to the floor with no fluid loss the fluid has to get around the piston in the master cylinder. The piston has a rubber seal on the outside of it that seals it against the housing the piston travels in. If the seal shrinks, gets a tear or micro holes in it the brake fluid can seep around the piston allowing the pedal to go the floor. Pumping the pedal up gets fluid back on the correct side of the piston restoring the brakes to normal use. But it will leak down over and over and the only fix is to replace or rebuild the master cylinder.

 

This diagram shows how the master cylinder works on most cars.



Here is an article I wrote about the brakes on my c4 corvette. It shows how the brake system works.

Brakes | Crowz Nest

 

A stuck caliper would cause the brakes to not work well but wouldnt cause the pedal to fall over time. As you can see in the above diagram once the fluid bypasses the seal there isnt anything to keep the pedal up.

 

That is a possibility I guess but I was taught that a master will leak down under pedal pressure slowly. This does not once it pumps up it is fairly stable. I was also thinking it may also be a frozen caliper by rusting due to the high humidity in the area. Things rust fast here.

 

I would do a fluid flush and bleed well. My past experience is that the air is always in the rear. Can't tell you why, but I've had to bleed twice now in the years I have owned mine. James

 

X2 on the bleeding, had it happen with all 3 of my Xfires ( the convertible only had 6000 miles on it when it happened, so I don't suspect anything is wrong with the master cylinder)...in this last case I replaced the flexible lines with stainless, as they are getting old now.
It appears to be due to the storage, but I don't know why. All three of mine were stored over the winter when it happened.....two in Texas and this last time in S Mississippi
I would bleed them and go from there.............