Is the brake fluid reservoir cap supposed to breathe?

If I push down on it I can hear air go out and in, same if I press on the brake pedal.

Is it time for a new cap/gasket or is this normal?


Also, for what it's worth, I have all new pads (Wagner thermo quiet) and rotors, I can't lock the front wheels. Is that normal?

It's an 88 GT.

[This message has been edited by notsonic (edited 10-16-2015).]

I believe the "breathing" takes place between the rubber seal and the cap, not the rubber seal and the reservoir.

Although I don't want to, I lock up the front wheels on my Formula (with stock brakes) at autocross all the time. Does you brake pedal feel mushy at all?

I can also lock mine up.
Do a fair amount of autocrossing to on stock brakes but with HP plus pads.
Have an adjustable proportioning valve as well to allow restricting the rears.
If you are having problems, start with the calipers to see if they are functioning and not stuck or bound up.
The stock proportioning valve could also be an obstacle.
Are all of the lines bled?
Did you bead in the pads when you installed them?

IMO, just a few things to check

"Is the brake fluid reservoir cap supposed to breathe?"
Yes. Clutch cap works same way.
The rubber gets suck down as fluid level drops. This is to keep air out of the reservoir.
The hard plastic/metal cap has a groove molded in or a hole to vent air to allow this to work.

"I can't lock the front wheels. Is that normal?"
Not on most cars w/o ABS.
Most cars brake design is setup so Rear lock is not allow most times.

Did you Clean the new rotors? Cleaning them is required because coated vegi grease stop rusting in storage.
If not... Clean rotors and coarse sand the pads to clear any glazing. Is best to take pads out and sand paper on wood or metal so you don't dig a hole.

Could be booster and/or vac line to it have problems.
Good booster and vacuum you can lockup most fronts w/ little pedal effort.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

Thanks for the info.

I defintiely cleaned the rotor surfaces. I've only got about 10 miles on these if that. I'll drive around more and bed em etc. to see if it gets any better. If not I guess I'll take em off and clean/sand.

I always assumed Fiero brakes were just terrible but I'm guessing it's my car now.

Yep. My 88 fronts lock up before the rears even think about it. I even posted a thread about it. (Turns out that that's a "feature" )
Somebody here used to sell adjustable proportioning valves, but he quit answering inquiries a long time ago.

quote Originally posted by notsonic: I always assumed Fiero brakes were just terrible but I'm guessing it's my car now.

The internet is good at pushing myths. Many myth to sell you whatever too... Like part to "fix" the "horrible Fiero bump steer problem" on 84-87 cars.

[This message has been edited by theogre (edited 10-17-2015).]