I have an 87 and I recently upgraded to the bigger brake booster ($100 brake upgrade). I also have new loaded calipers on all corners with working ebrake and rears properly adjusted. The stopping power is great, and I don't race so I have no need for more efficient brake cooling, ie. vented or larger disk upgrades. The problem comes when comparing my brakes to a modern car, where modern brakes are instantaneous, mine seem to take a moment before they have full stopping power, even when slamming on the brakes. I thought it was vacuum booster related so i made a vacuum canister from a soup can and one way valve and it definitely helped with brake feel, but not the substantial difference I was looking for. Any thoughts? are all fiero brakes like this. Thanks

How are your brake lines? Still have old rubber lines?

I recently replaced all the lines on my car, and redid the rubber lines with stainless ones. The difference is quite noticeable. If you have old rubber lines they can give you poor brakes.

Xanth is correctomundo it only takes one weak line to effect the whole brake system Im betting your weakest line is on the front,,,have a friend press th brake pedal whileyou observe the brake lines for swelling if you eyeball ANY replace as soon as possible
most times you an not see the small movement
clean fittings and joints and place a small amount of baby powder (I love to powder my babies bottom) on them if in doubt about miniscule leak
a soup can?? a booster should apply massive force ? is there a vacuum leak..
you should be able to match the stopping power of the 88 fiero which will stop just like the new cars

I should add you don't need to get the stainless lines like I did. If your rubber lines are bad you can just get new rubber ones and you should notice a difference.

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Ok so i will deff check my lines

bleed the brakes for a while, get some extra fluid. ive found that you ahve to leave the line open for a while and do a good gravity bleeding. this will remove the dead spot youre feeling. also lube the slider pins lots, if they get stuck the braking force will diminish.

Well i think i figured it out. I am pretty sure it is my brake booster. It holds a vacuum perfect after the car is off so i never suspected it. However, if the car is off and I hit the brake it leaks all the vacuum out as the brake depresses. That is why it feels like it has to build vacuum, because it does have to build a vacuum. When the car is running and i press the brakes it leaks out most the vacuum and then rapidly builds to assist. does this make sense or am i crazy.

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quote Originally posted by LZeppelin513: Well i think i figured it out. I am pretty sure it is my brake booster. It holds a vacuum perfect after the car is off so i never suspected it. However, if the car is off and I hit the brake it leaks all the vacuum out as the brake depresses. That is why it feels like it has to build vacuum, because it does have to build a vacuum. When the car is running and i press the brakes it leaks out most the vacuum and then rapidly builds to assist. does this make sense or am i crazy.

That's actually how a booster is SUPPOSED to work. When you aren't wanting boost, the booster lets engine vacuum suck on both sides of the diaphragm. When you step on the pedal, there is a spring loaded valve in the booster that opens the "close to you" side to atmosphere, so that there is more pressure behind the diaphragm than in front of it, pushing it forward (against the master cylinder piston, providing assist) That behavior is normal.\

I do know what you mean about the "brake lag" sensation though. I have noticed that relative to a new car, it always feels like there is about a half second between sudden application of moderate pressure to the brake pedal and when the brakes feel like they finally start to "bite in".

I don't really know for sure what causes that lag sensation on older boosters, perhaps the sizing of the valve that lets atmosphere in is conservatively sized to prevent the brakes from being too "touchy"