Whats wrong with my brakes, not enough braking power

[vr4gasmtt]

The brake pads on my car has been replaced about 6 months ago, and even though I don't drive my car that much, the brakes have always been... terrible.

I always have to slow down early and brake. The brakes are pretty bad, I just don't get if the brake pads were replaced shouldn't the car be stopping a little better? My parents Kia has better stopping power than my GSX.

It also makes a small squeaking sound in the rear area when I brake.

What should I be looking for? , I've never driven in another GSX before, so I have no idea what its supposed to be braking like, but I have been in a GST and it braked alot better than my GSX.

 

[coreyr]

have you bled the brake lines? maybe the MC is getting weak?

im sure with equivalent brakes the GST will stop better due to weight but it sounds like your brakes are pretty weak. try bleeding the lines. alot of times cheap pads will be a noticeable difference im stoping over a quality set.

 

[xRichieRich07x]

Check your rotors. Are they rusted pretty badly or still in good shape? Rotors alone wouldn't cause that noticeable of loss of braking however not bad idea to check. Did you have a mechanic "install" the brakes last time? If so check the brakes yourself. He might not even replaced them. You can't trust mechanics you don't know. Also trying bleeding them like corey said.

 

[IslandTSI]

Bleed the brake system. Then go from there

 

[Karma]

Bleed the brake system. Then go from there

That's what I was going to suggest. Also, ensure that the vacuum line going from your intake anifold to your brake booster is connected, and free of kinks or holes. OH! and make sure the fluid is topped up

 

[antlip]

Could be air in the brake line. Check for kinked brake lines. Maybe you twist them up while doing the brakes. Check the fluid. If everything is hooked up right and all parts in good working order then it could be your "power brake booster". Here is where it is located. http://auto.howstuffworks.com/power-brake.htm

 

[1GawdJunkie]

I had a similar issue where the brakes just did not feel right, the rear piston on the passenger side locked up.

easy things to do.

1. Inspect brake lines.

2. bleed the system. the pattern is passenger rear, driver front, driver rear then passenger front.

3. make sure the caliper pistons are not siezed. fronts push in, rear are threaded and twist/turn in (SEE SERVICE MANUAL)

4. hose from intake mani. to brake booster has a check valve in it and may need to be replaced. Also check that nipple on the intake manifold to make sure it is not obstructed. ( the previouse owner of my car had a pvc valve in that spot and the brakes worked like sh!t.)

Good luck

 

[wret]

Let's get some things straight first.

New pads (of similar material) will not improve your braking performance. Worn pads work 100% until the friction material is gone.

fronts push in, rear are threaded and twist/turn in (SEE SERVICE MANUAL)

Not in a 2g service manual.

Bleeding the brakes will do no good unless there is air in the system, in which case the pedal would feel mushy. Problems with the booster or vacuum would make the pedal ultra firm.

With larger front rotors and calipers, his GSX should stop every bit as good as a GST.

Braking, in normal street driving conditions, has more to do with the tires than the brakes. Your brakes should grip enough to lock the wheels (or engage the ABS) on dry pavement. If they can do this, you can’t expect any better braking unless you change to a grippier tire. After hard, continuous or repeated braking, the pads will heat up and lose friction. High performance pads maintain more friction at higher temperatures.

Can you brake hard enough to lock the wheels?
After some sustained medium to hard braking, feel your wheels. Are both fronts about the same temperature, and both rears?

 

[1GawdJunkie]

Thanks Wret,

The reason I had said "see service manual" was only because I was not sure if it was the same as the 1g.

 

[toybreaker]

This could be an issue with your brake booster and/or vacum check valve.

If you sit in the car, engine off, and push the brake pedal 10 times slowly, what happens?

A correctly functioning booster and check valve will provide enough reserve vacum for several engine off brake applications. After that, the pedal will get hard, and the travel will decrease.

Now, with the brake pedal depressed, start the engine. The pedal should drop some, as the booster starts to see vacum again.

Not having the booster assisting you will make for a hard pedal, and it will "seem" like you're not slowing down very much for the level of brake pedal pressure.

Also,

Can you drive the car a few miles and exersise the brakes gently a few times and then check all four corners to see if they're all getting some heat in them? Just feel the calipers and see if they're getting warm. This will eliminate sticking calipers.

You can also see the rust on the rotor is not removed by a sticking caliper, whereas a corner that's working will clean up pretty quickly, with a few gentle brake applications.

Please, use some common sense and don't burn your hand. Brakes get hot quickly.

Good luck, and let us know what you find!

 

[xveganxcowboyx]

If I remember right edmunds lists the 60-0 stopping distance of the GST at 122ft and the GSX at 123ft. In otherwords, nearly identical. Not that these numbers are accurate, but as benchmarks go you should be about the same as a GST.

Does the pedal pressure change at all if you tap the brakes and then apply them? I know mine have always felt soft and won't lock up the car on first depression, but if I tap them and then apply I get much harder braking. Pretty sure the master is bleeding back into itself a bit.

 

[Gregory]

what he said... have you ever driven a car w/o power brakes? how does that compare?

 

[antlip]

This could be an issue with your brake booster and/or vacum check valve.

If you sit in the car, engine off, and push the brake pedal 10 times slowly, what happens?

A correctly functioning booster and check valve will provide enough reserve vacum for several engine off brake applications. After that, the pedal will get hard, and the travel will decrease.

Now, with the brake pedal depressed, start the engine. The pedal should drop some, as the booster starts to see vacum again.

Not having the booster assisting you will make for a hard pedal, and it will "seem" like you're not slowing down very much for the level of brake pedal pressure.

Also,

Can you drive the car a few miles and exersise the brakes gently a few times and then check all four corners to see if they're all getting some heat in them? Just feel the calipers and see if they're getting warm. This will eliminate sticking calipers.

You can also see the rust on the rotor is not removed by a sticking caliper, whereas a corner that's working will clean up pretty quickly, with a few gentle brake applications.

Please, use some common sense and don't burn your hand. Brakes get hot quickly.

Good luck, and let us know what you find!

My friends 95 gsx had a bad brake booster and when he hit the brake peddle the peddle almost hit the floor and the car slowed like we had no brakes. A bad brake boost in his car sounds exactly like what was described. The shop put a new brake boost into it and the brakes worked like new again.

I could be wrong but the shop showed him a recipt for the brake booster and said they replaced it. They could of fixed something else and charged him for the brake booster, but under warrenty why do that?

 

[Karma]

They might have been telling him to rebuild the master cylinder, I had one apart a few months ago and there are quite a few essential seals and valves

 

[vr4gasmtt]

Whoa, lots of replies, thanks alot

Well I haven't been driving my car that much, but I'm checking up on it today, I'll let you guys know, but the brake pedal just feels firm overall. It really sucks when your just cruising going 30mph and almost rear ending a car because your brakes suck.

My rotors are kind of rusted, anyways I'll check everything you guys said to check, I might end up bleeding the brakes tomorrows since I'm still new to bleeding brakes.

 

[xveganxcowboyx]

If your pedal feels firm you probably don't need to bleed your brakes. If there is air in the lines the pedal will feel soft or squishy.

With a firm pedal feel i would re-read the posts above about the brake booster. Test that out. If you search around for brake problems you can find the whole procedure for testing a brake booster, but toybreaker covered the basics above.

 

[MitsGSX]

I'm having a similar problum with my '97 GSX. The pedel feels completly normal, pump it with the engine off and it gets hard, and I just bled the lines to all 4 corners. But when driving I can stand on them, everything feels o.k. (I've driven without power brakes and mine deffinitly has power) But pedel goes to floor and won't even squeal tires. Good inital bite also, just not the power I would expect.

 

[gdmbat85]

Most people dont know this or realize this, but another possible cause for soft brakes could be the brake lines. When they get worn out, or if you do a brake job and let the calipers hang by the lines, they can develope a weak spot in the line. When you step on the brakes upto 700psi goes through those lines and a weak spot in the lines could allow them to bludge; resulting in less pressure making it to the piston. Very similar to tires with buldges on the sides from hard turning.

I do brakes alot on many cars so maybe this might help.

Hard brakes:

-brake booster issue
-seised pistons

Soft brakes:

- air in lines
- old/contaminated fluid
- worn out pads
- master cylinder loosing pressure
- worn brake lines