I recently had the front rotors and pads on a 2000 Grand am SE. when I went to pump the brakes with the car off, the pedal became firm, then when I turned the car on, the pedal became spongy and unresponsive. Took it back to the mechanic a few days later, they said they would bleed the brakes, yet the pedal is still spongy, Master cylinder is fine, worked perfectly before the pads/rotors change. Could this be perhaps that they did not do a full system brake bleed?? PLEASE help, winter is coming and i want to have good brakes for the snow!! I heard maybe the brake pads just need to be worn in, if this is true, how long will it take for my brakes to go back to normal? Also wondering how much it could cost if i take it to someone to bleed the entire system and do nothing else? thanks2000 Grand Am Brake Issues Spongy?!?
Wow, I'm seeing some really incorrect information in the answers to this question.
The brake hydraulics are separate from the brake friction materials. The hydraulics must never have any type of air introduced into their system or a spongy or poor pedal, if any at all, may result. However, the only required disturbance to the hydraulic system when replacing pads is to retract the pistons back into the caliper to allow for the thickness of the new brake pads. This does not require opening the bleeder valve or disconnecting any hydraulics at all. So, stating that the system must be bled when replacing pads is incorrect. The only reason for it to be bled is because the system was opened and may have possibly allowed air to enter. So, if the shop removed the caliper from the brake hose or opened the bleeder valve, then they should be bled. Otherwise, it is not a requirement.
Next we go to the power booster. The booster uses engine vacuum to give an easier pedal to push. If the booster is bad, or if the vacuum line to it from the engine is bad or has a problem, it will definitely not give you a spongy pedal, it will give a very stiff and hard pedal, just like you felt when you push the pedal down a couple of times with the engine off. You lose the assist, therefore resulting in a hard pedal, not a spongy pedal.
New brakes may often feel different from the ones replaced. Correctly stated by Thomas E., the new pads need to %26quot;burnish%26quot; or seat themselves to the rotors. Once this has happened, the feel of the pedal normally improves. While the new pads and rotors are mating their surfaces, you must push the brake pedal harder to achieve the same friction on the parts as you use to, and the pedal feels spongier. I do disagree that the extra 10mm gives springiness or sponginess. Pads are very hard and do not %26quot;give%26quot; or compress at all.
Another thing to look at is the adjustment of the rear drum brake shoes. Although they may not have been touched by this shop, the combination of the rear brakes being out of adjustment and the new friction parts still breaking in may be giving you the sponginess you are feeling. When the shoes are out of adjustment, the brake pedal must move further to engage the rear brake shoes based off the combination valve regulating pressure to the front brakes before the rear brakes are engaged.
I have found success on the midsize GM vehicles with 4wheel ABS by cycling the ABS pump valves and solenoids and using the proper full system bleed procedure, not just a quick bleed at the wheels. Cycling the solenoids and valves requires a scanner capable of accessing and performing these functions. The dealer and a quality repair shop will have this scanner, but expect to pay $100 or so for this complete system bleeding service due to the complexity and tools required.
I didnt want to confuse you before when talking about opening the hydraulic system when doing a brake job. Although it is not necessary or required to do this or bleed the system when done, it is highly recommended to incorporate a specific method for retracting the pistons into the calipers that requires opening the bleeder valve on the caliper as the pistons are retracted. This allows the old dirty brake fluid to exit the system instead of being forced back up the lines against any check valves or where moisture in the fluid can corrode expensive ABS components. Since you should change your brake fluid every couple years anyway, this would be any ideal time to do this. Read the article at diynetwork, it shows pictures and states my opinion eloquently.
A good mechanic may still have to go through a full inspection and various types of bleeding operations including using the scan tool to try to correct this issue. It should not be boiled down to thinking a technician is poor if it takes him more than a half hour to do this. Especially if he did the brake job by the books and is now trying to hunt down what the heck happened and why you are unsatisfied.
By the way, have you heard of ASE Certification? An ASE certified Brake Technician is tested on situations like this and would know that a bad line to the booster would give a hard pedal, not a soft pedal, and would also be tested on knowing that some vehicles may have to have their pumps cycled. Find out if your shop is using an ASE certified brake technician. Experience doesnt count if it is bad experience.2000 Grand Am Brake Issues Spongy?!?
If pads and rotors were all that was done on the front then there's no need to bleed the system, if they took calipers off then a bleed would be needed. I'd take it back to them and advise they diagnose the system correctly.2000 Grand Am Brake Issues Spongy?!?
Bring it back to the same shop since they're the ones that did the job. They may hook you up for free since you're unhappy with their service. You don't need to bleed out the entire system though, just bleed out any air that may be trapped. Most of the time, a correctly done brake job needs no bleeding at all, if only doing the rotors and pads.2000 Grand Am Brake Issues Spongy?!?
When you pump the brakes %26quot;with the car off%26quot; all the vacuum power assist is used up after about 3 pumps. that is why the pedal got hard because there is no more power assist. it is normal for new brakes to feel more flexible than worn out brakes. you have an extra 10 mm of pad material that will compress some. also the pads may not be bedded to the discs yet adding a little more springiness to the system. most disc and pad changes won't even require bleeding the brakes. if no air is introduced into the system there should be no reason to bleed the brakes. Usually (?) the mechanic should just suck some fluid out of the reservoir and then pry back the pistons which pushes fluid back into the master cylinder reservoir. you don't say if it STOPS ok. if it stops ok - drive it several 100 miles and i think the pedal will start to feel firmer.2000 Grand Am Brake Issues Spongy?!?
When I replace brake pads I pop the top of the reservoir beforehand, and after the new pads are on, I bleed the brakes ALWAYS. It is indeed necessary to bleed the brakes after changing brake pads.
I think there are two possibilities. The first is that the power brake booster is bad (most likely)... that's the thing on the firewall that looks like two serving bowls put lip-to-lip, or less likely the brake system still needs bleeding.
The brake booster uses vacuum from the engine to operate. If the vacuum line to the booster is leaking or the booster developed a leak, then you will certainly notice the exact symptoms you mentioned.
ALSO DO NOT take the car back to those bozos. A REAL mechanic should be able to spot that problem in 30 seconds.
