GenVibe - Community for Pontiac Vibe Enthusiasts

Hi, I have a 2004 Pontiac Vibe with all-wheel drive and abs. I have been fighting the brakes since I bought the car. The top half of the brake pedal is soft. Basically you kind of feel the brakes engage but the pedal keeps going to halfway down and then you get full braking power the rest of the way down. I plugged the master cylinder and the pedal was rock hard, I couldn't press it down at all.

I have been told conflicting things about the brake bleed procedure. I have been told you bleed it traditionally which I did multiple multiple times. I took the car to a gravel road and activated the ABS 20 times and then bled the brakes. The pedal got solid for maybe two miles , several eight or nine stops. Then it got soft at the top again. I was told that you do need a scan tool to properly bleed the brakes. After the car was parked for 2 weeks the first time I pushed on the brake pedal it went all the way to the floor. Then it got back to how it was working before. I finally caved in and took the car to a garage and said please bleed the brakes because I can't get them to bleed traditionally hopefully with a scan tool they will bleed properly. pick the car up, no change in the brakes. I went in to ask them the procedure they used, and I had told them the whole story, and basically they bled the brakes traditionally as well. Really upset that they did that and charged me money when I told him I already done it multiple times.

Ireally need to know from someone that really knows, can you just traditionally bleed these brakes, does it take a power bleeder, do you have to have a scan tool with the proper programming?

Am I missing something, could it be something other than air in the lines?

Could be a bad master cylinder.

Neither the 03 Matrix or 03 Vibe service manuals provide an ABS specific brake bleeding procedure. Doesn't mean there isn't one somewhere.

Do AWD Vibes have rear drum brakes? if so, a long shot, but if the rear drums have a lot of play in them, then perhaps the initial soft push on the brake pedal is spent taking up that slack. They're supposed to be self adjusting, but that might not be happening. On other cars I've owned, you could force adjustment by repeated braking in reverse, don't know if that applies to Vibes though. How much do you have to pull the parking/emergency brake to get it to grab?

SSizler wrote: ↑Fri Aug 07, 2020 4:35 am Could be a bad master cylinder.

I had tested the master cylinder by putting Teflon tape on two bolts and running them into the master cylinder ports. I could not budge the pedal at all once the ports were plugged. Doesn't this usually indicated good master cylinder?

I've flushed and replaced brake fluid on several older Japanese cars with ABS and never had a problem with traditional bleeding methods. Start with the rear and pump a few more times to flush out the extra fluid in the ABS unit. It got complicated with the Prius I owned, which needed Toyota's software to run an electric booster pump. It sounds like a few other cars have specific procedures too.

The rear drums are where I'd check, too. The self adjusters don't always work.

As others mentioned, check your brake pad wear, especially the shoes in the rear.

There is no specific bleed procedure for the Vibe. As always, the recommended is furthest away from master cylinder first, working to the closest.

If the fluid is old and discolored, you may need to bleed all 4 corners.

Less likely, you could try a simple swap of the check valve on the brake booster..That's what helps build the vacuum for braking. It's possible the brake booster is dying.

Go test drive a different Vibe at a local used dealership or someone selling one, and see if you have the same experience.

The rear brakes were just adjusted. I bled the master cylinder and then the brakes again. No change.

I was told to pull the vacuum line from the booster and use a zip tie like a dipstick to make sure there isn't any brake fluid present. I will try that soon and report back.

This information may help you with the troubleshooting of your brakes. Improper braking not only effects your safety but everyone else that is on the roads safety is effected too. If unsure about the brakes then have a professional repair them as the cost to life is to great to over look braking problems.

The following attachments are info from 2003 Matrix manual:

The master cylinder has a piston stopper bolt in it. This could effect the travel of the pedal if the wrong bolt was installed or the end of the bolt was sheared off. Was the master cylinder ever replaced? You may not know what was worked on or changed if the car had brake problems when you bought it.

Next attachments:

The brake actuator or the anti-lock actuator attachments. You may have a bad brake actuator that is effecting the brake pedal so attached is info about that. Pay attention to any info about how the brake actuator works and what it does.

Something that was not brought up was the brake hoses. Have you checked the brake hoses? A bad hose can make the pedal travel increase but will also cause the pedal to be mushy. Have someone pump the brakes while you hold on to each hose and feel if the hose is increasing in diameter when pressure is applied; the hoses should not change with pressure.