GenVibe - Community for Pontiac Vibe Enthusiasts

Hi
I have a 2010 Vibe. I redid the driver side rear brake parts(all). When I went to bleed the brake line, I topped off the fluid in the master brake cylinder. After pumping the brake pedal a few times I would again top up the master brake cylinder. The level in the the master brake cylinder seems to go down way more that what I was getting in the discharge hose on the rear brake. There did not appear to be any signs of any leaks at either the master brake cylinder or abs. So I placed a large piece of cardboard under the car for the night. Next morning there was a large puddle of brake fluid on the cardboard. I took out my small camera a took several pictures of the area in question. Nothing to indicate where the oil was coming from. All the brake fluid lines to master brake cylinder and abs were clean and fluid free.
Any suggestions?

Get an assistant to pump the pedal and safely get under the car to look, using eye protection. Check the flex line at the caliper. What general area is the stain on the cardboard?

The oil stain appears to be under the master brake cylinder. But when I put my hand down there it’s free of oil. It seems that it could be coming from the oil lines that go to the back of the car. That seems really odd as I don’t believe there are any splices/fittings there.
I guess the idea that it’s a cracked brake fluid line may be possible, but I can’t find it.

First question, is this a base model, or GT, or AWD? The rear brake systems are different on these models. Next, why just the drivers side? Only replacing brakes on one side can cause the car to pull to one side or the other. Is it brake fluid or oil? You said oil on the card board. Did you spill brake fluid when you were adding to the master cylinder? When you say (all) parts, what does that mean? Did you replace, or rebuild the caliper? Where do you live? It could be rusted brake line. How does the brake pedal feel when you push it down and hold it? Soft and mushy, or hard and firm? As you hold the pedal down, does it stay at that level, or slowly goes lower to the floor? Is the master cylinder leaking out the back and into the power brake booster?

Brake are very, very important safety item as you not only endanger yourself, but everyone else on the road too. Do not drive car until it is fixed.

Posting the same question in more then one location on the forum is never a good thing, so expect to see one of your post removed.

andrewclaus wrote: ↑Wed Sep 02, 2026 5:23 am Get an assistant to pump the pedal and safely get under the car to look, using eye protection. Check the flex line at the caliper. What general area is the stain on the cardboard?

Did you ever try this?

Hi. When you say you changed all the rear driver side bake parts what are all the parts you change specifically?

Since you are now having a problem after changing some brake parts its likely something that didn't go right during the part swap if the leaking brake fluid wasnt happening before. This may provide some clues and point you in the right direction. Did all your new brake parts go together okay?
Maybe you got a bad rear caliper or sometging with defective seal. Though l, I've never heard of that happening. Maybe it's possible. Who knows?