Low brake fluid

[brenglen]

2006 Grand Prix Base

I had recently replaced my rear brakes 2 weeks ago. Last week I got the "Low brake fluid" warning and I refilled the reservoir. Yesterday my "Low brake fluid" warning came on again however I went to go check the reservoir and the fluid was still at the fill line. Also, when I hit the brakes hard then the warning light goes off.

Note: In the middle of replacing my Rear brakes, I realized I needed a GM tool to retract the caliper piston however the auto stores were closed when I did it so I used needlenose plyers instead and it worked. Could had I caused a rear leak?

So what do you think? Do I have a brake line leak? or do you think it's a computer malfunction?

Thanks.

 

[Scottydoggs]

theres a sensor in the master cylinder, maybe its dirty.

if the master is still full, there is no leak.

 

[penright]

My first question is why did you have to add brake fluid in the first place. It is a closed system. Once you replaced the pads the level should have returned on it's own. The car I sold last night at 239,000 had countless pads over it's 11 years I own it and never added a drop of fluid. Nor have I in my other GP, lots of pads but the fluid always returned. The only time I added was on a 97 PowerStroke, and I replaced the calipers, so of course I had to bleed them.

Did you have to bleed them? In old days there was a switch in the proportion valve and sometimes when bled either the front or back it would be out of whack and you had to bleed the other end. With todays computers, not sure if this is still an issue?

One other thought, in addition to what Scottydoggs mention, the usual disclaimer of a loose or shorted wire.

 

[brenglen]

My first question is why did you have to add brake fluid in the first place. It is a closed system. Once you replaced the pads the level should have returned on it's own. The car I sold last night at 239,000 had countless pads over it's 11 years I own it and never added a drop of fluid. Nor have I in my other GP, lots of pads but the fluid always returned. The only time I added was on a 97 PowerStroke, and I replaced the calipers, so of course I had to bleed them.

Did you have to bleed them? In old days there was a switch in the proportion valve and sometimes when bled either the front or back it would be out of whack and you had to bleed the other end. With todays computers, not sure if this is still an issue?

One other thought, in addition to what Scottydoggs mention, the usual disclaimer of a loose or shorted wire.

I've never had to add brake fluid either however a week after replacing my rear brake pads, my low brake fluid light came on and I saw that the fluid was not at the "Full" line. So I filled it up to the full line and the warning light went off. A week later the Warning light came back on but there is still brake fluid but not exactly at the full line.

 

[brenglen]

theres a sensor in the master cylinder, maybe its dirty.

if the master is still full, there is no leak.

Where is the sensor located? on the cap? or is it the wire?

Here's what happened, I refilled it 3 weeks ago to the max line. Today the brake and low brake fluid light came on, I checked the master cylinder and there was still fluid in there. Although, it wasn't at the max line, it was almost leveled in the middle of the cylinder. I have checked in and around the wheels, I didn't find any fluid leaks anywhere. I don't believe there are any air bubbles in the brake lines cause I pumped it after changing the rear pads. Also, when I brake real hard the warning lights go off. Wouldn't there be close little to no fluid at all to have the warning light go off?

 

[Scottydoggs]

that sensor is on the side of the master reservoir. where that wire leads to. inside you can try to clean it with a paper towel or your finger. or it could be bad.

if i was you id bleed the brakes, fill it up, and if it drops again keep looking for a leak. have someone pump the brakes parked, while you look for a leak, if its small, the line will look wet.