brake light?

[BerniniCaCO3]

Hi!

My sister called me the other day: her brake light is on, on her 1989 colony park.
Of course, she checked, the parking brake is not applied.

I know that this occurs in two scenarios:
1) parking brake switch
2) pressure differential detected between the two sides of the reservoir on the master cylinder

So!
I'm thinking, since she says the car stops fine as it always did, it's most likely the parking brake switch gone bad, possibly, the rear brake lines (since the fronts do most of the braking anyway, it wouldn't be as noticeable-- leaky front brakes you wouldn't miss!).

Now, if it's the parking brake, then if you put the car into the "on" position (key in position II), does the brake light come on with the parking brake at that point if you apply it?
So if the light is on when you're in park, foot off the brake, then it can only be the parking brake switch?

If you just disconnect the switch, I assume the light will go off (unless of course, it really is a problem at the master cylinder)?


Just checking!
thanks!
-Bernard

[gadget73]

89 should have a level sensor in the cap. Make sure the brake fluid level is not low. Also suggest she pull up on the parking brake pedal a bit while pulling the release out to see if that doesn't fix it.

[marquisman]

you could also try and unplug the pressure switch in the brake pop valve. i have had them stick on me before, even when the brakes felt good.

[sly]

and if the brake fluid level is low... might be time to check the brake pads/shoes/calipers/cylinders.

[GM_Guy]

If its like mine, any fluid level below the full mark has the light come on & off. Sometimes the float sticks also, so have her tap the side of the reservoir with her finger if the fluid is at level.

Alex.

[BerniniCaCO3]

Hah, she *finally* looks at it a month later... what have I been teaching my little sister about car maintenance?!?

The fluid was low, "like an inch". (the car is in iowa, I'm in Baltimore, so this is all remote advice).

We did her brakes here in Baltimore last Winter: new front calipers, hoses, pads, full flush. Examined the rear, no faults found.
So for it to go so much lower, in this period of time, unless she's a manic braker (rhetorical), there's a leak...

She'll have it checked out next week. I'm thinking wheel cylinders, or hoping.
The brake lines looked solid when we looked at it. If there's a pinhole leak in a line, could it leak very slowly? How much would one expect to pay for a proper patch (I have not worked with brake lines, I just remember hearing that there's a right fitting and an illegal fitting).

[BerniniCaCO3]

tangential question.
The only reason she brought it in to a shop, which noticed the low fluid, was that she had lost all power assist all of a sudden.
The vacuum line going to the booster had come off.

I think they just put it back on.

Question... since there's no pressure there, did it just drop off?
Would the only explanation for dropping off, be that it's possibly dry and hardened, so it could slip off? A still soft and rubbery vacuum line will hold itself on; only if it's dried and shrunken I'm thinking could it come off like that.
Should she look at replacing that vac line, or at least, put a hose clamp on, so it can't happen again?

[gadget73]

rubber line probably stretched out or something. no big deal. replace it, or at least chop the last inch off and re-fit it.

[BerniniCaCO3]

there's no rubber in the rear, right?
I replaced both front hoses, although just because they're new doesn't rule out 100%

[Piece-it pete]

Rubber line from the metal lines on the body to the top of the diff. Good luck, I've spend a coupla hours fighting it and it still isn't changed. Rock's got about 5 million on closeout.

Pete

[85crownHPP]

you could also try and unplug the pressure switch in the brake pop valve. i have had them stick on me before, even when the brakes felt good.

there is no prop valve or pressure switch like the older ones 88+

[sly]

if it's the wheel cylinders in the rear brakes... the bearing seals need to be replaced too. Brake fluid tears those things up something fierce.

ask me how I know.

[gadget73]

There is a rear rubber line, goes from body to center of the rear axle. Nobody ever replaces that hose either.