Brake fluid low?

[Jon205587]

So I just got my car back from the shop after replacing the motor (old one overheated). The engine runs great and only has 50K miles. However, the red "brake fluid" indicator is on.

I checked the brake fluid tank and there seems to be a decent amount in there, but its not full. Should it be? And if so, can I just go to the store, buy some, and mix it in?

[Kraut.Burner]

well, if you can see a decent amount sloshing around inside, i say get some DOT4 and top it off.....

[strad]

Couple of possibilities:

1The shop forgot to reconnect the brake fluid warning harness
2The shop bled the clutch in the process of replacing the engine, and did not top off the fluid.
3: there is an actual leak somewhere.

In any case, put some more fluid in there -- enough to get it to the full line (dot 4) and keep monitoring it and see what happens. If it goes down again, start looking for a leak.

[RNeil]

Some cars demand that you fill it to the tippy top to keep the warning light off. Just do it.

[blackbimma]

Don't fill it. It should be between the min and max lines on the side of the resevoir. If its in there and the brake fluid light is still on then somethings wrong with the sensor.

As said earlier make sure you use DOT4 brake fluid if you have to add some.

[poohlikeshunny]

I have a similar problem as the OP....although without the motor replacement...

where are the places to look for leaks?

I got into my car after parking it and the brake medal got mushy. It would bit down initially, but then get spongy and fall to the floor. Definitely not as responsive as before. My fluid as of now is above the min but below the halfway point. Did yours do this too Jon205587?

Where are the key locations to look at to find a leak?

[strad]

Follow any line that has brake fluid in it, including clutch master and slave and the hose from the reservoir to the clutch master. Take the wheels off and look for evidence of brake fluid leakage around the caliper. Remove the caliper if necessary so you can see the area around the piston's rubber boot. Pull back the boot to see if there's any fluid hiding behind it (the piston has an o-ring seal that could be leaking). There's no one common place to look for a leak. It could be anywhere.

edit: if you don't find anything, be sure and look very carefully at the area below the master cylinder for leakage. It's possible that the internal seals on the mc are dumping fluid backwards into the booster or if you're luckier down the outside of the booster where you can see it.

[poohlikeshunny]

wow...ok...lots of places to go through...where is the clutch master and hose? Are the clutch master and brake master the same? (noob question...I know...=)

[Albertan]

Hydraulic clutch uses same reservoir as the brakes. The slave cylinder is on the left (drivers) side of the transmission. If it looks wet it could be leaking. Of course it could be leaking into the bell housing and you would only see leaking from the bottom of the bell housing. If brakes were good before the swap that is where I'd start looking. (That is if just filling up the fluid doesn't help.) Always a possibility that when the swap was done they disconnected the slave cylinder and let all the brake fluid drain out. (It would do that if the hose fitting was left disconnected.) Then they might have just filled the brake reservoir up, bled the slave and called it a day. You would end up with air in the brake lines and thus a brake warning and mushy brakes. Just have to bleed them. Start at right rear, left rear, right front and finish left front.

[poohlikeshunny]

ouch...how about if your car has been doing fine, then randomly just started giving you mushy brakes? no leaks so far near the master cylinder/firewall...i dont see any near the wheels...

[RNeil]

The level will go down as the brake pads wear. This is normal. If you get the low fluid warning, add fluid.

[poohlikeshunny]

so if the fluid does not go down otherwise, chances are there is no leak...so would a mushy brake pedal mean bad fluid or air in the system?

[Albertan]

If there is no leak, then you must have air in the system. Bleed it and you should be good.

[strad]

so if the fluid does not go down otherwise, chances are there is no leak...so would a mushy brake pedal mean bad fluid or air in the system?

yes and yes, or it could mean that there is a master cylinder internal problem (not leaking externally but leaking internally).

[poohlikeshunny]

ok...so here's where I'm at...I'm taking it in tonight to drop off at the shop to get bled and total flush for tomorrow...and should be good. If it is still mushy and there are no leaks, then I'm replacing the master brake cylinder.

Would the "Brake Fluid" light come on as well? The red light that actually says "Brake Fluid", and not the one with the symbol and the odd dotted lines that alert you when your fluid is low. I notice there are actually two different ones, and I am getting the red "Brake Fluid" indicator.