Low Brake Fluid

[Puffster]

A bit of exuberant b-road nsl driving and a red warning sign came up - Low Brake Fluid - stop safely. Plenty of brake, no sponginess and the sign goes off when I press the brake on! I stopped and bought some fluid but it seemed nearly at the max anyway. I stopped mid-journey (4.5 hours, 275 miles) to check but no fluid loss. Braking efficiency is just fine. I know, according to the last service a month ago, front pads are getting low.

So any experience on what may be the issue here? I think that I may have braking round a corner and got a bit of air in the system, so might need bleeding. I've ordered some new pads and will try fitting them & see if it goes off. Anyway, any help or pointers appreciated.

[cheshired5]

Has the warning come back since you topped up the fluid?

[Puffster]

Originally Posted by cheshired5

Has the warning come back since you topped up the fluid?

Yes, which makes me think there's air in the system somewhere near the sensor.

I'm thinking maybe new pads will force the fluid back up into the reservoir and the air out at the same time.

[Clan]

Originally Posted by Puffster

A bit of exuberant b-road nsl driving and a red warning sign came up - Low Brake Fluid - stop safely. Plenty of brake, no sponginess and the sign goes off when I press the brake on! I stopped and bought some fluid but it seemed nearly at the max anyway. I stopped mid-journey (4.5 hours, 275 miles) to check but no fluid loss. Braking efficiency is just fine. I know, according to the last service a month ago, front pads are getting low.

So any experience on what may be the issue here? I think that I may have braking round a corner and got a bit of air in the system, so might need bleeding. I've ordered some new pads and will try fitting them & see if it goes off. Anyway, any help or pointers appreciated.

it is nothing to do with the pads or air in the system , it is a simple float switch in the brake fluid reservoir , if the level is on MAX then don't worry about a thing , nothing necessary . we shall have to blame your hooligan driving :-)

[Puffster]

Originally Posted by Clan

it is nothing to do with the pads or air in the system , it is a simple float switch in the brake fluid reservoir , if the level is on MAX then don't worry about a thing , nothing necessary . we shall have to blame your hooligan driving :-)

but the bloody lights keep coming on and annoying me

[Ian21401]

Is it possible to access the float in the reservoir and give a bit of “foreplay” with a thin piece of dowel or similar. If that fails, disconnect the wire and revert to the old fashioned way by checking visibly.

[green van man]

I have known the float to spring a leak and take on brake fluid. These systems often use a magnetic switch, float full of fluid is less buoyant than when empty and so sinks closer to the magnetic switch which is in turn falsely triggered to give low level warning.

Just make sure you have plenty of absorbent material around the master cylinder when you remove the top as if the float has brake fluid in it you don't want it dribling over your paintwork.

Paul.

[Puffster]

OK - next stupid question - htf do I get at the fluid reservoir?

I have access to it to top up as necessary but its surrounded by a big black plastic cover. Remove the cover and then how easy would it be to change the float or reservoir?

[Tatsfield]

I had a Peugeot where the car would put up low brake fluid warnings which were false. The cause was a dodgy micro-switch on the hand brake which drove the ECU mad and it hadn't got an applicable warning so it complained about the brake fluid. This was a common fault and it makes me wonder if there is some other similar trifling problem with some sensor function connected to the brakes which triggers an erroneous warning. Perhaps VIDA would find it.

[Puffster]

A bit more research shows that it might be a low pad indicator on Police spec cars. So I've got the new pads (no indicator visible?), will fit and see what we get.