okay guys, ive got a randomly flickering warning light, ive ignored it for a fair while now, but I guess its time to sort it out before I get stranded somewhere.

its popped up once before when my alternator wire broke, easy fix, and that's solid now so I doubt its that.

are there any problem areas where this could be affected? dodgy earths somewhere in engine bay maybe? potential watertraps? any help is appreciated

cheers guys! seannaayy

Which warning light is it? 300s don't have a generic warning light. If it is the (!) that is the brake fluid reservoir level sensor. I think the oil pressure warning light is an engine symbol. The battery light comes on when the voltage is low, if it is on whilst the engine is running the alternator is not charging.

awesome, sorry mate lack of decent info haha but yeah its the (!) symbol, so low brake fluid? brilliant cheers mate

seannaayy

There is a level switch in the brake fluid reservoir, more likely than not to be a dodgy connection/switch, but definitely worth checking!

Doesn't that also warn for low brake pressure, EG, leaking vac pipe?

Not unless it related to low fluid level

when I roll downhill, my ! Light comes on after about a minute, indicating no more power-brakes.

If not a wiring or fluid level issue, its too-low brake pressure. Eg leaking vac pipe/brake servo.

Question: does braking ever involve pulling on the steering wheel/is there a lot of pedal pressure required?

Maybe there isn't enough vacuum from the engine if you're 'free-wheeling' down hill Aaaaggghhhh otherwise it'll be the leaky rubber seal in the servo casing?? Fluid level ;-? The brakes were always pretty sharp.

Doesn't make much sense, the light is for low fluid and would make sense if the cars attitude changes. Also possibly a bad contact. Pulling on the steering indicates uneven braking. So maybe 2 faults.

nah, I'll show you the brake pressure thing by video (while stationary).

I do roll along; I roll a lot of the time like oldskool taxi driver.

And I mean like grabbing the steering wheel to help you push on the brakes; meant, kindof jokingly 'is more brake pedal pressure required than usual'

OK, so you go into neutral and 'free-wheel' for a bit so tick-over will be well-low. Then brake a few times and the brake warning light starts to come on and the brake pedal goes hard?? It sounds like its not getting enough vacuum from the inlet manifold due to tick-over being slow. Also, maybe the brake pedal is not returning to its correct height - I had that once due to the servo sticking. A temporary fix for that was to put my foot under the pedal after braking and pull it back. That was a different car though. Is the sender in the reservoir getting an air-bubble or something? Bulbs are ready to send up to you.

A common problem is the vaccum pipe going to the servo, it can get soft and collapse under vaccum, or can go hard and leak at the joints, 1 way valve can go faulty but rare. Again nothing to do with the warning light, which would more likely be linked to a soft pedal, but the warning is a just a warning it doesn't mean the brakes will definately not work properly, so if the light is coming on check the level and if its OK, then the sensor is probably fault and not a brake fault.

A hard pedal is either a stuck caliper or lack of servo assistance. The 300 brakes are pretty good so braking should not be difficult.

Other problems can overheating or fading, where the pedal gets soft and the brakes don't work well. There are various causes, but the brakes are fundamentally limited in the amount of heat they can dissipate and withstand, everything needs to be the best for this to be minimised, new fluid , new disks pads etc

Ride_on wrote:The MY80> 300 brakes are pretty good so braking should not be difficult.

FTFY. The pre MY80 ones are quite shite

Engine off, ignition on. Rolling. After a few uses of the brakes you run out of servo pressure and warning light comes on.

Indeed the vacuum assistance will go without the engine, however again I will say the warning light has nothing to do with this, it might be part of the self test when turning the ignition off/on but I don't remember how this works.

The brake warning light is a fluid level sensor only, there is no pressure sensor / switch.

I'll just qualify that by say 'for manuals', I'm not sure what goes on with autos.