24 replies to this topic

[felixy69]

my question is that 

if one of the electrical terminal is broken and is not connected....will it effect the performance of the braking system ?

 

[Alex_B]

No, the terminals connect to the brake fluid warning lamp on the dash panel, the only issue is you need a functioning low fluid warning circuit to pass your Mot

[felixy69]

No, the terminals connect to the brake fluid warning lamp on the dash panel, the only issue is you need a functioning low fluid warning circuit to pass your Mot

 

the switch still lights up when i press on it so i guess only one wire connected on the cap is alright :)

thx for ur help

[cal844]

It will light up! If it light whilst driving you have problems

[tiger99]

No, it is NOT all right. Pressing the switch only tests the bulb, not the brake system. The low fluid level switch on the master cylinder cap is a legal requirement and you commit a Construction & Use Regs offence if you drive without it working. Also, and far more seriously, you get NO WARNING OF LOW FLUID LEVEL. In that condition, if you have an accident due to brake failure, I can't imagine that your insurance company will be paying out, and worse, someone could be killed.

 

It needs to be fixed AT ONCE.

Edited by tiger99, 24 March 2014 - 09:44 AM.

[The Matt]

It does need fixing, yes. The cap needs replacing. In the meantime, checks of your brake fluid level may help reduce the risk of impending doom.

My Mini doesn't have a low-fluid-level warning light to malfunction. You should consider yourself lucky! ;)

[sonikk4]

No, it is NOT all right. Pressing the switch only tests the bulb, not the brake system. The low fluid level switch on the master cylinder cap is a legal requirement and you commit a Construction & Use Regs offence if you drive without it working. Also, and far more seriously, you get NO WARNING OF LOW FLUID LEVEL. In that condition, if you have an accident due to brake failure, I can't imagine that your insurance company will be paying out, and worse, someone could be killed.
 
It needs to be fixed AT ONCE.

Right there is no need for the dramatic answer. First thing here is no it will not affect your braking system at all. Secondly the OP is not in this country he is in Canada so no MOT requirement there then.

Now a lot of us older mini owners who do not have this switch have to resort to regular checks of things like oil levels etc so not the end of the world.

Now I would certainly consider replacing the cap for a serviceable item as and when you can get one. In the meanwhile just check the fluid level on a regular basis.

If your car was in the UK then it would need to be sorted for the MOT. As for car regs and tests in Canada I have no idea of their particular requirements.

Edited by Dan, 24 March 2014 - 03:35 PM.
Fixed quote.

[cal844]

it wouldnt need to be fixed for the MOT, if its not there they cant fail it!

[Ethel]

They can if it's supposed to be there, according to the age of the car.

 

It's hardly worth arguing over though, it's a straight forward fix, dismantle the cap and fashion a new spade terminal if your location makes it hard to source a replacement.

[Dan]

it wouldnt need to be fixed for the MOT, if its not there they cant fail it!

Originally here I wrote something about the MOT not working in that fashion, agreeing with Ethel. But I actually think in the case of the low fluid lamp this really is the case. It can only outright fail if it's lit or inoperative, I'm not sure if they know which vehicles should or shouldn't have one. Still, not relevant here anyway.

Edited by Dan, 24 March 2014 - 03:59 PM.

[cal844]

true!

[Tamworthbay]

it wouldnt need to be fixed for the MOT, if its not there they cant fail it!

Originally here I wrote something about the MOT not working in that fashion, agreeing with Ethel. But I actually think in the case of the low fluid lamp this really is the case. It can only outright fail if it's lit or inoperative, I'm not sure if they know which vehicles should or shouldn't have one. Still, not relevant here anyway.

spot on. Mine went though the first two years I had it with no problem. It was only when looking at something else that I noticed the connector and switched back from the plain cap to the one it should of had.

[felixy69]

lol

i am from canada so no need for this item to be working.

thanks for the advice tho

[tiger99]

The sad thing about this warning circuit is that, although mandatory in the UK on cars registered after a certain date, the test switch does not test the warning system at all, only the bulb. Laws like this are invariably drafted by non-technical people, and they fail completely to understand the issues. You will note that the feed to the test switch is routed via one terminal on the master cylinder cap, which is why there are two wires on it, and when you operate the test switch, continuity of these two wires is proved. But what about the other switch terminal and its wiring, or the switch itself, the most common point of failure? That is only tested by pressing the small button, if one is fitted, on the master cylinder cap, or removing the cap (bad idea doing that regularly, as dirt will enter the system).

 

The fact is thet the thing which the test switch tests, the bulb, almost never fails, because it is only illuminated when the test switch is operated, and bulbs that are never used never fail. It also creates the delusion, as far as the average driver is concerned, that if they press the switch and the light comes on, the brakes are safe. Many unsafe conditions are not revealed in time by that warning light, even if the float switch in the master cylinder actually works.

 

The PDWA was a fer better way of detecting brake system faults, but unfortunately early examples were designed in accordance with the letter of the law, not its intent, by someone skilled in the design of hydraulic components but who had less than zero experience of safety analysis, and introduced very serious dormant failure modes. The later, bulkhead mounted one was safer, until it started to leak from around the switch. It was supposed to do that if an internal seal failed, but people fitted a copper washer to prevent the leakage, and promptly re-introduced the dormant failure mode which links both systems, so that when one fails, they are both gone.

 

Most modern cars are no better, by the way.Just because a computer is monitoring the switch does not suddenly remove its major failure mode.

 

None of this is rocket science, and is fully understood in every safty-critical industry, except, apparently car manufacturers, where they merely pay lip service to a law that is just plain wrong, while they could comply with it and yet design proper warning systems that actually work. Instead, they prefer to spend money on bits of chrome-plated frippery and gimmicks.

 

If you have a few spare hours and fancy making a brake warning light test system that actually works, I would suggest rigging up a small solenoid which pushes the test button in the middle of the master cylinder cap when you press the button.It will still comply with the law, and will actually fulfil the intended function. It could actually be a useful aftermarket accessory.

[Wise Old Elf]

Has anyone repaired one of these caps? I have one with a snapped terminal and was thinking of trying to take it apart.