englandbrad

iTrader: (1)

I've just put my 3 door on the road after 4 years. Flew through the mot but have got a problem with the brakes if anyone can help.
The abs pump engauges when the ignition is turned on and continues to whine is this correct first of all or should in dis engauge like the fuel pump when it has pressurised?
The pedal is very firm and unresponsive with a vibration when pressed.
I've bleed both the rears and one front and the front pipes but unable to bleed the other fronts at the mo due to nipples all being previous broken, could it be this?
Is there a filter in the brake fluid res that could be sludged up due to standing?
Have been told that the black sphere attacted to the brake res requires oil and this again my be blocked.
Any help appreciated.

tabetha

The black sphere is a PRESSURE capsule, this is charged with pressure by the pump you hear running.
The pump should cut out once up to pressure, as there is a pressure switch that tells the abs ecu to cut the pump.
Normally they run for about 20-30 seconds, if they run continuously something is wrong.
I would try depleting the pressure by working the pedal say 20 times with the key out, then back in do this 3 times then leave for 10 minutes, this will normally sort it, but if not have a wiggle of the connectors, as may just be a dodgy joint.
The reason for leaving 10 mins is because the pumps can overheat otherwise.
I use a gunsons eezibleed to do the rears, by turning to position 1 and disconnecting the pump so it does not build pressure, they then bleed as normal.
The reason why pos 1 is needed is because it opens the abs valve block allowing fluid to flow, these valves close when switched off.
tabetha

Char1ie

iTrader: (6)

That's funny, I am trying to cure the same problem and I am about to replace my master cylinder assembly. Tabetha, do you know what turns the pump off when it has reached the correct pressure? Is there anything external to the brake master cylinder? a relay?



As a test, disconnect the three brake lines from the engine side of the master cylinder assembly then press the brake pedal. Mine has failed and the result is that the middle nozzle is blocked. Do you get fluid spraying out of each nozzle? I think the middle nozzle is for the back and the other two are front left and right brakes.

I am concerned that once I replace the MC I still have to sus out why it wouldn't switch off. I'll report back tonight once I have done it.


Charlie

COLEYST200

iTrader: (3)

the middle pipe is the rear brake ( Char1ie )

Char1ie

iTrader: (6)

Thanks. I thought as much. So can anyone tell me what can cause the pump to keep running? Is a replacement master cylinder a fix or is there something else that I should be attending to?

Charlie

tabetha

There is a screw in pressure switch, that tells the pump when to cut off, most likely this has gone dicky, I'll see if I can dig a piccie out, but easy to replace.
tabetha

Char1ie

iTrader: (6)

Thanks Tabetha. Is this switch part of the master cylinder assembly? I'm planning to replace the whole thing for a quick cure.

Charlie

foreigneRS

doesn't help with your problem but just to clear this up a bit - the fuel pump does not cut out when it has pressurised. when you key on it is on a timer as part of the program in the chip. when the engine is running, the pump will run continuously. there is no pressure sensor anywhere on the fuel system, unlike the abs unit as tabetha has advised

the abs has a separate loom with a couple of relays, but i would have thought that if they are the problem then the pump would not run, rather than run constantly

englandbrad

iTrader: (1)

Cheers for all the advice will try and get a proper look tomorrow, and try these first.