stevieturbo

This is fitted to a converted Focus.

I assume the motor spins all the time to provide power assistance to the brakes ?

The pedal is rock hard, virtually no brakes. There is 12v power to the motor with ign on and engine running.

There are 2 plugs in use. One upper, 3 wires. Then the 2 wire power the motor underneath.

The motor gets roasting hot in no time....so I assume its fucked ?


Can the motor easily be changed in situ, or must the entire assembly be swapped out ( which looks like a cunt of a job, as it wont fit past the engine.


Tried whacking it, but to no avail...ahh well.

Cheers in advance.

jon@work

iTrader: (5)

The pump shouldn't run continuously.

Is the car using the complete sierra ABS - loom, ECU, pump, solenoids, etc ? If so, there are not just 2 connectors - there should be a 5 way, a 2 way, another 2 way on the pump, a 3 way on the fluid level, and a 7 way on the (remote)(at least on sierras) solenoid block.

stevieturbo

Nope, no ABS, they just seem to be using it for power assitance.

The upper forward facing plug is a 5 pin, although the wiring only appears to have 3 pins.

The motor itself is a flat 2 pin affair.

The upper 2 pin isnt used.

I dont see any other wires going to it, but access isnt great.

The brakes were working when my friend got the car. But its been sitting parked up for nearly a year, only having been moved a couple of times during that period. Although last time 2-3 months ago, pretty sure the brakes were working.

jon@work

iTrader: (5)

OK I've had a look into this, and it appears that your connections, in theory, should be OK.

In the 5 pin plug, you need 3 wires as follows :
a brown/yellow feeding ignition-switched 12V to the connector
a brown wire to earth
a brown/black from a relay (pin 85) that switches the pump feed (87 & 30) (pin 86 will be another ignition-switched feed)

The wire colours listed above are the original colours, and obviously yours may have been changed, but you should be able to use the above info to check, for example, if your relay is sticking, or if the wires have melted together, etc.

stevieturbo

Thanks Jon.

Obviously this car has been wired by others, although the wiring itself looks to be a solid job.

The brakes had worked previously...so I suspect the fault is with the ABS pump, as opposed to wiring.

From the above...the upper 5 pin plug seems to control the actual pressure pump then ?

I assume its some sort of pressure switch then ?

But even with the 12v applied to the motor....the motor gets roasting hot. I can only assume this is siezed ? Although Im curious that no fuse has blown if that is the case, if there even is one.

Certainly wiring local to the ABS unit and as far as I can see, shows no signs whatsoever of melting.

I'll get a pic of the unit later

raggey

I have fitted the cosworth brakes to my kit car with the abs manifold but without the abs wiring.
When I first fitted it I had the pump running all the time this caused the pedel to go hard and push your foot back as it overpressurised the system and the pump got hot.
The way round it was to wire in the presure solenoid so that when it reached its pressure it switched of the pump.
The brakes work by charging the accumulator [ the black ball on top of the pump] which stores pressure. Once up to pressure the pump switches of and the accumulator takes over untill it needs charging again and then the pump starts again. So it looks to me as though the pressure switch has gone or the pump has been indipendent from the switch.
Hope this is of some help.
Paul.

jon@work

iTrader: (5)

The pump gets hot (the Ford manual states that the pump should not be run for more than 2 minutes) - but does it make a noise as if it's working correctly ?

If so, then it's either a sticking relay, dodgy wiring, as raggey says a dodgy pressure switch (that the 5 pin plug fits to), or perhaps it's an issue with the accumulator, the high pressure line, etc, etc.

As standard, the pump takes its feed through a fusible link, not a fuse. If the wiring has been replaced, then potentially the pump is not now fused at all.

stevieturbo

So....if I leave the system unplugged, how should the pedal feel ?

At present, it is rock hard, but only seems to be locking the rear brakes. Virtually no effort at all being applied to the fronts.

But as I say...any time I tested at either key on, engine running, there was 12v power to the pump section.

And when I say hot.....you wouldnt be able to hold your hand on it for more than a few seconds. It is worryingly hot, and the heat is not radiating from the manifold.

raggey

I think if you leave the plug of the pump will run all the time as when I first wired it up I did not have the pressure switch wired in and it ran all the time.
To make the pressure switch work if its a made up loom it would have to have a relay in it so that the when the switch worked it switched the relay and then switched of the supply to the pump. If the pump is switched through the p switch it could damage the switch.
I cant remember with out looking which 2 terminals are the switch but if you need to know I will look tonight for you. I think I still have a rough wiring diagram of how i wired it, as some one on here asked me for one if you need it but I did not use the plug.

If I remember right when you bleed a cossys brakes you bleed the front as normal but you put the pump on for the backs so when the pump is runnig all the time it might pressurise the backs more but im not sure about that.

stevieturbo

As I say, the wiring is probably sound. The brakes used to work fine. The problem has occured whilst the car has been laid up.

How can the pump run if its unplugged ? there is no power for it ?

raggey

sorry I thought you ment the solenoid plug not the pump plug
if you have a multi meter you could put it across the solenoid and see if it switches
This is just a thought but if you let the motor cool down then either pump the brakes without engine on or open a bleed nipple at the rear and bleed it.
This should drop the pressure so when you turn the ignition on the pump will come on it will biuld pressure and the solenoid should change state this would prove the switch.
paul

stevieturbo

But the point is.

I have no brakes, the pedal is rock hard. There is power going to the pump. SO regardless of what the pressure switch is doing...I have no brakes.

So surely the pump motor itself has to be fucked ? The brakes do not need bled, nothing has been touched. The car has been parked up for around a year.

The brakes have just stopped working during this time.

I dont see a situation whereby there is pressure in the system, and the pedal would still be rock hard, with no brakes ?


So I guess back to the original question.

Can the motor itself be changed in situ, or must the compete assebley be swapped out ?

jon@work

iTrader: (5)

according to the workshop manual, the pump can be changed in situ, but in a focus, who knows

raggey

i can only go by what happened to me when the pump ran continualy the pedal was too hard to push.
As for bleeding the brakes I was just trying to find a way to drop the pressure.
have you tried taking the plug of the pump and drive it slowly up your drive and use the brakes and see if the pedal comes back as the pressure decays
As I say im only trying to help and give you ideas

stevieturbo

Dont get me wrong..I do appreciate it.

I just dont understand how there could be pressure in the system for power assitance....yet the brakes do not work at all, from there being no assistance.

Ive driven the car up and down the road with the plugs attached. Ive also moved the car and stood on the brakes as hard as I can in the yard at home.

Regardless, I have no power assistance, and a rock hard pedal with no brakes.

MERKUR XR4ti

Hi guy's how did this all end then ? does it work ?