biker1981

Hi, newbie here.

I just wanted to post a question behalf of an my elderly Neightbour who has a 1987 Sierra Cosworth.

I help him out from time to time, hr has owned his cosworth for the past 20 years, and he is having a few issues with the ABS light coming on.

He has taken it to both a mechanic and an auto electrician to test the sensors etc, and they say there fine.

I just wondered if anyone has any suggestions please? he has told me that he doesnt think the ABS is working at all now? he can hear the ABS pump working on start up.

It needs an MOT and he does very little miles, he was going to pull the fuse out, but cant find the auxilary fuse box. The manual says it should be in the passenger footwell, but cant see out, there is something in the driversfootwell with some yellow relays etc... but cant really get to it.

Any help appreciated.

Mark 3D

iTrader: (29)

your elderly neighbour has a 3 door Cossie!!!! lol

just how elderly is he!!?

biker1981

Ha ha he must be mid 60's, he also has a mint 205 gti, and volvo T5... and a few motorbikes... I want to be just like him when i'm older

Think he having difficulties with it as alot of the local garages arnt really up on them... neither am I really.. but it sure is pretty

leebilly

Hi
Im a newbie too but have had a cossie for 8 years. If pump runs but light is on can be as simple as not quite enough fluid in reservoir, try shorting out the two pin plug on reservoir cap and see if that buts light out.

tabetha

Don't pull the abs fuse, the light has to function, and in a certain fashion to pass the test.
The most common reason is rust on the rear abs rings, just a tiny bit of flaky rust here can obscure the gap seen by the sensor, so wire brush out first.
tabetha

scottyrs

iTrader: (1)

as said if youve checked sensors ect id check the resovoir bottle is filled up or ive known a few to just change the cap and it goes out

Paul_RS

iTrader: (4)

Easisest thing to do is pull off all the plugs that go onto the brake reservoir/pump and give them a good clean. Also try topping up the fluid as it could be the low level indicator brinign the pump on.

chrisa3

iTrader: (1)

to check if its the reservioir at fault:
If the light comes on and stays on:

1. check fluid level.
2. take the two pin connector off the reservoir and bridge the two pins. If the light goes out, the level sensor is faulty.

If the light goes out and then comes back on after moving the car, its a sensor at fault.

martysmartie

iTrader: (1)

The handbrake/fluid warning/pressure light and the ABS one indicate two totally different things, the fact the former one in this case is ok shows the sender etc to be fine!

First thing I would be doing is checking the sensors, despite the garage etc saying they are ok, for each one you want to be seeing 1K Ω resistance or greater. Most likely though is the said dirt, either on the sensor pickups themselves and/or the ABS ring gear.

As said don't pull the fuse as this will disable the system all together and it won't pass an MOT!

If the light is on the ABS won't function as it indicates the system is inoperable!

All of the ABS wiring is behind the passenger dash, along with the engine management and fuel pump relays etc, it is not in the fuse box. The ABS fuse is 30A and I think the relay is purple IIRC. However this will have nothing to do with the problem he has.

Martin

biker1981

i tried briding the sensor and still nothing

He is taking it to the garage to have them check the sensors etc and I will take a list of things you have advised.

Is there anything else he can ask the garage to try please?

cossiedad

Hi there. I had the very same issue with my saph when it went for MOT. Pump was working but light stayed on. I have just rebuilt mine so know the mounting holes etc are clean and sensors seemed to be ok when tested. I got a bit fed up and started tapping (ok, hitting!) various places on the pump assembly to see if the light went off, and sure enough it flicked off when the pressure sensor was hit.

I had to have help here though, as it would only flicker so while I was hitting it I had my bro in the car watching the light.

I cleaned and checked the connector and wiring but no joy. And the sensor is a bastard to get at! As I remember it, it's the big gold-like cylinder pointing towards the front under the black pump. Has a wiring plug on the front of it and it's not the bottom plug. (crap description but I dont have a pic). I think it's a 36mm BUT, it's a funny shaped 'nut' and it doesn't grip in it.

I ended up changing the whole assembly - reservoir, pump etc - as a single unit. It's really not too bad to do that way. 4 bolts behind the top of the brake pedal inside, and 3 metal brake unions that go across the bulkhead to the ABS/distributor block. Worst bit was draining the brake fluid without getting it on the paintowork/inner wing/chassis rail.

I picked up a complete unit on ebay for less than £20 delivered and there were a few to pick from.

Hope this helps?

cheeRS