ABS Sensor: ABSolute pain!

[spritefzr]

Ironically as i write this "Back to the Future" is on tv!!! I have just had another bash at the abs. I took the wheels off and cleaned the only sensor I could find, although it appeared to be the speedo sensor. Do you nknow ifthe 1996 model has a combined sensor??? never heard of one before??? I then disconnected the battery, reconnected and went for a drive. THE ABS STAYS OFF!!!

[tornadored7]

Ironically as i write this "Back to the Future" is on tv!!!

You must have been reminiscing about the future, when you saw BTTF on TV (Interesting Oxymoron).

Cleaning the ABS Sensor seems to have worked in your case. That's an excellent result. What approach did you take to cleaning the sensor, and did you use any special solvents/agents ?

AFAIK, there should only be the ABS sensor mounted on the wheel bearing housing, and the brake pad thickness sensor.

I would have assumed that the Speedo sensor was attached near the gearbox/clutch ?

Regards,
TR7

[spritefzr]

Not being a mechanic I m not entirely sure where a speedo sensor would be found. I found a diagram on the net that seemed to show two sensors as part of the same unit, one was a speedo sensor the other the abs. They were located in the same place as the sensor I cleaned but there was only one sensor???? a touch confused. It was tucked in behind the brake disk. I think the diagram may have been from a later model. I simply sprayed wd40 onto the sensor and around a rotor which seemed to be connected to the hub. I then used fine sand paper and slid it between the sensor and the motor and gently scrubed away. I then scrubbed the rest of the rotor. There was a noticable difference in the clearance between the two (sensor and rotor) when I had finished. Hopefully this has done the job. I assume that disconnecting the battery has reset the ecu.

[Grandad Dave]

Any thoughts would be appreciated on my problem.

ABS light only came on - computer said problem and changed sensor in the nearside front wheel where fault indicated. Light stayed on for awhile and then went off. Suddenly noticed it back on again.

Went back to man with computer he said it probably needed re-setting now new sensors in. He did this with his computer.

Drove back with it ABS light off - now it has come back on again.

Anyone else had this problem?

Note: My friend does not have the correct chip in his machine to tell him what is wrong with the unit. Am relectant to pay VW garage fee for their computer but could mean I have to.

[tornadored7]

... Am relectant to pay VW garage fee for their computer but could mean I have to.

Dave,

This could be due to many issues within the ABS system, so to isolate the problem and also to avoid guessing, it would definitely be worthwhile scanning the car for fault codes (e.g. using VAG COM).

There are many forum members who I'm sure would be willing to do this for a fellow forum member.

Post a request for help specifying your location (VAG-COM - Help Requests), and also look in the VAG COM section of the forum (VAG-COM - Users Locations) ;

Regards,
TR7

[tdigolf]

sounds like one of the abs sensors is on its way out, i have had 2 now when i got the car it was on all the time tha abs light i fitted a new rear sensor then few weeks later when i was driving normal the abd would kick in when i was breaking normaly and the roads were dry! the light would come on then go off after while and it wouldnt do it then it would do it again, abs would kick in when i was driving noramaly and the light would follow it found out this was a sign of one of the abs sensors on the way out

[rossi_lfc]

toarnadored7,

wonder if you can help me!

after hours of stuggling i finally removed the front passenger sensor on my mk4 golf, only to find that the the new sensor i had bought would not fit into the old ones space!!

it was not a part from the VW dealer, just wondered if you came across a similar problem, or if this may be sorted by buying the official vw sensor?

cheers

[tornadored7]

Rossi,

Unfortunately I don't visit here as often as I would like to , so I hope that my tardy reply is still of some use, even if it's just for the record.

I didn't buy a genuine VAG/VW ABS sensor (IIRC Siemens is one of the main OEM manufacturers) either and I'm not sure whether the poor fit is due to the sensor not being OEM or rust/debris accumulation around the sensor mounting hole.

Since the ABS sensor was an almighty pain to remove, I positively wished to prevent recurrence so decided to increase the size of the sensor mounting hole.

Using a round file, I carefully filed around the sensor mounting hole (i.e. in the wheel bearing housing), to slightly increase the sensor mounting hole diameter, frequently cross checking fitment with the actual sensor, to ensure a good fit.

The mounting hole diameter was slowly increased, until the ABS sensor was securely held, but while it was also possible to remove the sensor with a firm pull (using mole grips).


Aside

If you are replacing front wheel bearings, and have the combined wheel hub/ABS reluctor ring removed from the wheel bearing housing, this is the ideal time to enlarge the ABS sensor hole in the wheel bearing housing, to pre-empt easier future removal.

Since the front of the ABS sensor is no longer covered by the ABS reluctor ring, the ABS sensor can simply be driven out.

Using a deep socket that is wide enough to fit over the ABS sensor head, but sufficiently thin to touch the ABS sensor shoulders, carefully hammer the ABS sensor out.
Then file the ABS sensor hole to increase the sensor hole's diameter as outlined above, grease the sensor and remount.


Part Numbers

Right Front ABS/Speed sensor: 1J0.927.804
Left Front ABS/Speed sensor: 1J0.927.803

Rear ABS Speed sensors (not sided)

2WD: 1J0.927.807.B
4WD: 1J0.927.807.D


TR7

[Grandad Dave]

Thank you.

A friend of mine has a new VAG with a chip that apparantely does all the range of the VW's.

He put it on mine and it read Terminal 30. He said he will look up what this refers to.

Anyone know what this is?

All feedback is interesting and appreciated.

[rossi_lfc]

tornado,

thanks for the reply, on closer inspection there was still some of the old sensor stuck, however this took some abuse to remove!

the part i got from eurocar parts was still a little big, but some gental sanding of the sensor ensured it fit.

on the whole if anyone is thinking of replacing a abs sensor, i would give it a go, it did take me the best part of 2 days, but saved a budel, garage wanted £160. i payed £35 for the sensor.

the removal of the old sensor it soul destroying i must add!

rossi