ABS Servicing in London

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alastair.purcell
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Any advice on having my ABS seen to in London?

Pushed from pillar to post by MB in Wandsworth. Had a "full ABS diagnostic" from them...Unsurprisingly was told it was the Control Unit. They "absolutely guaranteed" that if I had a control unit fitted by them the fault would be corrected. £2000 plus £80 labour! I'm gullible, but not that gullible......so I got a reconditioned [guaranteed] control unit from Frank Eiegemann at www.gw.gelaendewagen.de [part number 008 545 44 32]..........it arrived yesterday....I plugged it in today. But the ABS warning light is still on. I checked and changed the ABS relay behind the fuse box too [that's only £8] and checked the ABS on/offl switch on the dash [that's working fine too].

I realise there are sensors on the wheels, but don't feel qualified to check those. Any pointers very welcome.

Thanks, Alastair

Russ280
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Re: ABS Servicing in London

It's pretty easy to test the sensors:

https://m.youtube.com/watch?v=7eCJa7JZzfg

If you've got as far as swapping the ecu you can manage this.

Arnie
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Re: ABS Servicing in London

Unplug each sensor (under-bonnet, inner-wing) and check its resistance with a multimeter. you should read around 2kohm.

Be very careful if extracting the front sensors. They are likely to be stuck by rust in the location hole, which is quite deep, They are plastic and very weak. I broke one, trying to extract it, and that was even after applying a lot of WD40 and with careful jiggling, turning. In the end, I had to drill a hole in the remaining, broken-off half of the sensor, still inside the hole and then thread a long, self-tapping screw into it and extract like a cork-screw. They cost about GBP-105 from the dealer and about 70 from ECP - Bosch OEM.

Clean rust from the hole and replace sensors with copper-grease or other grease.

The ABS system does provide some basic fault-codes. See WIS for how to diagnose. the test-socket is on the actual ABS controller.

 

 

 

 

JASONGDS
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Re: ABS Servicing in London

On early 463 my sensors were metal , but took me an hour to remove the hexagon bolt holding it in place as bolt has really gone bad, now replaced with a Stainless Item.The connectors that Arnie says are on the inner wings, white plastic about a few inches long, they can be awkward to separate if not touched since the factory. Rear sensors a lot more money and the are sided( connectors on chassis passenger side rear), but same principle for testing. Also two relays on ABS unit and 2 on fuse board?

Did ABS stop working all the time or light came on when you went over a bump etc?

Arnie
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Re: ABS Servicing in London

Yes, remove the plastic cover from the ABS pump/ valve- block and you'll find a relay or two under there and possibly a fuse - cant remember exactly.

I also had to struggle a bit with the retaining screw, but likewise, replaced with stainless-steel, hex-head screw.

(i'd only wanted to remove the sensor to re-paint the wheel hub)

In fact, I also replaced all the screws for the wheel arch liners,  extended arches and side rubber strips with stainless ones.

KevinStuttgart
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Re: ABS Servicing in London

 Alastair, what G Wagen have you got? Is the light on as soon as you start the engine or does it come on once moving?

Arnie
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Re: ABS Servicing in London

KevinStuttgart wrote:

 Alastair, what G Wagen have you got? Is the light on as soon as you start the engine or does it come on once moving?

 

The ABS system does an electrical self-check of sensor wiring when the ignition is first turned on. Then, when the vehicle first reaches 19 km/h., the pump is primed and if you happen to have your foot lightly on the brake-pedal at that time, you will feel a click. If the light comes on at this point, it may be a pump fault, but it could also be a sensor which electrically checks out OK, but does not produce the pulses, eg because the castellated toothed, sensor -ring is broken.

 

davidk
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Re: ABS Servicing in London

I very highly recommend speaking with Steve at Trident Mercedes in Uxbridge beofre you have a service or  any work done and would go so far as to totally vouch for his knowledge and detail to work. He runs a old school garage and delights in GWagons. I have been to most "so called experienced" mechanics and since returning to the UK, have been fortunate to have Steve maintain it again. 1993 GE300. He did overhaul on the engine recently and it has not sounded like that since 20 years ago and accelerates hard at 80. 

01895 814 640 

Cowley Road, Uxbridge UB8

 

​Cheers 

David