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I bought this car 2 weeks ago, I've done 1000 miles in it and no trouble but the abs light has started to come on and go off. One day it's on, the next it's off, any suggestions?
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Worn brake pads? Just a hunch...
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Thanks smokie, I'll have a look at the weekend, after all thats what they were invented for.
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I can tell you what this is. It's a front wheel sensor dying. Check all your sensors with an ohmeter - they should all read 1000 ohms or so - the faulty one will read near zero 'cos it's an internal short. Of course you need to measure it when the fault is exhibited.
these are hard to get secondhand, but I've managed to obtain four in the last three years at about £40 each (for two different cars).
Once you've got your secondhand sensor, go to the dealer and get a new mounting block and screw. follow the following proceedure: 1) cut the old mounting block off the new sensor by cutting vertically 2) prepare the new block with 450 wet & dry then prime and paint with Hammerite or similar (but not down the hole). 3) thoroughly clean the sensor and mount in the painted block. 4) paint the sensor and block again to seal the sensor to the block. 5) mount on the car.
i actually manufactured my own mounting blocks out of aluminium. the problem is caused by the mazak OE items corroding and causing the sensor to be squeezed to death (a prolonged death - the fault will be intermittant for a while but will soon be permanent). If you are able to make your own I can let you have a scanned copy of my own drawing which I used.
Click on a users name (in red at the top of each post) to get their profile. Mine shows my email address if you require more info or that drawing.
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Well guzzler cyd is right-although the reasons for failure could simply be too many kerbings in the life of the car-I bet its the nearside sensor that has failed.My 96 827si exhibited exactly the same symptons as yours-the light will eventually stay on.I took my car to the local rover dealer for a diagnostic check and they confirmed the failure-the bad news was that it would be 500 pounds+ to repair-the sensors are 150pounds each side plus labour.These cars are worth loose change now-ridiculous i know because IMO they are superb motors.This fault was the only thing to go wrong in 6 years of motoring.The mechanic told me to live with it as it was-it made no economic sense to have it repaired-this ive done -i simply disconnected the warning light.Cyd is clearly very handy with cars-i am as well but it would be beyond me.As regards brake performance youve lost the enhancement of abs but the brakes remain sufficient.There could of course be an insurance implication if ,heaven forbid you have an accident!
Regards
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And in theory at least, as I understand it the car shouldn't get through the MoT in that state.
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Yes quite. I'm being somewhat holier than thou here but there are insurance implications in that a company could say their rating for a particular car was based on the fact it had ABS fitted. If you've disabled it they may have a case to recover (from you) any monies paid out on a claim.
The warning lamp behaviour is the only way the MOT test station checks the ABS. If you look on their walls you will see a chart that gives the behaviour of the light for each car.
The testers aren't daft, they know which models are fitted with ABS and if there is any doubt they will soon see the "rotors" on the hubs/driveshafts when the car is lifted on the ramp for other checks.
I can see this sort of thing being more of a problem as the MOT system is changed to a central computer over the next few years. This could mean that the MOT station will know from the chassis number that your car has ABS and taking the warning lamp out will no longer be sufficient to "fool" them.
MM
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You clearly have a very "lenient" MoT tester, Derek. On cars with ABS fitted the light must light with ignition switch on and extinguish according to manufacturers specified sequence (after about 10 seconds usually) to satisfy the MoT - removing the bulb will therefore cause a fail. It is a requirement of the MoT that the tester tests this and that the light also must not indicate a fault (I checked this with the MoT enquiry line at the DETR today).
Talking to Rover breakers, it's the right hand sensors which are in most demand - strange, you would expect the left to be most susceptible to corrosion.
How the dealer got £500 for the repair is beyond me. The sensor plus mounting block are around £200 each. It took me roughly 45 minutes to change them in my garage using a trolley jack and axle stands - a dealer with a ramp should be able to do it quicker. Even if you add 1 hours labour at £60 and a £50 diagnosis fee you shouldn't be paying more than about £310 per side. Try an independent garage, you'll have no choice but to use the OE sensor, but the diagnosis and fitting will be much less (an independent may be prepared to source a 2ndhand one for you and treat a new block as I've indicated - also have a new treated block put on the good side to prevent future failure there too).
The problem is not caused by kerbings. It is caused by the mazak housing corroding down the mounting hole. Mazak is 96% zinc (depending on the exact grade) and zinc corrodes easily to form zinc oxide. Like ferrous oxide, zinc oxide takes up more volume than the parent metal and so the small gap between the sensor and the hole is filled - as corrosion continues the corrosion product puts pressure on the walls of the sensor (just like a steel bolt seizing in its hole). The sensor is then squeezed in until the coils inside are also squeezed. Eventually the coils break down and either short or break to open circuit (usually they short). If you'd like to see a photo of a corroded block cut from a sensor then send me an email.
I have recommended painting the new block and sealing the sensor into it to prevent water and dirt starting the corrosion process off. I prevented the corrosion problem by making new blocks from aluminium (which I painted), you could also use stainless or maybe even nylon or ABS. Whether you make your own blocks or use new OE ones, this is not a difficult job as long as you own a basic socket set and suitable jacking equipment.
Rover really are taking the p**s with the cost of these sensors. They can't be more than about £10 or so to Rover and this is a problem well known to Rover engineers (only afflicts R800s). You would think under the circumstances they could reduce the price of the sensors to a reasonable level. The damage done to the brand name for those owners who suffer (almost all will) is considerable, they resent having the fault in the first place (caused by poor design) and then the cost of repair just rubs salt into the wounds. How do Rover ever expect to convert ex-800 owners into 75 owners like this? My 827 didn't show the fault till it was 9 years old, but my Vitesse had both sensors fail this way before it was 3. If I wasn't such a Rover fan (and familiar with Rovers engineering practices) I would simply not consider another Rover after this (and the gearbox problems afflicting the Vitesse too).
Perhaps Dave Lacey could tell us what the cost should be, with the proper service times?
If you want the number of some Rover breakers send me an email, or contact the Rover OC at www.rovertorque.co.uk
Why doesn't anyone put anything in their profiles? see www.honestjohn.co.uk/forum/post/index.htm?f=2&t=93...9
Regards
Cyd
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I think this is the same part that someone told me is identical to Vauxhall's, which cost < £80, except that the wiring connection is different...
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Can you be more specific Smokie? Which Vxs, what years? I'll then try my local breakers for one.
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Sorry, I can't be of more help. I had a N reg Sterling on which the ABS would cut in at v low speeds, while slowing to stop. A back street mechanic at first said he wasn't capable of doing ABS, which I was happy with. Then he had a look and identified that the sensor was broken in some way. It was he that told me about the Vauxhall one, but he said he considered it too risky to try to change the connector. This would have been about 1997/98.
And actually, thinking about it, he said the Vx part would have been £20, but the Rover part which he had to get was about £80 - and, nice guy, he fitted it for free.
It might have been complete bull, for all I know about it. Or we may be talking about a different part!
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On cars with ABS fitted the light must light with ignition switch on and extinguish according to manufacturers specified sequence (after about 10 seconds usually) to satisfy the MoT - removing the bulb will therefore cause a fail.
Cyd, what if someone were electrically compitent enough to cut the wires to the ABS light and then piggy back them instead to either the oil pressure light, or alternator light? The ABS light would go out, giving an indication to the tester that the ABS system is working.
Does the MOT require that each wheel be examined to physically prove the ABS is working, or is it solely based on whether the light goes out or not?
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The MoT does not test the functionality of the ABS "at the wheels". It is based on the functionality of the light only. If one were handy enough to be able to connect the bulb to a circuit that could replicate the correct function, then my guess is one would fool most testers.
IMO the only "fool" in this senario is the driver who values a few quid over his own (and others) safety.
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Costs i was quoted for repair were:sensors 146 pounds by 2:clamps 20 pounds by 2:labour 92 pounds:vat 68 pounds -circa 500 pounds in all-on a car i couldn't get 1500 pounds for!!
I'm keeping the car now so I'll have to bite the bullet and go and negotiate with my friendly Rover dealer
Regards
Derek
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Just spoken to the service manager who tells me the back wheel sensors are 146 pounds plus vat -the front he says are cheaper-i didn't realise there were sensors on the back as well-this could be a dear do!Cyd are the back ones more/less likely to go than the front?The car's being plugged in on Friday to see the extent of the failure-in the meantime i'll reconnect the warning light
regards
Derek
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I've just found someone who does these sensors for just under £70 new including vat and postage. I'm assured that they are Bosch parts, as used by Rover. The company is Best of British and they are on the Rover Mart site under the breaker section.
As for connecting the abs light to something else that works, surely the point of having abs is for it to work when you stamp on the pedal?
Anyway I changed the oil this morning and had a look while the wheel was off and it looks like a piece of cake to change the sensor. I hope this is not a case of "famous last words"
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I used "Best of British" on countless occassions with my Rover 416SLi..... It was the new shape, but the Honda engined auto, so breakers yards weren't exactly crammed with them.
Without fail these guys were superb. Can't recommend them enough for Rover parts, especially ECUs and ABS pumps, which they can have remanufactured.
You found the right people, Guzzler!
No Dosh - but then who has?
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Well Guzzler that's a bit of good news-just makes you realise that rover must be doing very well on the parts front if Best of British are making a profit selling sensors at half their price.
The next question is do you know which sensor has or is failing?And if the warning light stays on it may need to be reset by a rover dealer.
regards
Derek
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The rear sensors do not give the same trouble as the front.
If you can beg, steal or borrow an ohmeter, I've already described above how to test the sensors - if you want more details please email me (click on my name in red to get my profile).
Once fixed the light will reset itself.
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I think Maplin Electronics do a reasonable multimeter for about £20 that would fit the bill. Well worth having one in your toolbox.
No Dosh - but then who has?
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Yes i can get hold of a multimeter to check -I'll have a look this weekend-bit cold for outside work at the moment.Just as a matter of interest,whilst this car has been very reliable and is still relatively low mileage, can i expect any other "little" surprises in it's life?I've done all the belts incl cam belt and all the other bits -clutch,rad etc are original.Don't want to throw good money after bad....
Regards
Derek
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