I've got a problem with the brakes on my van and wondered if anyone else had had anything similar.
I'd just left the house, got to the end of the road and when I braked at the first junction I felt the ABS kick in where it wouldn't normally activate (dry flat road, loads of grip, <20mph speed) The ABS and 'service' warning lights came on and have remained on. The brakes still work and there's no obvious signs of leaking fluid etc.
I've booked the car in at the garage and the guy there said it might (hopefully!) be something simple like an abs sensor on one of the wheels.
Has anyone had any similar ABS probs with their car? if so, how much did it cost to fix? (for info, it's a Renault Kangoo - which I think uses much of the same chassis kit as the Clio/Megane)
Cheers
sorry to be the bearer of bad news but ABS sensors are normally bucks, my friend has removed the ABS from his Corrado G60 as it needed two very pricey sensors, he also works for a specialist garage and reckons that they often break landys with faulty abs sensors because they are so pricey.
On the flip side I think an ABS sensor I had to change on an Alfa was only about 50 quid. I guess it depends on which bit and where. I had a rear arm replaced and they couldn't get the old sensor off in one piece to fit to the replacement.
ABS sensors are in the region of 10's rather than 100s normally, it does indeed sound like one has keeled over. Problem is they're often stuck in and removing them can be a PITA job. On the positive side your brakes will operate as normal (i.e. just without ABS) but on the negative side it'll be an MOT failure IIRC. You can just remove the dash bulb if you require, but you should tell anyone driving or buying it that it doesnt have ABS anymore.
It could be that the reluctor ring has broken giving the sensor an in correct reading. This is done when the time between teeth is lengthened causing the ECU to think the wheel is slowing down or skidding compared to the other wheels
Like dan67 says, could be the toothed wheel missing a tooth....
I had a couple go a few months ago that required a new CV joint each time.
I replaced one recently for about £40. Easy enough job.
As coffeeking says it is an MOT failure and should be if the light doesn't come on and then extinguish when the ignition is switched on/vehicle started (each manufacturer works differently, there is usually a large wall chart which tells the tester what 'should' happen) but this is part of the MOT and the car should fail if the ABS light doesn't work, however 'some' test centres do not pay huge amounts of attention to this...
Also as coffeeking stated your brakes will function perfectly and will be exactly the same but without the electronic/hydraulic assistance of the the ABS system.
And unfortunately he is also right due to the fact they can be a huge PITA to remove, sometimes due to the disimilar metals of the sensor and the wheel hub corroding together very well!
if its a renault i dont think itll to be too expensive...i had my clio front strut (suspension arm) replaced for 50 quid. it might be something with nothing to do with the abs system.
The exact same thing happened on my volvo. Main dealer ran a diagnostic which showed up a faulty rear wheel sensor but on further investigation via web was actually the abs controller. Some companies on ebay repair the box which is worth bearing in mind.
The reason it's an MOT failure is because it's inherently dangerous to drive a car without functioning ABS.
It takes the place of the traditional pressure-reduction valve designed to stop the back wheels from locking. With all 4 wheels locked, you have absolutely no control of the car and it's incredibly easy to put it into a spin. A faulty valve has had me nearly spin a car on the motorway under heavy braking, and it's not something to take lightly.
I thought it wasn't important, but until it happened to me and the reason was explained by someone who designs ABS systems, I didn't take it seriously.
Renault are not to bad on ABS sensors ,70/80 ish pounds IRRC. After market products should be avoided.
Abs rings, the Renault parts web site usually says the only way to replace an ABS ring is with a CV Joint, however this is not always the case. Renault manchesters parts people have helped me out with part numbers for Abs rings when the parts system says it a full joint.
I can provide a contact name if it becomes important but i'm sure he won't want his name on a public forum. (E-mails in my profile).
It's an MOT failure because an inherent vehicle safety system has been disabled, not because the braking effciency of the car has been compromised.
If it was 'dangerous' to drive a vehicle without ABS surely the vehicle would shut down when a fault occured? The light is there to warn you there is something wrong which should be investigated by the appropriate authorised repairer not to stop driving the car. When a fault is detected the ABS system, in effect, shuts itself down and the valves/solenoids etc allow full flow and pressure of brake fluid to all four wheels.
Remember ABS only works when the wheelspeed sensors detect differences between the wheel speeds and then reduces brake pressure to the correspoding wheels. If you drive your car correctly/safely you should actually only ever have to test/use the ABS system in emergencies.
A week after finally getting the sensor replaced on the Alfa mentioned up there ^^^^ (145 Cloverleaf) we drove to Berlin for the singlespeed worlds. Cue the standard autobahn 120 to 60 braking emergency for a lane snaking caravan... I was just slightly pleased the ABS was behaving properly 😉
Thanks for the all the feedback (& the offer of Renault parts contact from Peregrine). The guy at the local garage had a look this morning - the cause of the problem is one of the CV boots has split and flailed around and shredded the wires to the sensor. The guy is gonna replace the boot and sensor. He reckons about £150 for parts and labour (the £70-80 estimate for the sensor was on the mark).
Once again, thanks for the feedback.