Short ABS noise whilst medium pressure braking

[JezzaMac]

Just come back from Europe in the car and after a couple of laps around The Ring ive started to get this strange noise occasionally during braking. It only happens some times when im braking with medium pressure and sounds as if the ABS is trying to kick in for about 1 second.

Cars going for an MOT soon and I really don't want it to fail! Any ideas would be much appreciated!

 

[Tony Hunter]

You may have a crack in one of the abs rings, I would check this first.

 

[EngineerD]

I have this, for me it's a cracked ABS ring, quite common.

 

[JezzaMac]

I dont have a clue what an ABS ring looks like, where should I look for it? lol

 

[.Stevo.C.]

A ridged plastic ring behind the brake disc.

 

[Owen92]

Picture of the ABS wheel on a 172 I've just found
http://forums.overclockers.co.uk/showthread.php?p=14931044

 

[M@tt_182]

Also had this problem, it's not an MOT failure just an advisory. Pretty sure Renault also don't sell 182 ABS rings, be sure to get hold of the correct size as 172 and 182 differ from memory.

 

[JezzaMac]

il have a look tomorrow! Im guessing if Renault dont sell them then its new discs with them already fitted or some second hand ones?

 

[M@tt_182]

Fronts are on the driveshafts, rears are on the discs. I imagine it'll be a front one but have a look, it might be hard to see it straight away.

 

[KevF182]

It's a metal ring. On the front its on the driveshaft outer CV joint. Heat from lapping may have caused an already corroded peice of metal to crack?

Easily checked.

Also look out for the gaitor clip failing and spilling grease onto it. In a bizare way, the ABS triggering may be an early warning sign of CV grease exiting and premature Driveshaft problems for some, the gaitor clips (as standard) are a known weak point.

 

[JezzaMac]

Interesting that you have mentioned CV joints because Rentec mentioned that they were starting to show the beginnings of wear.

Thanks for the help il have a right good poke around tomorrow or Saturday. Im not the best with all this stuff but im wanting to learn!

 

[KevF182]

Well, if it's been looked at on a ramp then Rentec would have noticed any grease exiting from the gaitor. If they said the joints themselves were just beginning to wear that will not be related to ABS. I was more pointing out that the grease on the pickup (reluctor) rings is a common reason for ABS faults. Just as common is them being corroded, or (hard to spot without close inspection) cracked.

Check that they are not cracked first. I've had both problems on various cars in last few years! - I'm not a mechanic by the way!

Kev

 

[JezzaMac]

Looking at it this way.. if i need 2 new CV joints as well would it make more sense to buy new driveshafts if they come with ABS rings on them already if 182FF rings are difficult to get? Thanks BTW Kev

Jamie

 

[KevF182]

I'm in the same boat. Good luck with the cost of it all!!!! (I doubt you need to do that though)

Just for info - after any service work on my brakes there is the odd ABS fart for the first few jurneys. Even though I shine up the rings there is a brief period for 30 miles or so when the ABS will be intrusive. I believe the rings are getting too corroded but after that it will be fine for thousands of miles afterwards.:S

Cost of new genuine shafts is extorsionate to me, its a small hatch!!! I would do it out of normal 80k servicing on any other car I've had, but not at over £400!

 

[JezzaMac]

Thought I would update since I just had a look.

There is some back and forward play on the NSF wheel, im guessing the CV joint. The ABS ring is fine and the boot and clip are still good.

On the OSF the ABS ring has cracked. Also the CV boot has split into 2 whilst still leaving the cable tie wrapped around the CV joint with hardly any grease in it. Sad times.

Im guessing new driveshafts both sides?