ABS - An MOT question

[R9UKE]

Evening.

 

Spent the day getting to know the Volvo properly today and it seems like a really excellent car, ready for the MOT if it wasn't for that bloody ABS shite.

 

The guy sold it to me with the light on, explaining that he had removed the fuse as it was cutting in early. I put the fuse back in today, and yes, it does cut in almost immediately, but only about half the time - and the light is now off. Say for example, during the braking efficiency test it cuts in early, is it likely to fail here? Or since the light is now off there may not be an issue at all?

 

Thoughts and experiences much appreciated.

[scaryoldcortina]

My 2p - If it self tests and the light goes out at MoT it will pass the ABS test, and it is very unlikely (if not impossible) for it to come on during a brake roller test because only one pair of wheels is turning and the roller is slow (won't be more than about 3 mph..)

 

Having said that, it probably has a fault, and in an ideal world wants fixing. I'd just take the fuse back out after the test though.

[Split_Pin]

Cutting in early and light off indicates a mechanical fault and ill bet its the ABS rings on the front. I know these are on the cv joints on an fwd car, dunno about one with no drive shafts at the front. Not sire on how it will fare on the brake test at Mot though.

[CreepingJesus]

They'll be on the CV joint as normal - it's an S70 he's got! Sounds like a reluctor ring issue, you can get replacement rings without junking a perfectly good CV here. Wish I'd found these before I lashed out on a whole new CV for the recently departed Megane, which had similar issues...

[R9UKE]

Brilliant stuff. I'll get those ordered and on to ebay for drivers door mirror glass. Then she'll be good to go me thinks

 

Cheers.

[Split_Pin]

Ah I see lol.

 

Only thing with getting just the rings is they can be a bandit to fit right.

 

You need to heat them to get them over the CV jpint, risking warping etc.

 

I ended up just getting 2 new CV joints as it worked out just as cheap labourwise at the garage.

 

Obviously if you can fit them yourself then go for the rings only, I think they are about £15 or so

 

EDIT, I knew of a company called ABS Rings Scotland that came recommended. Here s the Volvo S70 listing - its much cheaper :

 

http://www.ebay.co.uk/itm/ABS-Rings-Volvo-850-S60-C70-S70-V70-/190615252552?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2c618dee48

[Volksy]

Worth checking and cleaning the ones you already have on the car, and cleaning the sensors as well,

 

I had a similar issue on an old 850, where the ABS would randomly cut in, it seemed to work on mine.

 

You do know they have a check system, that automatically runs the pump for a few seconds when it reaches about 15mph just after starting? Used to confuse the hell out of me, and you can catch it out if you brake just as it kicks in, my street is just the right distance so it used to cut in just as I was braking at the junction.

[R9UKE]

Volksy - I'm really glad you mentioned this. Mine seems to be doing this every 30 seconds or so. And it seems after further driving this evening that the ABS in fact isn't cutting in early, it's just me catching it while it's doing this. We may be playing a whole different ball game now?

[Volksy]

Try this, in the comments a couple of people seemed to have the same problem as you...

 

http://www.carinstructions.com/volvo-s7 ... bs-module/

 

It's a pretty widespread fault having just done a quick google search, most saying that it was a damaged or dirty sensor or tooth on the reluctor ring.

[gtd2000]

You just need to POP the reluctor rings in hot water and they expand enough to fit.

 

Or they for me when I did it the other year on the Picanto.

 

There's a couple photos in this thread of mine:

http://

http://www.kia-forums.com/kia-picanto-f ... lem-3.html

[oldford]

An obviously damaged ABS component is a fail, if the tester can see that the ring is split or loose on the shaft, it could fail.