Over senistive ABS

[landymad]

Hi

The ABS on my 2002 HDI 90 seems to be very over sensitive.
It kicks in a the slightest bump in the road.
I have changed the front discs as they were warped and that has helped a bit as the judder used to kick in the ABS.
I noticed that the teeth on the CV hub that pick up the ABS sensor are very rusty and are starting to laminate (although you can clearly see the individual teeth), could this be the cause?
There is no fault light on the dash at all.

Cheers

[mjb]

Make sure all the teeth are present front and back (at the back you need to take the discs off to see them). Also check the sensors for excessive muck

[Welly]

I used to notice the ABS on my 1999 HDi used to jump in a bit early over drain covers, bumps etc. I wondered whether it was more a case of tired dampers letting the wheel loose contact for a second and actually locking under braking i.e. the ABS was doing it's job.

That said, mjb's suggestion is a good place to start (and a cheap place too)

[Panda]

Probably a split or loose ABS reluctor ring (the toothed ring) fooling ABS computer into thinking a wheel has locked. Official fix is new driveshaft but you can buy the rings separately from some gearbox / driveshaft specialists.

Some tips if DIYing:

1. If ring is split, you may as well take it off and take an accurate measurement of CV joint outer diameter so you can make sure you buy the correct ring
2. Whilst running without the ring on you will have no ABS at all and an "ABS system defective" message will appear. This will clear itself when you have fixed the problem
3. You have to strip the hub apart. Hub nut is 35mm if I remember correctly and will be extremely tight so you need a good socket set (preferably 3/4" drive) and a long bar to shift it.
4. If you change just the ring, make sure you clean all the rust off the CV joint - its the rust that expands and causes the rings to split eventually. I find that one of those wire brush attachments for a drill works well but do be careful not to damage the CV joint boot.
5. The driveshaft may come out of the gearbox when you're stripping the hub so you may as well drain your gearbox oil before you start.

[lofty]

I've been suffering with the same problems, ABS kicking in, normally at lowish speeds, over bumps. Very annoying and it's always at the back of your mind when braking.

I decided to have a look at the ABS sensors, thinking they may be caked in rubbish and snot.

Anyway, jack the car up high, as im rotating the wheel and spraying brake cleaner on the abs ring, i notice the ABS ring is fractured, and when pushed, will rotate round the CV joint!

Looked into the sourcing of an ABS ring on its own and realise it wasnt going to be easy, plumped for the next least expensive option, a new outer CV joint.

They list 2 for the hdi 406's, different numbers of splines on the 90 and the 110's apparently.

£36.00 including vat, comes with CV boot, hub nut, grease, split pin, boot clips. And an Intact ABS ring! LOL

Just gotta fit it now, although it dont look too bad a job to do.

The otherside CV joint ABS ring looks ok for now!

[TS4]

I've also experienced he same problem, with the ABS taking over the braking every now and then. Can be quite unpleasant if you need to brake strongly on a dry road and the ABS acts as if it is ice...
The ABS tooth rings on both front wheels were cracked. I guess the function of the teeth are to activate an inductive sensor. If any wheel loses the "beat" its brake is released. The ring is not subject for any forces but thermal and inertia forces. It should just follow the hub.
The Peugeot shop recommended to change both drive shafts but I was not so keen on that because I realised who was going to pay for it, so I got myself under the car, opened the ring just to get a piece of emery cloth in between the ring and the hub and cleaned the surfaces from rust. Then I put some epoxi glue in and pressed the ring together with hand-power for 15 minutes (don't forget to arrange some head rest). Same procedure at the other front wheel. This quick fix has worked on my car for 2 years now.

[ger]

It's possible to remove the broken ring, weld it and then fix it back onto the cv joint with some epoxy, obviously cleaning everything in the meantime.

It's a shame that the manufacturers didn't seal the ring better, so that no rust would build up underneath it. I'm notsure whether adding some waxoyl or similar stuff is a good preventative measure to everyone else, it might be worth a try I suppose.

[Welly]

Sounds like this problem is a lot more common than we thought......

[lofty]

Mine has been spot on since i changed it, on the 110 its a "knock on" type joint so no fancy circlip pliers are needed etc etc.

Much better now i have confidence in the brakes, especially in the wet.

[kebab22]

having the same prob on mine hit a speed bump sat night and came up with abs fault. went off after 2mins but abs feels very keen through the pedal

[lofty]

having the same prob on mine hit a speed bump sat night and came up with abs fault. went off after 2mins but abs feels very keen through the pedal

even though mine had got a broken abs ring on the N/s, infact you could rotate the ring round the cv joint with fingertip pressure, it never threw the ABS light on the dash or anything.

Its easy enough to check if they are broken, jack the car up high, lock the steering over and the outer cv joint with the abs ring on is very visable. Rotate the wheel round by hand slowly and check for any breaks in it.

[auldy]

I have also had the issue of ABS that's a bit to enthusiastic. My investigation of the ABS rings this evening reveals a beautiful example of what they shouldn't look like:


Just a little bit cracked but not moving on the drive shaft.


Anyone got a spare tooth, cause I lost one

Looking closely it's hard to tell if there's actually a tooth missing or if the ring has jsut been cracked and then spread by corrosion underneath.
Tempted to pull the fuse on the ABS till I get it sorted - I'm used to driving a car without ABS and driving one that decides occasionally to pretend I'm skidding down the road under gentle braking is quite disconcerting.

Anyone had issues with just pulling the fuse and running without ABS?

[kebab22]

found the prob on mine. the spring holding the in board shoes had come off in the rear drum knocking out the abs sensor and putting a grove in the abs ring. all sorted now

[nutski]

One of mine has been gone for a while, hit a bump going into the petrol station the other day and scared the hell out of the guy i was pulling up behind as he didn't think i was going to stop

[jonti007]

I have a fractured reluctor ring, now Peugeot will only supply the ring fitted to the hub unit at a cost of £240+vat.
ReluctorRings .com will sell them seperate or will fit them if you send the unit to them. They claim a fast turn around, but I have not tried them yet, I know there is a copany called Nigel Thomas Transmissions somewhere in the midlands who sell the rings single or in pairs and they are I am told are the cheapest.
I will report back when I have fitted or have fitted my ABS rings