What is the purpose of the ABS light?

Is it dangerous to drive the Car, if the ABS light won't go out?

 

Like most warning lights it is there to tell you there is a problem with the ABS system.

Fortunately the brake system is designed to work even if the ABS in not functioning. You will still have normal braking function you just wont have the ABS system attempt to prevent wheel lock.

Without ABS, under heaving breaking you will have to modulate the brake pedal to prevent a wheel from locking up...just like the old days before ABS.

With ABS you can stomp hard on the brakes and the system will apply as much breaking to each wheel as possible but not allow a wheel to lock.

Mark

 

Hi Mark

Thanks for replying

I only wish they had stuck with the 'Brake Booster' system, which is so simplistic compared to the ABS.

 

I was going to strip my 89 and go with non-abs system. The abs seems too problematic to be reliable.

 

Plus+1 On that!

I absolutely hate that ABS System, as you never know the moment that it will decide to bite you on the Backside.

I've got a Donar Car standing buy, in Case my fix doesn't work, which has got the old style 'Brake Booster' system.

If you decide to swap it over, please put up a Post of how you did it.

Just wondering how/where you connect the Vacuum Pipe?

Would you Tap and Drill a hole or just swap inlet manifolds?

Either way, it looks as though the Manifold has to come off, or else you might end up with swarf being sucked into the engine.

 

It's an MOT fail if the light doesn't go out which is stupid because the car will still stop like a car without ABS.
Go figure.

 

My warped sense of humour had me mentally replying that the light was there to ANNOY the owner, sounds about right at the moment.

Pull the globe, NO light, MOT pass, sort the rest when time permits.

As said, the brakes still operate just fine.

Probably a flat "bomb", as I seem to remember reading somewhere that was the prime cause of the ABS light ON.

 

Cheers Grant

But what's a Flat 'Bomb' ?

 

I believe that he is referring to the ABS Accumulator. Flat= lost its pressure.





Mark

 

It is also a fail if the light doesn't come on when you turn the ignition on; devious sods.

 

Nothing a delay relay and a couple of connectors won't fix!
Greg

 

I once "fixed" a Vauxhall Senator ABS "lamp fail" by wiring the bulb into the "sport" indicator... that did the same thing the ABS light should have done - came on when the ignition turned on, went off when the engine was started. I just needed to make sure it wasn't in Sport mode when it went into the MoT station....

Obviously, that's only a temporary bodge before you fix it properly, I wouldn't dream of suggesting anyone else did such a devious trick

 

Thanks Mark

Do you know how you go about re pressurizing it?

 

You'll need to take it to a specialist; as I recall it has about 80 bar of nitrogen inside.

 

Since you are in the UK, there are still thousands of OLD Citroen repair places around, and they regularly "recharge" the spheres on the CX etc models. They will have the specialist stuff to do it.

The only downfall is that when they actually go FLAT, the diaphragm gets damaged, and sometimes recharging is not possible.

The spheres are probably still available via the usual Jag supplies. The USA guys have been using a sphere from the local GM dealer, as lots of manufacturers used the Teves system, not just Jag.

Maybe good old Ebay can help, dunno.

 

Hi Steve

You probably just saved my life!

I had no idea there was so much pressure in there and I'm wondering what would have happened, if I had unscrewed it!!!!!

 

Hi Grant,

Thanks but I bet they cost a fortune, so I'll wait and see what happens when I get her back on the road.

 

Hi OB
It may be the bomb has no pressure but it is more likely that the low pressure line from the reservoir needs bleeding since you have stripped the complete system. If the pump can't get any fluid because of air in the system then it can't build pressure and eventually turn off the light. It should go out after about 30 seconds.Just a thought, can you hear the pump working? Does the pump continue to run and run or does it turn off?
If you work on any part of the system remember to de-pressurise it before you undo anything!! Just press the pedal about 20 times until it goes hard. The gas pressure in the 'bomb' is the the 'other' side of the diaphragm so you can undo it once the fluid side is de-pressurised. (just like the pressure vessel in your central heating}. Also have you bled the rear brakes properly? This can take 2 or 3 attempts before it comes good.
Stick with it, good luck
Dave
Good luck

 

Hi Dave

Before I pulled the whole thing to bits, the Pump was switching off after 30 Seconds but the light would not go out.

Probably not surprising for a Car that's stood for 12 years, so I'm not really starting to panic about that just yet.

She probably just needs a bit of a run to get her back into the game.

I'm having to divide my time, into getting Two of my XJS back on the road, only made worse by the fact that none of the shops where I live, sell even the

very simple things that you need when restoring a Car.

No one sells Stainless Steel bolts and even a two inch M8 bolt in ordinary mild steel will set you back 30 pence!

If you want a nut and washer with that then you can add another 20 pence!

Tools are non existent unless you want something simple and yesterday my Compressor went on the Blink.

So today I'm getting my Passport and going out of Town, to a place where you can buy this stuff in bulk at bargain prices.

 

don't forget that the light WILL NOT go out until the car has been driven over 15mph , the system will then self reset

this can not be done with the back wheels off the floor and spinning up the back wheels , all four abs pickups need to send a signal for the reset

this will not prove or disprove any faults with the system , just reset it so the light goes out after working on it , but you will then start with a fully reset system looking for new faults ( if any )

BB