ABS - feedback on behaviour pls

allanv6gt · 28-10-2010, 08:24 PM

Had two 'moments' ssince buying 3months ago.

1. Momemnt 1 - 80km'h zone, my green light, other driver pulls out in front thur red light. I hit the brakes and a cloud of my smoke catches me. No contact but noticeable ABS activity either. Dealer said (at 3000km service - 'weight transfer). yeh right......

2. Moment 2 - yesterday cyclist on bike path fails to stop when crossing the road infornt of me. Not a controlled intersection, just where the path crosses a back street in suburbia. Again, locking RHR tyre, but no big smoke this time as going the regl'n 50km/h....and no noticeable ABS activity.

So.....when I hit the brackes, I don't expect things to lock up and stay that way. What should I be feeling thru the pedal? Anything? How can I test that the <beep> ABS actually works?
My old Subaru gave you pulses thru the pedal, and didn't lock up with big smoke (only 1 'moment' in 7yrs and stopped in an amzingly short distance - all worked as described in the manual).

Feedback welcome.

AlanD · 28-10-2010, 09:24 PM

Hmm,

I have had one reason to stop fast in 15,000 km of travel - on that occasion the car stopped amazingly quickly with no brake lock up and no smoking tyres either. I can not recall any brake pulsing like I get in the Territory during panic stops.

Although I would not expect that deactivating the Traction Control would affect the ABS I do know that they are a part of the same system. You haven't accidentally deactivated the traction control before the two incidents by any chance?

After three months I think I might be demonstrating the wheel lockup and smoking tyres to the dealership and say "something isn't right here - please fix it".

Then after they claim they have, take the service manager for a test drive and check if it behaves differently.

I'm beginning to believe some dealerships know very little about imported Ford vehicles (Ford Oz as well) which leads to interesting discussions with service people. Other dealerships listen to owners, know the vehicles and fix the problems - see my last thread for an example.

Cheers,

obione980 · 28-10-2010, 09:34 PM

Mate - if I could understand just exactly what you are concerned about - I might be able to respond.

I can't.

svo supporter · 28-10-2010, 10:22 PM

If the ABS system is working properly, the brake pedal should pulsate and you shouldn't have any lock up of any wheels. Ie. No smoking tyres, hence it being called ANTILOCK BRAKING.

I'd be going straight to the dealer and get them to look at it

Mickmelb · 28-10-2010, 10:43 PM

Some ABS will pulse more than others when activated and may "chirp" a tyre while the system finds it limits but not lock up like you have experienced. you can not turn off the ABS on any car unless you remove a fuse or control relay. I find the best way to test it is to drive down a quiet road with a gravel shoulder and put 2 wheel on the gravel and then stand on the brake. The car should pull up in a straight line without locking any wheels. By having to 2 different surfaces you will know straight away if its working a non ABS car will lock the 2 wheel on the gravel and pull to one side.

obione980 · 28-10-2010, 10:59 PM

A 'pulsing pedal' is subjective ; in that one person's 'pulse' is another's hesitation. Smoking tyres are par for the course in heavy driving conditions. I learnt very quickly in the USA when driving on inner city freeways, that smoke meant slow right down - very quickly!!

They've all got ABS too.

mondo_broady · 28-10-2010, 11:46 PM

my mondeo XR5 does not pulse the pedal when abs is activated. i recently had to stop in a hurry when some kids played silly buggers as i drove past... car stopped damn quick, no skid and no pulsing pedal. i had abs on a VR crummydore and it definately used to pulse so i can tell the difference.

not sure if the brakes are different on the XR to other variants??

svo supporter · 29-10-2010, 12:48 AM

Working ABS means the wheels don't lock up. Only locked up wheels create smoke under extreme braking situations.

Just out of curiosity. Isn't ABS surposed to mean ANTI LOCK BRAKING? If it does, I'm sure it'll give you clues that the car should be looked at by a mechanic because you've got problems with the braking system.

NZ XR6 · 29-10-2010, 03:22 AM

Definitely something wrong - you should never get a wheel locking like that, except maybe just before the car stops. It's very strange that you're not getting a warning light though.

BTW, ABS means Anti-lock Braking System.

yelpir · 29-10-2010, 08:18 AM

Quote:

Originally Posted by mondo_broady

my mondeo XR5 does not pulse the pedal when abs is activated. i recently had to stop in a hurry when some kids played silly buggers as i drove past... car stopped damn quick, no skid and no pulsing pedal. i had abs on a VR crummydore and it definately used to pulse so i can tell the difference.

not sure if the brakes are different on the XR to other variants??

Mine is a petrol Zetec and it pulses. Slamming the brake hard at 60 km/h makes it pulse like hell. Perhaps XR5 are different but we need other XR5 owners to confirm this.

mondo_broady · 29-10-2010, 12:25 PM

you can still lock up a brake under heavy braking with ABS if the load is to great or road surface is bumpy. the wheel usually locks/releases/locks/releases etc... till the car stops.

eg: on my trip home from work a few years back when i had the VR, there was a bumpy section of road on a corner. if i was not thinking about it, i would hit these bumps under braking and the ABS would release and re-apply the brakes causing the car to understeer...

allanv6gt · 29-10-2010, 08:00 PM

Thanks for the responses.

Surface (both times) - Hot mix, nice and smooth, fine dry sunny days.
Last time @ 40km/h and definitiely no pulsing. Dealer check @ 3000km service said everything was fine.

Yelpir - thanks - yours pulses, mine don't.
Guess I'll try the 2-wheels-in-the-gravel test, and pay very careful attention to what is happening.

As someone said above.....lock, release, lock, release, etc etc

NZ XR6 · 29-10-2010, 09:34 PM

It's not a smooth ride when the ABS is working hard. When I had my moment with the truck, there was a lot going on with the back brakes, but no wheel lock as you've described. I didn't notice any pulsing through the brake pedal, but then I was far more worried about avoiding the truck.

mpsol · 30-10-2010, 04:16 PM

I did a quick test of my A.B.S and braking capacity yesterday. My car is a standard MA XR5T with about 18,000 km.

At the same time I did it with a 2009 Auto VE SS Sedan with 60,000 hard Km (FE2 suspension and upgrade brake pack - my work car, the only good thing about it is I don't pay for the fuel....)

Set up a run at about 50-55km/h, had a good couple of hundred meters to work with on a flat course bitumen surface with some loose bits. Did straight line first then did straight with a hard right turn.

XR5T - A.B.S had some small pulsations through the brake pedal, not nearly as much (or as noticable) as the SS.

XR5T - stopped in shorter distance (about 1.2 mts) than the SS on the straight test, about the same on the right turn test (weight issues I would suspect).

There appeared to be slightly more lock up on the XR5T than on the SS (SS's ABS seemed to be able to work slightly quicker) however XR5T felt more in control.

I'll keep my Mondeo thanks...

allanv6gt · 31-10-2010, 11:29 AM

Did the quick two-wheels-in-the-dirt test.
Yes, I have faint pulsing of the brake pedal from 60km/h, and the std MB XR5T pulls up straight. Without other 'distractions' I was able to pay attention to what the pedal was doing.

Might go and try it on some nice clean bitumen from 80km/h and see if I have gaps in the skid marks (denoting ABS on/off activity).

And yes, when a truck/kids/car/'roo leap out in front of you, you tend to be noticing things other than whether the brake pedal is pulsing (or not).....and finish up wondering if you need a change of underpants.

The old 2003 Outback was better at this.......

And my 40 yr old Capri is unambiguous - it's all up to the driver to stop/avoid collision. Much simpler.