Shark Man

Classic UK MY97 Turbo: Yes I know the brakes aren't too hot...uprated pads and discs up front anyway, seems to be more of an issue with the ABS.

Under emergency braking, when the ABS kicks in - the car stops slowing down !

It's a bit hard to describe, but there is still braking effort, but it seems to be reduced by a fair amount. It doesn't happen all the time - which just makes matters worse in trying to fix it

The previous times it has happened when I hit a bump, it was damp or cold, and I thought it was a grip issue (although had suspicions that the ABS wasn't helping).

But today, dry road. Not really cold....about to T-bone car that cut across infront of me at the last minute and I escape through pure luck. When I KNOW the car shoud have been able to stop EASILY in the distance given when it didn't come close.

Anyone please have any ideas on how to fix this, I have lost complete faith in the car, I was left shaking with shock and anger at how I was just a sitting duck, when in any other car I could have easily avoided the situation.

I am now going to pull out the fuse. Which leave me worried about re-procussions with insurance, MOT and if the car ever gets inspected by plod (defect notice, or after an accident - unroadworthy, etc.).

What is causing this? Seems that once it's triggered it just pulses the pedal and removes too much braking effort from the wheels that have still have the grip - no matter how hard I press the pedal.

Help please!

jowl

I can't help you on this one but an ex-neighbour has warned me about the ABS.

He has a 01 WRX and says he has been caught out a few times with ABS...says it nearlly caused him to crash a few times. Not even braking that hard...and when the ABS kicks in it slows down his braking.

Shark Man

Doesn't inspire confidence...I thought the newer Scoobs had improved ABS!

jowl

I also have a MY97 Uk turbo and never had any ABS issues.

Nearly had a failure to slow down enough for a roundabout yesterday but realised i was close doing close to 100 at the time (on a private road with a private roundabout obviously)

I never felt comfortable with ABS in my Pug 306 though. first time I had ABS but always felt more in control when pumping the pedal myself.

cong

could be just air in the sytem gett the brake fluid changed, but your brake systam should be checked over

Pedro_79

I have a similar problem on my '97 Turbo...

Fortunately I've never had to do an emergency stop, but I find even when braking moderately on an uneven surface, the ABS kicks in - especially in the wet...

And you're right - as soon as it kicks in, it's like someone has greased my pads!

Not sure about any issues surrounding fuse removal though.

scoobyboy

the common mistake people make is they think that abs gives you optimum braking and stops you in the shortest distance possible when in fact it does lengthen your stopping distance but it allows you to steer around objects thus avoiding the collision.
it is unnerving and i feel as well that if it hadn't cut in i could stop it in a shorter distance but then you take the chance of locking the wheels and it's a brave man that can take his foot off the brake pedal and reapply them when he's heading for crash to stop that happening. with locked wheels it won't matter where you steer your going to go in the direction you were travelling but the abs gives you a bit more chance to steer around it at the cost of slightly longer stopping distance.

Scooby-Mike

Its normal for abs to come on when braking when going over grids as the wheel on the grid usually stops so the abs senses that one wheel is going a different speed. My own MY97 does this, it is a bit too sensitive I agree. the more you fight the pedal to stop the car makes no difference, pain when your coming up to a junction at speed and NEED to stop.

scoobydood

I have had 1 really frightening experience in the Isle Of Man where I was doing approx. 110mph down a deserted but rather bumpy road trying to follow a friend on his bike... He was a fair way ahead of me (luckily) and he braked for a gentle bend. I braked as well but nothing happened. because the road was bumpy the abs kicked in immediately and i did not appear to slow down at all. I released the brake and re-applied and slowed down OK. Was frightening because I wondered what would have happened if it had been an emergency?

2nd experience was a very tight bend on a country road (which I know very well)... wasn't going fast +/- 50 - braked just before the bend. Hit a dip in the road as I entered the corner and ooops.. no brakes. Only just made it round that bend!

3rd experience was a wet road - straight line approaching an intersection. Braked - hit a patch of water. ABS kicked in but car slowed fine. No problem....

Experience 1 & 2 make me want to get rid of ABS. Experience 3 was minor and if it had been another car and the front locked up at the point I would have released and braked again. Used to it in my previous car....

Shark Man

I'm sorry, but this is irrelvent to my case- its something to do with my car only. Not with the operation of ABS in general. Any other ABS equipped can stop in far shorter distance than what I experienced in my car ON A DRY AND SMOOTH road at relatively slow speed (30mph).

There is blatantly somthing wrong if I can be out-braked by an ABS equipped Vauxhall Corsa on Roadchamp budget tyres (most lethal tyre in the UK IMO)

Air in the system is possible, The fluid was changed last year. Having beld over 0.5 lires of fluid out each corner myself, I know there isn't any air in the general "normal" part ofthe braking system, but there appears to be no way on bleeding the ABS pump/distrbution unit, which I feel could be a plausible explaination of inferior performance if there is air present within the unit and associtaed pipework, as normal non-abs braking is fine. So how could I bleed this? I guess I would need to activate the pump manually somehow.


I will change the fluid anyway and pay extra attention to any air bubbles, just weather there is air in the pump/distribution unit will remain questionable.

I already know a bit on the ABS's operation of its various compenents, the system operates by usage of a pump to pressurise the fluid and then it is distributed to each brake via solnoid valves that open and close according to the signal fed from the control unit

I was thinking perhaps there is a fault with one or more of the solonoid valves in the unit, whereby it is sluggish in reaction to a voltage being applied/removed. Meaning possibly that either one wheel snatches or locks more than the others - causing a vicious circle in which the overall brake application is reduced by the control unit to try and compensate, and thus reduced overall braking. Or that one or more solonoids do not open fast or long enough to allow enough pressure to be applied to the brake calipers. Theorectically each scienario would have similar effect and also depend on which wheel locks and initially triggers the ABS (which would also explain why it doesn't happen on every single emergency stop).

I've been driving today without ABS, and although its slightly damp, the emergency braking performance is far superior to what I experienced last night. I'm lucky that I spent half my life driving non-ABS cars, so I'm thankful I know how to control the brakes on a car in a steer-to-avoid emergency stop situation. Which is funny really, as that is what I had to do yesturday - thanks to the ABS. Any other non-car orientated person would have probably froze in shock and ploughed straight on into the car (I know my missus would!).

Miniman

iTrader: (2)

Not sure if this is the same.

I'm not sure I trust my ABS either (WRX MY02). For example, if I am driving along a road and not necessarily fast, I brake hard for a junction, but go over a metal man hole cover. Obviously one of the wheels skids, instantly the ABS kicks in and backs off the braking.

It feels like the car actually is accelerating again - I'm sure its a perception thing - my body/mind is expecting the deceleration, but finds its not happening, so interpretes this as acceleration.

I have found this a few times with man hole covers or bumps, where the ABS appears to kick in far too early (IMO). Garage assures me the ABS is working ok and I do manage to stop OK, but its still a very unnerving situation.

I've had more of these dodgy metal man hole cover/bump braking situations than ones where I have actually needed the ABS in a emergency braking situation. But then again I'm reluctant to kill the ABS in case I really do need it.

Beastie

iTrader: (2)

Sharkman I had a similar experience in another car that i owned. Turned out that the back brakes were not doing their job, causing all the braking to be done at the front. This made the ABS lethal as all the braking was being done by the front brakes which made the ABS kick in earlier and be less efective at stopping. Worth checking IMHO.
I had two very close calls before i realised what was going on.The first call I had to mount the pavement to stop hitting the guy in front - some gravel on main road set off ABS then no stopping me. Joker in front stopped suddenly on clear road no indication and his brake lights were not working.

MR_MAJ

ive got a 52 reg wrx and have had similar experiences, the worst one was when i crashed into the back of someone that braked hard, the abs kicked in and the car didnt slow much at all, couldnt swirve whilst braking as there were cars in the other lanes.

After I got the car fixed i went out to practice braking distances under emergency situations to get used to how it responds!

Shark Man

You maybe onto something there, Rear pads are still the OE ones (not worn out, so not uprated them yet). But if they perform like the fronts, it maybe cause for concern.

Thing is, how do you know the rears aren't working?

As you can't put the car on brake rollers to test them (being 4wd). I suppose I could take off the rear calipers and give the pistons a work out incase they are sticking, unless anyone has a better idea?

Shark Man

Update:

Well here's an interesting twist.

Since the last post I've changed the fluid and bled the system, can't say there was any difference in braking, but I was too scared to put the abs fuse back in...yes, it scared me that me much - that's how close the last inccident was!

Well, out driving, today was a damp/wet road. No abs, just started the journey. And thought I play with the brakes and see how good the stopping was. And heres the thing, for the first few attempts the rears kept locking, latter attempts the fronts locked Obviously wet road meant stopping distance and grip wasn't going to be fantastic, but that got me curious.

Now two things: Either, because it's an ABS equipped car. The brake biasing is set more to the rear, so there is a higher likelyhood of the rears locking.

Or, the front brakes are cold or glazed over and cannot bite as well as the rears.

If the latter is the case, then that would severly effect the dry stopping distance and would probably play havoc with the primitive ABS system which is optimised to prevent the fronts from locking more so than the rears.

The pads are uprated. EBC Greens, now I know these aren't favoured. BUT that was to do with hot temps and brake disc warping, however I don't drive hard enough or make a habit of cooking brakes, except for the original pads, which I'm not sure were OE or not, but were awful, overheated and faded and completely refused to work if I washed the car or drove through a fjord (seriously, no brakes what so ever). The EBC's were a massive improvemnet.

So, if it is glazing or cold pads, what can I do? I chose these pads as they claimed to work as well as the orginals when cold, they seemed to. But now I'm not so sure. Most other fast road pads sacrifice cold performace as well, so sawpping manufacturers would be hit and miss.

So I am stuck with what to do...put matching pads on the rear (currently OE - I think). Which should balance things out. Or swap the fronts back to OE, which I know will work when cold (but hopeless when hot). Or risk swapping the fronts to another manufacturer of pad - which to all intents and purposes could have the same cold performance.

Perhaps I inadvertantly stumbled onto the real reason why the Classic scoob's ABS isn't that good? (as everybody and his dog seems to uprate their front brakes and complains about the ABS). Makes you think!

Hopefully, with time permitting. I'm going to borrow a brake roller tester tomorrow - I know you should not use them with 4wd, but I have a trick. I'm going to unbolt the rear propshaft and push the car onto the rollers I'll try to do a hot test and cold test to see what difference there is.

I should add that both front and rear discs have virtually no wear. Fronts being uprated grooved discs, so the pads shouldn't glaze, but who knows!

I'll get to the bottom of this eventually. If anyone has any further ideas or solutions feel free to post

Shark Man

johnfelstead

the state of your dampers and the quality of your tyres play a major part in how early the ABS kicks in. If your dampers are tired/old they will improve matters when renewed. You should match your pad materials front/rear for the reasons mentioned, you dont want the rears working better from cold than the fronts.

Shark Man

If it was the tyres or shocks I'd expect the problem with the abs would be pretty much consistent. And be more prominent on bumpy or wet roads respectively. But the problem can happen on the dryest and smoothest of roads you can imagine at relatively slow speeds (40mph max).

Well, tried it again on a dry road and yep...Rears were locking when cold, front's lock after a few blasts to heat the brakes up. Didn't get round to the roller tests I'm afraid , but the tests were pretty conclusive and the road surface and tyres couldn't limit the grip this time.

So for now, I happened to have some part worn OE pads, which I kept from when I changed the discs (due to wear). Re-dressed the surfaces and stuck them back on. I'll need to wait for a few hundred miles to bed them in until I find out if there is any improvement. Haven't got the pads wet yet. It should be interesting to see if the wet braking problem (i.e complete lack of) returns again.

Looking at the pads that I just took off, they are glazed...they are more shiny than the car!

So, the rears haven't got that much life in them, so I'll be needing a new set soon (glazed front brakes may explain some of the wear ).

Now what do I get? fast roads or OE?

Bear in mind I'm not a heavy brake user, so most of the time I use the brakes they are pretty cold (unless I'm late or hacking about the lanes...which is a rarity in this day and age of Talivans etc.). So, is there any decent pads out there that actually work ok cold and don't glaze? I might just stick some OE spec Ferrodos on as I can't see I'll benefit from fast roads pads anymore.

Andrew Timmins

The roads do seem very greasy this year, even when they look dry there is little grip. Low temperatures in tyres at the start of a journey reduce the available grip too. Have you owned the car long? Has the brake problem just come on recently after months/years of acceptable performance?

If you are looking for a descent set of pads front and rear the Pagid Fast Road ones seem to be good without breaking the bank.

Shark Man

But that wouldn't explain why the backs lock up when cold...then the fronts lock up when warm!

I've had the car for about three years now it is a second car, but I use it more regulary these days. I'd say the perfomance reduction was so gradual I didn't really notice, until I pulled the ABS fuse after the initial fright and realised the rears were inclined to locking up more easily than I would expect.

Can you confirm that pagids actually work when cold and do not glaze? FR pad manufacturers seem very vaigue on actually how well they perform from cold.

johnfelstead

Very happy with my EBC Ceramic reds for fast road and normal trafic driving.

stockcar

if you want some information about pads then feel free to get in touch and i'll try and "steer" you thro' the maze..................

alyn

Andrew Timmins

[QUOTE=Shark Man]But that wouldn't explain why the backs lock up when cold...then the fronts lock up when warm!

I've had the car for about three years now it is a second car, but I use it more regulary these days. I'd say the perfomance reduction was so gradual I didn't really notice, until I pulled the ABS fuse after the initial fright and realised the rears were inclined to locking up more easily than I would expect.

Can you confirm that pagids actually work when cold and do not glaze? FR pad manufacturers seem very vaigue on actually how well they perform from cold.[/QUOTE

Just the difference in pad compounds could explain why the rears lock first when cold. The cold damp roads just decrease grip and make wheel locking more likely. If you have the same pad compound front and rear the rear locking problem should be reduced, unless there is a mechanical problem. As more braking force is at the front the front pads should warm up quicker than the rears.

Alyn would know as much about Pagid pads as anyone here, probably best you seek his advice.

Shark Man

Currently bedding in OE front pads

I'm not going to sniff at any other pads until I've bedded these in and can 100% confirm that this is the cause.

I'll be back in 300-500miles

jmk

Andrew - I'm running with Pagid 4.2.1 from Alyn and they feel great - no noise and not troo much dust. Can't remember what I paid so email Alyn.