Is my ABS mal-functioning?

[detroitmusclevan]

Hi,
Hi,

Just bought a used van, under 1 mornth warranty.

Drove to Devon last night.

Brakes (on 2006 135 CDTI Transit) generally ok except for the following:

After prolonged periods of fast lane cruising (15 mins plus), when I go to break, the pedal sticks at 1 cm down, there is a rapid clicking which I can feel through my foot for 1-2 seconds (during which the van does not slow down!), then the pedal drops and engages the brakes in the normal fashion.

Doesn’t happen every time but at least 3 times out of probably 8-10 applications under these conditions.

Obviously this (delay) is not ideal and presents a safety risk.

Dealer mechanic says this is normal ABS operation but I am sceptical as a 1 second braking delay on a motorway can't be ideal and why does it only happen after prolonged steady higher speed cruising?

Any ideas?

Thank you,

detroit
P.S> This is the newest vehicle I've ever owned so go easy on me if I'm being stupid please.

[Vee4]

Welcome aboard.

Interesting! Check this topic:

viewtopic.php?f=4&t=49185&start=0

Any similarities to your problem? As previously explained, I'd rather not have ABS so I can't comment from experience but I wonder if it is going into 'emergency stop' mode. Have you tried depressing the clutch pedal at the same time? Obviously, you should try that on a clear road with nothing behind you in case it does decide to do an emergency stop.

Also, is it possible that the sensor that tells the system you have taken your foot off the accelerator pedal is slow in responding?

I hate it when vehicles try to do the driving for you.

[detroitmusclevan]

Hello Vee and thanks,
Yes it does sound similar, except they don't mention the characteristic ABS pulsating (fells more like clicking).
I asked the AA inspector about it, he thought the occurrence only after prolonged high speed indicated that the higher vacuum at the higher speed might be adversely affecting a valve on the servo. Which sounds expensive.
The garage, unsurprisingly, are claiming it's all normal and are offering to clean the sensors and some sort of rod which accumulates the 'hall effect' which ABS sensing relies upon.
The fact is I don't have much experience of ABS, I know my 10 year old mondeo doesn't click and delay braking at 80 mph.
I also know that I need to nail this down before my warranty (got 20 days left) expires.
The garage boys are being slippery.
What to do? Is it worth taking it to Ford for a definitive check?
Help, anyone!
detroit

[Vee4]

Is it a Mk6? The ABS computer can be 'diagnosed' by a suitably equipped Ford dealer. If it's under warranty, surely they should do that for you. If there was a serious fault, I guess the warning light would be on but there are many sensors involved (wheels, pedals, etc.) so perhaps one of those is suspect.

[FATBOYFIN]

I have to have a 135 with ABS I drive it often through France and Spain somtimes not braking from one fuel stop to the next on the motorways but I have never felt anything that you describe only ever smooth and proper braking, the only time I feel the ABS cut in other than when it should is if I brake while on full lock I feel it pulsing then but I was told this was normal, hope this helps

[detroitmusclevan]

Is it a Mk6? The ABS computer can be 'diagnosed' by a suitably equipped Ford dealer. If it's under warranty, surely they should do that for you. If there was a serious fault, I guess the warning light would be on but there are many sensors involved (wheels, pedals, etc.) so perhaps one of those is suspect.

Vee,
It's a Mk6 i.e. the pre-remodel end of 2006.
w.r.t. warranty, it was bought from a fleet disposal co., the warranty is theirs i.e. a pledge on the invoice.
Getting them in the net over an expecnsive brake overhaul is going to be interesting I think.
Hopefully the service they promise will sort things out, if not it's going to FORD Gloucester for £80s worth of testing.
We'll know where we are then, they can sort it out or I can sue them (one would hope).
Fingers crossed.
Detroit

[detroitmusclevan]

I have to have a 135 with ABS I drive it often through France and Spain somtimes not braking from one fuel stop to the next on the motorways but I have never felt anything that you describe only ever smooth and proper braking, the only time I feel the ABS cut in other than when it should is if I brake while on full lock I feel it pulsing then but I was told this was normal, hope this helps

Thank you.

[STEVE P]

I have had this and found an easy fix on the 52 Jumbo I used to have.

If you look at the tyres I expect you have more tread depth on one axle to the other.

When I had my Jumbo I used to get this hard pedal and took it straight to the dealer, he diagnosed warn drums and replaced them. No change and he reckoned he would have contact Ford. He did but they had never had it before so they reckoned it was supposed to be like that.

Any way I had replaced the Front tyres before the fault appeard and was going to replace the rears a couple of months later as they were not as warn.

Replaced the rears as planned and the problem disapeared.

My conclusin is the ABS conputer is to sensative and the differance in wheel speed front to back is enough to lock the pedal for some reason.

There I hope that helps.

Steve P

[Vee4]

Any way I had replaced the Front tyres before the fault appeard and was going to replace the rears a couple of months later as they were not as warn.

Replaced the rears as planned and the problem disapeared.

My conclusin is the ABS conputer is to sensative and the differance in wheel speed front to back is enough to lock the pedal for some reason.

It's incredible but credible! It has to be something like that since Miriam's Mum was having a similar problem with a completely different vehicle. Could it be a problem with the ABS algorithms (software)?

[STEVE P]

Could be. I told my local Stealer how I had fixed it and he just shrugged his shoulders.

When I asked if the sensativaty could be turned down on the ABS he just said NO!

I am sure these dealers prefer not to get involved in proper investigation stuff these days, they are happy to replace a widget of whatever but when it comes down to some proper ''lets see if we can fix it'' the are not interested.

Steve P

[detroitmusclevan]

Could be. I told my local Stealer how I had fixed it and he just shrugged his shoulders.

When I asked if the sensativaty could be turned down on the ABS he just said NO!

I am sure these dealers prefer not to get involved in proper investigation stuff these days, they are happy to replace a widget of whatever but when it comes down to some proper ''lets see if we can fix it'' the are not interested.

Steve P

Steve,
I think you may be a genius.
The front passenger tyre was fit for skip (cheap b%^££$*s refused to change it).
changed it for the brand new spare.
Problem (seemingly but let's withold conclusion for a bit) solved!?!?
Can't believe the so called mechanic doesn't twig to this. They've wasted 2 hours of their time and 3 on mine. ridiculous.
Still, the van was underprice, if that's the reason and it's fixed I'm well chuffed.
slightly worried about having to juggle tyres all the time, any word on de-sensitizing the ABS sensors would be appreciated.
Anyone?...
Thank you TransitForum!

Dee-troit

[Vee4]

Steve,
I think you may be a genius.

Nice one, STEVE P!

[STEVE P]

I will let you all buy me a Beer!

I thought this was general knowledge.

The dealer as I have said realy was not interested when I told him the fix.

Steve P

[foggyred]

well what can i say this site is just fantastic,Ive had a problem with my brakes since Christmas with the same symptoms as described above,i took the van in to my local garage who does all my servicing and told him the problem about my brakes fair enough he had a quick look there and then and said he couldn't see anything obvious and if i wanted it looked at properly i would have to leave it with him for a couple of days which is right out of the question as i need it for work, i told him i would look on the transit forum and see if any body could shed any light on my problem which he just looked at me as if i was mad and walked off, any way to cut a long story short over Christmas i had two new tyres fitted on the back and the back ones fitted on the front which when i think about it that's when the problem started so it must be my abs not liking my tyres in their new positions. in a couple of months the fronts will be worn out so that should solve the problem for good any way thanks steve p you just saved me shed loads of money, what a top site and god bless spell check

[Vee4]

well what can i say this site is just fantastic

Agreed on that!

The ABS computers seem to be telling us something we know already, but are sometimes tempted to ignore: good tyres all round are essential for safety, handling, ride and long-term economy.