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« on: 11 January 2007, 20:04:00 »
First, for anyone not wishing the read the whole of this:
Can anyone recommend a thorought competent brake specialist, preferably somewhere from SW London the Hampshire, or otherwise anywhere in SE England?
Does anyone know a garage or brake specialist who use - or the supplier of - Tech1 (Tec1?) a system which electronically opens and closes the ABS valves while pressure flushing the brake fluid? This offers the lowest cost solution if my diagnosis is correct.
Current symptoms, after not using the (petrol, ABS) Omega for more than 2 weeks over Christmas:
Brake pedal "creep" is significantly worse than before, taking no more than 4 or 5 seconds at typical brake pedal pressure for the pedal to creep down to the end of available travel - or close to the end.
Releasing the pedal and immediately re-applying it results in the original travel and then renewed creep, ie the pedal "pumps up."
Checking on an empty motorway in the early hours, braking reasonably from 70mph, I can now confirm that the pedal creep DOES happen when the car is moving - not just when stopped (one of the excuses for why this symptom"does not matter")
The pedal creep is also evident with the engine stopped and ignition off, though because there is no boosted pressure due to the servo, it is less obvious).
(As before, there is no fluid loss and the master cylinder has been changed to no effect)
The Vauxhall service manager, trying to be helpful, asked me to get an independent report confirming that these are fault symptoms, so that he can show it to the Network Q people who deny that there is and get them to authorise him to fix it.
I asked the local MOT garage who did the recent MOT to check the brake creep - no problem, they say! I pointed out that the pedal virtually reaches the end of the available travel, ie the stroke of the master cylinder - and the chap said "it doesn't - not quite!"
One car inspection company, which was hesitant on the phone about whether these are fault symptoms or not, wanted £150 to come to check it out - cash I would of course lose if they said that there is no fault. Today I went to 4 "brake specialists". The first two had side street garages rather smaller than mine at home and I could not sensibly expect Vauxhall to accept their opinion in preference to their own. At the third, the moment I mentioned "brake problems" he said that I should come back in the morning, as they would not have the spares until then. Quite how he knew that he did not have the spares in stock, but would have in the morning, before I had told him the nature of the problem I do not know - but in the time-honoured phrase, I made my excuses and left.
The 4th, Kwik-Fit in Isleworth, agreed that the symptoms were odd but were not prepared to say outright that there was a defect. So overall, I am dubious about being able to get an enforceable opinion that there is a fault so that Vauxhall give in, and for that reason am not inclined to give the car back and sue for it to be fixed or replaced.
Vauxhall's view is that this is "normal" - indeed they told me they have the same symptoms on a new Vectra in the whowroom! They also say that it only happens when the wheels are not turning, and that the ABS allows the pedal to creep down in this way.
Can anyone fault any of the following logic of why this is GARBAGE?
(1) A few members of the Omega owners web group have confirmed to me that they have similar symptoms - others that they do not, after checking in the light of my comments. So how can this be "normal"?
(2) The car did not have this symptom when I bought it a year ago - or I would not have bought it. A month ago the symptom was only just noticeable, with high pedal pressure. Now it is obvious with modest pressure. So how can it be "normal"?
(3) For anyone used to non -ABS cars, pedal creep is an unmistakable sign of a fluid leak - so if this ABS system was designed to do this, the handbook would surely have pointed out that the symptom is "normal" - but it does not do so.
(4) Nothing I have found on any web site, for MOT testers, VOSA etc, nor any MOT tester seems to have any official circular stating that this is not a fault symptom on these cars.
5/ If pedal creep WERE normal - how would a driver know that a leak was developing elsewhere - eg in a master cylinder seal - before it became dangerous?
6/ As I understand it, ABS valves, being electrically operated, are either open or closed - no proportional opening is possible. When triggered they chatter open and closed at 30 cycles per second, making that rattling sound and pulsing feel on the brake pedal. As I understand it the 4 valves - one for each wheel - are the only designed-in way that fluid can be released deliberately. All those being the case, how could it be possible for a "normal" valves to allow a SLOW leak? If they are closed, they allow no leak, if they are open they allow a major leak, and it is not possible that they could cause a slow leak by chattering, as they are designed to do, because (a) the chattering would be clearly audible and (b) easty to feel on the brake pedal.
7/ I refuse to believe that anyone would design a system that would allow the pedal to take up all or almost all of its available travel
8/ If the system WERE designed to allow the pedal to creep down almost but not quite to the end of its travel, the system would need to know when the pedal/master cylinder had reached that point - for example. by leaking the fluid through a hole which gets covered up as the pedal reaches that point. Unless and until someone confirms that this is what happens, I refuse to believe it.
As things stand therefore I plan to find someone who can use the Tech1 or similar system to try to clear the fault, and if that fails get the ABS valve block replaced myself, and when I can then show that the symptom has been eliminated, ask Network Q to pay
see also brief next post
