AU1 danger warning plastic brake boosters!!

[Stav]

I am compelled to let my fellow au 1 owners that our brake boosters are dangerous!! On Monday mine gave way and I lost my brakes!! Only with a 20 metre gap and all of my weight on the brake pedal could I stop. So luckily I was close to home and just managed to get it to dads place. We went up to greenacre and got another au1 booster.Fitted it that afternoon and I was motoring again. Today after doing some work in Watsons Bay having made it past Broadway I heard a familiar hissing noise and lost my brakes ..again!!

I managed to get it to greenacre again at 15 kmph in peak hour traffic.Got another booster and stuck it in.. In the meantime in conversation with the wreckers he pointed out that the au 2 got a bigger booster made of steel!!

It seems ford knew of how dangerous this booster was but were never bothered to recall and upgrade ours. the au2 booster will not fit straight into our cars because its bolting pattern is different.However the wrecker gave me an au2 booster to try to install. He told me it was the first au2 booster he got rid of.

Anyway please be aware of this problem as it isnt fun without brakes.

[EFFalcon]

question.

why is it failing?
why are most other peoples fine?
I'd say theres more so a problem with your car, then the brake boosters.
EF/EL had plastic ones too, and the main issues i've heard with them have been to do with heat sources too close and thus melting them, or engine pulling on the vacuum line and splitting the fitting that goes into the booster and creating a big leak.

[Stav]

Vacuum is fine.There was no split at all.Both times the suction was right at my feet and the engine idled higher.The ef el ones have the same problems.It was mentioned in the conversation. Both times I had just stopped and then the brake pedal went alot farther in /At the same time the vacuum was heard. I dont know why it failed? But 2 in one week. I have done 80,000 kays on the old booster.I wish I knew why it failed ? I hope number 3 holds up.

[Stav]

I am going to have a look inside the booster tommorow to see what happened.It seems that the booster is too small for the pedal travel.When the brakes wear a little and pedal moves down a tad it sounds like the diaphram being ripped out of where its supposed to stay stuck..

[Stav]

I wanted to sneak out to wsid tonight and there is simply no way I am racing that!!

Maybe I will do the au2 conversion.

[Smoked]

Thats scary mate. John does make a valid point about it potentially not being a booster issue. Id agree and say there is something else not good in your braking system at this point.

[XR6-VCT-2000]

omg - a plastic brake booster ! , I think for safety sake it would be wise to try to adapt the steel AUII brake booster, now that you've got it anyway ;) .gl

[Stav]

Originally Posted by Smoked

Thats scary mate. John does make a valid point about it potentially not being a booster issue. Id agree and say there is something else not good in your braking system at this point.

On the face value I would say I agree.However I believe it is a combination of 2 things.
1/ Primarily the brake booster is too small.The full pedal travel would collapse the diaphram in half the time as an au2.The a2 is very close to twice the size.

2/ As my brakes have worn and the pedal has naturally travelled down a little it puts too much pressure for this booster.The au 2 doesnt not do this because of the boosters size and extra diaphram travel


Dam I was trying to be diplomatic in my looking at it but so far it appears that I am right and the booster is a piece of crap!!

I am going to cut it open and see where it failed.

[buickman]

Never had a problem with the booster with the AU1 that I had. I changed my front pads well before they got to low. Being 2 boosters now that has given you problems I would be looking at the master cylinder or a leak somewere as well as the calipers that might be blocked with dirt that might be some cause of the problem.

[Orbit]

i saw it happen going down a 70kph hill :
the lady had her wits about her to use her transmission to slow down, and ride it out, but geez it was a close one....she had to navigate a raoundabout quite quickley. luckily there weren't many people around.

[Free347]

I've always understood the AUII boosters to be superior to the series I but have never heard of the series I boosters have a problem. I've not experienced any problems so far (and hope I never do). Am keen to hear the outcome of your autopsy.

[EFFalcon]

AUII boosters are bigger because of the twin piston setup.

my parents AU1 wagon's brakes are flawless.
if this was a brake booster problem i think a lot more people would be having problems.
There is most likely something else causing the brake booster to fail.
installing a larger/metal one may just be a bandaid fix.

[Stav]

Alot of au1 drivers dont do 250 km a day in stop start traffic.What can go wrong with them?The diaphram rips.Why ? Because they are crap . Last night me and my liitle bloke bled the brakes so that the pedal doesnt go so deep into the booster and wreck the diaphram.Hope this fixes the problem.

Thank heavens that your au 1 brakes are good because it sux when they go. They only have to not work once for them not to be flawless and to end up in some trouble.
So tell me why they wreck ?

[Stav]

Originally Posted by EFFalcon

There is most likely something else causing the brake booster to fail.
installing a larger/metal one may just be a bandaid fix.

I dont know about that..especially since the wrecker has never sold an au2 booster but dozens of AU1 boosters.Whatever goes wrong you would think that au 2's would have the same problem.

[EFFalcon]

I can't tell you why they wreck because i havnt seen one wreck and havnt pulled it apart to look.
any failure i've seen with plastic brake boosters has involves exterior breakages.

the fact that AUII's dont have the problem could be for heaps of reasons since there was a number of changes betweent he 2 setups.

perhaps your brake system wasnt upto par, you say yourself you've bled the brakes in an attempt to 'fix' the problem.
maybe a well maintainted brake system won't have this problem?

[Free347]

Does that mean there might be a trap for those updating their AUI brakes to twin pots?

[The Dok]

Some interesting information about the booster issue, thanks "Useless". I have had some issues with the brakes on mine (AU1) however more related to pad/bleeding than anything else. Before "EFFalcon" turns this thread into another shytefight, why don't we turn to the guru's who would know if this is an inherent AU1 problem, you know, the absolute "oracle's" of the AU..................Taxi drivers. After all, if they had longetivity in taxi's, then there would be no reason to be concerned. Just a thought! :jab:

[EFFalcon]

shi* fight?
i'm simply questioning if the booster is primarily to blame.
start your own shi* fight "The Dok"

[The Dok]

Originally Posted by EFFalcon

maybe a well maintainted brake system won't have this problem?

Perhaps you should word your "opinions" differently then!!!!!!:

[EFFalcon]

see the question mark?

?

that denotes it as a question.

[Racecraft]

Well, well,

Yes the AU1 boosters can fail, do they fail often? NO!!!

I have seen more flexible brake line failures over the EF-AU1 than brake boosters

It isn't the plastic casing that is of concern, which EFFalcon alluded to, more simply the manifold pressure or lack of that controls the booster.. Now they are that rare a failure that I am only going by memory as it wasn't something I had to put alot of time into, but iirc the car that they failed on had a problem with the manifold pressure.. It used heaps of fuel and was just generally pooped out, it went thru 2 or 3 over the 4 years I owned it.. 2 or 3 over 25 AU1's running 24/7 isn't a major problem in my books

and yes the pedal goes hard but the car still stops just the same, you just have to apply alot more force.. Scarey when it happens, no doubt but worse if when the pedal goes to the floor from a split line and no fluid.

[The Dok]

Originally Posted by EFFalcon

see the question mark?

?

that denotes it as a question.

Makes absolutely no difference to poor sentence structure!!!
I'm sure "Useless" started this thread to be of some assistance to AU owners, by making a statement like that, combined with the fact you don't actually drive/own an AU, it's probably not an issue you can comment on with any authority. End!!!

[Racecraft]

Originally Posted by The Dok

Makes absolutely no difference to poor sentence structure!!!
I'm sure "Useless" started this thread to be of some assistance to AU owners, by making a statement like that, combined with the fact you don't actually drive/own an AU, it's probably not an issue you can comment on with any authority. End!!!

that EFFalcon doesn't drive one is irrelevant, his parents do and the S1 brakes are so similiar to the E'series set-up he is entitled to comment ...

[EFFalcon]

where exactly have i stated i don't drive an AU1? the forementioned AU1 is sitting 3 metres away from me so chances are i do drive it.
How ever, raising a question reguarding to maintenence was in now way implying useless' brake system is in dire condition, simply that if something as simple as bleeding the brakes fixes such issue, then perhaps the brake booster isnt at fault.

[Stav]

Originally Posted by Racecraft

Well, well,

Yes the AU1 boosters can fail, do they fail often? NO!!!

I have seen more flexible brake line failures over the EF-AU1 than brake boosters

It isn't the plastic casing that is of concern, which EFFalcon alluded to, more simply the manifold pressure or lack of that controls the booster.. Now they are that rare a failure that I am only going by memory as it wasn't something I had to put alot of time into, but iirc the car that they failed on had a problem with the manifold pressure.. It used heaps of fuel and was just generally pooped out, it went thru 2 or 3 over the 4 years I owned it.. 2 or 3 over 25 AU1's running 24/7 isn't a major problem in my books

and yes the pedal goes hard but the car still stops just the same, you just have to apply alot more force.. Scarey when it happens, no doubt but worse if when the pedal goes to the floor from a split line and no fluid.

This is interesting.My cars fuel economy since the edit is around 450 kays with city driving.It is the best its ever been. The wreckers checked my vacuum and said it was good. Coincidentallly the problem had started a few days after my auto gearbox had been replaced in the au? Do you think this can affect it?

[I6corp]

Calm down guys, honestly i didnt take EFFalcons question, as a bad thing!

And it could well be that a well maintained brake system would not have this problem, when u think about it, a well maintained system shouldnt have any problems... or if u did find one, you would fic it before it became a problem. IMO

[buickman]

Originally Posted by I6corp
[QUOTE

when u think about it, a well maintained system shouldnt have any problems... or if u did find one, you would fic it before it became a problem. IMO

Your right on with that comment

[FordGirl]

Originally Posted by useless

Alot of au1 drivers dont do 250 km a day in stop start traffic.

You overlook all the cabbies in this country? If there was an actual problem with them, you would've thought people would say "hey, that happened to me too!". I dare say its a problem with your car...

[Barry_v]

perhaps your master cylinder is to blame, by allowing too much travel.

[SIKSIX]

Since we are on the brake subject, i heard that S1 upgrades had a bigger/better brake booster?

Also on the problem, could it be a seized caliper piston? because we had that in dads XF and gave him greif but did not cause him brake faliure!