When bleeding the lines don't forget the master cylinder bleed valve, which is supposed to be done first. And don't forget to bleed the clutch.
Greg
Greg
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They can have my car when they pry my cold dead fingers from the steering wheel. -
tried the brake pedal test with ignition on and off........ no difference really.......took the car out again and really gave it some stick........abs worked perfectly but there a distinct boing boing noise from the front...... is this the abs sensors that I've read about somewhere?
KevinComment
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The boing noise isn't a spring problem is it?Originally posted by chancha
I had that when parking my CQ20V.
DavidComment
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David, dont think so..... read somewhere about incorrectly spaced abs sensors giving this noise. Cant see how they would give this noise however.........Comment
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You can't do a brake upgrade without consideration for piston sizes. Our cars are under servoed as they are. I run 6 pistons and through careful selection have no increase in travel and do not suffer a hard pedal.1995 S2 Avant with some upgrades
Designun Limited....
Aerospace, Space and Motorsport Design Consultancy and hardware supply.Comment
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If the ABS sensors are wrongly gapped or are dirty, the ABS pump can kick off at low speeds when you touch the brake, while parking for example. This makes a whirring noise and vibration in the brake pedal.
Check the caliper brackets are tight. Wheel nuts?Comment
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FFS, what a complete bodge up of a brake setup. Brakes are life or death stuff. If you dont get them right then its asking for trouble. Does he sell this stuff through a garage?? If so i would get an engineers report on it and sue him. Its damn right dangerous.
I dont think its a case of brake bleeding on this one. If its been bled that many times then there is no way air is in there. Servos on these cars work the same with engine off or on.
Kevin I will take a look at this for you when im in scotland in a couple of weeks, but i would suggest that the car isnt used until sorted out. Its not exactly a slow car to have **** brakes.sigpic
Tom C - www.rcmr.co.uk
Audi UR Quattro
Audi 100 C3 2.0 5 cyl 115ps
Audi S2 - 07k engine project aiming for 800ps
Audi B5 RS4 645ps 911nmComment
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A car that locks its rear wheels before the fronts is very dangerous. This is a very serious issue on a safety-critical device. Agree with Tom, do not drive this car under any circumstances.1995 S2 Avant with some upgrades
Designun Limited....
Aerospace, Space and Motorsport Design Consultancy and hardware supply.Comment
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Errr..!Originally posted by chancha
The idea was to start the engine.
Physically I don't think there is a lot of difference in size of the caliper. The critical element is the piston size. Ask Newsh what wheels he has.
Unfortunately have to agree with Audiman. If your are dealing with a self appointed expert you shouldn't have any trouble. Me, I'm a enthausastic amateur. After all brakes are safety critical!Comment
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Ok, the 996 conversion is on my S2, the ur has stock (late) brakes, like the ones I took off my S2.
The way to find if the servo is working ok is to start the engine and let it idle for a moment, then switch off, push the brake pedal down repeatedly and count how many times you need to press it before it goes hard, 10 - 20 is ok. Less and you have a prob with the brake system. The ur has a diverter which splits braking power between the front and back, you may have a problem there, there's a few things about the ur that're different to the S2, you could maybe try http://www.quattroforum.com
You didn't say if you'd washed the protective coating off the discs before fitting?Comment
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Incidentally, the stock RR brakes, if fitted with decent discs and greenstuff pads, work pretty well IMHO. At least they do on my WR which is maybe not quite as heavy..Comment
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Ahh!Originally posted by newsh
You were just ahead of me on that one! I was wondering how you managed to cram an A8 disc under the Ronal! It all makes sense now!Comment
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hmm....
can't really help out with the problems I'm afraid.....but parts wise,
The part number you gave earlier: 996.352.421 is definately a carrera 2/4 rear caliper.
The matching unit should be 996.352.422.
Colour is irrelevant to the dimensions. You should be able to get a matching pair in either red silver or black.....
I guess if its to go under 15,s then you're disc size will be correspondingly smaller & hence the reason for using rears. Do you know how thick the discs are you're using???
Having said that, If the rest of the hydraulic system is the same as on the S2, I'd have thought that using calipers with smaller pistons would give you a firmer pedal feel than the rest of us see with 996 front calipers......?
Front 996 calipers have 2x36 and 2x40mm pistons
Rear 996 calipers have 2x28 and 2x30mm pistons
I think the sizes for the standard G60 calipers are on pauls website. Anyone fancy doing the calculations?Comment
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Be careful when calculating as you have to consider the distance the pads travel too for a given master cylinder displacement as the standards are sliding calipers. It is not just a straight ratio of total piston area per caliper for comparisons.1995 S2 Avant with some upgrades
Designun Limited....
Aerospace, Space and Motorsport Design Consultancy and hardware supply.Comment
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Alistair,
Don't think calculations are necessary. Evidently there is a considerable difference in piston size as I expected. The only option, if he wants to keep those calipers is to find a master cylinder with a smaller bore than the one he has. Actually, if you have an RR, perhaps an MB one would have a smaller bore. When they used the wider vented discs on the 200q they used a larger one. Perhaps this is also the case on the Ur.Comment
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