Flexing 996

[bertman]

Have you ever replaced the wheel bearings in your ownship of the vehicle?

No haven't replaced them,I will suggest that to steve the guy who owns the garage,it wasn't mentioned as a contributing factor though.

[T2Andy]

So the 996 monoblocks are not as good as we thought ,or they may not be ideal
for S2 application i know a few people who cant get rid of the soft peddle,from
experience porsches have a firm\hard pedal

[bertman]

well i think you have just summed up what has just happened to me. with the engine off the pedal was rock solid started the engine and with the extra presure from the brake booster hydraulics the pedal went spongy i bet i have the same thing as you . have you had to replace many discs? as i am on the second set in 12 months of up grading and they are pretty much ****ed as well .

I take you have done the 996 upgrade?Haven't replaced my discs yet,they have done not a great deal of mileage yet

[bertman]

So the 996 monoblocks are not as good as we thought ,or they may not be ideal
for S2 application i know a few people who cant get rid of the soft peddle,from
experience porsches have a firm\hard pedal

I am sure the monos are great brakes,but various members have maybe obtained brakes with this factor,just an idea.
I have spent huge monies trying to eradicate this problem.Not bothered about the pedal feel,just want them to blooming work well,which they have on occaision.But the last week or two has seen them get worse

[denniselbows]

So the 996 monoblocks are not as good as we thought ,or they may not be ideal
for S2 application i know a few people who cant get rid of the soft peddle,from
experience porsches have a firm\hard pedal

do you know what set up a porsche has for the master cylinder is there a servo or brake booster fitted? perhaps the baking pressure of a s2 is a lot more than a posche and is why the caliper is flexing. if the s2 is heavier than a boxster there would be more force needed to clamp the disc to stop the car.not sure if you all will get my thinking or even be on the same clowd as myself

[denniselbows]

I am sure the monos are great brakes,but various members have maybe obtained brakes with this factor,just an idea.
I have spent huge monies trying to eradicate this problem.Not bothered about the pedal feel,just want them to blooming work well,which they have on occaision.But the last week or two has seen them get worse

it certanly does get to you after a wile dosent it

[T2Andy]

When you say they dont work well Rob ,do you mean fade or bite

[bertman]

When you say they dont work well Rob ,do you mean fade or bite

Neither mate,they are just pants.Thats my scientific explanation for them
They have always been hit or miss,but more miss.I can't drive the car properley,cause they are just as bad as the standard brakes,on the s2.

[twoqu]

No haven't replaced them,I will suggest that to steve the guy who owns the garage,it wasn't mentioned as a contributing factor though.

Its very difficult to assess the state of the bearings. Sometimes you get a floaty feel or a bit of groaning. I would seriously consider getting them replaced. Those A8 discs are no lightweights! Wheel bearings are one of the most overlooked components on these and indeed other Audi's due to the aggro involved in doing them.
Would be worthwhile to see how much run out those discs have.

[bertman]

Its very difficult to assess the state of the bearings. Sometimes you get a floaty feel or a bit of groaning. I would seriously consider getting them replaced. Those A8 discs are no lightweights! Wheel bearings are one of the most overlooked components on these and indeed other Audi's due to the aggro involved in doing them.
Would be worthwhile to see how much run out those discs have.

I will ask him to check the bearings and ask about the influence on the brakes.I can see the logic behind checking the bearings,if there was play it certainly wouldn't help.But I don't think this what the problem is though.But I could be wrong......I have been wrong so far

[denniselbows]

i dont see how a wheel bearing can corse the caliper to flex/ spread open

[T2Andy]

I would try some more callipers but i think you would do that anyways ,
im going to try some ferrodo D2500 PADS ,Andy caseys brakes felt very strong on the
track with these

[twoqu]

Suppose the last thing to ask him about is pad "knock off"!
To be honest its unlikely but...
This is where the disc run out is excessive and it effectively knocks the pads back further than they would ordinarily sit. The consequence is that when you come to reapply the brake, the pedal has to move further to push the pads back into position if that makes sense to you. I would have thought it would happen to both pads but I guess it would depend to a certain extent on were the run out or distortion of a disc had occured.
Hope you get some answers shortly!

[Keeper of The Kitten]

Are both calipers exhibiting the same kind of deflection? I just don't think the load you can apply will bend them that easily. If it was moving 2-3mm I would be looking for a crack.

[bertman]

From reading about the monoblocks it does seem that there is a tendancy,especially if they have been subjected to high amounts of heat that it is possible for the metal to become weakened,and when you couple that with the higher loads that an s2 master cylinder might put on the pistons within the caliper,the tedancy for flex is greatly exaggerated.
The question is,can anything be done to strengthen the caliper or has anyone used a different master cylinder to reduce the amount of pressure going to the pistons?