boring technical question for V8V owners
Discussion
my car (fab tho it is) like many which are forced to sit in traffic, develops squealy brakes from time to time. This was a topic that was fairly well covered early on in the life of these cars (mine is well over a year old now) and my dealer kindly took the car back, worked some magical modifications and brought it back, sqeal free. However, since the problem reasserted itself pretty swiftly I made some enquiries and learned that its just a function of the choice of brake pad - in this case Pagid RS5s (I think). I also discovered that if you give the brakes some beans, it usually clears the problem up. I have similar pagid pads fitted to my track-only caterham, which also squeal like a hamster in a sellotape factory if you pootle around but sure do work if you stand on them.
Recently however, my usual technique did not work. The rear nearside pads just would not stop piercing the eardrums of innocent pedestrians. So I thought I would take a sneaky peek and discovered that about a fifth of each end of each pad is chamfered off to nothing.
Is this normal? I have never seen pads built like this? Is this the dealer's magical modification? In which case, with 2/5ths of the pad removed, I am seriously worried about how compromised the brake performance is.
Can anyone who knows about this stuff enlighten me? I don't want to tackle my dealer until I am pretty confident of the facts.
Cheers
M
Recently however, my usual technique did not work. The rear nearside pads just would not stop piercing the eardrums of innocent pedestrians. So I thought I would take a sneaky peek and discovered that about a fifth of each end of each pad is chamfered off to nothing.
Is this normal? I have never seen pads built like this? Is this the dealer's magical modification? In which case, with 2/5ths of the pad removed, I am seriously worried about how compromised the brake performance is.
Can anyone who knows about this stuff enlighten me? I don't want to tackle my dealer until I am pretty confident of the facts.
Cheers
M
"chamfering" the ends of the pads is a pretty normal solution for brake squeal, as the squeal is cause by the pad repeatidy slipping and gripping at a high frequency as the nose of the pad digs into the disc surface. i expect the person who "fixed" your brake squeal simply linished a nice big chamfer onto the leading edge. I wouldn't worry about brake performance with this mod, there is still plenty of pad area left, as most road pads are sized to get between service interval under worst case use, rather than sized to cope with ultimate stopping power pad area (typically race / rally brakes will run with only 50% of the area of a road pad)
Squeely pads are a problem on lots of cars, in fact Brembros (who make the AML calipers) do seem to suffer acutely. other solutions require more stainless anti-squeel shims or springs or simply the application of plenty of copperslip or similar to the back of the pad to damp the oscillations. the best solution however is to simply use the brakes harder! (easier said than do, especially in this weather!)
P.S Pads are Pagid RS4-2-2, a slightly softer RS4-2-1 might cure the squeel, but would not be recommended by AML just in case you wanted to lap the 'ring
Squeely pads are a problem on lots of cars, in fact Brembros (who make the AML calipers) do seem to suffer acutely. other solutions require more stainless anti-squeel shims or springs or simply the application of plenty of copperslip or similar to the back of the pad to damp the oscillations. the best solution however is to simply use the brakes harder! (easier said than do, especially in this weather!)
P.S Pads are Pagid RS4-2-2, a slightly softer RS4-2-1 might cure the squeel, but would not be recommended by AML just in case you wanted to lap the 'ring
Cheers
I'm very familiar with the idea of chamfering the leading edge of pads to reduce dust build up and hence reduce oscillations. However, there is a difference between chamfering the edge and removing 40% of the pad area!
Reducing the pad contact area will have a much greater effect on braking than switching to a softer compound - even, I suspect, with fade. Alternatively I suppose a different brake pad manufacturer eg Ferodo or Mintex might be worth a try.
Not only are there stainless anti-squeal shims but I have also ensured there is plenty of coppaslip already in place.
BTW, personally, distance for distance, I don't think the ring is particularly hard on brakes compared to, say, Snett. But thats a whole other story.
I'm very familiar with the idea of chamfering the leading edge of pads to reduce dust build up and hence reduce oscillations. However, there is a difference between chamfering the edge and removing 40% of the pad area!
Reducing the pad contact area will have a much greater effect on braking than switching to a softer compound - even, I suspect, with fade. Alternatively I suppose a different brake pad manufacturer eg Ferodo or Mintex might be worth a try.
Not only are there stainless anti-squeal shims but I have also ensured there is plenty of coppaslip already in place.
BTW, personally, distance for distance, I don't think the ring is particularly hard on brakes compared to, say, Snett. But thats a whole other story.
My V8V is also suffering from this continued annoyance and has already been dealer returned under warranty to stop squeal, and is about to go in again next week for the same problem. The car has 3500 miles and is driven on a variety of roads at various speeds. I have also specifically tried to get heat into the pads to de-glaze them and still the squeal persists.
My dealer Stratstone Amersham has forwarded me a copy of the Factory internal bulletin (After Sales Policy Letter 0270, issued 10/2006) regarding brake squeal "phenomena", and it suggests the solution lies in "customer self help" utilising the brakes in a "spirited" fashion and with "periodic more aggressive useage".
More amusingly it states that customer self help can be practiced to ensure that the brakes are periodically used towards their "upper design threshold" to help eliminate glazing.
Alternatively garage maintenance is referred, comprising of manual deglazing routines can be carried out. Hence mine going back under warranty once more...
Interestingly Aston do comment on most customers finding the squeal both irritating and embarrassing....and yet this is the official fix?
My dealer Stratstone Amersham has forwarded me a copy of the Factory internal bulletin (After Sales Policy Letter 0270, issued 10/2006) regarding brake squeal "phenomena", and it suggests the solution lies in "customer self help" utilising the brakes in a "spirited" fashion and with "periodic more aggressive useage".
More amusingly it states that customer self help can be practiced to ensure that the brakes are periodically used towards their "upper design threshold" to help eliminate glazing.
Alternatively garage maintenance is referred, comprising of manual deglazing routines can be carried out. Hence mine going back under warranty once more...
Interestingly Aston do comment on most customers finding the squeal both irritating and embarrassing....and yet this is the official fix?
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