Rolls

iTrader: (2)

Hi guys - got a question for you all.
My car has 355mm floating discs, and it seems to occasionally have a knocking like noise when you are driving it, coming from the front nearside..
it doesn't do it when you corner, doesn't do it at low speed (although the disc's do obviously move about and make a bit of noise), but it does seem to to it at higher speeds on the m/way - say at 60 or 70 mph - it almost sounds as it you are driving constantly over small cat-eye's....

I've just taken the wheel off, to check everything, it it all seems to be ok - but the discs to seem to be able to move a fair bit - and 2 of the bolts on the face of the disc have lost their little washers so that are moving about more too... - how lose should all of the bolts be for the disc's? - do they seen to be "set'up" periodically, or are they fit and forget?

cheers for any help

Rich

NUTS RuS

iTrader: (35)

Which bolts you on about ?

The disc to bell bolts?

They should be 11-14 Nm and should use the clinch type nuts so they dont come loose

Rolls

iTrader: (2)

Yep - they're they kiddies...
I'll get some pic's in the morning as to how "loose" they are.

I did have a look on AP's website but it appeared to be about as clear as mud

Rippers

Mine came with this written on them

Rolls

iTrader: (2)

lol - ok - i'm guessing that the bolts aren't actually loose? - as on mine you can move them around - 2 ticks, and i'll get a pic...

Rolls

iTrader: (2)

righty - 2 pic's - showing just how much you can move the bolts about, and the second showing the lost washers... - i'm guessing that a phonecall to Mr Rainbird will be in order to get some new bolts, and get them tightened up correctly????




Cheers

Azrael

This looks dangerous....

bige

dont drive with the car before you change ALL the bolts - disk can explode

adamski frst

mate dont drive it like that!!! you need bolts ASAP

Rolls

iTrader: (2)

ritey - probably just as well that i only drove to the petrol station and back, and don't use the car at all during the week etc...
New bolts will be on order tomorrow

Cheers for the info peeps!

Damo V

Have the bolts not worn the holes in the bells?? looks like it??

Bet if you take them all out those holes have been elongated/worn...

DaveEscos

that looks FUCKED

where are the gubbins for the bells?

Rolls

iTrader: (2)

T'is odd - its only the 3 that are next to each other that have gone like that. the other bolts can move a tiny bit (you can't get a finger nail behind them...), but no-where near as much as those 3 - new bolts and gubbins are on order so i'll have a proper look at it at the weekend!

Mike Rainbird

iTrader: (3)

Just seen this post and didn't realise that it had gone like this .

You may need new bells afterall . You need to check and make sure that any of the holes in the bell are NOT ovalised. They need to be circular, if not, you need new bells . Regarding the holes for the bobbins (or "gubbins" as Dave calls them ) that go on the disc itself, they should be slotted (elongated with flat sides) for the bobbin to float in.

DaveEscos

ok ok , bobbins!

mcossie

What do you say, you are floating disc??? bells and discs are one part (when bolts are new...). This are special calipers?

Mike Rainbird

iTrader: (3)

The disc has slots for mounting points instead of holes, so they are not fixed solidly to the bell, they have freedom of movement (which makes them rattle at slow speeds).

Azrael

mcossie those are floating discs - at this size fixed disc would cause vibration very quickly.

dojj

iTrader: (3)

does this mean that you can retrofit them little washer things to a set of discs and have them float too?

Mike Rainbird

iTrader: (3)

No, as floating discs have to have SLOTS for mounting onto the bell and not circular holes.

mcossie

I said that because I want to fit AP 355/32 discs with porsche 996 4 pots calipers...

I make a mistake???

Mike Rainbird

iTrader: (3)

In that size, they should be floating to avoid pad knock-off. This occurs in hard cornering when the wheel bearings flex and due to the size of discs (and depending on which way the car is corning) will lean on the pads and push one of the top and on one of the bottom pistons back (diagonally opposite each other) if they are fixed bells. What then happens is the next corner, you have no brakes (without furiously pumping the pedal to get the pistons back out ). With a floating arrangement, this has no effect on pistons, as the bell can twist and flex independantly of the disc.

mcossie

it's difficult to change fixed disc in floating disc... simply the bolts???

Mike Rainbird

iTrader: (3)

You need a special type of disc with slots instead of holes where the disc mounts to the alloy bell.

If you don't intend on REALLY hard cornering (like track days), you should be okay, but you absolutely must NOT go beyond this size with solid mounted discs IMO.

dojj

iTrader: (3)

good desrpition there but:

how does this effect peeps who run 330mm discs then mike?
are they ok as non floaters or would it be advised that they turned to floaters as well?
or is this for cars that are running bigger than the 330mm's that the majority tend to run?

Azrael

dojj even many standard cars are affected by this problem, you can see this on BEst MOtoring videos when they press brake pedal on long straights with left foot to cancel pedal free play before hard braking.

GUZZLER

iTrader: (3)

Mike, do have any pics of the 'bobbins' ???

THE RADMAN

iTrader: (2)

i dont want any floaters

Mike Rainbird

iTrader: (3)

Doesn't become as big an issue until the discs get much bigger. Just imagine a small ruler and pivot it about it's centre, then get a much longer one and pivot it the same amount, the movement at the end due to it's increased length is dramatically increased. Same principle with big brakes .

Guzzler,
Will put some pictures up tomorrow .

Franco

iTrader: (2)

Dont worry Rolls, mine did exactly the same!

I wasnt blessed with the torque measurements on the disk, so tightened them up rather well!

My bells have become ovalised, but speaking to Martin H he said they should be fine (i will be replacing obviously!!).

Cheers

Jason

Ps - We all make mistakes mate!

Rolls

iTrader: (2)

Yeah - just pleased they will be easy enough to replace... - got new bells, and bolts / bobbins on the way (Well...as soon as i get to Barclays to transfer the money to Mike - Poxy traders not having a clue with exchange rates stopped that today )

mcossie

I saw on AP range, there are 355 bolted and floating discs... but all the 378 are floating...

I use my escos for track day, so I'll try to fit the 355 bolted...

Thanks all

Marc

Franco

iTrader: (2)

No Marc you need floating for track days! not bolted!

mcossie

Mike said that it is possible !!!

Franco

iTrader: (2)

Yes but didnt advise it!! Due to cornering speeds on track!

Mike Rainbird

iTrader: (3)

I have my very own secretary bitch .

Cheers Jay .

Now make me a coffee (and bring it back to bed ).

Franco

iTrader: (2)

Get your elbow out me back retard!

Ps i'll be going to source for my bells/bobbins this time Mike - i know you'll understand!

Franco

iTrader: (2)

Update to make Rolls feel better..........

I had to strip my bells off to send up to Martin yesterday, ended up loosing most of the skin on me knuckles, and having to smash shite out of the bolts with a hammer to get out of the bells (i'd tighten one bell up so tight, one bolt sheared!).

Rolls

iTrader: (2)

LOL! - well, i'm now just awaiting delivery of my nice new shiney ones.... - oh the joys eh!
So.................
on that note - how often should you tighten /check the torque on these buggers?

Franco

iTrader: (2)

Didnt think you'd need to being honest................ Dab of thread lock should sort that (arnt the nuts nylon lined??).