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Model specific boards => Golf mk2 => Topic started by: ozegti on 06 January 2009, 19:25

Title: Redrilling brake discs
Post by: ozegti on 06 January 2009, 19:25

Just wondering if you can safely redrill a 5x100 to 4x100?

Title: Re: Redrilling brake discs
Post by: JC on 06 January 2009, 20:44

 :shocked: :shocked: :shocked:

to save £36

 :shocked: :shocked: :shocked: :shocked:

Title: Re: Redrilling brake discs
Post by: ozegti on 06 January 2009, 22:36

Quote from: chuff on 06 January 2009, 20:44

:shocked: :shocked: :shocked:

to save £36

 :shocked: :shocked: :shocked: :shocked:

how bout you ask before flaming like that??

I'm using VR6 carriers and calipers, but4 stud flange, and Ive just put everything together with G60 discs, and they don't fit. Too deep. So was going to get the VR6 discs drilled to 4x100.

SO- to cut it short, I need VR6 offset in 4x100 OR sell off my stuff as I found out I need Mk3 arms so getting really fed up at the moment. grumble

Title: Re: Redrilling brake discs
Post by: Thom89 on 07 January 2009, 00:29

Quote from: ozegti on 06 January 2009, 22:36

Quote from: chuff on 06 January 2009, 20:44

:shocked: :shocked: :shocked:

to save £36

 :shocked: :shocked: :shocked: :shocked:

how bout you ask before flaming like that??

I'm using VR6 carriers and calipers, but4 stud flange, and Ive just put everything together with G60 discs, and they don't fit. Too deep. So was going to get the VR6 discs drilled to 4x100.

SO- to cut it short, I need VR6 offset in 4x100 OR sell off my stuff as I found out I need Mk3 arms so getting really fed up at the moment. grumble

You tell him! :evil: :laugh:
Tom

Title: Re: Redrilling brake discs
Post by: JC on 07 January 2009, 09:19

 :grin:

and no - as an engineer - I wouldnt re drill anything like that, espeically brake discs  :lipsrsealed:

good luck with your search

Title: Re: Redrilling brake discs
Post by: jammac on 07 January 2009, 20:13

maybe he wants to decrease his life expectancy

Title: Re: Redrilling brake discs
Post by: DOA on 07 January 2009, 21:02

Or just wants an honest opinion?

Personally I wouldnt do it (another engineer) but assuming you can clear the locating hole for the disc and the other 4 existing holes it "should" be OK. They are drilled to start with and fancy drilled discs are far more prone to cracking (yet hardly ever fail completely), plus you do have the wheel clamping the disc which should prevent excess stress concentrations around the wheel bolt holes but as I say, I wouldnt choose to do it.

Title: Re: Redrilling brake discs
Post by: JC on 07 January 2009, 21:10

if that was the case wouldnt they just make discs with multi fitment  :wink:

Title: Re: Redrilling brake discs
Post by: DOA on 07 January 2009, 21:18

Lol, you tell me  :rolleyes:. Cant actually see there being that big a market myself but hey. You would also think it would be easy to get hold of undrilled discs by the same logic but I dont see many places offering them either. Doesnt look like he will be doing it anyway by his other posts and if you read my post, I dont exactly advocate it but nm lol.

Title: Re: Redrilling brake discs
Post by: DarnPB on 08 January 2009, 19:13

Another engineer here, and I would not do it either. It would probably cost more to get them drilled properly than buying a new set anyway!

Title: Re: Redrilling brake discs
Post by: Lewy on 08 January 2009, 19:14

Quote from: chuff on 07 January 2009, 09:19

:grin:

 as an engineer -

Who is? A what?

Publication flicker more like!

Title: Re: Redrilling brake discs
Post by: pro-biotic on 08 January 2009, 19:52

personally as an engineer again - i`d do it.

on the basis that:-

1)the disc is held concentric using the centre hub
2) the location screw is mearly there to stop the disc turning during fitment of the wheels
3) the main reaction stopping the disc turning is the friction of the clamping force between wheel and hub.

this is on the basis that:-
 1)a reasonable amount of material is left between new and old holes
 2)the holes are done using a dividing head
 3) the holes are about 1mm oversize to the wheel stud - or whatever a std clearance is

perhaps the older holes could be inserted or welded.


i personally can not see anything wrong with the idea, the only thing you may have to watch out for is disc balance, but again if you have access to a machine shop i guess you know how to balance a disc

Title: Re: Redrilling brake discs
Post by: JC on 08 January 2009, 20:25

Quote from: Lewy on 08 January 2009, 19:14

Quote from: chuff on 07 January 2009, 09:19

:grin:

 as an engineer -

Who is? A what?

Publication flicker more like!

 :tongue:

Title: Re: Redrilling brake discs
Post by: VeeDubGTI16v on 08 January 2009, 20:30

nova boys have been doing this for years on their v6 disc brakes. it will be fine

Title: Re: Redrilling brake discs
Post by: jammac on 08 January 2009, 21:41

Quote from: pro-biotic on 08 January 2009, 19:52

personally as an engineer again - i`d do it.

on the basis that:-

1)the disc is held concentric using the centre hub
2) the location screw is mearly there to stop the disc turning during fitment of the wheels
3) the main reaction stopping the disc turning is the friction of the clamping force between wheel and hub.

this is on the basis that:-
 1)a reasonable amount of material is left between new and old holes
 2)the holes are done using a dividing head
 3) the holes are about 1mm oversize to the wheel stud - or whatever a std clearance is

perhaps the older holes could be inserted or welded.


i personally can not see anything wrong with the idea, the only thing you may have to watch out for is disc balance, but again if you have access to a machine shop i guess you know how to balance a disc

Well id never do it. Basically vandalising something that stops your motor from moving is asking for trouble! by drilling another 5 holes in a brake disc you are weakening it beyond what its been designed to do whatever anybody says.

it might be ok, but it might not! from my experiance if something can go wrong it will.

Title: Re: Redrilling brake discs
Post by: Conker on 08 January 2009, 22:07

Why drill one hole when you can drill hundreds of the f##king things - the less metal the better.  Weight saving innit.

Drill some holes in the brake pads as well while your at it.

 :laugh:

Title: Re: Redrilling brake discs
Post by: DarnPB on 09 January 2009, 02:32

They would need to be either,exceptionally good and very expensive disc's, or made of gold to even think about re-drilling them for fitment to another pattern. Like I said before, cheaper to go buy the correct ones for the application, rather than butcher existing ones.
If I bought a car and found that whilst having a wheel off for some reason, I would think WTF??.. and replace them immediatly.

Title: Re: Redrilling brake discs
Post by: DOA on 09 January 2009, 05:57

"perhaps the older holes could be inserted or welded."

You certainly wouldnt want to weld them (too much stress and possible deformation, its a long process anyway with the sort of materials used) and inserts wouldnt do anything but Im with you on the other points.

Title: Re: Redrilling brake discs
Post by: VeeDubGTI16v on 09 January 2009, 09:13

i cant see the problem, the holes are only there to allow bolts to pass through, wont the stress will be acting on the face of the disc/wheels? (since theres so many 'engineers' in this thread  :grin: )

basically i agree with pro-biotic.

Title: Re: Redrilling brake discs
Post by: topher on 09 January 2009, 09:51

Since it's such a popular phrase around here..

as an engineer.. the wheels hold the brake discs on anyway.. BUT 4x100->5x100 is a tricky conversion. You'll use one original hole and space out from that, but that won't give you the (and this is the 'as an engineer bit') 3xdiameter of the bolt spacing you need. You'll end up with 2 situations of a smidge over 15mm c/c, which with a 1mm oversized hole for the M14 bolts means you'll have an overlap as per the pic below

(http://i42.tinypic.com/ivz9cw.jpg)

Which means at any given time in any direction under braking you'll have the rotational resistance in the disc spread over 4 bolts rather than 5. I could now spend several hours in calculations involving applied forces for shearing but why bother when 4 stud cars drive around fine without shearing hub studs?

Title: Re: Redrilling brake discs
Post by: VeeDubGTI16v on 09 January 2009, 10:02

jeez you could have used solidworks, autocad is soo last year  :drool:

Title: Re: Redrilling brake discs
Post by: jammac on 09 January 2009, 11:33

Quote from: topher on 09 January 2009, 09:51

Since it's such a popular phrase around here..

as an engineer.. the wheels hold the brake discs on anyway.. BUT 4x100->5x100 is a tricky conversion. You'll use one original hole and space out from that, but that won't give you the (and this is the 'as an engineer bit') 3xdiameter of the bolt spacing you need. You'll end up with 2 situations of a smidge over 15mm c/c, which with a 1mm oversized hole for the M14 bolts means you'll have an overlap as per the pic below

(http://i42.tinypic.com/ivz9cw.jpg)

Which means at any given time in any direction under braking you'll have the rotational resistance in the disc spread over 4 bolts rather than 5. I could now spend several hours in calculations involving applied forces for shearing but why bother when 4 stud cars drive around fine without shearing hub studs?

you seem to have rather alot of time on your hands. like a true engineer huh!

Title: Re: Redrilling brake discs
Post by: al_b on 09 January 2009, 13:13

I'm a sound engineer - does that help ? I say attach some reeds to the left over holes and with careful use of the break pedal you could probably play tunes with it. :cry:

Title: Re: Redrilling brake discs
Post by: pro-biotic on 09 January 2009, 14:44

Quote from: DOA on 09 January 2009, 05:57

"perhaps the older holes could be inserted or welded."

You certainly wouldnt want to weld them (too much stress and possible deformation, its a long process anyway with the sort of materials used) and inserts wouldnt do anything but Im with you on the other points.

an insert of an interference nature would do something if you were thinking of any radial forces acting upon the edges of the bolt holes - but as we know the disc is clamped 
if an insert was skimmed over so the faces are true it would help uniformly distribute the load - only thing to watch out for is thermal expansion of dissimilar materials.

the welding point i agree with the temps would cause hardening thus internal stresses (i aint a materials kinda person) - and would distort - but a quick skim would true up the disc.

personally i reckon too much work tbh mate

Title: Re: Redrilling brake discs
Post by: ozegti on 09 January 2009, 17:27

Amazingly, i've sorted this out 2 pages ago!! just bought the right hubs and carriers, pulled my flanges from my the VR6 hubs and away we go! Still interesting seeing who actually knows their stuff and who just say no- because it looks scary!

Cheers for a good read guys/gals!

Title: Re: Redrilling brake discs
Post by: danny_p on 09 January 2009, 17:31

still say buy undrilled disks,  just because the companies don't advertise them dosent mean they cant be perswaded to sell them

Title: Re: Redrilling brake discs
Post by: DarnPB on 09 January 2009, 19:13

Quote from: ozegti on 09 January 2009, 17:27

Amazingly, i've sorted this out 2 pages ago!! just bought the right hubs and carriers, pulled my flanges from my the VR6 hubs and away we go! Still interesting seeing who actually knows their stuff and who just say no- because it looks scary!

Cheers for a good read guys/gals!

Give me a break! Does not look scary, just looks fcuking dangerous!

Title: Re: Redrilling brake discs
Post by: JC on 09 January 2009, 19:13

 :grin: :grin: :grin: :grin:

Title: Re: Redrilling brake discs
Post by: ozegti on 09 January 2009, 21:59

Quote from: Darnpistonbroke on 09 January 2009, 19:13

Quote from: ozegti on 09 January 2009, 17:27

Amazingly, i've sorted this out 2 pages ago!! just bought the right hubs and carriers, pulled my flanges from my the VR6 hubs and away we go! Still interesting seeing who actually knows their stuff and who just say no- because it looks scary!

Cheers for a good read guys/gals!

Give me a break! Does not look scary, just looks fcuking dangerous!

yes, they do look F'n dangerous, but there was a set of wheels i have seen that came factory with bolt holes VERY similar to the 5x100/4x100 drill pattern. THAT was scary! What holds your wheels on?

I can understand that brake discs are clamped by the wheel, but if you take the meat of the metal from the trailing side, then you'r more at risk of doing risky damage. From the leading side (as the wheel rotates meaning the wheel stud will locate against t he undrilled part of the disc, I don't see MUCH issues with doing it that way, but I wanted to know if th ebolt holes were alligned or not. It was answered, so it's all good. But if you want to rant on and on trying to prove a point that was made ages ago.. go ahead!

I just think it's funny!

Title: Re: Redrilling brake discs
Post by: mattneck(Beavis) on 09 January 2009, 23:04

im sure ive seen multi fitment discs before..  :lipsrsealed:

ill try and find the set at work tomorrow.. im sure there was lots of holes on a set i saw once! and no.. they werent cross drilled before somebody asks.

Title: Re: Redrilling brake discs
Post by: my white golf on 10 January 2009, 11:20

im just amazed at the amount of engineers on here, must be half of englands engineering population!

Title: Re: Redrilling brake discs
Post by: pro-biotic on 10 January 2009, 12:24

i aint engilsh :undecided:

Title: Re: Redrilling brake discs
Post by: Lewy on 11 January 2009, 00:39

Quote from: pro-biotic on 10 January 2009, 12:24

i aint engilsh :undecided:

And neither is your spelling boyo!

Title: Re: Redrilling brake discs
Post by: jammac on 11 January 2009, 10:18

Quote from: Lewy on 11 January 2009, 00:39

Quote from: pro-biotic on 10 January 2009, 12:24

i aint engilsh :undecided:

And neither is your spelling boyo!

haha...rinsed


isnt it funny... everyone is either an engineer or a motor racing expert of some kind.

Title: Re: Redrilling brake discs
Post by: pro-biotic on 11 January 2009, 10:31

i knew my spelling was weak up there ^^ lol, i have a spellchecker on my browser i just chose to ignore it - but i still am not engilsh, i may be British tho

you get nail varnish operators with the words technician after their names nowadays so why cant everyone be an engineer! they even call maintenance fitters and electricians, engineers in our work - they simply are not!

Title: Re: Redrilling brake discs
Post by: Jay on 11 January 2009, 11:17

^ That's true  :grin:

I'm an engineer and know funk all nothing about real mechanics.

Ask me how a computer, Network etc work and I'll tell ya, ask me how an engine works I'll tell ya petrol gets squirted in and blowed up init :grin:

Title: Re: Redrilling brake discs
Post by: Gloves88 on 11 January 2009, 12:56

Quote from: Lewy on 11 January 2009, 00:39

Quote from: pro-biotic on 10 January 2009, 12:24

i aint engilsh :undecided:

And neither is your spelling boyo!

Engineers dont need to be able to spell :) :tongue:

We were actually told in Uni it doesnt matter if we spell something wrong in a report aslong as we keep spelling it the same way for the rest of the report  :grin:

Title: Re: Redrilling brake discs
Post by: sidecarphil on 11 January 2009, 13:44

i'm a mechanical engineer :grin:  :grin:

Title: Re: Redrilling brake discs
Post by: JimR on 12 January 2009, 17:40

I'm an engineer too!!

Don't worry too much though, we'll all be out of work soon.....

Title: Re: Redrilling brake discs
Post by: DOA on 12 January 2009, 18:57

^^^
Dont say that, Im just doing a degree to make getting into motorsport easier, used to design machines for the paper industry among others and it bored the sh!t out of me, had no money in it and bugger all jobs as it was lol. At least I know i can get a job somewhere even if I hate it lol.

Title: Re: Redrilling brake discs
Post by: sidecarphil on 12 January 2009, 19:51

Quote from: JimR on 12 January 2009, 17:40

I'm an engineer too!!

Don't worry too much though, we'll all be out of work soon.....

not me mate buisness ere in holland is booming :)

Quote from: DOA on 12 January 2009, 18:57

^^^
Dont say that, Im just doing a degree to make getting into motorsport easier, used to design machines for the paper industry among others and it bored the sh!t out of me, had no money in it and bugger all jobs as it was lol. At least I know i can get a job somewhere even if I hate it lol.

i found my way into motorsport by mechanicing for a sidecar team

we are now competing in the world superside championship :)

ok ok it's not F1 but it get's me into the pitlap at MOTO GP  :grin: :grin: :grin:

Title: Re: Redrilling brake discs
Post by: ozegti on 12 January 2009, 21:42

Multifit discs from brembo

http://cgi.ebay.co.uk/SEAT-LEON-CUPRA-R-AUDI-A3-S3-BREMBO-DRILLED-BRAKE-DISCS_W0QQitemZ270317996747QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item270317996747&_trksid=p3286.c0.m14&_trkparms=72%3A1299%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318

Title: Re: Redrilling brake discs
Post by: jammac on 13 January 2009, 01:24

Quote from: ozegti on 12 January 2009, 21:42

Multifit discs from brembo

http://cgi.ebay.co.uk/SEAT-LEON-CUPRA-R-AUDI-A3-S3-BREMBO-DRILLED-BRAKE-DISCS_W0QQitemZ270317996747QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item270317996747&_trksid=p3286.c0.m14&_trkparms=72%3A1299%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318

designed for the job. not some gash as f**k self attack with a cordless drill

Title: Re: Redrilling brake discs
Post by: jammac on 13 January 2009, 01:25

sorry was that abit coarse? im aircraft engineering on nightshifts and id rather eat my own sh!t than be here right now!  :angry:

Title: Re: Redrilling brake discs
Post by: DarnPB on 13 January 2009, 02:15

Quote from: jammac on 13 January 2009, 01:25

sorry was that abit coarse? im aircraft engineering on nightshifts and id rather eat my own sh!t than be here right now!  :angry:

You and me both. Mind you, its quite warm out on the line now at -5. It was down to -20 last week!

Title: Re: Redrilling brake discs
Post by: jammac on 13 January 2009, 06:04

ouch! atleast im cozy warm in the hangar

Title: Re: Redrilling brake discs
Post by: ozegti on 13 January 2009, 11:01

Quote from: jammac on 13 January 2009, 06:04

ouch! atleast im cozy warm in the hangar

Bloody hell! You could always do time trials up and down the runway!

Title: Re: Redrilling brake discs
Post by: DarnPB on 13 January 2009, 18:11

Quote from: ozegti on 13 January 2009, 11:01

Quote from: jammac on 13 January 2009, 06:04

ouch! atleast im cozy warm in the hangar

Bloody hell! You could always do time trials up and down the runway!

Tried that last night. Got done for speeding by the Hun! 43kph in a 30. :angry: