Does this need fixing?

UK forum for general and technical discussion about the Z3 roadster
Post Reply
User avatar
pingu
Joined: Fri 30 Apr, 2004 16:01
Posts: 3412

  M roadster S50

Does this need fixing?

Post by pingu »

Like the title says, I'm not sure if I should bother fixing this. It's only making a slight noise and there's only a little vibration...

Image

Image
Pingu
User avatar
Althulas
Joined: Fri 13 Feb, 2009 00:55
Posts: 818

  M roadster S50

Re: Does this need fixing?

Post by Althulas »

An application of this http://www.metalclay.co.uk/paste/ should tidy it up nicely and see you ok until you apply your brakes :D
If you like gaming with mature minded players visit our retirement home http://www.oap-clan.co.uk/
ImageImage
User avatar
Koolflyer
Joined: Fri 05 Jul, 2013 15:51
Posts: 586

  Z3 roadster 2.8

Re: Does this need fixing?

Post by Koolflyer »

.....or turn it 90 deg so you can't see it :wink:
Image
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
User avatar
Brian H
Joined: Tue 16 Dec, 2008 19:55
Posts: 2505

  Z3 roadster 3.0i

Re: Does this need fixing?

Post by Brian H »

Looks as if it has been there a while, I would leave it if I were you :shock: (not)
User avatar
Southernboy
Joined: Thu 07 Oct, 2010 12:39
Posts: 6436

  Z3 roadster 3.0i
Location: Johannesburg

Re: Does this need fixing?

Post by Southernboy »

Try sourcing a second hand part from a breaker and replace it. It's the rear disc / drum, so not as serious as a front. However, you really don't want a disc coming apart whilst driving. You could end up having parts smashing into the bodywork under the wing and arch.
"Normal is overrated"
Image

Z3 Upgrades and Additions
User avatar
colb
Joined: Sat 05 May, 2012 22:46
Posts: 690

  Z3 roadster 1.8 TU
Location: Newport South Wales UK

Re: Does this need fixing?

Post by colb »

Certainly needs replacing, when it comes to brakes don't mess about its a life and death component and not necessarily your life.
It would fail an MOT in this cracked state.
I would change both sides given the state the cracked on is in the other won't be far behind.
New pads at the same time.
You should source the parts at Car parts 4 less or Euro parts on the web, expect £120+ for each disc.

Colb
Colb
1999 BMW 1.8 Z3
2003 BMW 2.5 Z4
1998 Honda Deauville NT650V
Hairyscreech
Joined: Thu 16 Apr, 2015 12:08
Posts: 69

  Z3 roadster 2.8

Re: Does this need fixing?

Post by Hairyscreech »

Nahh, looks fine to me.

If your really worried run a line of mig weld up it and take it back with a flap disc. Should get another few thousand out of it.

:shock:
Mike Fishwick
Joined: Fri 19 Jun, 2009 10:27
Posts: 2093

  Z3 roadster 2.8
Location: Daglan, France

Re: Does this need fixing?

Post by Mike Fishwick »

It looks like a front vented disc on a 2.8.

Those who advised you to 'leave it' etc obviously have a death wish,and/or do not know what they are talking about - they are a very bad adverisement for DIY maintenance!

A cracked disc will not operate too well, and will also wear the pads quickly - not to mention making the car unroadworthy. forgetabout fitting a used disc unless you can measure the thickness - but your other front disc is probably close tothe minimum anyway, so a new pair of discs and new pads are the only real answer. You do not have to spend a lot - visit GSF and ask.

Remember that a cracked disc may break up and lock the wheel - whic his not fun on a front wheel.
A Z3 is not just for Christmas - it's for life!
Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2136

  Z3 roadster 1.9

Re: Does this need fixing?

Post by Del »

I think Pingu knows it needs changing asap and is having a joke :D
therealdb1
Joined: Tue 25 Jun, 2013 21:47
Posts: 263

  Z3 roadster 2.0

Re: Does this need fixing?

Post by therealdb1 »

I am certain that those that suggest leaving it or gluing it back together are only having a bit of fun and are knowledgeable enough themselves to realise that this is a serious safety issue and the car should not be driven in this state.
The worry is that the OP is obviously not so knowledgeable otherwise the question would not have been asked but he is looking for guidance from the more experienced members here.
Humourous as some of the responses are to the more experienced, they should be presented in such a way to make that obvious and include genuine advice on what to do about the problem when it is such a safety related issue as potential brake disc failure.
Little rant over!
Hairyscreech
Joined: Thu 16 Apr, 2015 12:08
Posts: 69

  Z3 roadster 2.8

Re: Does this need fixing?

Post by Hairyscreech »

He has just said in the brakes thread he has a full set of pads and discs on the way.
User avatar
pingu
Joined: Fri 30 Apr, 2004 16:01
Posts: 3412

  M roadster S50

Re: Does this need fixing?

Post by pingu »

Hairyscreech wrote:He has just said in the brakes thread he has a full set of pads and discs on the way.
and that was posted BEFORE I posted this :wink: .

Anyway, when the new stuff arrives, it can sit in the loft until I REALLY need it :shock: . Although, just to protect the bodywork, I may fit one of the new discs (it doesn't matter which one, does it?). :wink:

I like the idea of welding and grinding back - I might give that a go and see how I get on. The gap in the wheel is a bit tight to get the welder nozzle through, but it might be worth a shot :) .

I also like the idea of just turning the wheel and the problem goes away :D .


BTW, it's the front left disc on the M.
Pingu
Mike Fishwick
Joined: Fri 19 Jun, 2009 10:27
Posts: 2093

  Z3 roadster 2.8
Location: Daglan, France

Re: Does this need fixing?

Post by Mike Fishwick »

Oh what a laugh . . .

Maybe I lack such a sophisticated sense of humour, but the post looks like it was written by someone whose limited ideas verge on the downright dangerous.

Do you really get a kick out of posting such nonsense - what is the point?
A Z3 is not just for Christmas - it's for life!
gookah
Z Register member
Joined: Thu 07 Aug, 2008 09:51
Posts: 2737

  Z3 roadster 2.8

Re: Does this need fixing?

Post by gookah »

You could grind it out, and then also do a few more, saves buying those expensive grooved discs.
Image

Z3 2.8 Progress Journal (Mine)
Z3 1.9 Sport Progress Journal (Wifey's)

I have an element of 'M-styling' on my car, If that's a good enough reason for the manufacturers to adorn a 320 with the M badge, then its certainly a good enough reason for me..
peter2b
Joined: Sat 01 Nov, 2014 18:47
Posts: 963

  Z3 roadster 2.2i
Location: cheshire

Re: Does this need fixing?

Post by peter2b »

Don't use your car till its fixed the disc could shatter at any time leaving you without any brakes or worse, a friend in another kit car club had some thing like that in his tin top, his wheel fell off as he was leaving his drive
Peter2b
User avatar
billysally208
Joined: Sat 11 Jul, 2015 12:53
Posts: 38

  Z3 roadster 1.9i

Re: Does this need fixing?

Post by billysally208 »

Southernboy wrote:Try sourcing a second hand part from a breaker and replace it. It's the rear disc / drum, so not as serious as a front. However, you really don't want a disc coming apart whilst driving. You could end up having parts smashing into the bodywork under the wing and arch.
Used brake discs from a breakers? - false economy, chances are it will be as bad as the one your replacing - we're talking brakes here - get new ones and replace both sides, and change the pads at the same time.
User avatar
pingu
Joined: Fri 30 Apr, 2004 16:01
Posts: 3412

  M roadster S50

Re: Does this need fixing?

Post by pingu »

Mike Fishwick wrote:Oh what a laugh . . .

Maybe I lack such a sophisticated sense of humour, but the post looks like it was written by someone whose limited ideas verge on the downright dangerous.

Do you really get a kick out of posting such nonsense - what is the point?
I would hope that most regular forum members would recognise from my other posts that I am reasonably competent and would understand that I wasn't serious.

Anyway, just to be absolutely clear and so there is no doubt left in anybody's mind...

This is an extremely serious condition for the car to be in and is close to requiring recovery. As it happens, I discovered the problem when I was 5 miles from home and I returned home (using minimal, light braking) and swapped cars before restarting my journey. The car is not going to be used until BOTH front discs are replaced and NEW disc pads are fitted. I ordered rears and will do these at the same time as a precaution and as they are slightly grooved.

The car will be safely jacked up and supported on correctly positioned axle stands on flat level ground whilst I do the work. I will be wearing PPE appropriate to the task. I will have read and fully comprehended the latest BMW instructions on the subject and will be complying with all instructions therein. I will be using a calibrated torque wrench where torque wrench settings are quoted.

I will be using the correct hierarchy of tools for undoing and tightening nuts and bolts to reduce the possibility of damage.

And then I'll drop it on the ground and wheelspin off the driveway :D .
Pingu
John Wilson
Joined: Fri 12 Jun, 2009 12:11
Posts: 252

  Z3 roadster 2.0
Location: Diss

Re: Does this need fixing?

Post by John Wilson »

So........
Are you going to fix it,then?
User avatar
Koolflyer
Joined: Fri 05 Jul, 2013 15:51
Posts: 586

  Z3 roadster 2.8

Re: Does this need fixing?

Post by Koolflyer »

Maybe I lack such a sophisticated sense of humour
Umm....perhaps you do, but sometimes one has to "chillout". Clearly Pingu knows his stuff (plus Health & Safety by the looks of it), and he was just having a bit of fun, therefore I personally would allow him a little more credibility. However, for those who wonder what to do with a cracked disc....BIN IT!
Image
1997 Z3 2.8 (M52) Roadster Montreal blue
2013 330d (F31) M Sport Alpine White
User avatar
Robert T
Site Admin
Joined: Mon 12 Jun, 2006 10:35
Posts: 10170

  Z3 roadster 1.9
Location: Cheshire

Re: Does this need fixing?

Post by Robert T »

I was actually expecting you to say that this was someone else's car and they had asked you the question of whether they should bother replacing the disc. I didn't expect you to be driving on a discs with lips on them bigger than Mick Jagger's!

Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
Image
User avatar
Alfie
Z Register member
Joined: Thu 29 Apr, 2004 14:28
Posts: 3312

  M roadster S54
Location: Broadchurch....

Re: Does this need fixing?

Post by Alfie »

This thread is hilarious....!!!
:roflmao: :joker:

A.
Image
User avatar
stevov
Joined: Sun 21 Dec, 2014 15:56
Posts: 182

  Z3 roadster 2.0
Contact:

Re: Does this need fixing?

Post by stevov »

The sad thing is the discs were left to get to this point. Discs have a minimum thickness and should be checked for it.
spurs fan in a coupe
Joined: Fri 18 Apr, 2008 19:24
Posts: 1446

  Z3 coupe 2.8
Location: woking

Re: Does this need fixing?

Post by spurs fan in a coupe »

A true mixture of irony, immaturity and ignorance here!

Makes great reading

:lol:
we expres: " He did hear the bells ringing, but doesnt know where where the clapper hangs".
User avatar
pingu
Joined: Fri 30 Apr, 2004 16:01
Posts: 3412

  M roadster S50

Re: Does this need fixing?

Post by pingu »

stevov wrote:The sad thing is the discs were left to get to this point. Discs have a minimum thickness and should be checked for it.
Disc was measured on 14/07/2014 and was 26.79mm. Minimum thickness is 26.4mm.

I'll measure the disc when I remove it and report the result.
Pingu
User avatar
kruisn
Joined: Sat 22 Oct, 2005 22:28
Posts: 403

  Z3 roadster 3.0i
Location: Keikeri,New Zealand

Re: Does this need fixing?

Post by kruisn »

Don't forget that all safety regulations call for a minimum of at least three pints or two shots of a suitable spirits before starting the job. :lol: :lol:
Don't drink and drive home -
Take the Zd and fly home -
User avatar
Southernboy
Joined: Thu 07 Oct, 2010 12:39
Posts: 6436

  Z3 roadster 3.0i
Location: Johannesburg

Re: Does this need fixing?

Post by Southernboy »

I think you should just use an angle grinder to tidy up the crack, then make a few more matching grooves and call it a "slotted" disc.... :lol:
"Normal is overrated"
Image

Z3 Upgrades and Additions
User avatar
stevov
Joined: Sun 21 Dec, 2014 15:56
Posts: 182

  Z3 roadster 2.0
Contact:

Re: Does this need fixing?

Post by stevov »

pingu wrote:
stevov wrote:The sad thing is the discs were left to get to this point. Discs have a minimum thickness and should be checked for it.
Disc was measured on 14/07/2014 and was 26.79mm. Minimum thickness is 26.4mm.

I'll measure the disc when I remove it and report the result.
Don't know if you noticed but that was over a year ago. You also don't say how old the discs are or what the original quality was. When discs are on the limit which yours were a year ago they are much more suspect to thermal shock. In the same way a car on tyres that are technically still legal at 1.8mm for tread depth will be useless in a downpour and worst case scenario will void your insurance as being unfit for conditions so your brakes if in an accident fail due to being out of spec will void your insurance. A valid mot does not nessasarily mean fit for the road.
John Wilson
Joined: Fri 12 Jun, 2009 12:11
Posts: 252

  Z3 roadster 2.0
Location: Diss

Re: Does this need fixing?

Post by John Wilson »

MOTs are the way the government has devised to check whether a car is safe. Most people dont check the thickness of their discs between MOTs or a lot of other things on their car, because they are not knowledgeable enough and havent got a fully equiped workshop. Thats why we have to pay someone else to do it every year.
User avatar
stevov
Joined: Sun 21 Dec, 2014 15:56
Posts: 182

  Z3 roadster 2.0
Contact:

Re: Does this need fixing?

Post by stevov »

Iirc disc thickness is not measured on an mot. http://www.mottesting.org.uk/index.html
Mot simply means that at that moment in time your car met a few relevant standards. As soon as you leave the station it becomes just a piece of paper. ie put the cat on to pass emissions then remove after test is just one thing all performance cars have had done to them. Ask all the people who have been stopped by a roadside vosa check just after an mot only to fail at the roadside how much their pass is worth. On a performance car forum I assume there is a slightly higher level of mechanical knowledge than Joe public present. Fast cars and mechanical ignorance don't really fit together. “Does this need fixing“ should probably read “thankfully I didn't kill anyone"
John Wilson
Joined: Fri 12 Jun, 2009 12:11
Posts: 252

  Z3 roadster 2.0
Location: Diss

Re: Does this need fixing?

Post by John Wilson »

So, how often do you have to check every mechanical part of your car before you drive it. Do you have your car up on your ramps looking at every steering joint before each journey, as you seem to be suggesting?
I have a car that is well capable of doing Iver 100mph, but I dont drive it on the road at that speed because it would be dangerous and illegal. My car is safer on the road at the legal speed limit than normal saloon cars because it has better brakes, wider tyres etc. Your picture shows that you take your cars around tracks on their limits. Most peop?e with Zs,MX5s, etc, drive on roads, and I would think that most of them have little mechanical knowledge about their cars, or need to have.
User avatar
billysally208
Joined: Sat 11 Jul, 2015 12:53
Posts: 38

  Z3 roadster 1.9i

Re: Does this need fixing?

Post by billysally208 »

Image - Now this is a worn disc!
User avatar
stevov
Joined: Sun 21 Dec, 2014 15:56
Posts: 182

  Z3 roadster 2.0
Contact:

Re: Does this need fixing?

Post by stevov »

John Wilson wrote:So, how often do you have to check every mechanical part of your car before you drive it. Do you have your car up on your ramps looking at every steering joint before each journey, as you seem to be suggesting?
I have a car that is well capable of doing Iver 100mph, but I dont drive it on the road at that speed because it would be dangerous and illegal. My car is safer on the road at the legal speed limit than normal saloon cars because it has better brakes, wider tyres etc. Your picture shows that you take your cars around tracks on their limits. Most peop?e with Zs,MX5s, etc, drive on roads, and I would think that most of them have little mechanical knowledge about their cars, or need to have.
How are your brakes better than a normal saloon. How are you safer in a lighter car on worn wide tyres in standing water. Your in a convertible, sitting lower reducing visibility.. When I think of a safe vehicle, z3 is not at the top of the list.. Yes I regularly check my cars for mechanical problems. It's my legal responsibility not the mot test stations. I'm aware of this more than most as I see it daily. It's frightening what's on the road. Note the pic just posted. Somebody was driving around on that. At some point an mot station probably passed that when it was around minimum thickness and the owner thought it would be fine.
John Wilson
Joined: Fri 12 Jun, 2009 12:11
Posts: 252

  Z3 roadster 2.0
Location: Diss

Re: Does this need fixing?

Post by John Wilson »

Its safer because the discs have more area to stop the car, the tyres have more rubber on the road so have a shorter stopping distance (they are not worn because they recently passed an MOT), the car is light so it can stop in a shorter distance,probably half the distance of a 4x4,it has firmer suspension making the steering more predictable, etc,etc.
User avatar
stevov
Joined: Sun 21 Dec, 2014 15:56
Posts: 182

  Z3 roadster 2.0
Contact:

Re: Does this need fixing?

Post by stevov »

The discs are the same size or smaller than the 3 series saloon. A popular brake upgrade is to put the 300mm discs from saloons on with the original calipers and pads. Z3 has 280 mm discs. So no more area than everything else. The calipers are common to a lot more than just z3's. As far as wider tyres means more rubber not nesassarily. You have to determine tyre width sidewall height, diameter, tyre pressure to see the resultant contact patch. As said 1.6 mm is the legal limit on tread depth for an mot so mot means nothing. New depth is 8mm give or take and a new semi slick is 4-5mm. Nothing special about the suspension that's not found on other bmw 3 series of the time. Basic bmw compact suspension unless upgraded. Different brake pads have different coefficient of frictions so will determine how aggressive or no the braking is. Your braking is subject to the abs system which overrules all unless your proficient in threshold braking. A lighter car on wet surfaces may actually be harder to brake as the abs will kick in sooner. Choice of tyre manufacturer is extremely important to the overall capability of braking and handling. I have seen tyre tests where the the difference between tyres stopping from60mph in the wet in an emergency was over 30 meters. But your right the vast majority of people will get away with a mot once a year and a service every 2 years and never know the pleasure of driving the car to its limits. Myself and my customers do tend towards more enthusiastic use of our cars.
gookah
Z Register member
Joined: Thu 07 Aug, 2008 09:51
Posts: 2737

  Z3 roadster 2.8

Re: Does this need fixing?

Post by gookah »

Southernboy wrote:I think you should just use an angle grinder to tidy up the crack, then make a few more matching grooves and call it a "slotted" disc.... :lol:
you don't say.... finger on the pulse :D

gookah wrote:You could grind it out, and then also do a few more, saves buying those expensive grooved discs.
Image

Z3 2.8 Progress Journal (Mine)
Z3 1.9 Sport Progress Journal (Wifey's)

I have an element of 'M-styling' on my car, If that's a good enough reason for the manufacturers to adorn a 320 with the M badge, then its certainly a good enough reason for me..
gookah
Z Register member
Joined: Thu 07 Aug, 2008 09:51
Posts: 2737

  Z3 roadster 2.8

Re: Does this need fixing?

Post by gookah »

Bet you didn't expect this Pings
Image

Z3 2.8 Progress Journal (Mine)
Z3 1.9 Sport Progress Journal (Wifey's)

I have an element of 'M-styling' on my car, If that's a good enough reason for the manufacturers to adorn a 320 with the M badge, then its certainly a good enough reason for me..
User avatar
pingu
Joined: Fri 30 Apr, 2004 16:01
Posts: 3412

  M roadster S50

Re: Does this need fixing?

Post by pingu »

stevov wrote:Don't know if you noticed but that was over a year ago.
[sarcasm]
Don't know if you noticed, but time has no relevance.
[/sarcasm]

Mileage can be used as a guide to estimate FUTURE wear, assuming the same driving style is adopted.
stevov wrote:You also don't say how old the discs are or what the original quality was.
I assumed that the discs were originals, but (granted) that is only an assumption. I have no idea of the original quality. I would like to think that they weren't made from castings from the metal from old Fiat 124s, but they could be :shock: . Anyone buying any second-hand car would have the same problem unless the history can be fully verified. Even then, if someone decides to fit a cheap set of discs and not record it, the documentation would suggest that the originals are still fitted.
stevov wrote:When discs are on the limit which yours were a year ago they are much more suspect to thermal shock.
Just found that out :shock:

When I measured the disc in 2012 (10,000 miles earlier), it was 26.85mm. If the wear rate continued as measured I should still have more than 50,000 miles before I'm out of spec, assuming I drive the same as before.
stevov wrote:In the same way a car on tyres that are technically still legal at 1.8mm for tread depth will be useless in a downpour and worst case scenario will void your insurance as being unfit for conditions so your brakes if in an accident fail due to being out of spec will void your insurance.
They were in-spec when I last measured them and I will report back as to whether they are still (dimensionally) in-spec.

The disc is out-of-spec because of the crack. They would have grounds to void my insurance if I drove it knowing about the crack (I'm not sure how they could prove that) and had an accident.

I disagree that your insurance would be voided if you had 1.8mm on your tyres, as the tyres are in-spec. But that's a totally different discussion - more to do with insurance company's making up random rules to avoid payouts.
stevov wrote:A valid mot does not necessarily mean fit for the road.
Agreed :)
Pingu
User avatar
pingu
Joined: Fri 30 Apr, 2004 16:01
Posts: 3412

  M roadster S50

Re: Does this need fixing?

Post by pingu »

gookah wrote:Bet you didn't expect this Pings
Surprised by some, but not all :wink: . Still, it helps to pass the time in the wee small hours :D .

[edited to add] I'm glad that I don't drink. It would be interesting to read back what I'd written if I did. :twisted: :D :D :D
Pingu
User avatar
billysally208
Joined: Sat 11 Jul, 2015 12:53
Posts: 38

  Z3 roadster 1.9i

Re: Does this need fixing?

Post by billysally208 »

Anyway - I went to Albert Looms this morning and they haven't got any Z's in - will the discs off an Astra fit? :)
gookah
Z Register member
Joined: Thu 07 Aug, 2008 09:51
Posts: 2737

  Z3 roadster 2.8

Re: Does this need fixing?

Post by gookah »

pingu wrote:
gookah wrote:Bet you didn't expect this Pings
Surprised by some, but not all :wink: .

Oohh I wonder who... :roflmao:
Image

Z3 2.8 Progress Journal (Mine)
Z3 1.9 Sport Progress Journal (Wifey's)

I have an element of 'M-styling' on my car, If that's a good enough reason for the manufacturers to adorn a 320 with the M badge, then its certainly a good enough reason for me..
User avatar
pingu
Joined: Fri 30 Apr, 2004 16:01
Posts: 3412

  M roadster S50

Re: Does this need fixing?

Post by pingu »

billysally208 wrote:Anyway - I went to Albert Looms this morning and they haven't got any Z's in - will the discs off an Astra fit? :)
You must be local. Or is there more than one Albert Looms?

As for the Astra discs. Give it a go. If they are in-spec, they are legal :D .
Pingu
User avatar
pingu
Joined: Fri 30 Apr, 2004 16:01
Posts: 3412

  M roadster S50

Re: Does this need fixing?

Post by pingu »

As promised...

26.77mm

New measurements

Disc 27.73mm
Pads 13.73mm (inc bedding-in material)

Run-out (after cleaning and filing rust off hub):
Left 0.004"
Right 0.003"
Pingu
User avatar
T48 TRE
Joined: Mon 10 Nov, 2003 07:22
Posts: 359

  Z3 roadster 2.2i
Location: Coventry

Re: Does this need fixing?

Post by T48 TRE »

Hi Pingu, I was surprised to see that crack, but my son in law had a better one. He had to send his Mercedes van in for an MOT, and quite early on had to go back to the garage. One of the front disc brakes had two fractures, which had met in the centre, and the only thing holding it in position was wheel and nuts. He didn't even feel anything when driving or braking. Needless to say he had both sides done , but the garage mechanic siad he had never seen such a thing in his 20 odd years of working on Cars.
Albert
Image
Post Reply