Brake Drums - a word of warning! Greg Mackie

Nearly everyone knows by now that I managed to invert my 'Blackish' 59 Beetle at the Supersprints on Saturday. What is perhaps not commonly known is what caused this to happen.This is straight from the 'horses mouth'.

As the original rear drums were worn in the splines, I decided to replace them with new ones for the Supersprints. This turned out to be a mistake, as the outside rear drum (brand new) collapsed under cornering load, and the result was a potentially serious roll-over. Fortunately, aided by good safety gear and some body strengthening, I walked away unhurt.

I am well aware that I was placing a great deal more stress on the drums than was intended by the manufacturer, but I feel compelled to bring this to the attention of my fellow VW enthusiasts.

Cheers, Greg

Greg,

Being there I can attest to the severity of the rollover. If you plan to rebuild what will you do differently? Convert to disc brakes? Install a full roll cage or do you think you will hang up your helmet for racing?

Not rushing into a decision. I think that I'll hang up that helmet.........but I might get a new one!

Glad to hear it Greg do you mind if i post some pics of the car here?

Not at all.

omg i got a sick feeling in the stomach after going though those photos...
thats crazy. Sorry to hear the bad news.

What did u mean by the new brake drum collapsing? It just fell to bits (collapsed in on itself) due to the kerb weight + g's & at the speed u were going?

scary stuff.

The 'friction' section parted company with the 'spline' section. Don't know the reason for this, but I will be having it checked out by an expert. When I have the results of testing, I intend to publish them here.

Cheers, Greg

Yeah, not good Greg... "potentially serious roll-over" is a bit of an understatement !!!

Any chance of some pics of the failed drum ???

You can see the smashed rear drum in this first photo:

ive got an up close one of the drum, will post up when i can, unless someone else beats me to it

Not to sound gorish but does anyone have video or pics of the roll over?? I was looking at the person who spun on the last corner when it happened and missed it

Ian.

Glad you weren't hurt man

pic as promised, would also be curious to see a video, seems everyone missed the start of it

STIDUB wrote:pic as promised, would also be curious to see a video, seems everyone missed the start of it

That's because it happened so quickly. When the drum broke, it just 'dug in', and flipped. Even I didn't know what was going on - that's never happened to me before, thankfully.

Hope to get the offending drum tested soon.

Cheers, Greg

that is farkin scary,cant beleive you walked out like a superhero would of....

I'm glad you're okay. Thanks for the words of warning.

CT

Hi Greg,

We were SO glad to see you get out and walk away. The whole racetrack went quiet.
I think everyone held their breath until we saw you get out.
It hurt to see what happened to your Bug. Its amazing you came out of that unscathed!!!! Will we see another Black 8 Bug???
Glad to hear you're not thinking of hanging up the helmet!!!!

HappyDaze wrote:That's because it happened so quickly. When the drum broke, it just 'dug in', and flipped. Even I didn't know what was going on - that's never happened to me before, thankfully.

Hope to get the offending drum tested soon.

Cheers, Greg

Good to see You are still with Us Greg

Lee

So this drum u are getting tested, if it was a fault with it, could u get compensation?

I'm more concerned in finding out if there is a problem with these drums, than getting compensation.

RatBug on here had a similar thing happen to a rear disc on his buggy. No roll over though. after market job.

if im thinking of the right one wasnt that one ^^^ caused by them being drilled for 4x4 6stud? without being thick enough for the holes, that comes to mind anyway, true about finding out if they are poor quality too, wouldnt want to see it happen again 🙂

That drum has broken during the rollover from side impact

not prior too

the axle is very bent

sorry if u disagree

STIDUB wrote:if im thinking of the right one wasnt that one ^^^ caused by them being drilled for 4x4 6stud? without being thick enough for the holes, that comes to mind anyway, true about finding out if they are poor quality too, wouldnt want to see it happen again 🙂

no it wasn't.
They were 5 stud falcon. as purchased from dealer

no probs, wasnt sure if that was the same🙂

johny rotten wrote:That drum has broken during the rollover from side impact

not prior too

the axle is very bent

sorry if u disagree

I'm not expert but I did see the actual rollover and it was the passenger side that took the impact, you will note the fractured drum is on the relatively undamaged side of the car.

IMO.... for side impact to fracture the brake drum the wheel rim itself would show signs of damage. Inspect the rim it has NO damage.........if you like come over and have a look for yourself.....So for Greg to have driven this car around Wakefield for the last 3 and a bit years doing numerous laps with a race driver record well above par.......change brake drums before race meeting with new ones and have a result as you see leaves very little to driver error in my opinion...sorry you disagree

Greg, did you hear the drum shatter?
Glad you're OK 👍

No, but I felt it!

HappyDaze wrote:No, but I felt it!

No argument here.

Glad your still with us Greg, the car is a mess, you were very lucky. I bet you're a bit stiff today.

I feel fine thanks Matt - apart from a couple of sore spots. OK for an old bloke. That 6 point quality harness was good value, although I would rather have not had to rely on that.

Cheers, Greg

johny rotten wrote:That drum has broken during the rollover from side impact

not prior too

the axle is very bent

sorry if u disagree

Hi

Greg is a very experienced driver and has done 100s of laps of this track, he is the one person that would know if a mechanical fault preceded the roll over.

So what makes you so sure the axle is bent? You could make a fortune in industry looking at photos and diagnosing faults.

Its a swing axle car and has just been manhandled onto a trailer, of course the axle will settle at an odd angle

Steve

Anyone have video ?

That corner seems to always have rollovers, I've seen 5 or 6 cars go over there !

Hi Greg it was good to see you at the VW Nationals yesterday after your adventure at Wakefield park I didn't see the accident at all because I was flagging at turn ten the last corner before the straight and as I said to you on Sunday you were really pushing that little thing onto the main straight you would of been one of the fastest cars through that corner if not the fastest and I know on the run where you rolled your car you were coming into ten very very fast and on your 1st and 2nd laps the wheels were braking loose and smoking the tyres and on the 3rd lap you were really on the limit and you found it where you spun but just as quick you smoked the tyres and you were off but then I had the call over the two way red flag red flag looked around and seen you get out of the car (turn 10 is along way from where you rolled over) and I said to my offside it greg silly bugger spun off again little did I know that you had rolled the thing in spectacular way and when you showed me the passenger door on Sunday I realised then how very lucky you were. And just to say in Greg's favor I have seen the man drive at very close range and if he said it is not driver error I am a believer.
Greg do you give racing driving lesson I am about to venture into Super Sprinting and I wont to come Salt Racing I have confidence in your driving ability.

Jeff Dunn Club Vee Dub

Very sorry to see those pics of your car Greg, but heaps happy to hear your okay.

Cheers Col

i hope you bought a lottery ticket after that one,lady luck was obviously on your side.
bad news about the car. great new's to hear you walked away.

I understand that the Formular VEE guys have been seeing a similar problem

they apparently have designed a outer cover to help hold the drums together
( would be good to get some input for the VEE guys and how many times this has happened )

Greg remmeber what Boris and i said to you seperatly before the race we both agreed good S/Hand drums would have been better to be used

Sorry it had to destroy the car and we are all glad you able to tell the story

great advert for your door pillar center brace what gauge is that material ???

what sort of testing are you haveing done to the drum i hope there a similar thickness to the origionals
most probaly the material will vary

So where are the new drums manufactured ?

Can you still buy german ones or are they all aftermarket suppliers now ?

vw54 wrote:I understand that the Formular VEE guys have been seeing a similar problem

they apparently have designed a outer cover to help hold the drums together
( would be good to get some input for the VEE guys and how many times this has happened )

Greg remmeber what Boris and i said to you seperatly before the race we both agreed good S/Hand drums would have been better to be used

Sorry it had to destroy the car and we are all glad you able to tell the story

great advert for your door pillar center brace what gauge is that material ???

what sort of testing are you haveing done to the drum i hope there a similar thickness to the origionals
most probaly the material will vary

Would be interesting to hear of other drum failures.

You did mention your preference to the original drums, but if YOU remember, it was Sunday, not Saturday.

The centre brace is 1.6 pressed steel.

Could be a while before I have any test results, in the meantime I don't think we need to 'panic'. I know that I was working those drums far harder than they were designed for. 'Normal' use would probably not be a problem. What we need is constructive, factual feedback here, so we can all be aware of the limitations of the stuff that we put on our (special) cars.

Cheers, Greg

Wow. Bad luck and im glad you are ok.

At mentioned before the Formula Vee's run a plate to strengthen the drum.

Greg

I remember discussing the drums with you on Saturday in the pits right after u told me you got new ones
and had fitted the alloy cooling fins as per your origionals you even mentioned the brand

I wonder who we can contact re the Formular Vee Failures

try craig from vwma, he is in the vee scene now

not many 1200 / drum brake vees running any more

most are 1600cc disc brakes etc now

"tassupervee" has been in vee's for a long time. he may have heard about this happening


http://forums.aussieveedubbers.com/viewprofile.php?memberid=1504

or ask here

http://www.fvee.org.au/

John Alder is doing a job for me next week, he may know...I'll get his angle as his vee's are running up there with the best of em.

I also saw a drum failure late last year (or early this year), but it was an aftermarket drum with a jap 6 stud off road pattern from a local supplier. Similar break although it was more obviously a thin zone near the machined stud pattern.

Hi

Something that I don't think has been brought up, VW went to burst proof door locks in Australia with the introduction of the 1500 Beetle.

If the doors had stayed shut on Greg's car during the rollover it may have stayed in better shape, still would have been buggered but the roof would maybe not have collapsed as much as it did with a door still in the opening.

Steve

i think it was in one of the other threads someone mentioned how bad 6 volt doors are for flying open in accidents.
my best mate and his sister rolled in her 64 and naturally both doors flew open and the windscreen pillars gave out
the latches are such a bad design when you look closely

Richard holzl has the right idea using mexican doors which have 6 volt windows but the later bear claw type latch

Steve, talk about syncroncity, did you see only yesterday someone posted that classic nurburgring vid on GL with all the vws rolling on that corner.
theres a shot in that where a guy is ejected out of his early bug cos the door flies open and it has no seatbelts

Joel wrote:Richard holzl has the right idea using mexican doors which have 6 volt windows but the later bear claw type latch

That's actually VW's idea, the shells are available new like that.

Hi

That you tube video is scary stuff

Craig of course its VW idea, Joel was saying that Richard retro fitted Mexican doors to early bugs, the Steve MvMullan/ Alex Hozl Oval has them.

Steve

oh I was refering to the shells you can buy from Fermans, the mexican/brazilian ones that came like that from the factory.

Like this one

How many VWs were destroyed in that YouTube video?

I've always been worried about my beetle turning into a ball.

Sheeesh.

1303Steve wrote:If the doors had stayed shut on Greg's car during the rollover it may have stayed in better shape, still would have been buggered but the roof would maybe not have collapsed as much as it did with a door still in the opening.
Steve

The doors would have done SFA in stopping the roof of the car from caving in. The only thing that would stop that would be a properly designed and installed roll cage. Even with one, the impact on the roof still would have been extensive.

fullnoise wrote:How many VWs were destroyed in that YouTube video?

I've always been worried about my beetle turning into a ball.

Sheeesh.

Thats what motor sport is all about... You cant worry to much about crashing when your driving your car at 10 tenths. Other wise you will throw it off into the trees or armco.

vw54 wrote:Greg

I remember discussing the drums with you on Saturday in the pits right after u told me you got new ones
and had fitted the alloy cooling fins as per your origionals you even mentioned the brand

I wonder who we can contact re the Formular Vee Failures

Drum failures on early F Vees were a chronic problem...
The drums out of 1200 cars did not have this problem, the brakages started to appear with usage of 1300 drums...
( the same shape as Greg's drum )
To prevent this to happen, Frank Kleinig designed the device, which is spun 2.0 mm steel, kind of a top hat which bolts on the drum by axle nut and wheel nuts..
If the drum brakes, it still keeps the wheel in the position ( kind of )..
I think that I have a pair in my shop , will try to take some pictures..

bat69 wrote:The doors would have done SFA in stopping the roof of the car from caving in. The only thing that would stop that would be a properly designed and installed roll cage. Even with one, the impact on the roof still would have been extensive.

Hi

I don't agree but I'm not going to crash a car to prove my point.

This super bug had huge hit in the front, what do you think would have happened if the doors had flown open.

Steve

fullnoise wrote:How many VWs were destroyed in that YouTube video?

I've always been worried about my beetle turning into a ball.

Sheeesh.

too many
I cringe when i see that bug cabrio fly through,
if it had rolled like the others thats 4 people probably not wearing seatbelts
the vid is shot in 1970 so that cab was brand new
way to total a brand new car if it got ugly liek the others

i always cringe at that purple bug... completely owned in the front. but you are right steve... the doors saved the driver, in a sense. the cage is still bent at the top of the a pillars, and given enough force where the cage bolts/welds to the floor at the front, it would still be crushed. I dont remember the speed that purple super was going, but double it and the driver would be dead.

Here is the promissed photo of the device...

Thanks John, but rather than a 'Band-aid' fix, I will most probably be using Type 3 drums (genuine VW ones).

The chassis is OK and so are most of the suspension bits. Engine and gearbox look good - not even a bent axle.

A roll cage is a definite for the re-build!

Cheers, Greg

I noticed all three mirrors are all good two greg,

HappyDaze wrote:Thanks John, but rather than a 'Band-aid' fix, I will most probably be using Type 3 drums (genuine VW ones).

The chassis is OK and so are most of the suspension bits. Engine and gearbox look good - not even a bent axle.

A roll cage is a definite for the re-build!

Cheers, Greg

That's OK Greg, this applies to F Vee only, because of regulations...they can not use other than type 1 components../ as you would know 😂 /

johny rotten wrote:not many 1200 / drum brake vees running any more

most are 1600cc disc brakes etc now

Yes most Formula Vee cars have gone to disc packages even many of the 1200's. The Historic guys still run drums and the other "problem" we battle with is left stub axles .... this we solve be bolting through the speedo cable hole.

Regards,

Ian

HappyDaze wrote:A roll cage is a definite for the re-build!

Cheers, Greg

A VERY smart move Greg.

71-BEETLE-SEDAN wrote:I noticed all three mirrors are all good two greg,

Yeah Josh, that's so that I can LOOK BACK on all this and say "What a great bunch of people the VW crowd are - all those offers of help, and good wishes were very much appreciated".

Cheers, Greg

chequer57 wrote:

johny rotten wrote:not many 1200 / drum brake vees running any more

most are 1600cc disc brakes etc now

Yes most Formula Vee cars have gone to disc packages even many of the 1200's. The Historic guys still run drums and the other "problem" we battle with is left stub axles .... this we solve be bolting through the speedo cable hole.

Regards,


Ian

I know Vees need to comply with the rules, but as I CAN up-grade, the stronger drums are a better option.

Thanks for the stub-axle-bolt tip Ian, I like the idea.

Cheers, Greg

May I ask why your not going to go to rear discs?

trickysimon wrote:May I ask why your not going to go to rear discs?

Just 'Oldschool' stubbornness, I suppose!

Hi all,

Greg Mackie has sent me these photos and asked me to post them up. These are obviously photos of his fractured brake drum/hub. I will just explain that Greg has manufactured and fitted a cooling system to the drums to radiate heat, hence the cooling vanes.

You will also see the baking plate is extensively bent fromt he fractured hub, yet has not caused any damage to the axle or the axle tube.

Regards, Kev

Im guessing that the outer ring and vanes are aluminium and an interference fit to the drum?

The rings I know are aluminium, as far as I know from what greg told me they are just heat shrunk onto the drums.

Someone correct me if i'm wrong though..❓

Correct guess! The cast aluminium rings are machined to suit the drum O.D., -0.035". Drums do not need to be machined.

The first time I did this mod. was in 1962 and it kept the drums nice and round, as well as improving the cooling.

If I had known about Frank Klienig's ' safety disc ', there may have been a better result when the drum collapsed, perhaps?

Cheers, Greg

HappyDaze wrote:Correct guess! The cast aluminium rings are machined to suit the drum O.D., -0.035". Drums do not need to be machined.

The first time I did this mod. was in 1962 and it kept the drums nice and round, as well as improving the cooling.

If I had known about Frank Klienig's ' safety disc ', there may have been a better result when the drum collapsed, perhaps?

Cheers, Greg

No chance to research it yet or run it past some metalurgists but I'm wondering about the thermal expansion rates of the aluminium vs the steel. The aluminium would also be sitting at a different temp to the steel so even if the expansion rates are the same there would still be a difference in the growth of the metals.

I've seen similar set ups on drums that end up glowing red during racing, but the finned metal has always been the same as the drum.

I'm curious if your drums would ever get hot enough that the aluminium starts to "choke" the drums expansion. Even still, I would expect the aluminium to fail before the steel stresses excessively in the middle.


Just thinking out loud...

For a start the drums aren't steel, they're cast iron. As aluminium expands at a greater rate than iron, the ring would probably be more likely to come loose than 'choke' the drum.

I ran that set-up for many road and race miles in the early '60s on a Beetle (100MPH stops at Bathurst, Warwick Farm etc.) without a single problem. Also the present car has done almost 4 years of racing, on the original (50 years old) drums, with the fins fitted, without any trouble. The drum that failed was brand-new Zimmerman, fitted for the Nats. Supersprints ❗

Cheers, Greg

Just a thought Greg. Got anyone lined up to look at the shards?
Had a metallurgist look at some failed "forged" name brand pistons which turned out to be simply cast and hot pressed on the crowns. I think you might find some rather ordinary casting in those drums.

'rather ordinary casting' is probably being kind, Matt. A friend of mine has been in the industry for many years, and he will be 'checking it out' for me. This could take a little time, but meanwhile it is important for us to think carefully about the 'repro.' bits that we are using. I certainly have learned a lesson from this.

Cheers, Greg

geez this is scary. life relying of a piece of cast iron.