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...there is maybe a hairline crack and a welding seam in the front brake drum
Posted: Tue Nov 16, 2021 7:40 pm
by Wolf
Yes - it is a dual single shoe brake, one side there is maybe a very fine crack and on the other side of the hub the drum way have been welded.
First of all - it works very well - only when cold/have been sitting for a while it tends to screech but the retardation is always impressive.
What do you think - should I do anything? Or just drive on?
Many thanks and kind regards
Wolf
Re: ...there is maybe a hairline crack and a welding seam in the front brake drum
Posted: Tue Nov 16, 2021 9:11 pm
by blethermaskite
never seen a repair like that
I certainly would not be happy to keep on using this......if this started to come apart while you were out on the road the result could be fatal, I know these particular brake drums are now getting expensive and a bit hard to get but how much value do you put on your life .......this is just my opinion others may differ.
Cheers,
George
Re: ...there is maybe a hairline crack and a welding seam in the front brake drum
Posted: Wed Nov 17, 2021 1:59 pm
by Wolf
George,
thank you for your worries -this is the reason for my post that I am in doubt wether it is safe to ride it. The previous owner was aware of the cracks and told me so.
I've just ordered a "Dye Penetrant Inspection" -system. I will let you know what I'll find.
Just say no to crack
Wolf
Re: ...there is maybe a hairline crack and a welding seam in the front brake drum
Posted: Wed Nov 17, 2021 10:49 pm
by Ducadini
Didn't even know it was possible to weld that without damaging the aluminium exterior.
Could it be that the bike has been left sitting for a while in a damp environment and the brakeshoe left an "imprint" ?
If I find a damaged drum, i'll cut it to see how the iron inner and alu outer are "connected".
ciao
ducadini
Re: ...there is maybe a hairline crack and a welding seam in the front brake drum
Posted: Sat Nov 20, 2021 5:02 pm
by Wolf
...here are the results from my crack inspection:
The one where I was very certain that it might be a crack is maybe not, visible in the first picture.
The one which looks like a welding seam did show a respone, but this is maybe caused by a not complete removal of the red agent.
I will skim the brake drums on a mill and will redo the crack detection test.
Cheers
Wolf
Re: ...there is maybe a hairline crack and a welding seam in the front brake drum
Posted: Sat Nov 20, 2021 7:21 pm
by blethermaskite
really interested to see the result of the skim test. I have been were you are with this before only on a Very expensive 4ls racing brake drum.
Cheers,
George
Re: ...there is maybe a hairline crack and a welding seam in the front brake drum
Posted: Sat Nov 20, 2021 9:09 pm
by Eldert
you can put new liners in . already replaced 210 and 230 mm liners with turned down car drums .
180 mm is a very common diameter for car drums . i think VW fox has them to
Eldert
Re: ...there is maybe a hairline crack and a welding seam in the front brake drum
Posted: Sat Nov 20, 2021 10:46 pm
by graeme
We’re the cast iron drums cast into the hub or shrunk in to the alloy originally ?
Graeme
Re: ...there is maybe a hairline crack and a welding seam in the front brake drum
Posted: Sun Nov 21, 2021 1:39 pm
by Wolf
Hi Eldert,
this is an information of great value! You just put the hub on the lathe, remove the old brake drum and shrink a machined VW sparepart into the hub? Sounds promising! The will be the last option, if the skimming of the brake drum will not work in the intended way.
Although I have to admit, that shrinking parts into another is always very exiting for me...
Many thanks
Wolf
Re: ...there is maybe a hairline crack and a welding seam in the front brake drum
Posted: Fri Dec 10, 2021 4:07 pm
by Wolf
...the machining is done, tomorrow I hope to do the crack inspection.