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Author Topic: Another day, another problem - Cracked Alloy  (Read 777 times)

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December 28, 2017, 10:16:45 PM

rj1986

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Another day, another problem - Cracked Alloy
« on: December 28, 2017, 10:16:45 PM »
So MOT came back with 2 failure's - 1 was Ball joint dust cover was too damaged, but the other was a cracked alloy.

SO this was the same alloy that i had welded last time out (about 3 years ago). It appears the weld has come away and the cracked re-opened.
Am i right in thinking this can just be sanded off, and re-welded if it is indeed the exact same spot?

December 29, 2017, 07:31:23 AM
Reply #1

snrbrtsn

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Re: Another day, another problem - Cracked Alloy
« Reply #1 on: December 29, 2017, 07:31:23 AM »
Technically, yes!
The weld could be dressed and rewelded!

I would favour replacing the Alloy as the wheel is now fatigued and structure compromised, personally, I would advise against rewelding, however the next guy would suggest it’s fine!
Anyone skilled can dress a wheel for repair, the proper process of Alloy welding involves heating, (to remove impurities & oils) allowing to cool, further heating and trench welding to get an effective and lasting repair that penetrates the structure as opposed to surface welding which give a short term fix! Understanding the metallurgy of the wheel will give different heating temperatures and cooling periods, typically the process should take circa 36hours, we all know it’s a drive in drive out affair with a run of the Tig rod!

For the purpose of Mot, any wheel can be fitted as long as the wheel size is matched! (Though even then, I don’t think the statement is correct, as long as the tread depth is above the legal limit)

Inpart it’s due to Runflats, due to having stiffer sidewalls, but primarily due to the state of our roads, too many pot holes!

December 29, 2017, 10:45:55 AM
Reply #2

Kleynie

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Re: Another day, another problem - Cracked Alloy
« Reply #2 on: December 29, 2017, 10:45:55 AM »
I had one of my 19” alloys welded on my old E61 and it cracked again two more times in the same place. As Sean says above, it’s best to replace the wheel if you are keeping the car. What wheels are they?
2015 535d F07 5GT M Sport

December 29, 2017, 04:05:56 PM
Reply #3

rj1986

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Re: Another day, another problem - Cracked Alloy
« Reply #3 on: December 29, 2017, 04:05:56 PM »
They're the 20" 214 style. Front one so the slightly narrower ones.

I've emailed a couple of wheel repair places to find out costs, so weighing up repair vs replace.

In the mean time I'll stick the 18" winters all round to get it through the MOT

January 26, 2018, 07:50:51 PM
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Reedster

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Re: Another day, another problem - Cracked Alloy
« Reply #4 on: January 26, 2018, 07:50:51 PM »
I would always replace a damaged alloy, its not worth risking it failing whilst driving. Sods law would kick in when it did fail and be when its under heavy stress.
Do like I have bolt an old alloy to the wall and use it as a hose reel....... complete with BMW centre cap.