So how do you stress relieve it?

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68 Mini
70 Moke

You can shot peen it or the preferred method is heating at 500 ish degrees from memory for a few hours. But it all depends on which type of steel you would like after heat treatment.

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Simplify and add lightness

Hmmm, I'm thinking I'll look at fitting a sump guard now.

I forgot to ask in my original post how much is a bare subframe worth?
And how long would it take a mechanic to remove and replace it with another one?
And I also forgot to mention that the car now sits 1-2cm lower on that side (front only) and feels like I'm driving on a flat tyre, and it's not I've checked.

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won't help in that situation - or might make it worse

shot peening is a surface hardening technique and does not provide stress relieving of welds or cold formed bends.

you can heat the whole part up and hold it for a period of time(i would have to look up the temperature and time, but i bet drmini can tell you from years of experience) to allow the grain structure to return to a normal state, but the temperature needs to be accurately measured. the temperature must be kept under the critical range where pearlite turns into austenite. for small parts you can get away with a domestic oven (without wifey finding out) if you use an accurate thermometer. For a large part like the subframe, you can heat the area locally using a gas torch to a "deep cherry red" and hold it there for the time you need, but again accurate temperature measurement using an infrared thermomoter is better than eyeballing for the inexperienced.

GT Mowog, if you say most cracks are where there is no welds, then I bet it is due to the bends being cold formed and then not stress relieved. Also, the other welded areas you talk about are probably not subjected to cyclic loads of the type found at the top of the towers.

cheers
michael

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the world is a book, and those who do not travel read only a page
66 Mini Minor sponsored by http://www.lifeonthehedge.com.au/ The Dog Harness Specialists
It was a pleasure ausmini. I'll miss all you misfits and reprobates

Just saying that I've not seen them crack from 'stress'. In fact if you have a good look at NAVs first pic, you can see there is two cracks, the first one is fairly clear, the second is across the flat un-formed area of the tower top

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I've had a much closer look at the subframe and it is indeed cracked where GT says. I guess i'll toss that one and get another.

Anyone have a bare subframe in the Brisvegas area??

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doesn't exactly look like a new crack anyway does it?

SSSSSHHHHhhhhh!!!

It wasnt there when I resprayed the engine bay less than 12 mths ago, so it isnt old.

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Yeah, it only JUST happened

(Hope you can sort it)

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It was a definate and pronounced crack like a big stone hitting the glass, and the car felt different immediately after.
My mate who was following me noticed my car leaning to the left straight after. And there is a measurable drop on the passengers side.

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hey mate, bad luck, well at least this way you have an excuse to get that gearbox fixed up while the engine is out use the opportunity.. (owning a mini your always having to fix something ) arrhh the fun as for NSW RTA paying for it, I would be suprised if they do come through...

I know the road very well, and the flood waters through there are always washing the road away.... hence these humps and bumps, where Mr fix'ets come along and "Repair" the road with a shovel and some tar

I always drive in the centre of the road down there, aviod the harsh edges, but in ur circumstance with another car coming down the road you couldn't....

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Bluey-1973 Clubby - 1330, high lift, big cam, 7 port madness in progress..

Gumby-1978 Minivan, British Racing Green - 1310, high lift, mild cam, enlarged porting and chamber shape with big valve head, supercharged build in ever slow progress!

[quote="NAV"]I forgot to ask in my original post how much is a bare subframe worth?
And how long would it take a mechanic to remove and replace it with another one?
quote]

I've seen them range from $50 - $200 with all arms etc...

I would personally be getting the original one welded up and made stronger...

I am about to take the engine and subframe outta Little Red this weekend, and I'm banking on it taking me around 5hrs,, and you know how slow I am,,,

I would say a mechanic would take a good day to pull out and replace it all back... Someone who knows what they are doing anyway,,,,

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Bluey-1973 Clubby - 1330, high lift, big cam, 7 port madness in progress..

Gumby-1978 Minivan, British Racing Green - 1310, high lift, mild cam, enlarged porting and chamber shape with big valve head, supercharged build in ever slow progress!

They won't pay for the gear box..that's for sure, but they will come through
on the subframe providing NAV has enough proof. My wife severely damaged
an old Fairlane we had due to the RTA not having any signage to warn
of road works on the M3. It took a letter and then a signed declaration
that we would not sue and they paid out $5000 the value of the car.