how to remove the seized exhaust housing on Garrett GT?

[popdemonic]

today i started to remove the Garrett GT2871 for a rebuild and Billet compressor wheel.
it's a bit tough since the bolts and nuts on the exhaust were all seized and tough to get
them out one by one.I sprayed and soaked them with WD-40 seems little helps.
once everything taken apart except the exhaust housing was seized on the CHRA.
I have tried to hammer,WD-40,heat gun(I think it's useless) etc.all didn't work out bit.Damn it.this's PITA.
anyone has any ideas to remove the exhaust housing.i couldn't hook up the bearing cartridge and remove the turbine shaft since there's the backing plate left behind the exhaust housing.i will do the full write-up on how to assemble/disassemble the Garrett
GT ball bearing turbo since this's not available through the internet and someone is selling the DVD for 20quids IIRC.i found there're a couple tips working on the Garrett turbo and hope it helps for someone wants to do it besides paying big money to the shop.

[andy10v]

Heat. (oxy acetylene or propane, not a heat gun)

Warm the hotside housing evenly and it will expand, also helps break any corrosion bond.

[popdemonic]

Thanks Andy.it's all out now with lotta heat on the housing.

[EspenW]

Yep, heat on the outside and if that is not enough, use freeze spray on the bolts, for maximum thermal expansion/contraction effect.