Exhaust manifold and down pipe wont part company

[CarlM]

Hello starting to do a decoke on Herald and was feeling pleased that I had managed to release the three nuts on the exhaust manifold, with threads and studs intact. But I can’t drop the exhaust down pipe, it seems ‘mated for life’ and gentle persuasion not working. Any tips for work around or a more aggressive approach.

 

[Colin Lindsay]

Make sure all the bolts are removed; three on the Herald cast manifold, and it's not supported anywhere else below. Let it hang on its' own weight. Tap it gently with a hammer all the way round the flange, keep tapping and set up a good rhythm of fast regular taps. Eventually this will split the years of heat- and rust-related bonding and it will drop off. Be careful not to fracture the manifold; they're common until you need one. 

[johny]

Well as a future recommendation flood difficult work areas repeatedly with penetrating oil WELL before starting the job. People put it on 10 mins before starting to undo whereas 10 days before is more like it😁 Now heat is your next option in the form of a gas burner but dont set anything alight!

[Pete Lewis]

38 minutes ago, CarlM said:

But I can’t drop the exhaust down pipe

but why if the flange has parted just remove the manifolds leave the pipe to dangle 

or lift the head complete with manifolds if you eat plenty of spinach 

does the down pipe really need removing ?????

Pete 

[CarlM]

Pete the flange hasn’t parted, despite smacking it (piece of wood and hammer method).

[Pete Lewis]

ok so the gasket and probably some historic sealer has removed the need for any bolts  Ha!

i can only suggest a gentle pry and a good wiggle the flanges are in need of a bit of care as said they break off when you dont want them too.

good luck 

let us know how you get it off 

Pete

Edited October 22 by Pete Lewis

[CarlM]

Some good advice here, followed the Colin method, and in 24 hr the flange has parted by 1/8 th of an inch, under its own weight and with copious amounts of bulldog bdx.  Good progress considering yesterday was tight.

Just applied more bulldog and taps with hammer and will await further parting of the ways tomorrow.

something about patience being a virtue….