Technical Exhaust manifold separation and gasket renewal

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Technical Exhaust manifold separation and gasket renewal


Apr 12, 2017
Hello all

just discovered a large exhaust leak at the manifold to down-pipe flange.

Naturally the four nuts look nice and rusted. Apart from soaking liberally with WD-40 any tips, please?
ie is it best to remove the nuts from below with the car on low ramps? or do it from above?
has anyone had any luck loosening the nuts without shearing the studs? if so what's the secret?
sharp knocks of the spanner or slow steady pressure?
OR go straight to the nut splitters and get it over with?

I hope the gaskets are easily available from the usual sources.

Anyone got a good spare manifold cover that they will part with (1500 engine).

thanks for all input in advance.


By coincidence have been looking at the same bit of the car today as I know my (original!) exhaust won't last much longer. Nuts are well seized and showed no sign of budging this morning after soaking overnight in penetrating oil. Access is easy if you take out the removable panel between the engine and rear boot. Also a good opportunity to check for rust under boot floor etc. Eurosport sell new gaskets and I've also got new locking nuts for the manifold bolts. I think that the nut splitter is likely to be the best way forward for me but have bottled out at least until MOT time in August as exhaust ain't actually broke yet so why fix it. Will be interested to hear how you get on.
Yes take the access panel out, wire brush all the loose rust off, spray penetration oil on to the studs as many times as you can, use heat from a blow torch if necessary and see if you can get some movement on the nuts or even the studs themselves. Rinse and repeat. With luck either the nut or the stud will loosen off. New gaskets, studs and nuts (brass) available from Eurosport uk. If the nut or stud loosens off work it back and forth with plenty of penetration oil and or heat!
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many thanks Neg. But access panel? Is there one from the boot area or do you mean from below?
I foresee skinned knuckles and worse here....Yes Eurosport always very helpful, great supplier.
Boot area, the bulkhead has a removable panel....the earlier cars pre ‘78 I guess don’t have one.

brilliant Neg thank you. I never knew that! Mainly because that area is covered by the only nice bit of carpet on the car. Mines 1987 so should be there. Cheers for now RDS
just noticed that I didn't expressly thank Iggy also. Apologies! Yes I will report back when I get back to this project.
Cheers RDS
weather has stopped play on this but I have been soaking the flange nuts.

Apart from those nuts, the only other fastenings needing to be undone to allow fitting the new gasket are the three thtough-bolts on the silencer aren't they? Or can those be left alone?
Finally returned to this matter after soaking the broken stud with wd40 and waiting for a stud extractor to arrive.

I thought I didn't have one so bought a cam-type extractor only to find one already neatly in my box that was smaller. Anyway both of them were useless in the confined space on an M8 stud and upside down near the engine block. I was left wondering whether the "chuck type" extractor would have been a better buy.

Instead i used my mini-Stilsons wrench followed by dad's good old Footprints. Success straight away - much easier to use too.

Anyway i want to clean up the threads of the other studs. They are M8 but what thread pitch? M8 x 1 or x 1.25?