Exhaust header nuts and bolts

So winter here in the U.K. and although not cold, it’s a good time to do some jobs. One of which is to see to the exhaust header nuts. Like most I imagine these have become corroded, however still intact. I’m just wondering, is it a job worth doing? Is it going to create more problem? I have new nuts and new studs, should the studs all show corrosion. Anyone done this job and advise on anything I should be aware of when carrying this out?

Firstly, don't leave them too long if they are the original thin wall 10mm hex open ended nuts. Sure they are neat and stylish but as a fitment for the environment they live in they suck big time!

Remove them with a 10mm single hex socket and a breaker bar after slathering them in penetrating lubricant for a couple of days. Stick the socket on the nut and gradually increase the torque. The longer the lever, (ie the handle.) the greater control and feel you will have as to whether things are moving or the stud is likely to shear. Go at it gently, over time, perhaps applying a bit of heat, and at least where I am they will usually crack loose.

When they do chuck them in the toolbox and then use 13mm stainless dome nuts in their place. Use new Schnoore washers and a dab of nickel based anti seize on the threads. The dome nuts exclude moisture and corrosives and the lube means you may be able to take them off again some time before hell freezes over.

Thank you Pete, clear guidance as always.

As with all GRiSO nuts and bolts, I’m expecting them to be made of cheese. I have dome nuts ready to put on. Should the studs be replaced as well?

I'm in the UK and have replaced mine with stainless steel studs, spring washers and nuts. A couple of the nuts had rusted beyond spanner fitting.

Still look pretty

Brass nuts also work well in this situation

I would stay away from stainless steel nuts. I replaced mine on a 1400 Cali and three out of the four galvanized to the studs. I was unable to undo them, even with the studs held firm in a vice.

Pete Roper wrote:

Firstly, don't leave them too long if they are the original thin wall 10mm hex open ended nuts. Sure they are neat and stylish but as a fitment for the environment they live in they suck big time!

Remove them with a 10mm single hex socket and a breaker bar after slathering them in penetrating lubricant for a couple of days. Stick the socket on the nut and gradually increase the torque. The longer the lever, (ie the handle.) the greater control and feel you will have as to whether things are moving or the stud is likely to shear. Go at it gently, over time, perhaps applying a bit of heat, and at least where I am they will usually crack loose.

When they do chuck them in the toolbox and then use 13mm stainless dome nuts in their place. Use new Schnoore washers and a dab of nickel based anti seize on the threads. The dome nuts exclude moisture and corrosives and the lube means you may be able to take them off again some time before hell freezes over.

What size Schnoore washers should I use here?

8mm

Thank you Pete and all.