26-25Buick

Restorer32 is right. The purpose of heating the metal is to get it to expand and put some pressure on the rust to break its bond. Once you get above 850F (450C) the expansion of most carbon steels is virtually a flat-line so adding any extra heat after that doesn't help the process. If you heat 'till it glows you're actually up around 1200F (650C) while 850 is just above where it turns blue. Without a doubt raydurr will have hardened the the surface with his quench process but I think why it is still a success is the hardening has been limited to just the surface but it does run the risk of initiating cracks at the surface (which may not be visible to the naked eye at the time you do it). Don't get me wrong I'm an advocate for using heat but you don't need to heat it to a glow and you shouldn't be quenching unless you're planning on tempering after, which is a whole different ball of wax.

Another alternative would be Belzona 1111 epoxy which you could fill the holes with or if it's too bad you can use it to bond a new plate over them. Has excellent resistance to most hydrocarbons but this stuff can be pricey too, but it does work when welding or other hot work is not an option or could be a little tricky. http://www.belzona.com/ViewFile.aspx?id=52299

We've got the same problem Bob but we couldn't get ours to move at all. I didn't find an easy solution so just left it for the time being for fear of breaking the casting. So I'm interested to know if someone has an answer to this one too

Good point Don, I hadn't thought of the hardening being also for the purpose of the gland nut. Being in the corrosion business for over 30 years you see stainless being over specified and used in so many places it should never have been used. Don't get me wrong, in the right place it can't be beaten but buyer be ware like everything, it has its limitations. By the way my hats off to all who actively participate in this forum as the knowledge, experience and opinions you share are invaluable. I have learnt a lot in a very short time.

Time to weigh in to the discussion with a bit of metallurgy and corrosion theory. Ok why is as AzBob reports the original Buick shaft hardened as hardening in most cases won't improve corrosion resistance, well certainly the hardening processes in 1926 would not have. My guess, and anyone chime in if they have another theory, Buick was trying to improve the erosion resistance of the shaft both from solids in the cooling water like rust, dirt, etc and from any cavitation caused by the impeller. Hardening also helps with fatigue however I think you can rule out fatigue as there is very little load on this shaft. So will the non-hardened shaft in the WPK-260 kit work just as well as the original one, from a corrosion perspective for most of us yes, as the water quality today is significantly better and we can control the water chemistry with inhibitors so rust and erosion in the system is less of an issue. If you're contemplating using a stainless steel shaft think very carefully, while most of the issues can be controlled get it wrong and it will go bad very quickly. The most obvious issue is carbon steel is anodic to stainless i.e. the carbon steel will corrode if it's near the stainless like for instance the internals of the pump casing or near the gland nut, in fact using a stainless shaft may actually increase corrosion in the pump casing. Keep in mind that corrosion rates increase with temperature in the temperature ranges we are talking about here, so the more you use the car the worse the problem gets. The next issue is the most common types of stainless work great where there is oxygen available however if you have a crevice say where the bearing is pressed on or perhaps at the gland packing or you use a corrosion inhibitor which contains an oxygen scavenger it will pit as bad, if not worse than, everyday carbon steel as there is no oxygen to form or maintain the passivisation layer. The final thing to think about is one of most common free machining stainless steels is 316L and its used in lots of things from cookware to nuts and bolts because it is so easy to machine in to shafts and draw and roll in to shapes. The problem with it is it is prone to crack in temperatures around 150F and above in the presence of chlorides or sulphides. So you need to know what's in your rad water and any additives you are thinking of using because you are certainly operating in the crack initiating temperature range. Sorry for for rather long and technical response guys and girls

Facing the same proposition Bob while I have the generator and water pump out

Nicely done Bob