Frozen bobbins

[jono]

My latest acquisition has clearly had standing water inside the boot and passenger footwells for some considerable period of time in its life.

I am trying to remove the seat runners and ultimately the chassis for a full resto but, damn, the bolts are frozen solid in the bobbins. I've been soaking them with penetrating fluid but no signs of joy yet (worried to force them in case they shear). I'm thinking of forming little pasticene bowls around them and filling them with pen fluid and leaving for days.

Any thoughts - how about a heavy hot copper soldering iron held onto the bolt head to get some heat in?

Ultimately I may need to cut, drill and re tap but I would rather exhaust all options first.

Anyone been there and 'done that' and what worked?

[TBG]

I cut drilled and fitted stainless steel bolts straight through. No more problems and easy to undo in 20 years time!!

[jono]

Thanks, so used a nut and bolt or tapped them to the next size?

[TBG]

Nut and bolt - stainless Nyloc nuts.

[mbell]

I cut drilled and fitted stainless steel bolts straight through. No more problems and easy to undo in 20 years time!!

Aren't the bobbins aluminum? I thought stainless steel and aluminum combination was an issue for Galvanic Corrosion. I would have thought a normal zinc plated bolt would be better.

I could be completely wrong thou.

[TBG]

No problems with galvanic corrosion at this end.

[ericbushby]

Hi Mbell,
I think you are right. Aluminium and stainless steel are too far apart on the galvanic table.
If they are in contact in damp conditions they will start a fight and may be difficult to separate later.
Stainless is sometimes used as a replacement to solve problems and instead it introduces new problems.
Eric in Burnley
1967 S3SE DHC

[Elan45]

Mr TGB,

Mixing aluminum and stainless steel is not a good situation. Because they are so far apart on the valent chart, the aluminum will then corrode and the joint will fail. Best to go back to steel fasteners and use an anti seize product such as NeverSeize.

Roger

[USA64]

I've had good luck with time, and patience. I had the wheel splines frozen on my XK-E. Every day when I came home from work I gave it a squirt of penetrant and a couple of whacks with a mallet (on the tire). After a month of this, one day, it just fell off like no problem!

[alan.barker]

Drill out and fit Helicoils in tapped Bobbins
Alan

[mikealdren]

Mr TGB,

Mixing aluminum and stainless steel is not a good situation. Because they are so far apart on the valent chart, the aluminum will then corrode and the joint will fail. Best to go back to steel fasteners and use an anti seize product such as NeverSeize.

Roger

Not sure what Neversieze is but don't use Copperslip grease, it also promotes aluminium corrosion, use Ally grease.

It's not too hard to replace the bobbins......

[alan.barker]

Imho it's much easier to fit a Helicoil in Bobbin than replace and much stronger.
Alan

[nmauduit]

Drill out and fit Helicoils in tapped Bobbins
Alan

I would rather use a solid threaded insert rather than a coil, so that it has internal integrity not relying on the supporting soft laterial - it could even be glued in if need be (hole damaged during removal of previous bits), in which case having the pod or a long threaded rod for alignement may be of use.

[baileyman]

I wonder what the effect of the increased threaded diameter in the aluminum is of using a threaded insert. John

[alan.barker]

After working in the Aero Space Industry for 20 Years as a QC Engineer i can assure you Helicoils present no problem
Alan