Hitchcocks Forum

Hi All



Able to detach the gearbox. gearbox screws are bit stuck. used WD 40 still no luck. destroy the face of one screw already.

i am thinking of buying impact screw driver as shown below: hit with hummer and bang .. not sure if it is suitable for this type of work

any suggestion/ideas are welcome

Regards
ET

Well, WD 40 is not really a penetrating fluid. You may have better luck with the proper stuff. First off, try clouting the end of your screwdriver as you twist, that often works. The impact driver will probably do the job but if the budget's big enough a cordless impact driver is a useful tool to have around the workshop.

It will need a lot of heat, preferably from an oxy torch to expand, and contract with penetrating fluid, the screws and the casting around them, breaking the corrosion, formed by electrolysis between the two different metals, locking them together.

Post script: If the screws are forced out cold, the chances are the thread in the alloy will be ripped out with the screw.

Try a metal round metal bar just a bit smaller than the screw head a give a few healthy taps to send a shock wave through the screw, then try to tighten the screw, you know it won't tighten but the pressure may be enough to disturb any crud in the thread, as you try to tighten then untighten all in one action. Other than that drill the heads off.

I'm with RoSy on this one. Don't use an impact driver, if the screw slots are already gone it will just make things worse. Getting stuck screws out is a skilled task and a 'wonder tool' like an impact driver is not necessarily the best answer! Get a plumbers blow torch, use MAPP gas cartridges, these burn really hot. The small investment in this tool will be really worth it with the rusty parts you have already shown us! If local heat doesn't work do as RoSy suggests and drill the heads off, the steel of these screws is soft and once the cover is off you will have a much longer shank of the screw to work on.

I find a 50:50 mix of paraffin and ATF makes a good penetrating oil.



On the assumption you're going to strip the whole thing, I'd be tempted to take off any parts I can and put the whole thing in a bucket of diesel for a week.

Oh yeah, another tip for stuck cheese-heads from my Jawa owning days (they have cheese-head crankcase bolts). Best thing I found to remove them was a bit and brace. So a large flat-head screwdriver bit clamped in the chuck of an old-fashioned drill brace. This allows you to press down hard on the screw with one hand/your chest to stop the bit cam-ing out while you crack it loose with the handle. A tiny dab of fine grinding paste on the end of the bit can help it grip.



The Jawa toolkit screwdriver (which I still have) was also good for these because you could do a similar thing with it.