Unable to remove screws

911buff · 911buff's Garage

I have a problem. I am attempting to rebuild my '74 2,0 but I cannot remove the heads because the screws holding the tin underneath the cylinders will not budge. The previous engine builder did not use anti-cease or used lock-tite on them. Either way, they will not budge and I don't want to destroy the screw (the head is beginning to deform. Does anyone have a method of removing stubborn screws? I cannot reach them with vise-grips or similar "tool". Is there some kind of easy-out, etc, that can reach that far into that area? I am guessing someone has had to deal with this at some point. Thanks!

Nostril Cheese · 02-04-2013, 01:33 PM

Impact driver.

Impact Screwdriver Set with Case

Tobra · Tobra's Garage

Those cheese head screws that hold on the tin are pot metal and will deform pretty easily. Spray some PB blaster on there and let it sit a while. Sometimes if you put a little grinding compound on the end of your screwdriver it will bit a little better. Heat can loosen stuck fittings.

I don't know if I would use an impact driver on it, depending on where it is exactly.

NICE 69 S · 02-04-2013, 03:48 PM

If all else fails, use the impact driver. If you break the head of the screw off, drill it out once you get the case apart (on a drill press if you have one). Then go on line and buy a 6X1.0 Helicoil kit. Cost about $20.00 and you will probably use it again. Very common thread size for VW and Porsche (and every Japanese motorcycle ever made).

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Note that the screws on the underside of the under-cylinder tin are an odd size, either M5 or M4, instead of the M6 screws used on the rest of the engine tin.

A good penetrating oil can help. HEAT can help, too. Impact tools as well, of course. Make sure you use a screwdriver that fits the slot in the screw correctly; the wrong size slot makes it much tougher to remove the screws.

--DD

wndsnd · 02-04-2013, 04:43 PM

What has worked for me is heat and the longest largest screwdriver that will fit the head. I also tap the top of the screw driver with a hammer and use PB. Only some break off ;-)

pgeorgeson · 02-05-2013, 01:30 PM

I had the same problem. I soaked in PB, then heated them up with a torch, then used the impact driver on them. They all came out that way.

jeffs9146 · 02-05-2013, 04:09 PM

I have had luck with a pair of vice grips around the head and a large screw driver all at the same time after soaking over night in PB! Some times I put some heat also!

I replace the screws anyway so the vice grip damage is fine!

The cap'n · 02-09-2013, 06:38 AM

"Pot metal"? I think not.

The Cap'n

tomk · 02-09-2013, 07:15 AM

its really hard to recommend a set procedure for getting these old fasteners out, I just finished a rebuild and the screws near the intake plenum gave me trouble. I ended up breaking them, drilling and going to a 7mm tap and screw. Once the head is off you can drill it out on a drill press and retap with pretty good results. on reassembly i used allen head stainless fasteners to replace the crummy cheeshead screws. good luck

911buff · 911buff's Garage

Tthanks for the advise. I had soaked them with some PB and after I turned the engine over and was able to get at them better, I tapped on the screw driver as I unscrewed and they eventually broke free. So all is well.