tough screws.. really tough screws

[james.ed]

bit of a novice question..

just got me self a shiny set of new screws for the gearbox cover panel. the old ones are pretty knarled and the washers are rusty. as new carpet is arriving i'm replacing them to avoid staining (as had happened before). I've got most of the screws out and replaced with new covered in a healthy amount of grease. i'm having serious trouble with several tho.. they just won't budge. any tips for easing up a lodge screw. i'll hire an electric screw driver from uni to get a bit more torque but if there's any oils or solvents that can help let me know.

worst case is the don't come out.. what then! i could leave them, but i'd really like to get the panel up and new sealing strips put on the underside.

also.. completely different topic.. i'm spraying the gear stick / gear stick gater. i'll be using a glossy black enamel. can this go to bare metal, or will i need to prime beneath?

as always, thanks!

[chickenjohn]

The screws are made of brass so you will have to drill them out and tap the captive threads in the floorpan. I'm pretty sure these are BSF threads. Will just go and check for you!

[mogbob]

James
Plus Gas is my favourite dismantling fluid, applied and left overnight ,if possible to do it's work.
( WD40 is a poorer substitute, it's more a water dispersant/ lubricant )
Spraying from underneath the car would be the most effective way to hit the threads.

Inside the car
An impact screwdriver will usually " shock " the screws free.
If " not available " use an old screwdriver, you are not concerned about, and give it a sharp rap with a hammer on the screw head.
Extra force required ?, lean down hard on the screwdriver and rotate the shaft of the screwdriver with a a mole wrench clamped to the metal shaft.

Getting desperate ?
Apply heat with a hot air gun / hairdrier ( if the other half isn't watching ! ).
Repeat / try all of the above again.

Good luck..persevere , chant the mantra "I will not be beaten " it's only a little screw.
Paint personal choice..I'd go for a primer and then top coat/ coats for a better finish.
Bob

[chickenjohn]

The trouble with those brass screws, is if they don't come out cleanly then the heads shear off, or the cross slot rounds off and you can't grip the screw anymore. Penetrating fluid may help unless the screw heads are already rounded.
An Impact screwdriver with a large phillips head and a wallop with a hammer may help as well on the impact driver.

Hence the need to drill any that don't come out with the screwdriver (soft brass-easy!) and I just checked and the captive threads are 1/4 BSF, tap with a 1/4 BSF TAP AND use new screws to replace those that had to be drilled (cheaply available from the usual suppliers).

[james.ed]

right.. i'll try the penetrating oil and a wack from a hammer approach! i've still got pretty good head in the screws so i can get a grip. I've already got new screws waiting to go in. all the others came out easily enough.

how (in simpleton steps) would i drill out the screws. do i use a drill bit to chew through the centre.. all the way? and then how do i get the the remaining thread out?!

this is one of those jobs that was supposed to take an hour

[aupickup]

sometimes it can help to try and tighten a tad, this sometimes works, use this method in the buildinmg game for screws that are hard to shift

[taupe]

Re the painting.

If you are using smootherite it can go straight on the prepared metal.

Any other paint, acrylic etc needs primer first - there are normally directions on the tin of paint regarding preparation.

[MarkyB]

Make sure the screw slots are completely clean and that the screwdriver bit is a good fit, not any old crosshead.
An Impact screwdriver and a squirt of Plusgas from underneath will both help too.

[Ratbag]

right.. i'll try the penetrating oil and a wack from a hammer approach! i've still got pretty good head in the screws so i can get a grip. I've already got new screws waiting to go in. all the others came out easily enough.

how (in simpleton steps) would i drill out the screws. do i use a drill bit to chew through the centre.. all the way? and then how do i get the the remaining thread out?!

this is one of those jobs that was supposed to take an hour

To drill out:
1. File top flat if uneven.
2. Centre punch.
3. Pilot drill 1/16"
4. Drill through to the root size of the thread.
5. Pick out the remaining with a scriber / sharp implement.
6. Run a tap through if any thread damage (unlikely if you drilled centrally).

You'll need a new/sharp drill bit for brass. Do not use a lubricant as the brass if self-lubricating.

Cheers,
Phil.

[Alec]

Hello James,

I'm uneasy about the advice of using an impact screw driver or a hammer as the captive nuts are not held in a very strong cage. If the cage is damaged the nut will start to spin, which then becomes a major job. Marky's advice about using the correct size (and type) of screwdriver is spot on. They are bigger than the more common screwdrivers around, I would guess they are Phillips not Pozi drive, from their age.
Are some ot the screws visible under the car, if so are they gummed up with underseal or paint?

Alec

[MarkyB]

My cheap and nasty impact driver has a large bit the is a good fit, as you say I wouldn't want to hit the drive with it in a brass screw.

My guess is that the screws would respond very well to a modicum of heat as the expansion rate of brass is very different to that of steel (guesswork).

A tip I've seen elsewhere is to warm the offending bit then push a candle against it, apparently the wax gets drawn up in the thread.

[bmcecosse]

This seems an amazing kerfuffle for very little advantage....

[james.ed]

I wouldn't fret to much.. only i get oily muck coming from under the plate every so ofter. little fedup of cleaning it off things so i'm intending to replace the sealent beneath to get it back to shape. can't think of a way of doing that without getting those pesky screws out. sadly i'm limited to one day a week for the car (if i'm lucky). role on next week.. i'll get them from the underside. its a personal crusade!