Brake reservoir screw head issue

[satchit]

I was planning to replace my front brake discs and before starting I wanted to to remove some of the brake fluid from the reservoir as it was way over the top level. I anticipated I would have to push in the pistons and would need the space in the reservoir.

One of the screw heads on the reservoir has got gouged out (I did use a JIS head).

I'm hoping I'll be able to take it out with a straight screwdriver. Is there any other approach which might have a higher chance of succeeding?

I remember seeing a thread about replacing those screws with allen key head screws. I cannot find that thread. Are there any other replacement screws I could find in a hardware store to use here? Or does someone know what terms I could search with to find the other thread?

Any help is appreciated.

[the Ferret]

Try sticking the flat of a rubber band down in there with a screwdriver ( old mechanics trick)

[Gone in 60]

If that doesn't work, you could use a Dremel and a cutting blade to cut a slot in the screw to use a flat-blade screwdriver.
Since the screw is beveled, might be easier to just replace with an OEM screw and use a small dab of anti-seize on it.

[satchit]

Ferret and Gone in 60, thank you for your responses. I will apply WD 40 to all of these screws and let it sit overnight before trying your suggestions.

Looks like these are [url=https://www.partsfish.com/oemparts/a/hon/52f28bedf870021404ec5a35/front-brake-master-cylinder-1]M4x12 screws. Also, I'm guessing these are countersunk even though the description says flat.

I will check if home depot has something similar. The other screw came off easily, so I should be able to compare if I find something at home depot - hopefully with a head which will take an allen key.

[Lord Popgun]

You might also try putting the screwdriver in the head and tapping lightly, but sharply (if that makes sense) then seeing if it will come out. Or sometimes putting torque on the screw while tapping.

Whatever you do, protect your paint. The brake fluid will mess it up RIGHT NOW. Put some plastic over the tank.

[GoldOxide_imp]

(dang) I remember doing this crap back in the early 80's and thought: Can't they engineer these reservoirs better?

Take the best of a chemical and mechanical engineer and make the issue go away? Maybe it has ... in outer space, but not in the civilian domain.

Heck, maybe not use "Phillips" screwheads might solve half the problem.

[max]

1 Would try to remove the one good screw and see if you can rotate the lid so as to break the head loose.
2 sharpen a flat head screw driver so it has the widest grip on the bad screw and very sharp biting edges.
3 try tightening and un-tightening alternatively and use some wd40 or equivalent.

Thanks for the picture, that really helps.
Also put the new screws in with some grease in the threads, let us know how you get on.

[rich_imp]

i have used valve lapping compound in the past
if you try the rubber band make sure to clean off all the WD40

[Juancho76_imp]

I always pound a beer and whisper the obligatory statements.... "Please work this time" or "She ain't going nowhere" before I begin these types of delicate projects.

(I might also add a very important note, this has NEVER been a successful solution for me in the past)


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[dave]

I'm surprised that nobody has suggested drilling the screw and using an Easyout.