Rounded Master Cylinder Screws

Thom · World Chat Champion Joined: 24 Oct 2007 Karma :

Any ideas for getting them out, they are completely rounded off and cutting a groove for a flat headed screw driver isnt an option or ill cut into the cap.

Also keeping in mind i dont have a drill bit small enough to drill them out...

Or any means of welding a nut to the top of them to extract them that way...
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Current Bike: 1996 Yamaha TRX850 (The Japanese-Ducati One).
Previous Bikes: 1990 Honda NSR125 'Rothmans' (The smoking one), 1990 Suzuki GS500e 'Caf? fighter' (The loud one), 1987 Kawasaki GPX400r (The quick one), 1997 XJ600s Diversion (The reliable one), 2000 Kawasaki ER-5 (The spontaneously combustive one)

Vincent · Banned Joined: 16 Oct 2006 Karma :

How about one of those "screw extractors" they've got advertised on TV at the moment? You got a reversable drill?

Finglonga · World Chat Champion Joined: 27 Jul 2004 Karma :

Ichy · World Chat Champion Joined: 15 Jul 2005 Karma :

Centre punch and a hammer will sort it. Like this but on the top face.

https://www.metacafe.com/watch/1144728/un_screw_you/
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map · Mr Calendar Joined: 14 Jun 2004 Karma :

Thom · World Chat Champion Joined: 24 Oct 2007 Karma :

I decided to be a typical guy and find my way around it. i back bled the system without even removing the cylinder cap. just alot of brake pumping and forcing of the syringe until it was all fluid and no air.

Seems to have worked.

Also, i didnt round the heads off im glad to say, the heads didnt exist when i bought the bike!
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Current Bike: 1996 Yamaha TRX850 (The Japanese-Ducati One).
Previous Bikes: 1990 Honda NSR125 'Rothmans' (The smoking one), 1990 Suzuki GS500e 'Caf? fighter' (The loud one), 1987 Kawasaki GPX400r (The quick one), 1997 XJ600s Diversion (The reliable one), 2000 Kawasaki ER-5 (The spontaneously combustive one)

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

Just drill the heads off, not the whole screw out. You can easily undo the stump this leaves behind using mole grips.

Like this:
https://www.bikechatforums.com/files/master1.jpg
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

Phil_G · Traffic Copper Joined: 27 Mar 2006 Karma :

carvell · Scuttler Joined: 05 Sep 2003 Karma :

S'what I did too.
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Yamaha TDM 850

Vincent · Banned Joined: 16 Oct 2006 Karma :

alains · World Chat Champion Joined: 08 Jul 2004 Karma :

if it's a NSR125R the cover is thin , the risk , when the heads are off that you wont have enough length to grip the screw . mark the center very acuratly the drill at diameter 3 , about 1/2" deep , then drill at diameter 5 to take off the heads . if you are able to take off the remains of screw , all ok otherwise drill at 3,2 mm then thread it again with a 4 thread 80 screw-tap .
i've done that 2 years ago . new screws countersinkscrew diameter 4 length 16 or 20 mm
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Odie · World Chat Champion Joined: 24 Jul 2004 Karma :

[quote="Vincent"]

Thom · World Chat Champion Joined: 24 Oct 2007 Karma :

i got rid of my nsr recently Alains it's my GS500e that im working on.

I'll try the mole grip thing when i get some screws to replace them, thanks for the help guys!
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Current Bike: 1996 Yamaha TRX850 (The Japanese-Ducati One).
Previous Bikes: 1990 Honda NSR125 'Rothmans' (The smoking one), 1990 Suzuki GS500e 'Caf? fighter' (The loud one), 1987 Kawasaki GPX400r (The quick one), 1997 XJ600s Diversion (The reliable one), 2000 Kawasaki ER-5 (The spontaneously combustive one)

alun111 · World Chat Champion Joined: 31 May 2007 Karma :

my usual method is to either get the best fitting cross head screwdriver bit you can and try that - pressing as HARD downwards as you can, or try the best fitting flat head screwdriver bit!

It's absolutely essential that you put a LOT of pressure downwards.
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Summer: '00 Honda CB600F Hornet
Winter: '93 Suzuki GSF 400 Bandit VP Variable Valve
Past Bikes: Lifan LF100-5 Lifan LF125-A Honda C70

Ichy · World Chat Champion Joined: 15 Jul 2005 Karma :

Vincent · Banned Joined: 16 Oct 2006 Karma :

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

We're getting away from the main point which is that if people used the correct size screwdriver, the heads wouldn't be burred in the first place. They are never in THAT tight.

Mine was being drilled because it came not only pre-burred but had been hammered out with a punch then -wait for it- hammered back in again! Rolling Eyes

If anyone feels they are not capable of selecting the correct size and type of screwdriver, replace them with socket head screws instead.

I didn't even bother my arse using a countersunk screw to replace that one I removed. It's only holding the lid on against a big fat rubber gasket. As I recall, I replaced it with a cheese-head out of the bottom of my toolbox that was wider than the countersunk bit.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

Vincent · Banned Joined: 16 Oct 2006 Karma :

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

I hadn't realised how piss poor a lot of screwdrivers are until I got some good ones.

That said, a great many burred screw heads result from a phillips/pozidrive mismatch.

https://en.wikipedia.org/wiki/Pozidriv
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

69.9mph · Crazy Courier Joined: 20 May 2006 Karma :

FlashBashly · Derestricted Danger Joined: 18 Apr 2008 Karma :

I've just rounded one of mine off (cos I'm a complete numpty Rolling Eyes

).

Solution : Use one of the REALLY sharp screwdriver bits from a socket set and give it a right good hammering into the screw thread. Makes a nice bite into the soft metal then just screw out with the driver shaft.

Oh, and replace with a new cross head one Whistle

Flash

StealthDJ · Nova Slayer Joined: 21 Apr 2008 Karma :

..... · Quote Me Happy Joined: 15 Jan 2005 Karma :

Sorry to dig up an old-ish thread but it's better than starting a new one. I've just battled with the same problem and got the screw out and some nice new ones waiting to go in, but my question is, is it OK to use copperslip on the new screws to stop them seizing?

Seems like there's a couple of contradictory views in this thread.

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

I would (and do).

Although not actually sure how it works as I think the copper is meant to be less reactive by to trigger corrosion in other dissimilar metals that it is in contact with.

All the best

Keith
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Grav · World Chat Champion Joined: 12 Jul 2004 Karma :

Copperslip is worth it's weight in gold and should be used wherever possible. I have never had any trouble with any fastener I have coated with it. It does not react with Alloy or Steel and keeps corrosion at bay. You dont need an awful lot, just a thin smear on the threads and as you tighten the fastener it will coat the threads evenly all round giving complete protection without fear of making the fastener loosen or stick like poop to a blanket. Thumbs Up

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