How to get stripped master cylinder screw out

Buzz Bomb

Member
May 9, 2000
706
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My friend's front break master cylinder screw is in really tight, and he stripped the head. What should we do to get it out? I tried a dremel with a little metal disc attachment to grind a slot in the screw, but the piece of too wide and won't cut deep enough into the screw without damaging the master cylinder cover. Are there smaller pieces for a dremel? The ones I have are about 2/3 of an inch in diameter.
 

Showtime_144

Member
May 21, 2001
12
0
stripped screw

You could drill a hole in the screw then use a screw
extractor to get it out. I had this happen and I took
a punch and taped the screw at an angle to back it
out but if its in there good it probally wouldn't work.
You might also be able to tap a robertson screw
driver in it if the head is stripped in a square shape.
I guessing it's a phillips head.
Just trying to throw ideas out there.
 
Last edited:

zilla

Member
Nov 4, 2001
218
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If you can get the other screw out, I'd take a drill bit and drill just the head off the stuck screw, leaviing the threaded part of the screw. Then you could remove the cover, clean things up with CRC, and try to get a pair of vice grips on the stud that will be left after drilling the head off. If all else fails you MAY have to redrill and retap the hole. What year bike and what make are we talking about here. ?

zilla
 

bscottr

LIFETIME SPONSOR
Sep 20, 2001
1,255
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Buzz,

Zilla is dead on. I had the same problem. After you remove the cover there will not be any tension on the screw (unless cross threaded), it should back right out.

Good Luck,
Scott
 

02yz125

Member
Sep 25, 2001
162
0
If ya wanna send it to me i'll get it out for ya! Doubt you'll do it but just an offer. It's probably gonna be no larger than a #8 screw (but metric), so I would use a bit no larger than a #35. I drill about 25-50 stuck screws a week on average on aircraft that are stuck. Zilla is exactly correct though. Since you dont have an opening on the other side this is the best bet. Use a larger bit and drill a little at a time and use the cover as leverage to snap off the head. The more you have sticking out the better off you are. It would take me about a minute at the shop!!
 

David Trustrum

~SPONSOR~
Jan 25, 2001
1,396
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Used that method a few times, just be sure not to graunch the MC sealing surface with the vice grips (steel rule may help protect things here).

Before you do I have a sacrificial set of wood chisels that I use to cut a step in the bolt head. Then I use a sacrificial screwdriver to tap the bolt around near the circumference & at about 30 degrees from horizontal. Found this has worked many times. Keep new screws in toolbox.
 

Buzz Bomb

Member
May 9, 2000
706
0
Sorry I didn't respond to this earlier. I usually keep spares, but this is the first time I've needed to go through this much trouble with a break master cylinder screw before. I ended up just driving over to Sears and get a little engraving tool for the dremel. It was kind of like a drill bit used to drill out cavities in teeth and worked fine. I just carved a straight line across the head of the screw and it only cost me $3. Thanks for your help, though. Oh yeah, whoever asked what bike it was, just read my signature.
 

ADS

Member
Nov 21, 2001
144
0
To keep from stripping those soft, little screws again when opening up your MC, lightly tap your screwdriver a couple times with a hammer (remember,lightly), this securely seats the screwdriver in the screw head, then loosen it.
 

eunos

Member
Jan 17, 2002
61
0
If your outdoors and hav`nt a drill a saw cut across the corner thru both the screw and cap lets you get a flat blade screwdriver in,you can repair the cap easily when you get back with JB Weld.It only happened once to me when some nerd squeezed the brake whilst I was changing pads and popped the brake cylinders, now I always replace the screws with allen head bolts.
 

Buzz Bomb

Member
May 9, 2000
706
0
I thought about getting allen head screws but the local place didn't carry them in metric sizes. Where did you get them from?
 

eunos

Member
Jan 17, 2002
61
0
Sorry buzz-bomb can`t help on that. Over here in G.B. all bolts and screws are metric since we joined european common market.Good Luck.
 
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