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Went to bleed the brakes on my CBR250R and one of the cover screws wouldn't budge, even using the proper JIS screwdriver. It started to cam out and displace metal in the screw head.
I decided to get a ball-peen hammer and carefully beat the protruding metal back down into the screw head. This made the screwdriver fit very tightly and I was able to break the screw loose by momentarily turning it clockwise and then counter-/anti-clockwise.
This is the screw after I loosened it:
![[Image: c63b8054c089224357f43d54073f8527.jpg]](https://cb1100forum.net/forum/uploads/imp/202106/c63b8054c089224357f43d54073f8527.jpg)
Looks like there's some galvanic corrosion happening between the screw and the cover, so both will be replaced with new + a small amount of anti-seize compound.
This method was less scary than a drill and a tiny back-out, and saved the master cylinder itself from being damaged.
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(06-15-2021, 06:50 AM)Stichill_imp Wrote: Went to bleed the brakes on my CBR250R and one of the cover screws wouldn't budge, even using the proper JIS screwdriver. It started to cam out and displace metal in the screw head.
I decided to get a ball-peen hammer and carefully beat the protruding metal back down into the screw head. This made the screwdriver fit very tightly and I was able to break the screw loose by momentarily turning it clockwise and then counter-/anti-clockwise.
This is the screw after I loosened it:
Looks like there's some galvanic corrosion happening between the screw and the cover, so both will be replaced with new + a small amount of anti-seize compound.
This method was less scary than a drill and a tiny back-out, and saved the master cylinder itself from being damaged.
You are reinforcing my strategy of keeping bikes for a max of 4 years or 20K miles.
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There is a product called : Drive Grip , this will increase torque when removing stuck screws . Product Vibra-Tite 47002 . I only used it once and it did work well .
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Next time try an impact driver.
stick it in, give it a twist and smack it with a hammer
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I agree, I probably would have tried an impact driver, though with a very light hammer. Glad you got it resolved.
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Vessel even has an impact JIS screwdriver.
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New parts are cheaper than new bikes. Plus I like this one a lot and they don’t make them anymore (much like the CB1100). Assuming a 4-year replacement interval, all US CB1100s would need to be retired by their original owners by now.
No-go on the impact driver attempt before this solution. It didn’t work and was stressing the master cylinder (risked shearing the locating pin on the handlebar).
I’ll look into Drive-Grip, Houtman. Another idea I have going forward is stainless steel hex head screws.
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(06-15-2021, 08:09 AM)The ferret_imp Wrote: Next time try an impact driver.
stick it in, give it a twist and smack it with a hammer
Ah!! Well, likely better than the ol' 4 lb mallet.
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(06-15-2021, 09:21 AM)Stichill_imp Wrote: New parts are cheaper than new bikes. Plus I like this one a lot and they don’t make them anymore (much like the CB1100). Assuming a 4-year replacement interval, all US CB1100s would need to be retired by their original owners by now.
No-go on the impact driver attempt before this solution. It didn’t work and was stressing the master cylinder (risked shearing the locating pin on the handlebar).
I’ll look into Drive-Grip, Houtman. Another idea I have going forward is stainless steel hex head screws.
wow.... "back in the day" we used an impact driver all the time on stuck engine case screws.
(06-15-2021, 07:03 AM)rickcb_imp Wrote: (06-15-2021, 06:50 AM)Stichill_imp Wrote: Went to bleed the brakes on my CBR250R and one of the cover screws wouldn't budge, even using the proper JIS screwdriver. It started to cam out and displace metal in the screw head.
I decided to get a ball-peen hammer and carefully beat the protruding metal back down into the screw head. This made the screwdriver fit very tightly and I was able to break the screw loose by momentarily turning it clockwise and then counter-/anti-clockwise.
This is the screw after I loosened it:
Looks like there's some galvanic corrosion happening between the screw and the cover, so both will be replaced with new + a small amount of anti-seize compound.
This method was less scary than a drill and a tiny back-out, and saved the master cylinder itself from being damaged.
You are reinforcing my strategy of keeping bikes for a max of 4 years or 20K miles.
20K isn't even ONE good year's worth of riding (doubt I'll make that this year although I'm already over 5K)
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A countersunk bolt has a lot friction under the head, specially if it hasn't been loosen for a while. A drop of wd-40 on the perimeter would've helped.
