Broken tap in master cylinder cap screw hole

[Evans Ward]

Thought I was being patient but ham fisted the tap I was using in one of the brake master cylinder cap holes and snapped it. Was tapping it due to A stripped screw and having to drill out screw. The tap is not protruding much from hole level and I can't get on it with my vampliers or a vice grip. I also have no welding skills. Is the master cylinder for RZ350 made out of aluminum? If so, I was reading about a chemical process using potassium alum in hot water to eventually break up the broken tap. Any other ideas? May have to pay someone to extract it. BTW, this isn't on my bike- just one I was rebuilding and refurbishing for resale. I have a FZ8 Master with gold dot R1 rotors and calipers on my RZ.

[Washerman]

I have broken a few at work over the years taps are hardened steel so they are brittle and will break if too much force used. I have removed them using small picks and screwdrivers to try to get them unscrewed. That's pretty small so its not going to be easy try to get something small down in between the fluted teeth portion and try to get it to start moving. Take your time with it maybe it will start to loosen up and once it starts working loose use the tools to try to get it to unscrew enough to get a grip on it. Spray it up good with lubricant and be patient there will be chips in there making it tougher. If it starts moving and you see chips blow them out with air and spray again and keep working it. Good luck.

[Dvsrd]

I guess the broken tap is M4 or M5? Those sizes are really tricky to work on. On M6, I have used this type of tool successfully in the past. They normally come in 3, 4 and 5 flute versions, and most thread sizes.

https://www.amazon.com/Walton-10104-Flute-Extractor-Square/dp/B0006NGFP0

[sav0r (CL MotoTech)]

You could get a little rough with and remove some material around the tap, then once removed have the reservoir decked off. The lost volume probably wouldn't be too significant to operation.

[forexer]

as mentioned earlier dental picks PB blaster and patience - Good Luck!

[1976RD400C]

The problem is it is probably jammed in there since it caused the tap snap. You may have to take it to someone who has a mig welder. Take a flat washer with a hole the size of the tap and place it on there and weld in the hole to the broken piece. Next weld a nut on top of the washer. Use the hex of the nut and wrench it out.

[EE]

I've also seen a friend get a broken tap out with and automatic center punch you know the spring loaded ones. Because the taps are fragile he just kept using that on the tap and it kept breaking up the tap. He said he'd done it lots of times. i thought it was pretty clever.

[Evans Ward]

It's wedged in there good. I was torquing on it pretty good when it snapped.

Who has a mig welder that wants to make some $ extracting this broken M4 tap? 

[RD7]

Do a google search on removing broken studs with Alum. Alum will erode the tap and spares the aluminium. It is slow needs warmth but does work.

[m in sc]

very carfully cut a slot in the top if the tap with a dremel and a fiber wheel, preferable front to back, back out with a small flat blade screwdriver.

[oxford]

It's wedged in there good. I was torquing on it pretty good when it snapped.

Who has a mig welder that wants to make some $ extracting this broken M4 tap? 

If you want to send it to me with a return shipping label I will give it a try on getting it out.  No guarantees but it isn't my first rodeo with broken taps.  Pm me if interested.

[Evans Ward]

It's wedged in there good. I was torquing on it pretty good when it snapped.

Who has a mig welder that wants to make some $ extracting this broken M4 tap? 

If you want to send it to me with a return shipping label I will give it a try on getting it out.  No guarantees but it isn't my first rodeo with broken taps.  Pm me if interested.

Oxford- thank you for that offer but Danny at 27 Cycles had offered earlier today to give it a go so will send to him. Thank you though!

[SUPERTUNE]

I just tig weld dabs of weld on top of the tap to make a post, then weld a nut to it.
I have milled out bigger taps in the mill with a high speed carbide splade drills, but this is too small for that method.
Burning out in a EDM machine is the other way its done. EDM machining is used in mold making shops.
C

[Dvsrd]

Do a google search on removing broken studs with Alum. Alum will erode the tap and spares the aluminium. It is slow needs warmth but does work.

That is clever! Most solutions would be more likely to dissolve/corrode the aluminium, and leave the tap..

[Plasticman]

+1 on welding something on the top to get that tap out. 

Rob