Problem with bleed screw, clutch master cylinder- HELP!

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mrossk
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Problem with bleed screw, clutch master cylinder- HELP!

Post by mrossk » Sat Nov 04, 2017 7:09 pm

Hey y'all- Wonder if anyone has any thoughts/insights. I was bleeding my clutch as it felt a little spongy. Did the slave cylinder, no problem, got a bubble or two out. Started to do the master cylinder and the bleed screw stripped in the hole. Or, I can't get it to tighten at any rate, and mineral oil leaks out. I removed the screw fully to take a look, and there's a lightweight spring around the threads, which looks pretty knackered. Wasn't expecting that, not sure what its function is. Don't know if I should order a new bleed screw (@ USD $25), or whether I'm going to be looking at replacing the entire master, @ $400 !- though I did see a used one on ebay for $85 or so) I'm bringing in to the shop on Monday for help. The bleed screw on the master works just like any other bleed screw, right? Squeeze clutch lever, open screw a little, tighten screw, release lever, repeat, correct? Nothing unique that I would have screwed up doing it like the slave cylinder, or brakes, right? And yes, mineral oil is what I used.
Thanks for any help,
Michael

big tall dave
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Re: Problem with bleed screw, clutch master cylinder- HELP!

Post by big tall dave » Sun Nov 05, 2017 5:44 pm

“Light weight spring around the threads” = Sounds like the steel thread insert from the factory has pulled out of the casting. I’ve done this accidentally a few times over the years.
You could try a HeliCoil, but i’m not sure if the hole is deep enough and you don’t want to damage the machined surface that the bleeder screw mates against. Then again, you’d have to buy another one anyway, so might as well try.

mrossk
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Re: Problem with bleed screw, clutch master cylinder- HELP!

Post by mrossk » Sun Nov 05, 2017 6:54 pm

thanks, that seems right. But that bleed screw is designed to be screwed open and shut, isn't it? I'm not missing something in the bleeding procedure, am I? Any idea how it could happen? I don't think I was doing anything untoward...
Thanks,
Michael

Volvor
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Re: Problem with bleed screw, clutch master cylinder- HELP!

Post by Volvor » Sun Dec 03, 2017 1:16 pm

mrossk wrote:thanks, that seems right. But that bleed screw is designed to be screwed open and shut, isn't it? I'm not missing something in the bleeding procedure, am I? Any idea how it could happen? I don't think I was doing anything untoward...
Thanks,
Michael
It was over torqued at some point, hence the “spring” which is in fact threads pulled out of the master. Just bite the bullet, buy another one, and go very easy on the new one. That bleeder is the tiniest one I’ve ever seen! It’s like it should be on an RC car or some toy.


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mrossk
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Re: Problem with bleed screw, clutch master cylinder- HELP!

Post by mrossk » Mon Dec 04, 2017 11:01 pm

Bit the bullet and bought a used one off E-Bay. Seems to be working. Lesson learned, I hope ;)

big tall dave
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Re: Problem with bleed screw, clutch master cylinder- HELP!

Post by big tall dave » Fri Dec 08, 2017 4:17 pm

mrossk wrote:
Mon Dec 04, 2017 11:01 pm
Bit the bullet and bought a used one off E-Bay. Seems to be working. Lesson learned, I hope ;)
I don’t blame you one bit. That sucker is tiny! The weight of the wrench alone is prob the factory torque spec. Lol

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