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Master cylinder leak

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Old Jan 7, 2017 | 10:06 AM
  #1  
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Master cylinder leak

I bought a MC from CPP it's been a year before I was able to get the brakes and body ect. work done so that I could bleed the brakes. So now that brakes are working but I have a leak at plugs or some where on the master and I'm not sure of the location but most likely leaking at plugs on the side of MC. So I call CPP before the xmas and after tightening the plugs a number of times it still leaks now they tell me to use loc tight blue on the thread just thought I'd get other opinions before I jump on some glue to hold brake fluid ??
 
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Old Jan 7, 2017 | 10:16 AM
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Loctite is to prevent a bolted assembly from coming loose. It will seal the threads but I would find the leak.
 
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Old Jan 7, 2017 | 10:20 AM
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It sounds like you might have a cracked brake line at the flair. Could also be a small piece of rust trapped in the area where it seats .You don't use sealant on any type of compression fittings.
 
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Old Jan 7, 2017 | 10:32 AM
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This is not on the line side they have plugs on the other side for other use.
I have looked at loctite site and they have thread sealant for brake fluid so?
Just not sure
 
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Old Jan 7, 2017 | 11:39 AM
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When I assembled the brake system on my F4, I used Loctite 569 hydraulic pipe thread sealant and primer T on the 1/8" npt threads on the adapters. If those plugs are pipe thread, they do need sealant on them. I didn't have any leaks with the Loctite.
Mark
 
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Old Jan 7, 2017 | 12:36 PM
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Plugs are not pipe thread, and loctite says to use 567, 665, 569, or545
Would the threads need to be clean from fluid( brake cleaner)then primer and sealer?
 
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Old Jan 7, 2017 | 01:13 PM
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Master cylinder leak

Roy
Since those are just plugs, why not try Teflon tape.

The plugs should have a flair on the tip that should match the flair on the inside of the m/cyl - which should stop the leak.

But if there is no flair, then they are just a plug. Teflon tape or Teflon paste might work.

CPP should know how to deal with this - thought they would come up with a better fix than plain old lock tight.

Photos might help us all understand the problem better.

Good luck

Dan
 
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Old Jan 7, 2017 | 02:03 PM
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Originally Posted by burnettd01
Roy
Since those are just plugs, why not try Teflon tape.

The plugs should have a flair on the tip that should match the flair on the inside of the m/cyl - which should stop the leak.

But if there is no flair, then they are just a plug. Teflon tape or Teflon paste might work.

CPP should know how to deal with this - thought they would come up with a better fix than plain old lock tight.

Photos might help us all understand the problem better.

Good luck

Dan
Correct, the plugs should have a machined face to seal against the flare seat inside the master, if they dont they are not correct. Threads should not be doing any sealing at those connections and should not need sealant.
If you must try something I would use a thread sealer called BLUE BLOK which is oil and gas resistant, teflon tape may dissolve in brake fluid. I buy it at home depot and use it on home heating oil tank filler pipe threads.

That said I would want the correct plugs and not use any sealer.
 
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Old Jan 8, 2017 | 05:24 PM
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I just sent a email to CPP telling them that I don't want to fix a new master cylinder and that I would like them to send me a box so I can return the MC they can repair it and send it back to me
See what happens
 
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Old Jan 8, 2017 | 06:00 PM
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We'll be watching for your out come Roy. Good Luck.
 
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Old Jan 8, 2017 | 07:05 PM
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Another reason I stick with OEM type parts whenever possible, I just don't trust aftermarket parts much in most cases.
 
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Old Jan 8, 2017 | 08:04 PM
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Yes I hear you dave that is a hard thing to stay with for a me. I read a thread about another member not buying anything from this out fit I'm learning things the hard way. I hope I have used the right words in this case in my note to them I have had this brake setup for over a year getting rust removed and body/paint takes me a long time
 
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Old Jan 8, 2017 | 08:53 PM
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Master cylinder leak

Roy
Let's hope they do the right thing which would be to replace the master cylinder and send you the correct plugs.

If that doesn't happen, I know a place that might be able to provide the correct plugs.

Good luck.

Dan
 
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Old Jan 10, 2017 | 04:29 PM
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I have a similar M/C from CPP and I thought that one of those plugs was leaking too but after lots of repositioning and tightening of lines I found that it was a flare fitting. Luckily I had not removed any of the plugs.
 
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Old Jan 10, 2017 | 05:47 PM
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Same here, petemcl, on the CPP installation. I ended up wishing I had annealed all the flares on the ends of the new lines I put in. I hate that moment of thinking about all the work that would have to be re-done if you put just a little too much torque on that last twist of the line wrench.
 
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