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Discussion Topic:
NAPA master cylinder leaks
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fordv8j |
09-12-2015 @ 8:37 AM
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New Member
Posts: 176
Joined: Jan 2015
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Just replaced the master cylinder on our 38 with a new NAPA unit..went to Motorfest 6..came home it was leaking..they will replace it...they are made overseas..anyone make a good rebuild kit...if the next one leaks..I may rebuild my old one..any one had this problem? THANKS
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supereal |
09-12-2015 @ 11:30 AM
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Senior
Posts: 6819
Joined: Oct 2009
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Rebuilding is usually a waste of time. Getting a leaking cylinder is not unusual today. I'd let NAPA replace it. If the fluid is coming out around the boot, it is probably a bad bore. If it is coming from around the filler plug, the gasket may be torn or missing.
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TomO |
09-13-2015 @ 7:58 AM
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Senior
Posts: 7271
Joined: Oct 2009
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I agree that in most cases rebuilding a master cylinder is a waste of time. most of them have deep rust pits and will leak soon after rebuilding due to the oversize bore needed to clean up the pits. I have had good luck with the Wagner re-manufactured master cylinders. They seem to be much better than the ones made overseas.
Tom
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FordFreak |
09-13-2015 @ 7:20 PM
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New Member
Posts: 118
Joined: Nov 2013
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I just replaced the m/c on my '37 with a new (not rebuilt) Wagner that I got at Mac's . No leaks .
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alanwoodieman |
09-15-2015 @ 8:24 AM
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Senior
Posts: 868
Joined: Oct 2009
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if you happen to be using Dot 5 fluid (you should be) it will leak when dot 3 will not. I have pulled a new cylinder apart and honed it out to a smoother finish and re-installed the piston and they did not leak. It worked for me!
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supereal |
09-15-2015 @ 8:14 PM
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Senior
Posts: 6819
Joined: Oct 2009
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DOT fluid is silicone based. It will not mix with the more common alcohol based DOT 3 fluid. To convert, all traces of the 3 must be removed. The system can be flushed with denatured alcohol, but we replace all the wheel cylinders and the master, and flush the lines only. Converting is a long and expensive process. Leaks, such as at the stoplight switch are common. I don't use it in my cars, preferring to simply replace the fluid every couple of years. That eliminates difficult bleeding and the usual "soft pedal" problems with DOT 5.
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