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Leaking brake cylinder fittings

D

drone_pilot

Well Known Member
So I put fluid in my brake lines for the first time. I had two leaks where the brass elbow connects to the brake cylinders. Removed tubes and tightened elbows another turn. Now I'm down to 1 drip very 4 or 5 days. I did not use any sealer on the elbow threads based on the advice of a mechanic. Should I have sealed these threads? If so, what type of sealer should I use?
 
I have used Permatex Form-a-gasket II on all pipe threads, automotive and aircraft for over 50 years. Never had a problem.
 
Permatex, Seal Lube, etc. you need a lube to allow you to tighten adequately and a sealant to seal when tightened. I also don't know what your mechanic was thinking. All NPT fittings should have this. The flared fittings should go on dry.
 
After a couple iterations I ended up using proseal fuel tank sealant on one of my fittings to get it to stop the drip
 
Does the RV-7 also have Matco Brakes? In the manual they advice Locktite 567, or equivalent. Thats what I used and never had any leakage.
 
Had the same problem. I disassembled my Matco masters and ran a pipe tap 1-1/2 turns into the ports. I ran the tap because I read somewhere that maybe the ports had very slight oval shaped holes. They were reassembled using Loctite 567. I called Matco and that's what I was told would work and it did -no leaks since.

By the way, I had leaks on the sender manfold, as well. Used the 567 on that, too, and problem solved.

I think the original error I made was I used Fuel Lube on all those fittings and that's not what it's for. Better to use Titeseal or the Loctite 567 from the get-go.
 
Had the same problem. Originally used fuel lube on my AN elbows. Teflon tape did the trick for me, no more leaks. Have been told that teflon paste would also do well for hydraulic oil.
Michel
 
Like Mel says ...

...Permatex #2 works like a charm. Mine were originally installed with EZ Turn, which leaked. Had to remove all the fittings, clean off the EZ Turn, and reinstall with Permatex. No leaks since.:)
 
Like Mel says ...

...Permatex #2 works like a charm. Mine were originally installed with EZ Turn, which leaked. Had to remove all the fittings, clean off the EZ Turn, and reinstall with Permatex. No leaks since.:)
 
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