What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Leaking Oil Pressure Relief Valve

rwtalbot

Well Known Member
My AEL-77808 Oil Pressure Relief valve has been leaking out the thread. Is there a way to disassemble and reseal it or am I up for a new one?

Someone suggested backing it out and using red Loctite to seal the threads. Has anyone done it?

242wnzn.jpg
 
Which threads are you talking about? I presume the smaller "adjustment" threads? I thought I detected a very slight amount of oil on those at the last oil change, not enough to fret about, but just watch...unless there's an easy "fix" I can do :).

TIA!
 
My AEL-77808 Oil Pressure Relief valve has been leaking out the thread. Is there a way to disassemble and reseal it or am I up for a new one?

Someone suggested backing it out and using red Loctite to seal the threads. Has anyone done it?

242wnzn.jpg
No way to fix that I know of.
Good Luck,
Mahlon
 
I also have a slight leak past the threads on the adjustment stem (Lycoming part in my case). I've done plenty of research online, and can find nothing about any kind of a serviceable seal, O-ring, or anything. I think mine's been leaking since near-new.
 
I have one of these old (obsolete?) non-adjustable regulators around - adjusted by the number of washers under the spring. Has no upper threads to leak...:)

Not my pic, if you are interested I get a pic of mine...

me8bpkOkByhIVLzxhA0DFpg.jpg
 
There are two types of non adjustable caps. They are not interchangeable. One looks like a Bat Masterson derby hat (Like the one in the picture of the previous post) and the other like an Abe Lincoln stove pipe hat. The Abe Lincoln style is the newer of the two and can be used in lieu of the adjustable type one that has the seepage problems with out any issues. But the Derby looking one is used with an older style crankcase that has a steel cage mounted in the crankcase, where the relief valve assembly mounts, to keep the relief valve ball centered on it's seat. You can mount the derby style one on a non caged crankcase, as it will fit fine, but the ball will be allowed to drift sideways during engine operation due to the lack of the centering cage, and you will have weird, unsteady and unreliable oil pressure because the ball can be and often will be misaligned with its seat.
Good Luck,
Mahlon
 
Thanks

There are two types of non adjustable caps. They are not interchangeable. One looks like a Bat Masterson derby hat (Like the one in the picture of the previous post) and the other like an Abe Lincoln stove pipe hat. The Abe Lincoln style is the newer of the two and can be used in lieu of the adjustable type one that has the seepage problems with out any issues. But the Derby looking one is used with an older style crankcase that has a steel cage mounted in the crankcase, where the relief valve assembly mounts, to keep the relief valve ball centered on it's seat. You can mount the derby style one on a non caged crankcase, as it will fit fine, but the ball will be allowed to drift sideways during engine operation due to the lack of the centering cage, and you will have weird, unsteady and unreliable oil pressure because the ball can be and often will be misaligned with its seat.
Good Luck,
Mahlon

Thanks for the info Mahlon.

It did come with an old style ND case and my engine assembler replaced it with a newer adjustable one.

I'll check and confirm it's the derby hat one, and simply dump it if it is to get it out of circulation...:)
 
Reviving an old thread, same problem . . . 77808 leaking from adjustment threads, drop drop drop. ACS has a new one for $290, but too much . . .

Only 70 hrs on the new engine.

Anything new on a sealing solution??? Anyone take one apart to see how it is made?
 
AEL77808

I did not know that these were a problem. The internal O-ring is
P/N AS3582-109. By the drawing, it looks like it comes apart easily.
 
WOW - Thanks!!

Outstanding, I will get that o-ring and post my repair. I don't have a drawing, but assume it is easy to push out the roll pin and thread out the shaft. I will measure the shaft-to-housing distance for the spring platform on the bottom and return the shaft to the same position. That way it won't affect the oil pressure relief point. If I am missing something, please let me know.

Thanks James, that was very helpful. If you could post/send a photo of that drawing, it would greatly be appreciated. Email is good, I'll sign an NDA. :D


edit: finding this o-ring is presenting a little trouble. It is silicone! ACS on it.

Final Update: 2.17.21 I wrapped the valve with a white towel and secured with a zip tie to confirm leakage for warranty. It did not leak - - I don't know if it was some intermittent issue or how the oil got there, but nothing there after 25 hrs. I dropped the issue and kept flying. Sorry for the lateness of the closure.
 
Last edited:
Luck on upper seal?

My turn,

Just wondering what success anyone has had in taking the oil pressure relief valve apart and replacing the small upper seal on the adjustable threads?

Thanks

Tim
 
Same Issue

I, too, am looking for an update on this issue. Discovered today my oil pressure relief valve has a slow leak through the threads (inner adjustment threads). Wondering what it takes to replace this seal.

Any experience with this is much appreciated.
 

Attachments

  • D46AB0D6-A1CF-41FA-9192-8D8FC325C3AA.jpeg
    D46AB0D6-A1CF-41FA-9192-8D8FC325C3AA.jpeg
    49 KB · Views: 51
Loctite

Loctite worked for me. Give it a good clean with solvent first. Blue would be a good start, otherwise the one recommended by Vans for fuel tank leaks. A lot cheaper than a new valve.
 
Last edited:
Why not an external o-ring ?

Could you use a thin jamb nut to compress a silicone oring where the threaded shaft comes out the casting ? It obviously depends on the distance available to the keyed nut above. BTW, what is the keyed nut for ?
 
Thanks for the replies. Is there not risk of contamination with introducing Loctite into the oil system like this?
 
Back
Top