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Constant Pressure Clamps VS Hose Clamps

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Frankster13

Active Member
I am looking to replace my oil return line hose clamps with constant pressure clamps on my Lycoming O-390. It seems hose clamps loosen over time and need re tightening during condition inspection and leak oil. Does anyone know the optimal type, size and part number to order for constant pressure clamps? Also looking for feedback on my logic. Would this be a reasonable idea?
 
Frankster13 said:
I am looking to replace my oil return line hose clamps with constant pressure clamps on my Lycoming O-390. It seems hose clamps loosen over time and need re tightening during condition inspection and leak oil. Does anyone know the optimal type, size and part number to order for constant pressure clamps? Also looking for feedback on my logic. Would this be a reasonable idea?
Click to expand...
It is a very good idea, and there are other threads here in the forums on the subject.
As for the actual clamp you need, it is dependent on what hose you are actually using. The clamps need to closely match the OD of the hose.
 
Frankster13 said:
I am looking to replace my oil return line hose clamps with constant pressure clamps on my Lycoming O-390. It seems hose clamps loosen over time and need re tightening during condition inspection and leak oil. Does anyone know the optimal type, size and part number to order for constant pressure clamps? Also looking for feedback on my logic. Would this be a reasonable idea?
Click to expand...
You might want to consider ClampTite. It uses safety wire to create a clamp.
 

Oil return lines

So a question came up over beers this evening... Seems a common source of small oil drips are the little rubber hoses joining the hard lines from the cylinders to the oil sump...the oil "scavenge" or return lines. Hard line from the cylinders to rubber hose to the engine. Why don't they use...
vansairforce.net vansairforce.net

source for oil return hose

Is the hose used to connect the oil return lines to the case typical automotive hose or something special? It looks like one of them is weeping a bit of oil that simply tightening the hose clamps isn't seeming to cure. I only need a couple inches of it, so I'd like to source it locally...
vansairforce.net vansairforce.net
 
Frankster13 said:
I am looking to replace my oil return line hose clamps with constant pressure clamps on my Lycoming O-390. It seems hose clamps loosen over time and need re tightening during condition inspection and leak oil. Does anyone know the optimal type, size and part number to order for constant pressure clamps? Also looking for feedback on my logic. Would this be a reasonable idea?
Click to expand...
This is what I used on my IO540:

This is a pack of 4 so you need to order 1 pack for a 4 cyl. and 2 for a 6.
(Edit) Tom from TS flightlines makes replacement braided hoses for oil return. Looks like they might be a little difficult to install on a flying aircraft but they should cure the leak issue.

-Marc
 
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swjohnsey said:
You might want to consider ClampTite. It uses safety wire to create a clamp.
Click to expand...
I bought their system in Oshkosh one year, and it looks like it would be great for a temporary repair, but I'm sure I could never get it into the area where the oil return lines are. I like the little "constant pressure clamps" - they work great and are easy to install.
 
Just did this on my 10 last month. Used Gates 3/8” power steering return hose (Partshawk was cheapest for 3’) and 16mm low profile constant tension clamps from BelMetric.com. Some here used mislspec hose from ACS. On my 9 I was able to slide 15mm ctc over the hose but it wasn’t Gates. No drips in 3-4yrs on the 9. Killed 2 birds with one stone on the 10 by installing SDS no leak intake flanges while I was at it. Intake tubes had to come off for access anyway. As you’ve already noticed space is very tight there so that’s why I used low profile version.
 
A tad bit of RTV on first, slide on hose/ worm gear clamp. Rtv seals the ends…. No leak/weep since. 3+ years now.
 
Constant pressure clamps are a no brainer. Just get them and use them. They work very well. Having been a mechanic for 55+ years, I was real glad when they became the go to clamp. They work and do not come loose. You will never regret using them.
My luck varies Fixit
 
I agree with the buy the hose first. Ace, tractor supply, Lowes all had them in stock.
 
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