SS line compression fitting problems

[peanotation]

i've had horrible luck with compression fittings on stainless steel lines, and before i continue to screw myself over i'd like to see what i'm doing wrong. i built the SS teflon clutch line, and the aeroquip fittings i got constantly leaked. i got earl fittings after that, they leaked to. they all leaked at the brass compression fitting.

first off, the design behind these things is absolutley retarded.

http://slowboyracing.com/more.php?id=1184
http://slowboyracing.com/more.php?id=1183

that's the style i'm talking about. has anyone had experience with leaking fittings, and what was the problem? any input? i don't want a FUEL leak. i can deal with clutch fluid leaking though.

 

[Eagle 5]

Where is the leak at? Is it leaking from between the fitting and the hose? Or is somewhere on the actual fitting leaking?

I used SS braided line and an fittings for my external oil cooler. No leak problems there. One possible problem is that when you put the ss line into the fittings, you did not install the line all the way in or you could have pushed the line back out a little when you went to slide the inner fitting part (part that goes inside hose) in.

Also, you can put a tad bit of oil on the threads that dig into the ss line to help install better.

by the way, those are AN fittings and not compression fittings. Compression fittings are used to clamp onto a tube. but anyway, just letting you know

 

[peanotation]

but arn't they compression fittings where the fitting meets the hose? otherwise, how would it form a seal with the hose? all my fittings leaked where the compression fitting bit down onto the hose.

 

[SleeperG]

the fittings you used for your clutch line were compression fittings. they use a compression sleeve or ferring. not like reusable flare fittings.
earls/ aeroquip style fittings are just aluminum reusable/feild flare fittings. they couple to the hose in a different way than compression-all line fittings.
just put a little oil on the threads and leave about a 1/4 inch of space between the hose and the end of the part it slides over before you screw the collar on. this will allow the hose to expand as it gets compressed into the fitting.

you won't have any problems with these. and there are no ferrings involved

 

[99gst_racer]

but arn't they compression fittings where the fitting meets the hose? otherwise, how would it form a seal with the hose? all my fittings leaked where the compression fitting bit down onto the hose.

If you have multiple leaks where the hose meets the fittings, then you are installing them incorrectly. I sell these fittings daily, and have used them many times and I've never had a problem with them leaking before. Trust me; there is one right way and many, many wrong ways to do it.

 

[snox135]

Your problem may be the fittings you are using are not designed to hold that much pressure. I know for brake systems Earl's does not recommend the use of aluminum fittings. They do make different fittings for brake/clutch lines.

One other thing can you post a picture of the fittings you are using? I don't remember ever using AN style fittings (the links you provided) that use a brass compression ring. The brass compression ring sounds like a compression fitting like you had stated.

 

[99gst_racer]

Your problem may be the fittings you are using are not designed to hold that much pressure.

He's corrrect. The fittings in the pics in the link that you provided are not supposed to be used in high pressure applications such as clutch lines and brake lines. All of the premade high-pressure hoses that we sell use teflon coated hose and they come with steel AN fittings that are crimped on.

 

[peanotation]

so with the two links i posted, the style of the fittings wouldn't happen to be this, would it?

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that's my aeroquip fitting that i used on my ss teflon line.

 

[snox135]

That style fitting is different than your previous links. I do know that they make reuseable fittings for brake/clutch lines. I've always used the crimped style fittings For brake/clutch lines, but that does appear to be the correct fittings to use with a S.S. Teflon hose.


You did put the brass fitting between the hose and the S.S. sleeve and not over the S.S. sleeve.

Teflon* Racing Hose with Reusable Fitting

Step 1. Cut hose square to length with fine-tooth hacksaw or cut-off wheel. To minimize wire braid flare out, wrap hose with masking tape and cut through tape. Remove tape, trim loose wires and flush with lube before next step. Burrs on bore of tube should be removed with a knife. Clean the hose bore. Sometimes wire braid hose will “neck down” on one end and “flare out” on the other end. This can be used to an advantage. Slip two sockets back to back over the “necked down” end of the hose, position approximately 3 inches from each end. Mount nipple hex in a vise. Work the hose bore over the nipple to size the tube and aid in separating the braid prior to fitting the sleeve. Remove hose from nipple.

Step 2. Push the sleeve overthe end of the tube and under the wire braid by hand. Complete positioning of the sleeve by pushing the hose end against a flat surface. Visually inspect to see that the tube butts against the inside shoulder of the sleeve. Set the sleeve barbs into the Teflon* tube by pushing a round nose tapered punch into the end of the sleeve and tube.

Step 3. Lubricate nipple and socket threads. Use a molydisulfide base lubricant for stainless steel fittings (e.g. Molykote Type G); lubricants containing chloride are not recommended. Other material combinations use standard petroleum lubricants. Hold the nipple with hex in the vise. Push hose over nipple with twisting motion until seated against nipple chamfer. Push socket forward and start threading of socket to nipple.

Step 4.Wrench tighten hex until clearance with socket hex is at .031 inches. Your thumbnail
is a convenient measuring device. Tighten further to align corners of nipple and socket hexes. CLEAN, PROOF TEST TO TWICE OPERATING PRESSURE AND INSPECT ALL ASSEMBLIES.

To disassemble: Unscrew and remove nipple; slide socket back on hose by tapping against flat surface; remove sleeve with pliers. Important: Fittings may be disassembled and reused at least once. However, all such fittings should be carefully examined for distortion,
thread damage and I.D. dimensions. New sleeve is recommended upon reuse of fitting. Replacement brass sleeves are available.