Can I Re-Install Bite-Ring Fittings?

[OK-944]

A question inspired by Byron’s very graphic post (Byron…thanks for sharing, and so sorry for your loss!).

I recently replaced my under-hood fuel lines…and think I may have a very slow fuel leak (can smell a bit of fuel after the engine cools) from one or both of the new “bite-ring” fittings, located inside the wheel well, which are used to attach the new rubber lines to the existing hard lines.

The thing about bite-ring fittings is that they can be over-tightened to a point where an underlying hard-line can start to collapse. But as I’ve not had much experience with bite-ring fittings, I’m not sure if I may have either over-tightened these fittings…or have not tightened them enough.

So my options, as I see this, are to either try tightening these bite-ring connections a bit more, or to disconnect the bite rings completely and re-install them.

While disconnecting/reconnecting these fittings would seem a safer bet…I question the possibility that I could re-smooth the hard line(s) at the old connection interface(s), so that a fresh connection would remain viable - so I would not need to cut more material from the hard lines.

As is, I’m not sure if the new rubber lines would be long enough to allow any further shortening of the hard lines, and so would much prefer it if I could simply refresh the hard lines to allow for a viable re-connection. Then again…I could simply tighten the rings further, but at the risk of collapsing the hard lines (assuming that they’ve not already collapsed), which would necessitate a further shortening of the hard lines. Anyone?

[jjeffries]

You mean what I’d call a compression fitting, with an olive/ferrule? I used Len Cummings’ lines and that’s what he supplied. They were relatively big/meaty (17mm wrench size IIRC) and would have been difficult to over-torque.
I’d also be looking at the fuel pressure regulator and dampener at either ends of the fuel rail.

John

[OK-944]

Sounds like the same type of fitting...and its not so much that such a fitting itself might be compromised by over-torquing - but that a hard fuel line could be crimped by overtorquing the bite ring fitting.

Oh...and no fuel smell at either the dampener or regulator - not at the hard connections...nor upon removing attached vacuum lines.

Am back on an island and away from my car until next Sunday...so I'm scratching my head remotely for the time being!

[OK-944]

Just saw a video where the presenter, in demonstrating the torque limits of a bite ring fitting...first torqued the fitting down pretty tightly (looked tighter than what I'd done with my fuel lines), then took the fitting apart to show that all was well. He then re-assembled and re-torqued the fitting....but this time with a couple of honking huge wrenches, and upon disassembly it was obvious that both the inner pipe and the "olive" part of the bite-ring were very compromised.

The point the presenter was trying to make with his video was that bite-ring fittings can tend to get over-torqued, and he lamented the fact that manufacturers don't supply torque specs for these fittings.

In my own case...it looks like I can torque my fittings down just a bit more - which is what I will do when I get off of this island!

[jjeffries]

… if you believe they are the source of your leak.

John

[OK-944]

Yup...first thing I do is remove the passenger side plastic wheel well cover to gain good access to those bite rings, then take the car out for a brief warmup, get it up on my lift immediately afterwards, remove passenger front tire, and watch those (and all other) connections closely...occasionally dabbing with a q-tip, as things cool off.

Biggest motivator at this point? Byron's most recent pix!

[jjeffries]

Roger that. On my 924S, the fuel lines come up from the rear under the brake booster, i.e., driver’ side of the car (LHD) and intake side of the motor.

John