Failed Oil-Pressure Gauge Fitting

Anglophile · Mar 10, 2013

So, when I got home from a short ride (luckily it was short!) I noticed oil dripping all over the motor. I quickly realized it was the fitting for the oil pressure gauge and shut the motor down. I had to cut the plastic tube and plug where the fitting bolted in order to stop the leak. Makes me wonder if it's a good idea to even have this contraption on the bike. It's nice to keep an eye on the pressure but not if the kit is likely to fail. I have under 4k mikes on it and can't imagine what I would have done had it happened on a highway a long ways from home. Ugh.

concours · Mar 10, 2013

Those fittings are GREAT for compressed air.. on something that doesn't vibrate. Shaking, the sheet metal lock ring will dig a trench in the tube, and then leak. The old fashioned Eastman compression fitting for the plastic tubing would last better in this application. Or, fabricate a simple wire loop stand off and put it under the rocker cover bolt.

comnoz · Mar 10, 2013

Wow, I am surprised they would use a pushlock fitting for that application. Heat and vibration will kill them with time, every time. Jim

travelerjerry · Mar 11, 2013

Makes me wonder if it's a good idea to even have this contraption on the bike. It's nice to keep an eye on the pressure but not if the kit is likely to fail. I have under 4k mikes on it and can't imagine what I would have done had it happened on a highway a long ways from home. Ugh.

Had the same thing occur at the rocker spindle adapter swivel fitting. Had to release it and cut the worn depression off and reinsert. I carry the original spindle covers & gasket in tool pouch in event that fitting leaks on me while on the road. Yea, air line probably not the best line to use. However it hasn't melted yet. But do like the contraption.

slimslowslider · Mar 11, 2013

Must have been lucky for the last 8 years and 30000 km's...

comnoz · Mar 11, 2013

slimslowslider said:
Must have been lucky for the last 8 years and 30000 km's...

No, it just stays cool out there. Attach it to the head and see what happens.

bwolfie · Mar 11, 2013

I went a bit sturdier, those plastic lines make me uneasy,

Old Bloke · Mar 11, 2013

If you must have an Oil pressure gauge, isn't there an electrical oil pressure sender unit available which would fit, I had one fitted to an old Escort years ago. That would alleviate the need for an oil pipe to the gauge? Theres enough points of failure on the Commando without adding to them................imo of course :shock:

comnoz · Mar 11, 2013

Old Bloke said:
If you must have an Oil pressure gauge, isn't there an electrical oil pressure sender unit available which would fit, I had one fitted to an old Escort years ago. That would alleviate the need for an oil pipe to the gauge? Theres enough points of failure on the Commando without adding to them................imo of course :shock:

Sure there are several varieties that would work. But most of them wouldn't last long attached to a Norton head. Jim

slimslowslider · Mar 11, 2013

comnoz said:
slimslowslider said:

Must have been lucky for the last 8 years and 30000 km's...

Click to expand...

No, it just stays cool out there. Attach it to the head and see what happens.

That sure helps, I guess.
Have it om my A65 as well, on a brass tee that goes where the oil pressure switch fits in the cranccase, so also a bit cooler, tee takes switch and push-in fitting, done it in 1981, no problemo since.
I actually removed the line from the fitting a couple of times and re-used it again, no leako.
To be honest, it amazes me it holds that long.
The fitting and line to the gauge is not even the same size as the oil line, it is 6mm.
Anglophile, what was the actual damage, a cut or did the O-ring fail?

Anglophile · Mar 11, 2013

slimslowslider said:
Anglophile, what was the actual damage, a cut or did the O-ring fail?

Everyone, thanks for the tips. Slimsslowslider, I'm not sure if there is even an o-ring inside the fitting but after disconnecting the tube and examining it, it does looks somewhat distorted. I'm assuming from heat. I may try another "oil" line. Is there a source? (better quality?). The vendor I used doesn't appear to have a replacement.

travelerjerry · Mar 11, 2013

Anglophile said:
slimslowslider said:

Anglophile, what was the actual damage, a cut or did the O-ring fail?

Click to expand...

Everyone, thanks for the tips. Slimsslowslider, I'm not sure if there is even an o-ring inside the fitting but after disconnecting the tube and examining it, it does looks somewhat distorted. I'm assuming from heat. I may try another "oil" line. Is there a source? (better quality?). The vendor I used doesn't appear to have a replacement.

Anglo, if you have this type of fitting. To release the pipe, place fingernail with downward pressure and with other hand pull the black pipe out. No o-ring, cut off compressed portion of pipe and push it back in. Hope this helps.

Old Bloke · Mar 11, 2013

comnoz said:
Old Bloke said:

If you must have an Oil pressure gauge, isn't there an electrical oil pressure sender unit available which would fit, I had one fitted to an old Escort years ago. That would alleviate the need for an oil pipe to the gauge? Theres enough points of failure on the Commando without adding to them................imo of course :shock:

Click to expand...

Sure there are several varieties that would work. But most of them wouldn't last long attached to a Norton head. Jim

Ah you got a point there, forgot about the Motors somewhat enthusiastic vibration

slimslowslider · Mar 11, 2013

Anglophile said:
slimslowslider said:

Anglophile, what was the actual damage, a cut or did the O-ring fail?

Click to expand...

Everyone, thanks for the tips. Slimsslowslider, I'm not sure if there is even an o-ring inside the fitting but after disconnecting the tube and examining it, it does looks somewhat distorted. I'm assuming from heat. I may try another "oil" line. Is there a source? (better quality?). The vendor I used doesn't appear to have a replacement.

Looks like a Legris fitting, more info here http://mdmetric.com/prod/legris/section_e.pdf.
Should be available from shops that do pneumatic systems. The info shows an O-ring.

comnoz · Mar 11, 2013

There is an o-ring in them. They can be pretty tough to replace especially if they have gotten hard from heat.

It's likely that cutting the end of the hose back a little will fix the leak- until next time.

If you go to a shop that sell truck brake parts you can find a small brass inset that is designed to fit in the end of the plastic line to keep it from collapsing. They are designed for collet type fittings but will help keep the pushlock fittings from leaking as well. Jim

slimslowslider · Mar 12, 2013

The insert is beneficial for sure.
Then again, max working temp for this fitting, depending on line material, is quoted by Legris as 230F, 110C.
The actual temp where it sits, mounted on the head, gets higher easily.
Something, O-ring or line, is bound to fail eventually.

Anglophile · Mar 12, 2013

It is a Legris fitting. I'd do what Travelerjerry suggests if the line was long enough but I also kinked it during disassembly. Got to source a replacement line before either remounting or selling the kit. Thanks again for the suggestions.

travelerjerry · Mar 12, 2013

Anglophile said:
It is a Legris fitting. I'd do what Travelerjerry suggests if the line was long enough but I also kinked it during disassembly. Got to source a replacement line before either remounting or selling the kit. Thanks again for the suggestions.

Make sure the pipe fully inserts into the fitting. The o-ring may be ok as your pipe may have not been fully inserted. This happened to me. Put alot of miles and no melting of plastic line.

I made an incorrect previous saying there's no o-ring which there is.

Kinking of the pipe is not good.

Failed Oil-Pressure Gauge Fitting

Similar threads