The International Cessna 170 Association

Time to replace the original (1951) oil pressure line. Anybody found a source for a braided line? Saw a picture somewhere where someone had installed one after a copper line failure but can’t find it anywhere. Any recommendations?

See this thread: viewtopic.php?f=24&t=11983&p=112727&hil ... se#p112727

I made my own by ordering the materials from Spruce. A Mandrel is not needed for 1/8” hose.... you can use the smooth shaft of a 1/8” drill bit. Pressure-test it by plugging one end and pressurizing it with air while submerging it in water.

Custom hoses may also be ordered thru Spruce. Stratoflex makes 3/16” primer fuel lines for Pipers or according to custom orders, with 2D end fittings.

Aeroquip 303 in 1/8” size hose can also be used with oil (despite being described as for air) if you wish to make your own.

It is a really good idea to check your flexible oil line and replace periodically. I just removed the flexible line on my 120 and the fittings were extremely loose and I am shocked it didn't bust and dump oil overboard. I should have replaced this hose much earlier and feel lucky I didn't have a problem. It had been on the on the aircraft at least 12 years. Hoses have a service life, and with the smaller dimensions and less material in these small oil pressure hoses it is a good idea to replace regularly. I'm planning or replacing every 5 years going forward.

Most Pt 135 Ops have limits such as at Engine TBO or a chronological limit on flammable fluid hoses FWF.... (a typical limit is 5 years).... The C145/O300 engine has a TBO of 1800 hrs or 12 years whichever occurs first..... Certainly a good rule to consider.

On a 170 the gascolator to carburetor was originally a plain rubber hose... One might consider ordering a FireSleeved hose for replacement.

Good afternoon, all,

What is the proper bulkhead fitting for the oil pressure line for a 1953 170B? Also, how do you get the air out when adding kerosene to the hose running from the bulkhead to the instrument? Just patience as it comes back up the tube your filling?

Thanks in advance for your time and assistance!

All my best,
Rob

RobfromME wrote:Good afternoon, all,

What is the proper bulkhead fitting for the oil pressure line for a 1953 170B? Also, how do you get the air out when adding kerosene to the hose running from the bulkhead to the instrument? Just patience as it comes back up the tube your filling?

Thanks in advance for your time and assistance!

All my best,
Rob

It’s unnecessary to do that. The kerosene in the lower portion (between engine and firewall) prevents the oil from coagulating.

Thanks!

Very much appreciated.

All my best,
Rob

Also, to update this subject….

Precision Hose Technology is who supported us this last year by mfr’g an oil pressure sense hose for the maintenance seminar…as well as supplied us with their complete hose specification booklet handout. They are also able to make the oil pressure hose for your airplane.

They can make up a hose using 193-2 hose (19-20 inches recommended for the standard airplane…. measure yours for a custom length)
…and 311-2D end fittings (female nipples). Precision Hose Technology is a Stratoflex shop.


https://www.aircrafthose.com/custom-quote

800-331-5946

Thanks so much for the information! Very much appreciated. You read my mind...I was going to ask a good source to procure the hoses from.

All my best,
Rob

I'm glad to see so much discussion on this topic as it's exactly what I need as well, already reached out to Spruce about a SF193 hose with -2 fittings. Need an opinion on filling the line with kerosene.

Do I fill the line with kerosene, then connect the bulkhead side first? Is it the "finger over a drink straw" effect that keeps the kerosene from draining into the oil sump?

Might also consider PTFE hose assembly from Spruce AE3660240B0180
The 0180 is 18 inch and you might need a different length.

msheen wrote:I'm glad to see so much discussion on this topic as it's exactly what I need as well, already reached out to Spruce about a SF193 hose with -2 fittings. Need an opinion on filling the line with kerosene.

Do I fill the line with kerosene, then connect the bulkhead side first? Is it the "finger over a drink straw" effect that keeps the kerosene from draining into the oil sump?

The kero in the line is intended to prevent/delay coagulation of oil in cold wx. I’ve never experienced that since I converted to the hose about 15 years ago. The larger volume of the hose may be the reason.