Oil pressure sending unit........

[714Speed]

I own a 71 350 4 speed. Yesterday I was tightening the tach cable on the distributor and my hand broke the oil pressure tube as it goes into the sending unit. Can I simply replace the little brass fitting on the tube I have or do I have to replace the whole tube all the way to the gauges? Thanks a million!

 

[cruisin-davey-g]

Hey Speed: Is the oil sender tube plastic (neopreme) or brass? Either way, if 'ya got enough slack in your tube to do it, just cut off a little bit of the broken end so it's straight (even) again, get another ferrel (little brass thingie that slips over the tube) & re connect the tube to the fitting in the block. Make sure you slip the female fitting onto the tube before slipping on the ferrel. Push the tube into the male fitting in the block until it bottoms out, screw the female fitting to the male fitting & tighten it up & your in business. Sounds a little like sex (Dave, get your mind out of the gutter) Good luck. Hey, I'm outta here! ................Dave

 

[714Speed]

Whew...yes it is plastic, so I'm in good shape. Did not look forward to taking the gauges apart. Many thanks

 

[cruisin-davey-g]

No Problem:

Speed: Your welcome! If you need any other help concerning your '71, just give me a holler!

Dave

 

[Jack]

I own a 71 350 4 speed. Yesterday I was tightening the tach cable on the distributor and my hand broke the oil pressure tube as it goes into the sending unit. Can I simply replace the little brass fitting on the tube I have or do I have to replace the whole tube all the way to the gauges?

714Speed:
Your 71’s mechanical op gage came w/ only fittings & tubing ... senders are used w/ electric gages.

I suggest you replace the entire length of your thirty + year old plastic OE-tubing ... it’s old & fatigued ... likelihood of another failure is increasing.

You might also consider replacing the fittings ... I earned a high-dollar T-shirt due to a failed op gage block fitting on my 71’s base 350.

Maybe my block fitting was not original ... but it appeared to be OE. My fitting’s female insert was integral to the fitting ... and the ferrule was integral to the clamping nut. The tiny brass female insert broke away from the block fitting ... the interference-fit between insert-tube-ferrule was compromised ... permitting the tubing to blow out of block fitting. I believe the tiny brass female insert broke away due to decades of vibration and possible mishandling during maintenance. I also believe a soft (brass) fitting with such a tiny integral insert is a poor design ... OE or not.

Total replacement is a bit of a hassle ... but very cheap insurance.
JACK:gap

 

[eastnder]

I agree with Jack. I have a 73 that the same plastic line failed on(while driving) I ordered a new one and was glad I did cause when I changed the line out, I could see the whole length of it was brittle. Good luck....Jim

 

[cruisin-davey-g]

Speed: Yeah, I definately agree with the others about changing out the entire line to your guage, just for insurance sake. "neopreme" does last along time, but 'ya never know. I was just giving you a "quick-fix" to your problem, since you mentioned that you really didn't want to get into changing it altogether. The other thing to worry about is the possibility of the opposite end breaking (at the guage). Remember, your radio is located directly under this guage & hot oil dripping on your radio isn't gonna make it. Trust me, I blew out a unit (radio) that way.
I replaced mine (tubing) with brass & I also put a 90 degree fitting coming out of the guage to lessen stress due to vibrations & such. Just giving you some pointers & something to think about.
Take care.................Dave

 

[JohnZ]

I replaced mine (tubing) with brass & I also put a 90 degree fitting coming out of the guage to lessen stress due to vibrations & such. Just giving you some pointers & something to think about.
Take care.................Dave

I hope you didn't use copper tubing - copper tubing will work-harden with normal engine vibration, then fracture. The original metal oil pressure lines prior to '68 weren't copper (common misconception) - they were copper-plated STEEL. The '68-up lines were nylon and were pretty much impervious to vibration, but they do get brittle with age (nobody ever expected them to last for 30 years).

 

[714Speed]

Guys you don't know how much it means to me to have your experience to lean on. This is my first shark and probably my last simply because it is a nice solid car and all there. My previous car was a 92 LT1 Quasar blue and there was basically nothing for me and my experience level to work on if something broke. But I am familiar with 68-72 technology and am very pleased with the prices of parts for C3's vs C4's. Thank you again

 

[cruisin-davey-g]

I hope you didn't use copper tubing - copper tubing will work-harden with normal engine vibration, then fracture. The original metal oil pressure lines prior to '68 weren't copper (common misconception) - they were copper-plated STEEL. The '68-up lines were nylon and were pretty much impervious to vibration, but they do get brittle with age (nobody ever expected them to last for 30 years).

John Z: I dunno about the copper tubing. I changed mine about 15 or so years ago & never had a problem. I do know that some of the more expensive aftermarket mech 710 pressure guages use copper tubing (or maybe it is copper plated steel tubing? Looks like copper tubing?) & those guages are usually used in drag; oval; off road; & road racing applications where vibrations are brutal. I do know one thing; I used a 90 degree fitting at the guage & got more clearance & probably less stress. But, it worked for me!......................Dave