68 Oil pressure guage question..

[jims427400]

My 68s oil pressure guage didnt work, so I hooked up an external guage to the block to varify good pressure, and it was. So it had a cheap plastic line at the time so I removed it and installed a nice copper lined one and attached it to the guage and no readings.
My question is am I suppose to bleed the line first before attaching to guage ? If not, any suggestions what my problem may be ?

 

[Vettehead Mikey]

There's no need to bleed the line. Best make it's not really a 'copper' line, that's a bad choice for this usage, it will become work hardened in short order and break. The plastic lines are a better choice.

Sounds like you might have a bad gauge.

 

[GaryS]

...So it had a cheap plastic line at the time so I removed it and installed a nice copper lined one and attached it to the guage and no readings.
My question is am I suppose to bleed the line first before attaching to guage ?

The "cheap plastic line" is what was originally there. The "nice copper lined one" will eventually leave you without brakes when you want them the most. As has been stated, the copper becomes brittle and then bye-bye brakes. Hello, brick wall!

Fwiw, my original "cheap plastic line" is 37 years old and still working fine, thank you very much.

No need to bleed the line at all.

 

[Art Jett]

The "cheap plastic line" is what was originally there. The "nice copper lined one" will eventually leave you without brakes when you want them the most. As has been stated, the copper becomes brittle and then bye-bye brakes. Hello, brick wall!

Fwiw, my original "cheap plastic line" is 37 years old and still working fine, thank you very much.

No need to bleed the line at all.

I'm confused here! The thread started out asking about an oil pressure gauge line and all of a sudden you are saying if this line gives it up he has no brakes? Please explain!?Art

 

[Vettehead Mikey]

I think it was an innocent 'tangential' thought. Unless someone one wants to speculate that that a broken oil line would cause the engine to seize, which would deprive the booster of vacuum just at the same moment that the driver needed to make a panic stop, only to find that he had a hidden fault in his booster- a defective check valve. Ya, that's it.

 

[jims427400]

Dont your brake lines tie into your oil pressure guage ? I'm sure my thread just got a little redirected.
I was surprised to hear that the plastic lines were standard equipment back in the day.

 

[pbcanney]

My 68s oil pressure guage didnt work, so I hooked up an external guage to the block to varify good pressure, and it was. So it had a cheap plastic line at the time so I removed it and installed a nice copper lined one and attached it to the guage and no readings.
My question is am I suppose to bleed the line first before attaching to guage ? If not, any suggestions what my problem may be ?

I always thought you had to bleed them, but as I just did this exact thing using an autometer sport comp gauge, I was pleasantly surprised to find it didnt need to be bled to work. (70 psi cold / 30 - 40 driving at temp)

maybe in the old days, the lesser expensive ones needed bleeding... maybe it's manufacturer ... who knows.If your gauge is reading without bleeding, I think your good.

not sure what that brake reference is.. maybe someone used the Cliff notes version of Evelyn Wood speed reading

 

[jims427400]

It must be my guage..
I wonder where I should buy a new oil pressure gauge that matches my originals ??
BTW, I'm buying a plastic line tomarrow.
thanks all

 

[JohnZ]

It must be my guage..
I wonder where I should buy a new oil pressure gauge that matches my originals ??
BTW, I'm buying a plastic line tomarrow.
thanks all

Make sure you get the GM (or correct repro GM) plastic line kit; the original plastic line had a tiny brass insert pressed into each end which prevents the line from collapsing when you tighten the (special) GM-proprietary tapered fittings at each end. The factory line did NOT use loose compression sleeves like you find on the lines/fittings that come with aftermarket gauges. Paragon (among others) has the correct plastic line and fittings. Photo below of the special GM tapered male and female fittings.

 

[jims427400]

Thanks johnZ, do you agree that the line does not need to be bled before attaching to the guage. I havent been convinced on that part yet.

 

[GTR1999]

John is dead on with this. I have aftermarket plastic line and fittings in the shop and couldn't get them to work. Bought the whole kit from Paragon last year to solve the problem.
With your gauge you might want to look it over once you get it out. On my 69 it stopped working years ago so I pulled it out. There are 2 "chocks" glued to the back and one came loose and jammed in the bellows of the gauge. Once I removed this the gauge came back to life. Worth checking.

 

[jims427400]

Gary, great info on the guage, looked at a Paragon catalog tonight and did'nt see the fittings that John talked about. I'll call them on monday and ask. I'll check out the back of the guage as soon as I get the cluster off.

 

[Vettehead Mikey]

Thanks johnZ, do you agree that the line does not need to be bled before attaching to the guage. I havent been convinced on that part yet.

Basics physics will tell you that the there is no benefit in bleeding the line- pressure in = pressure out. It doesn't disappear somewhere in the middle.

I used to run a fuel control test rig when I started my engine career back in the late 70's and would deliberately NOT bleed the lines going to gauges. The compressibility of the air in the lines would dampen minute fluctuations making the gauges easier to read and reduce wear and tear on the instruments too.

 

[jims427400]

I hated physics.

 

[JohnZ]

Gary, great info on the guage, looked at a Paragon catalog tonight and did'nt see the fittings that John talked about. I'll call them on monday and ask. I'll check out the back of the guage as soon as I get the cluster off.

Just noted that you have a '68 BB - they're different. You need Paragon's #2135K, which includes the line and fittings and a new adapter fitting for the block end.

You don't need to bleed the line - just hook it up and go.

 

[jims427400]

I cant believe how much they did'nt like about the 68s, cuase of all the changes they made for 69.
Thanks johnZ..

 

[SR'71]

Just noted that you have a '68 BB - they're different. You need Paragon's #2135K, which includes the line and fittings and a new adapter fitting for the block end.

You don't need to bleed the line - just hook it up and go.

I have a '71 BB. Oil gauge reads 1/2 what an external guage reads. Tried to replace the fittings. No Joy. Can't find the fittings. Where do I find fittings for a '71 454 oil press engine to guage . Thanks

 

[wallyknoch]

I think it was an innocent 'tangential' thought. Unless someone one wants to speculate that that a broken oil line would cause the engine to seize, which would deprive the booster of vacuum just at the same moment that the driver needed to make a panic stop, only to find that he had a hidden fault in his booster- a defective check valve. Ya, that's it.

I dont have power brakes, so how will a oil line stop me from using the brakes and relying on them?....

 

[69vert]

palstic line

auto zone has a kit for oil guages about 7.00 or so anf its made of high themp nylon line and all the fittings

 

[JohnZ]

I have a '71 BB. Oil gauge reads 1/2 what an external guage reads. Tried to replace the fittings. No Joy. Can't find the fittings. Where do I find fittings for a '71 454 oil press engine to guage . Thanks

Paragon #2134K - complete line and fittings.