So yeah, super new to cars, trying to learn as I go. The oil pressure gauge on my 73 Mach 1 351 Cleveland is pretty erratic, but for the most part (especially after the car warms up) it reads at zero. Ok technically it just has a Low and a High meter, but the needle is as far down on the L as possible. Which has me worried about oil pressure.
So I went out and got an oil pressure testing kit (Harbor Freight special!
http://www.harborfreight.com/engine-oil-...98949.html)
So my question is... where do I hook it up? I am under the impression I need to hook it up where the sender currently is on top of the back of the block? (Looks like this guy:
http://route66bitz.com.au/customsidemenu...Z9278A.jpg).
But finding info online isn't working all that great for me and I don't want to screw anything up when it comes to pumping oil throughout the engine.
On a side note.. any clue what each of these 4 hoses are and where they are supposed to go to? They are all hooked up, but just for my own reference:
![[Image: 4Hoses.jpg]](https://dl.dropboxusercontent.com/u/153502309/4Hoses.jpg)
Your links wouldn't let me see what you are looking at but here is a general reply.
If it is an electrical pressure gauge tester then yes, hook it up to the gauge. If it is a actual manual gauge tester then pull the sending unit and hook up the line to the oil sender location.
As to the four hoses that run of the vacuum junction block. Two go to the modulator valve on the transmission and two run vacuum on the motor. One to the back of the carb plate and one to the driver's side (although I do not exactly remember where it hooks up).
Cool yeah, with dumb luck I think I figured out how things work the hard way haha. And it's a mechanical tester gauge, while the car of course has an electrical one.
I figured I'd just try unscrewing the Sender from the head, which it just spins (I think). I unhooked the power line from the top when doing this, and forgot to hook it back up when I started the car to see what it was doing now.
Of course the Oil Pressure Gauge was completely dead
then I remembered I forgot to re-hook up the power wire to the top. So I shut the car down, attached that, and restarted the car and the gauge came back to life as expected. Decided to see if any of my fiddling fixed the issue so took it about 8mins away to the grocery. Well the Gauge starts off with high oil pressure, then gets to about 80% and sets there for a short while (3mins maybe?) but then slowly drops down to 0% where it stays. After shopping for a good 30ish minutes and coming back out and starting the car, it still reads at 0% (aka Low).
The car is too loud for my neighborhood to be starting it up and toying with this late at night. So I will go about trying to remove the sender unit tomorrow and attaching the mechanical gauge to the open port. It came with a bunch of brass fitting of different sizes, and I have read that I should use threadlocker tape when attaching it to minimize possible oil leaks so I will go about down that as well. Hopefully all of that is the right process, if not let me know! And thanks for the reply.
It sounds like you have the process pretty well figured out.
The mechanical gauge will tell you the story you need to know. Here's hoping that you do have pressure at all times.
Let us know how it all goes.
Well, went out there and had a go at it today. Can't get the damn thing to do much more than budge. It's a bit difficult to get to.... I tried using a short length 9/16 wrench (since it's pretty tight around the bottom nut) but I can't get the thing moving. If I do get it to turn at all, it's a tiny amount which, but then the wrench head gets stuck on the socket.
Might have to recruit some help with it or maybe there is a better suited tool I am missing.
Some wrenches are designed better than others which will help.
I use a wrench and I really hate to say try a pair of vice-grips but they may help you out. Vice-grips will burr off the head unless used precisely and well.
Once it is partially loose you may be able to turn it with your hand.
Can you fit a deep socket over it and use an extension drive?
That was my first thought but then I believe that the pressure switch on the 71 351C will look like this.
Yeah that's the type, no getting a socket over it, lol. I went and got some Crowfoot Wrench heads to try out. Prolly shoulda picked up some standard wrenches that were more right angled instead of straight on while I was at the tool store but didn't think about that till I got back to work.
Will let you all know how it goes!
Yesterday i was actually using a short lengthed wrench with a socket on the far end, which I had a metal rod going through so i could get a couple hands on it to try and turn... no such luck, but that was more due to the head of the wrench getting pinned against the engine block.
Steve said it, Vice grips, the standard flat head wrench will try to round off the edge of the nut, go and buy a good pair, not harbor or a cheap set. get it as tight as possible and clamp the levers together with a hose clamp. this will keep it from springing apart . Put a pipe over the end ,make sure you put it facing the direction you want to turn it, its all about leverage here,(uses gloves, the kids don't need to hear if it slips)might try tapping lightly, If it dose not give, you might have to tear off the bellows so you can get a socket on it, Just get it in your head that it needs to come loose, If you force it and it breaks' well it needed replace anyhow,
Also when your are upside down, looking up, be sure your turning it the right way. things happen.
