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Power Feed Oil Leak

gbyoung

Cast Iron
Joined
Feb 2, 2011
Location
Richmond, VA
My Bridgeport came with a Model 8F power feed for the table. Sometime over the summer, the gearbox apparently developed an oil leak and I have had to add oil to keep it up to the line in the window. I haven’t dug into it yet to see just where the oil is coming from, but I’m sure it’s a seal, but which one?

Crazy thought: To avoid pulling this thing apart right now, has anyone ever tried just adding an oil with “stop leak” capability? I’m thinking something like Lucas Power Steering Fluid, or one of the motorcycle fork oils. This device is not a critical, high stress component like an automatic transmission, obviously, so wondering what harm would it be in trying it?

Thoughts?
 
My Bridgeport came with a Model 8F power feed for the table. Sometime over the summer, the gearbox apparently developed an oil leak and I have had to add oil to keep it up to the line in the window. I haven’t dug into it yet to see just where the oil is coming from, but I’m sure it’s a seal, but which one?

Crazy thought: To avoid pulling this thing apart right now, has anyone ever tried just adding an oil with “stop leak” capability? I’m thinking something like Lucas Power Steering Fluid, or one of the motorcycle fork oils. This device is not a critical, high stress component like an automatic transmission, obviously, so wondering what harm would it be in trying it?

Thoughts?

I dunno. This thing has been leak-free since I got the mill and mounted up the table and power feed 7 some years ago. No evidence of any crack then, and no drama that could cause a crack now that might cause a leak. I see one seal in the parts diagram and will dig a little deeper once I get the time. Oil drool on the floor just showed up earlier in the year. This hobby machine doesn’t get used all that often, and it sure isn’t any spring chicken (~56 years?). I’m thinking inactivity might be the culprit if it is that seal.

Time will tell.
 
There's a seal all around the face of the unit where the sight glass is. It's a nonasbestos fiber type gasket. One could replace it with rtv I would guess. I've had to do repairs to my drive system lately, spring broke and then was having issues with engaging the feed to the left. Had to weld to build up some material on the cam face.
 
I took mine apart for repair recently. There’s a gasket that disintegrated as I removed the plate. I cut a new one from readily available gasket paper. Works fine!


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The 2 biggest points where Bridgeport power feeds leak are into the motor and through the shaft (if you have an older shaft seal) which leads to the electronics and beyond.

Where is yours leaking from? What weight oil are you using?

We recommend a 90 weight gear oil.

Jon
H&W Machine Repair
 
The 2 biggest points where Bridgeport power feeds leak are into the motor and through the shaft (if you have an older shaft seal) which leads to the electronics and beyond.

Where is yours leaking from? What weight oil are you using?

We recommend a 90 weight gear oil.

Jon
H&W Machine Repair


The oil is dripping off the bottom of the long angled housing that sits just below the motor. Don't see any evidence of it leaking elsewhere. The oil I added way back when is Spindle oil, but don't recall the weight. I will look when I go back out to the garage.

I have 90wt. gear oil and can change it out, but since it's already leaking that may not do any good.

I'll just have to dig a little deeper to see if I can find the source of the leak. Anything I try now would just be a band aid, and I would like a permanent fix.
 
The oil is dripping off the bottom of the long angled housing that sits just below the motor. Don't see any evidence of it leaking elsewhere. The oil I added way back when is Spindle oil, but don't recall the weight. I will look when I go back out to the garage.

I have 90wt. gear oil and can change it out, but since it's already leaking that may not do any good.

I'll just have to dig a little deeper to see if I can find the source of the leak. Anything I try now would just be a band aid, and I would like a permanent fix.

Oil was Mobil Velocite Oil No. 10 Spindle Oil, Medium.
 
when you drain your oil, take the front cover off. The shaft that covers the seal should cover the entire brass bushing and seat on the bottom of the casting. Here is a pic of the good one.

38-161 - Shaft Seal

If it doesnt look like this, then you need one like this.

Jon
H&W Machine Repair
 
I've never seen one that eventually didn't leak. Just part of the game.

Didn't figure I had a special case, and the reason I asked.

Repair parts on order (parts: reasonable; shipping: ridiculous). In the interim, I am going to try adding some power steering fluid with stop-leak properties. Have absolutely nothing to lose, so might as well try it.
 
FWIW – drained out the remaining fluid in the power feed drive unit, and refilled with some Lucas Power Steering Fluid that has the stop leak additive. Can’t say that it has stopped the leak completely (yet), but it has definitely slowed it down.

Do have the repair parts, but will wait and see what the overall effect is of this Lucas stuff before I do anything further. If it keeps leaking, we’ll pull it apart and install the new seal……. which, is the weirdest seal I have ever seen. Not in the form factor to what I am used to seeing.
 
FWIW – drained out the remaining fluid in the power feed drive unit, and refilled with some Lucas Power Steering Fluid that has the stop leak additive. Can’t say that it has stopped the leak completely (yet), but it has definitely slowed it down.

Do have the repair parts, but will wait and see what the overall effect is of this Lucas stuff before I do anything further. If it keeps leaking, we’ll pull it apart and install the new seal……. which, is the weirdest seal I have ever seen. Not in the form factor to what I am used to seeing.
checking back after all these years.. did the stop leak lucas stuff work? did it ruin other seals?
 
gbyoung has not been seen or heard from since Jan 2019. I doubt he will respond to your request.
I have used a stop leak product in the headstock of my 14" Rockwell to stop a couple of O-rings from leaking. Both O-rings were replaced when I rebuilt the headstock a few years before. Probably the cheap O-rings I used. So far after 6 or 7 years it has not leaked knock on wood.

These stop leak products are designed to swell the rubber slightly so they re-seal. It's just a stop gap thing that works until things can be torn down and seals and such are replaced. They are not a permanent fix for a leaky seal.
 








 
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