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MatthewSetzer
MatthewSetzer New Reader
8/12/20 12:04 p.m.

Now that we've all seen JG's money maker, I've got another truck quandary.  I think I've found the inner seal which is likely the culprit of the axle oil leak.  Now how to get that off and (hopefully) go get a new one.   Also, the brake pads are soaked with oil.  If i can't replace the whole pad i read that you can get them resurfaced.  Any of you people have experience with that?

 

ShawnG
ShawnG UltimaDork
8/12/20 12:15 p.m.

Shoes can be relined, we have it done all the time for the stuff we work on.

Google the service in your area and you'll find someone.

Be sure to let them know what you're working on and whether the drums are steel or cast iron and they will help find the best lining for your application. Woven lining is better for steel drums, molded lining is better for iron.

The axle seal looks like it's just a felt packing, it should either pull off or there will be a diagonal split in it somewhere that will allow you to remove it. New felt packing can be bought from McMaster-Carr by dimensions. If you ask your FLAPS for it, they will be confused and not be able to help you.

MatthewSetzer
MatthewSetzer New Reader
8/12/20 12:17 p.m.

Well... soon as i ask for help i figure it out.  I got the inner seal out, carefully used a crowbar.  Now i assume the oil leak is from this, right?  As i understand it oil comes down through the floating axle, hits the end of the hub, goes through the outer bearing first, then the inner bearing, then should stop at the inner seal.  Ive got axle oil inside my brake drum, i think that's the only way it can get in there, right?  I'm cleaning stuff up and looking around.   Nothing obvious, so im suspecting the inner oil seal.

outasite
outasite HalfDork
8/12/20 12:34 p.m.

Yes, inspect the axle tube surface for wear. The part number of the seal should be stamped on it.

TurnerX19
TurnerX19 SuperDork
8/12/20 2:55 p.m.

This can probably be upgraded to modern seals by dimension too.

JG Pasterjak
JG Pasterjak Production/Art Director
8/12/20 9:21 p.m.

I wonder if these are a common enough size and configuration that there's some sort of easy, bolt-on solution from a more modern truck parts catalog? Like would late-model 4500-series something or other be an easier replacement than finding original stuff? Or are these commmon enough that finding original-size stuff is easy?

MatthewSetzer
MatthewSetzer New Reader
8/12/20 10:46 p.m.

Okay, I took measurements of that inner seal.   I'll put that below.  I dropped off the brake shoes at a shop to get new pads installed.   They were soaked in oil...  i can order new felt on McMaster Carr and install that onto the old inner seal.  I took the piece to our family mechanic today, he didn't think it looked too bad and thought a felt job might do the trick.  There's no real damage on the shaft, I'll post pictures.  I'm inclined to get something completely new on there however.  There's no number stamp on the thing, mystery seal.  I like JG's idea of fitting a newer truck seal on there.   I'm going to jump on some GMC truck forums too.  

I've seen nothing about using high temp gasket maker... so I'll just assume that's a hard no.  I did get it registered with permanent tags today for $176 if anyone is interested.

Inner seal dimensions (hope this makes sense) 
79mm inner
120mm flange side 
111mm non flange side
13mm felt thickness
29mm deep
1mm metal thickness

 

outasite
outasite HalfDork
8/12/20 11:12 p.m.

Does the seal press into the hub before final assembly? I think there should be a rubber seal on the inside of it to ride on the machined axle housing. Just attempting to figure out how to keep gear lube from leaking out of hub. I just see grease on everything in the pictures of disassembly. No gear lube.

MatthewSetzer
MatthewSetzer New Reader
8/12/20 11:22 p.m.

In reply to outasite :

I didn't have a rubber seal in there, it curves to match up against the shaft.  Maybe the felt should be tighter around the shaft?  

1988RedT2
1988RedT2 MegaDork
8/13/20 8:13 a.m.

Somebody correct me if I'm wrong.  If this is a full-floater, the bearings would rely on gear oil for lubrication.  No way (IMO) a felt seal is going to keep oil, even heavyweight gear oil, from getting past it.  I too would expect a rubber seal.  I too see grease.

Any chance we can ID this axle?  Should be some numbers stamped into it near the pumpkin.  Might not still be legible after so many years....

ShawnG
ShawnG UltimaDork
8/13/20 9:14 a.m.
1988RedT2 said:

Somebody correct me if I'm wrong.  If this is a full-floater, the bearings would rely on gear oil for lubrication.  No way (IMO) a felt seal is going to keep oil, even heavyweight gear oil, from getting past it.  I too would expect a rubber seal.  I too see grease.

Any chance we can ID this axle?  Should be some numbers stamped into it near the pumpkin.  Might not still be legible after so many years....

Not at all uncommon on older stuff.

Half of the transmissions I work on don't have any seals at all.

Not much oil washes down the axle tube, the bearings will be grease-lubricated. There's probably a slinger or splash shield part way down the tube to help with the slosh. Once the felt seal is well oiled, it will do a pretty good job.

Don't forget, these are drum brakes on an old medium duty truck, you're expected to be in there cleaning and adjusting the brakes every 1000 to 3000 miles and having a look at things.

 

Strizzo
Strizzo PowerDork
8/13/20 9:19 a.m.
1988RedT2 said:

Somebody correct me if I'm wrong.  If this is a full-floater, the bearings would rely on gear oil for lubrication.  No way (IMO) a felt seal is going to keep oil, even heavyweight gear oil, from getting past it.  I too would expect a rubber seal.  I too see grease.

Any chance we can ID this axle?  Should be some numbers stamped into it near the pumpkin.  Might not still be legible after so many years....

I was just thinking that.  Granted, my experience with full float axles is limited to watching Ant rebuild birfields on wheeler dealers, but something he was adamant about was that grease goes in the hub and oil stays in the axle.  was the hub full of gear oil when you took it apart?  seems to me like the failed seal could be in the outer hub keeping oil in the end of the axle tube rather than keeping oil inside the hub.  

MatthewSetzer
MatthewSetzer New Reader
8/13/20 9:53 a.m.

Thank you for the replies!

I definitely need to identify that axle, might help out.

I'm not sure what seal on the outter bearing retains oil in the hub.  I'll post a picture of what i pulled off of there. 

 

TurnerX19
TurnerX19 SuperDork
8/13/20 10:09 a.m.

In reply to MatthewSetzer :

The outer seal you are seeking is presently within the ring at the bottom of this picture.The one that was so thoroughly glued on to the hub with orange RTV. It appears to be a modern neoprene lip seal too. Possibly installed backwards, I can't tell now. Also when seeking parts for any USA or English made machine remember to use inch measurements. GM in the US did not use Metric, and neither did any of their suppliers until much after this was built. While the felt grease seal would probably work fine for the grease, as ShawnG says,  I would make every attempt to upgrade to modern, I am 99% certain you can easily.

MatthewSetzer
MatthewSetzer New Reader
8/13/20 12:30 p.m.

I looked around and got a couple axle numbers.   This is stamped directly on the floating axle near the splines "3412*F".  And the pumpkin was stamped "19750".  Pictures attached.   The serial number for the truck might be helpful too, someone on an old truck forum asked me for that.   It's not the same as the VIN.  There's an ID plate on the driver's side firewall, i assume that's it "i574-ii4307".  I used lower case i's to avoid confusion with the number 1.  

I'm going to buy a digital caliper and re- measure everything right now.   New measurements coming!

MatthewSetzer
MatthewSetzer New Reader
8/13/20 5:00 p.m.

Okay, I think I found the serial number.  There's an ID plate on the drivers side firewall.  The number is "i574-ii4307".  I used lower case i's to avoid confusion with the number 1.  
I also found a number on the floating axle "3412*F"
And on the transmission pumpkin "19750"

I also got some calipers in US Standard measurements this time, much better.  

4.49" - Wheel Drum inner diameter
3.12" - Shaft inner diameter
4.37" - seal outer diameter non flange side without felt
4.48" - seal outer felt washer diameter
4.75" - seal outer diameter felt side
3.12" - seal inner diameter (same as shaft diameter)
1.15" - seal thickness 

If possible I'd like to buy a new inner seal, ideally with improved design.  I found felt washers on McMaster Carr (https://www.mcmaster.com/felt-sealing-washers), that's an option to keep the metal seal and replace just the felt.  Not completely sure how I'd get the felt in there without destroying it...

Strizzo
Strizzo PowerDork
8/14/20 6:44 a.m.

I think there is something missing from your pic of everything you took off, there should be a piece that bolts to the end of the hub to engage the splines on the axle.
 

Like turnerx19 said it looks like the seal to keep oil in the tube is sandwiched between that outer part and the piece in the bottom of your pic above. 

MatthewSetzer
MatthewSetzer New Reader
8/14/20 10:56 a.m.

Ah yes, that piece you're talking about is permanently attached to the end of the axle.  That's what bolts onto the center of the hub.  In the picture I attached those two bolts are just to help me pull the axle off.  It's held on there with 8 nuts.  You can see the outer seal that's covered in gasket sealer. 

I think the oil is getting into the hub through the inner seal.  I just don't think there's any other way for it to get in there, the outer seal just sloshes the oil from the axle tube down throught the two bearings.  Unless.... I'm missing the picture here, which is totally possible.  

I took those measurements, I think the felt is not snug enough on the shaft.  It's just a little under... which is a disaster.  Still looking, still researching.  As always, thanks everyone for the interest and helpful tips.  

 

 

ShawnG
ShawnG UltimaDork
8/14/20 11:48 a.m.

Ok, I believe you have a GMC H050 axle in that thing. They used those post-war so you should be able to dig up some parts using the googles.

The axle flange seal on the outer end hasn't changed in forever. It's still the same part number used on the Avalanche.

MatthewSetzer
MatthewSetzer New Reader
8/14/20 1:49 p.m.

Same part number as the avalanche!?  Wow.

While im in there im going to replace that outer seal too.  No reason not to.

JG Pasterjak
JG Pasterjak Production/Art Director
8/14/20 1:51 p.m.

This thread would be much spicier with some pictures of the actual truck. It's pretty rad.

ShawnG
ShawnG UltimaDork
8/14/20 2:22 p.m.
MatthewSetzer said:

Same part number as the avalanche!?  Wow.

GM. They're good at that sort of thing.

MatthewSetzer
MatthewSetzer New Reader
8/14/20 7:39 p.m.

Ian F (Forum Supporter)
Ian F (Forum Supporter) MegaDork
8/14/20 7:51 p.m.

I would suggest joining this club: Antique Truck Club of America

Many members who own trucks like this and keep them running.

Mr_Asa
Mr_Asa Dork
8/14/20 8:09 p.m.

That thing is awesome.  I want one

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