Rear drum brake question

[Clunker]

I started doing the rear brakes today. When I pulled out the first axle, a bunch of gear oil poured out, which I expected. But isn't there supposed to be a seal that prevents oil from getting into the bearings? What is the point of packing bearings with grease if they are going to get saturated in oil anyway? It is a rusty mess in there, and whoever did the brakes last obviously did not have the right tools, so it would not surprise me if he left out some parts.

[Clunker]

One more question. The outer bearing appears to be slightly bent. Also, the axle housing has a slight groove worn into it where the bearing rides. I'm no expert with brakes, but I imagine that is not a good thing. Any thoughts?

[sargentrs]

Yeah....that's not good. Sounds like your axle bearing went bad and took the seal with it. Got any photos of that area in the housing where the groove's worn? About half way down this page are a couple of pics of the end of the housing, seal, and axle bearing. http://www.fordification.com/forum/view ... &start=210

[Clunker]

Thanks for the link, but those pics are of a whole different animal than what I'm dealing with. My truck is a 1970 F250 CS with the large rear drums. It looks to me like someone damaged the bearing during the last brake job and reinstalled it anyway. The outer bearing is still silky smooth but not quite round. The inner bearing and housing area look great. I will upload some pics if I can figure out how.

[Ohiotinkerer]

Try this link - hopefully the diagram for what you have is there......

http://www.fordification.com/tech/schematics_a.htm


I don't know if the Ford 3/4 ton rear end (never worked on one) works the same as some of the Chevy 3/4 ton stuff I have worked on but Chevy rearend bearings were lubed by the gear oil going down the tubes from the pumpkin.......

[Clunker]

Thanks for the link. I don't see anything in the exploded view that looks like a seal. Also, many Chevys used the same Dana 60 rear end as Ford, so you may be right that the bearings are lubricated by gear oil. I saw one step-by-step procedure where the author gave instructions to pack the bearings, so I just assumed they should be sealed from the gear oil.

Anyway, the grooves worn into the axle housing might still be a problem. Here are a couple pics. Is there any way to fix this?

[Ohiotinkerer]

That is not a pretty (or cheap) sight....... ........I'm not gonna say if it can be fixed or not but if I were you I would look for an axle that I can get a look at the bearing surfaces before I bought it and swap it out.......just my

[colnago]

I rebuilt my rear hubs/brakes last year. I have a '67 CS F250, with the heavy-duty 2-1/2" brakes, and the full-floating axle. As I recall, there was no seal on the inside to keep the oil out of the grease. I forget the rationale they used for this particular design, but it must have been a good choice, because they're still on the road. The only seal should be at the back of the rear hub, I think. This will "trap" the inside bearing within the hub, when you pull that off of the axle housing. In the exploded view I'm looking at, it would be number 1175.

I'm not sure what to tell you about the groove. Maybe you could find a rear axle assembly at the junk yard that has the 3.54 gearing, and get a bump up in your fuel mileage as the concession prize (that's what I want to do, after I finish the engine/transmission). At the very least, measure the wear with a caliper, and see if you can find some numbers somewhere to see if you're still within spec.

Joseph

[Clunker]

I was thinking of getting a locking rear axle anyway, but I wasn't planning on doing it right away. For the time being I was going to just reassemble, so I can get it out of the driveway. Unfortunately, I almost finished reassembly and discovered that the first drum is out of round. It rubs against the shoe at one spot and then turns one full rotation before it rubs again at the same spot. Even if it was still under warranty, you never get that time back. This really was not a very difficult brake job except for faulty brand new parts and the PO's poor craftsmanship, resulting in a permanently damaged part.

One more question. The write ups I've read suggest that you should tighten the first axle nut to 50 lb-ft and then loosen it 1/3 or 3/8 rotation depending on who gave the instructions. Moving this nut this far seems way too loose. You can easily make it wobble. Has anyone else run into this?

[colnago]

One more question. The write ups I've read suggest that you should tighten the first axle nut to 50 lb-ft and then loosen it 1/3 or 3/8 rotation depending on who gave the instructions. Moving this nut this far seems way too loose. You can easily make it wobble. Has anyone else run into this?

I don't remember it wobbling, but I do remember it being loose (I backed mine off 3/8 turn). I thought the torque number was higher, though (I want to say 80 ft-lbs, but I've had so many torque numbers going through my head lately that I could be way off). I figured that since I was following the spec, it must be right. I certainly don't know any different, so I wasn't going to doubt the manual. I followed what was in the Chilton manual, by the way.

Joseph

[colnago]

I was able to find the section in my Chilton's tonight. The torque spec was 50 - 80 ft-lbs, so I split the difference, and torqued it to 65 ft-lbs. Then I backed it off 3/8 turns, lubed the locking wedge, installed the lock nut, and torqued it to 100 ft-lbs. Bent the tabs on the wedge, and buckled it all up. Whenever I'm given a range for torque specs, I always try to get to the mid-point. If there are multiple nuts/bolts around a circumference, I'll try to go in a star pattern.

Hope this helps,

Joseph

[Clunker]

Thanks for the specs and info. I ended up not backing off the first nut at all, and there is still some play. Most likely it is caused by the groove in the axle housing. Even with a new bearing, it will not seat correctly. For now, it will stay in my driveway until I figure out a permanent solution.

For all those following this thread, has anyone tried to retrofit a later-model Dodge Dana 70 rear end onto their bump? I found a local guy with a totaled pickup, and he is selling his newly-rebuilt Dana 70 with 4.11 gears, Posi, and disc brakes. This question should probably be posted in the Drivetrain section, so I'll repost there.

[colnago]

I looked at a Dodge Dana 60 with drums, but I can't weld, and I'd have to move the shock mounts. I think the later truck axles are longer, so they line the front wheels with the rear. Not sure about the rear discs, and how they would change the geometry. You will need a new MC, and a new proportioning valve, at the very least.

Joseph

[Clunker]

If welding is involved, then I'm not going to try it. In fact, I may end up selling the truck over this issue. Every time I fix something, I find at least two more things wrong with it.

[sargentrs]

Every time I fix something, I find at least two more things wrong with it.

Ah, the joys of owning a "classic"!