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Rear end axle seal leak

3K views 10 replies 5 participants last post by  sedanbob 
#1 ·
I had a seal go bad after 1000 miles on a 9" Curry rear end. replaced the seal and guess what, It still leaks. Talked to Curry and it sounds like I did it right. Actually there's not much to do wrong. Any ideas on what I can try?
 
#5 ·
The seal is put on to the axle and then a collar is pressed onto the axle to retain it. It is all one piece with the bearing.

As far as the grease is concerned I do not remember which type I used. How ever I normally would have gone for the synthetic. I will drain and watch for further leaks.

Thanks two both for input
 
#7 ·
So you have the tapered roller bearings and the external seal. Sometimes you can wad the seal up when installing the axle. There is a little rubber lip that goes around the outside of the seal that can get damaged when installing the axle. Is it leaking around the outside of the seal or around the axle?
I used synthetic oil in hundreds of rear ends with no problems. Most new synthetic oils have additives in them that cause seal swell. Lack of seal swell is what caused oil leaks with the old origianl synthetic oils.
 
#8 ·
I can't tell where exactly it is coming from due to having a emergency drum and shoes which keeps me from really getting a good look at it. I did notice when I first noticed the leak that where it was running down the inside of the tire that the oil/grease was causing some swelling of the rubber. Tells me that I have a synthetic in there. Maybe I should run this for a while and see if the seal swells from the grease. When I took it back apart the seal looked like it did when I first installed it.
 
#9 ·
Petroleum oil naturally causes seals to swell. Years ago when people would change from petroleum oil to synthetic they would get massive oil leaks because the seals would shrink. This is where synthetic oils got the reputation for causing oil leaks. New synthetic oils have additives that cause seal swell, like petroleum oils, so oil leaks from synthetic oils are uncomon now.
 
#10 ·
Oil leak gone

After replacing the seal and driving a couple of miles I still had a leak. I decided to take the car for a longer ride and give the synthetic oil a chance to swell the new seal and maybe stop the leak. Ran it about 20 miles and the next morning when I checked it voila, no leak. Thanks for the input.
 
#11 ·
Not in this case, but related to synthetic gear lube and leaks - blue and red RTV interacts with synthetic gear lube if used on housing or pinion gaskets. Over time the synthetic causes the RTV to separate causing the leaks. Black and silver RTV generally do not. Some types will say they are compatible with synthetic.
 
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