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Axle Seal Leak Help

Waldo

Contributor
Jr. Member
Joined
Jun 16, 2012
Messages
79
Long time lurker, first time posting. Looking for advice on leaking axle seals on a 1975.

Situation: Upgraded rear brakes from stock 10" drum to disc with new axles/bearings, but now the axle seals (both) leak like a sieve.

Background: Converting my 1975 (10" drum and large bearings) with TBP brake conversion (#7500SL), and new 28 spline axles/bearings from TBP (#2849/2848). Install complete, but now the axle seals leak like crazy.
Here are the areas I have addressed so far:
1) new seals are pressed/seated into the axle housing.
2) rear end fluid not overfilled as it is same level as before the conversion, and it didn't leak before.
3) metal spring is still in place on the inner side of the seals.

From other posts, I have read that using "National" brand seals will provide a tighter fit around the axle. So that is one potential solution. Do I need to use silicone/sealant with the bearing and the axle housing? What else am I missing/forgetting?

What can the Bronco Brethren offer for help guidance? Thanks!!
 

garberz

Bronco Influencer
Joined
Jun 24, 2007
Messages
6,856
Loc.
Conejo Valley, Ca.
I use a very light coat of RTV on the outer surface of the seal before I seat it in place. The other thing is, when sliding the axles in, you need to be carful not to drag the axle over the seal lip. Sealed axle bearings with inboard seals usually seal up fine and aren't problematic. The SET20 bearings, not so much!

Mark
 

B RON CO

Contributor
Bronco Guru
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Jun 29, 2016
Messages
2,412
Loc.
Statesville, NC
Hi, my thought is to make sure the axle vent, attached to the hydraulic brake block, is clear.
Any time I see both seals leaking, I think the vent must be blocked.
Besides that, how did it feel when the axle shafts slide in? If it was a fight, well....
Anyway I lube the seals with oil before sliding in the axles, but I doubt you could wreck both sides with a careless install.
Good luck
 
OP
OP
Waldo

Waldo

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Jun 16, 2012
Messages
79
HI B Ron Co,
I can't see it being the axle vent as the only changed parameters have been the axles/brakes and it wasn't leaking before. But I will take a look at it...hadn't thought of this angle.
 
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OP
Waldo

Waldo

Contributor
Jr. Member
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Jun 16, 2012
Messages
79
Hi Garberz...Had thought about some RTV or other sealant around the outside of the axle seal. Was wondering what others had experienced with this approach.
 

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,795
Loc.
Ridgefield WA
Hi Garberz...Had thought about some RTV or other sealant around the outside of the axle seal. Was wondering what others had experienced with this approach.

I try to avoid using "blue glue" wherever possible. I do apply old Permatex #2 to the seal shell in that application.
If you keep having rear axle seal leakage, you might consider how you fill the axle housing with oil. When cold, never fill more than "pinky deep." That allows about 1/2" for the oil to expand when hot. If you're filling a heated axle, then you can fill it till it drools out.
 

spap

Contributor
Bronco Guru
Joined
Jan 2, 2010
Messages
2,458
Just a thought check the condition of the axles where the seal rides, I have seen some pretty decent groves in axles before from the seals, maybe the new seals changes that location on the axle just a bit to leak. If they are groves bad you can use a speedi sleeve to fix it
Good luck
 

garberz

Bronco Influencer
Joined
Jun 24, 2007
Messages
6,856
Loc.
Conejo Valley, Ca.
Just a thought check the condition of the axles where the seal rides, I have seen some pretty decent groves in axles before from the seals, maybe the new seals changes that location on the axle just a bit to leak. If they are groves bad you can use a speedi sleeve to fix it
Good luck

His axles are new 28 spline from TBP's.

Mark
 
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OP
Waldo

Waldo

Contributor
Jr. Member
Joined
Jun 16, 2012
Messages
79
Hello all
Issue resolved. Went back to the beginning of the process and realized I hadn't checked the inner diameter (ID) of new seals with ID of old ones. You guessed it...new ones different size (too big). TBP shipped the wrong seals (but in the correct packaging/billing). New seals on the way. And yup...I feel like an idiot for not checking the fit before installing. Happy trails to all!
Waldo
 

jperry1290

Sr. Member
Joined
Jul 1, 2010
Messages
908
Done this job twice, once w a hand in a cast. Not fun either time. I did dab a little black RTV when installing the new seal.
 
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