C30 Dana 70HD issue - The 1947 - Present Chevrolet & GMC Truck Message Board Network

SCOTI · 05-19-2015, 08:28 PM

I serviced the rear brakes last year as part of my rear suspension upgrades & correcting very poor braking (no rear brakes). I replaced the drums, shoes, hardware, hub bearings, & inner + outer hub/axle seals.

Fast-forward to current day & I was swapping new tires into place when I noticed a very small puddle of fluid that accumulated inside of the pass rear tire that had trickled down from the the drum.

At first I thought it might be brake fluid but it was rear end lube. So I pulled the drum/hub again to inspect the seal. The seal surface area looks fine w/no signs of damage. The rubber material wasn't damaged or mis-shaped. So, I pulled the seal to inspect further & the internal tension spring was damage free as well.

I'm @ a loss as to what the remedy needs to be here. The seal was a quality manufacturers brand & not the cheap house brand. It seemed to fit the rear end hub snount properly (slight interference fit/was not loose).

What steps can I take to make sure the repair is succesful given the fact that there's no obvious reason for the initial failure? Any useful suggestions?

bilfman · 05-20-2015, 12:41 AM

Get another seal and make sure to lube the mating surfaces , an installed dry seal can be damaged enough to leak before the natural lube hits it.

SCOTI · 05-20-2015, 08:43 AM

Quote:

Originally Posted by bilfman

Get another seal and make sure to lube the mating surfaces , an installed dry seal can be damaged enough to leak before the natural lube hits it.

I did wipe the surfaces w/bearing grease prior to installing.

My buddy that gave me a 2nd set of eye's on everything (to ensure I wasn't missing anything), said when he's done FF rear seals, he's packed the inside of the seal (where the tension spring is) w/grease to help prevent damages there as well. I guess I'll do everything the same & hope for the best.

The brake pads appear to have soaked in the fluid..... I sprayed them down w/brake clean & wiped the drum w/laquer thinner w/o much diff in appearance. Think I should replace them despite they're basically unused just because it's lube on a friction contact surface?

95 S_Trucker · 05-20-2015, 08:56 AM

I would replace the brakes. Oil soaked brakes do not work like they should. You can try to clean them, but you will not be successful.

Look very close where the seal meets the axle tube. Make sure there isn't any rust or a groove from the old seal.

I worked on an old 1990 ford 450 that had a dana 80, and the one side simply wouldn't seal. I couldn't explain it. Everything was nice and clean, no groove or rust. The third seal I put in was the charm. The first I put in was a timkin, then a national, and then another timkin. That all happened about 5 years ago and its been leak free since.

**hatzie** · 05-20-2015, 09:16 AM

If you have a grooved, pitted, scratched, or gouged axle tube where the seal rides you can fix it with a speedi sleeve.

http://www.skf.com/us/products/seals...eve/index.html

KQQL IT · 05-20-2015, 10:16 AM

My Dad would soak the seals in gear oil prior to install.

05-19-2015, 08:28 PM	#1
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 21,941	C30 Dana 70HD issue I serviced the rear brakes last year as part of my rear suspension upgrades & correcting very poor braking (no rear brakes). I replaced the drums, shoes, hardware, hub bearings, & inner + outer hub/axle seals. Fast-forward to current day & I was swapping new tires into place when I noticed a very small puddle of fluid that accumulated inside of the pass rear tire that had trickled down from the the drum. At first I thought it might be brake fluid but it was rear end lube. So I pulled the drum/hub again to inspect the seal. The seal surface area looks fine w/no signs of damage. The rubber material wasn't damaged or mis-shaped. So, I pulled the seal to inspect further & the internal tension spring was damage free as well. I'm @ a loss as to what the remedy needs to be here. The seal was a quality manufacturers brand & not the cheap house brand. It seemed to fit the rear end hub snount properly (slight interference fit/was not loose). What steps can I take to make sure the repair is succesful given the fact that there's no obvious reason for the initial failure? Any useful suggestions? __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.*

05-20-2015, 12:41 AM	#2
bilfman Registered User Join Date: Dec 2011 Location: Regina, SK, Canada Posts: 622	Re: C30 Dana 70HD issue Get another seal and make sure to lube the mating surfaces , an installed dry seal can be damaged enough to leak before the natural lube hits it. __________________ 1979 Chevy Dually Crew 4X4 454, D60 Tru-trac, D70 Detroit Locker, 3.73, 4L80E/NP205 1971 GMC 3/4 Ton 4X4

05-20-2015, 08:56 AM	#4
95 S_Trucker Registered User Join Date: Oct 2009 Location: . Posts: 2,181	Re: C30 Dana 70HD issue I would replace the brakes. Oil soaked brakes do not work like they should. You can try to clean them, but you will not be successful. Look very close where the seal meets the axle tube. Make sure there isn't any rust or a groove from the old seal. I worked on an old 1990 ford 450 that had a dana 80, and the one side simply wouldn't seal. I couldn't explain it. Everything was nice and clean, no groove or rust. The third seal I put in was the charm. The first I put in was a timkin, then a national, and then another timkin. That all happened about 5 years ago and its been leak free since.

05-20-2015, 09:16 AM	#5
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,941	Re: C30 Dana 70HD issue If you have a grooved, pitted, scratched, or gouged axle tube where the seal rides you can fix it with a speedi sleeve. http://www.skf.com/us/products/seals...eve/index.html __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

05-20-2015, 10:16 AM	#6
KQQL IT At the body shop. Join Date: Aug 2009 Location: Land of fruits and nuts. Posts: 5,199	Re: C30 Dana 70HD issue My Dad would soak the seals in gear oil prior to install. __________________ " That didnt make it any newer " " Dont antique the equipment "



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