9 inch pinion seal blowout

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steve cowan
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9 inch pinion seal blowout

Post by steve cowan » Sun Apr 30, 2017 9:45 am

hi guys,
brand new strange nodular case
aluminum pinion support
1350 billet yoke
new yukon 4.1:1 street gears
new billet axles
has about 4 hrs run time on the street
spat pinion seal out on the hwy last night,lucky to get it stopped before it was terminal
by the photo the witness mark is nearly non existent on the seal,when i got it home on the hoist i could push the seal back in with my fingers about half way
there was no sealer around the outside of the seal,it was put in dry,this diff centre was built in usa by reputable company and not myself
i am going to fix it myself though,i have not taken any measurements as of yet,the breather is clear as i assembled the complete housing,centre,axles and brakes myself
i am looking for ideas as to why it has failed and ideas on the correct method to fit the seal without further failure
i believe it was the dry seal fitted into a smooth machined pinion support with no sealant around the seal
any thoughts????
thanks in advance
steve c
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Re: 9 inch pinion seal blowout

Post by BigBlocksOnTop2 » Sun Apr 30, 2017 10:35 am

That made a mess! I would get everything degreased and reinstall the seal with green locktite. Make sure the housing vent is open....very important.

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Re: 9 inch pinion seal blowout

Post by BirdMan » Mon May 01, 2017 1:12 pm

I would measure the carrier and then research the actual seal sizes while in the store to determine the largest dia. one.
Dale C.

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Re: 9 inch pinion seal blowout

Post by steve cowan » Fri May 11, 2018 10:04 pm

seal retainers 003.JPG
i made a couple of retaining brackets in case the seal tried to move again
i used STAG on the outside of the seal,i dont like using to much of anything in case it finds its way inside the diff.
i have had no problems with the seal again and the retainers have clearance so it would give me an indication.
seal retainers 004.JPG
steve c

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Re: 9 inch pinion seal blowout

Post by psychomotors » Tue May 15, 2018 3:53 pm

They actually make a retainer just for that problem. I found it in Summit or Jegs.
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Re: 9 inch pinion seal blowout

Post by joe 90 » Tue May 15, 2018 5:24 pm

Maybe it's getting too hot inside?

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Re: 9 inch pinion seal blowout

Post by steve cowan » Tue May 15, 2018 6:26 pm

psychomotors wrote:
Tue May 15, 2018 3:53 pm
They actually make a retainer just for that problem. I found it in Summit or Jegs.
thanks psyco did not even know about that one
joe 90 wrote:
Tue May 15, 2018 5:24 pm
Maybe it's getting too hot inside?
Joe,
that may be right,this happened on the the cars first long highway trip to the dragstrip( 2 hrs each way ) so it probably getting hot but as i say have not had a problem since,i think it is because the seal fitted dry into alloy pinion support with no sealer,i have been made aware of a few guys who have had same problem,i made the retainers as a precaution,when you are driving down hwy at 60-70 mph and diff seal blows out there is really no telltale of a problem,i got lucky as it could of been a disaster
steve c

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Re: 9 inch pinion seal blowout

Post by psychomotors » Wed May 16, 2018 10:46 am

https://www.google.com/aclk?sa=l&ai=DCh ... 6QI&adurl=
Apparently my memory is crap. It was on Speedway Motors.com.
It's a little pricey for something you can fabricate yourself, but oh well. :D
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Re: 9 inch pinion seal blowout

Post by Momus » Thu May 17, 2018 9:33 am

3 x 3/16" button heads cap screws tapped into the housing with flat washers retaining the seal and a big diameter vent has worked well on road race cars for me.
The proper fix should be at the factory with the pinion seal bore grooved for a wire retaining ring. Ditto for full floating hubs.

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Re: 9 inch pinion seal blowout

Post by ChevyEFI » Sat May 19, 2018 11:46 pm

Aluminum expanding can show problems, while others remain hidden, like bearing pre-load becoming endplay,

Agreed with the seal dimensions comment; if one is 0.002" larger in the store than another, it is probably a better option in alum. than the smaller one.

As for the bearing support in alum., copying steel parts in an alloy without adjusting dimensions may be the root cause. The rubbery clad material over steel shouldn't require sealant if the part is machined to a properly operating functional size.

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Re: 9 inch pinion seal blowout

Post by steve cowan » Mon May 21, 2018 5:52 am

CHEVEFI,
i hear what you are saying,there should be a machined groove inside where the seal is retained instead of having a smooth finish,maybe even some small grubscrews coming in from the side but that would add cost and possibly other problems,
steve c

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