Leaking Differential Seal

[DanLazer]

I recently changed the cv joints on my 1999 5spd aspire. The differential seals looked a little old so I changed them. The right side was leaking so I pulled it all back apart again. There are no burrs on the sealing surface of the cv joint and the seal has no visable cuts or tears. The spring was still properly installed in the lip portion of the seal. I installed a new seal and put rtv on the outer rim to make extra sure it was sealing in the bore. The shaft is definitely installed all the way in. Still leaking.

When I had the shaft out, I tugged on the inner race of the output bearing in the tranny and it had no play. With the shaft reinstalled, I can grab the inner cv joint and shake it back and forth about a millimeter which is slightly more than the side that isn't leaking.

My first theory is that the remanufactured cv shaft has been machined out of tolerance (shaft too small where the lip seal contacts it or where it goes through the inner race of the tranny output bearing). Anyone know the dimensions and tolerances for the right side inner cv shaft? Then I could pull the shaft, measure and return to Autozone if it's out of spec.

The remaned right side cv axle didn't come with the rubber mass damper about halfway down the shaft like the stock one did. My second theory is that there is some kind of vibration causing the seal to leak because of the absence of this damper. Anyone else have trouble running without the damper?

Any other ideas? Thanks for the help.

[juryrigger007]

The right and left side diff seals have different part numbers. Be sure to verify that. I got burned by Napa on this, back in '06. New festiva owner (me) walked in to Napa, asked for differential seals, and was sold two of the same seals. Did not know better. Installed, and one side leaked constantly. The missing damper is common, with remanufactured axles, but I doubt that could be the cause of your problems. I just recently replaced my axles, but did not replace my seals. The driver side leaked for about a month, but has since stopped. Perhaps you might run it, for a while, and my luck will happen to you. I'd check on the diff seal part numbers, first.

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Cheers,

Scott

[DanLazer]

I put a Timken 2007N seal in the right side. Does that sound right? Both Autozone and Oreilly's websites say this is the correct seal.

[blkfordsedan]

I have seen some lesser quality reman axles that are indeed machined too small, too rough or out-of-round where the seal lip runs. Not very common, but i've seen it happen. I could also see where worn splines could allow the axle to move around radially, relative to the seal, which could also cause a leak. I would be tempted to try to exchange the axle for another one if possible, just to eliminate another variable. You can look up the designed shaft diameter in a seal catalog (or maybe on-line), based on the seal part number. Then you can put a caliper or mic on the shaft (where the seal lip runs) to compare. Most Timken, TCM, NOK or SKF (CR) metric seals have a rubber covered case or soft paint (called bore-tite) so they shouldn't require any additional sealant on the housing bore.
Also, It is very easy to nick the seal lip when removing/installing the CV axles, therby causing a leak. It doesn't take much and can be next to impossible to see the damage with the naked eye - especially a double lip seal that's still in the transaxle. Just a few suggestions....good luck.

[bravekozak]

I just took a bunch of bagged OEM Festiva parts to the Ford parts department for identification last week. They gave me an exploded view of the differential. Both seals show as 1177 on the exploded view. However, he said that both seals were different. The larger seal was E8BZ-1177-B and the smaller seal was E8BZ-1177-A. Don't buy aftermarket on those critical seals. Green Sales shows 66 of the A and 39 of the B in stock. The Green part description says O-ring, however the Ford part bags just say SEAL. I would have them verify this before you purchase them.