Tony

Any tips...tricks...gotchyas for a front main seal replacement on an 87 S4?

Seems pretty straight forward, but ive told myself that before.

Fabio421

Not really. I walked the old one out with two dental pics and drove the new one in with a piece of PVC pipe. Remember the orientation of the washers next to the gear. ( although I'm sure you already know that )

Tony

Did you drive it in dry or smear a bit of oil on both sealing surfaces?(block/crank)

dprantl

Lip seals should always be installed with oil on their surfaces. If you are careful and patient, you don't even need a drift. I have done lots of front and rear main seals with just a small hammer and no drift.

Dan
'91 928GT S/C 475hp/460lb.ft

Leon Speed

Don't nick it

Btw I think AO had a thread a few years ago about installing a front main seal which contained a picture showing how far it should be pressed in (needs to be recessed IIRC).

PorKen

I've done two in as many months, recently. I hammer a flat blade screwdriver into the side of the old seal, through the handy slot, until it is deformed enough that the seal can be easily levered out. (Careful not to damage the sides or edge of the slot!)

I used the side of the hammer to tap on a short piece of 3" ABS pipe to drive the new seal in. (Bearing grease on the inner lip.) It should slip in easily.

Tony

I like this idea...

Imo000

.....and I don't. That PVC is pressing on the worst possible point of the seal. It needs to be pushing as close to the outside edge as possible, not right at the middle. If this pipe was just a bit wider, it would be perfect.

I just changed one and use the hammer a flathead from the side slot and pry it out method. Installing is was a small hammer, slowly tapping it in, in a circular pattern. Went in like a dream.

Tony

Funny..i just came in from the garage after removing the seal and i looked at this again. You are correct the metal/structural part of the seal doesn't extend that far toward the center. The thing i like about this is the gradual insertion of the seal buy turning it. Appears to me you would have better control over it...perhaps a light tap here an there to make sure it goes in square.

It was actually a bit of a bitch to get out..strong SOB!

GeorgeM

I made me one of those PVC tools when I did the job.... no hammers, just a turn of the bolt... very nice. At about $3, you can't beat it.

Tony

I just cut mine apart to have a look at the cross section...

There is a fair width of metal there but i still would try and get something as close to the OD of the seal as i possible.. ..
The PVC above works I'm sure but as i look at the seal in front of me it would have to be dead on center as to not damage the rubber closest to the center where there isn't any metal behind it....the redline is where the PVC tool would appox. sit based on the image above.

PorKen

3" ABS (black) pipe fits the seal where the metal is and has a thick wall.

blandis

Outside surface should be dry! Learned that lesson the hard way.

Imo000

Dry?!?! Why do you say that?

dprantl

That's also the first I've heard of that. I have installed many front and rear seals, all with oil on both sides, never had an issue after 50k+ miles.

Dan
'91 928GT S/C 475hp/460lb.ft