915 Differential Output Seal DEPTH?

[DRACO A5OG]

Hey Fellas,

So I replaced my seals, placed them flush but I noticed when I re-atached the D-side fange, the flange pressed the seal in about 3MM in and the flange is touching the seal.



Now the P-side, there is a gap so the seal will not touching, WTD?

Question, should both seals be set in about 3MMs+ and should I push the D-side in further to keep it off the flange? I assume yes, but just want to verify.

TIA,

[DRACO A5OG]

So it appears from the PAG diagram it should be flush.

Now I need to check why one flange is deeper than the other side, note mine is a LSD but that should not make a difference

[Targa Me]

Hello Jim,
It would be my guess that the seal should rest at the bottom of the cavity, or bore, that is accepting the seal. In other words, seat the seal at the bottom until it will no longer travel.

[john walker's workshop]

One side is flush and the side cover is deeper.

[DRACO A5OG]

Ah ha.

That is what the original seals were like

P-side was flush and D-side was set in, I will push D-side in a bit further to keep it off the flang

Thanks Dr JW

[john walker's workshop]

I use the flat side of the old seal and a plastic hammer to sink it in evenly. Watch your fingers.

[DRACO A5OG]

That is how I did it too, YES, ouch, smashed my fingers several times

So, I visited HD and found a SST for the install instead

The OD of the seal is 2.7 inches

This coupler's OD is also 2.7 :-)


Label is 2 X 3/4 PVC

I will use a large washer and Diff bolt to "arbor" like press it in.

Too close for comfort so I will shave/sand the PVC down a tad so I can get D-side in the depth needed, if it won't fit on the diff easily

[DRACO A5OG]

Ah Poop,

Wouldn't you know it, the bolt is too short ok back to finger smashing time :-o, actually not, because of the height of the HD SST, plenty of room as not smash the fingers with the rubber mallet

Seals All Good


P-Side

D-Side

1MM Gap from seal surface both sides

[MBEngineering]

HI DRACO A5OG

what year is the gearbox, it looks like a SC/3.2 box,

which LSD have you fitted,

the diff seals are at 3 depths depending on the box/diff side plate,

the main case seal should be around 2mm below the case

the diff side plate (without the oil pump) is around 2mm for a SC and 8mm for a 3.2 (depending on which diff side plate is fitted) in from the outside of the case

the side with the oil pump is 12mm in from the outside of the case

it you have a box which started life with a open diff, do you know which/where the LSD came from, as the early diff will not sit in the middle of the diff case, causing one output shaft to sit close to the seal and the other to be well away from the seal, in a badly set up box and seal could cause the oil leak, due to the diff beeing fitted to deep in the case, the oil seal in to deep and the shaft is not sitting on the seal

the Porsche diff oil seal setting/fitting tools for 915 gearbox



regards mike

[DRACO A5OG]

Brother Mike,

It was built by Peter Zimmerman and he stated he used oem LSD. Yes, I can concur, the P-Side (as one is seated in the car, right side) flange is definitely positioned outward further than the D-Side.

The diff plate for the D-side, I noticed is definitely has a recess/concaved then a lip to accommodate the seal vs the P-side lip which is flush with the diff case surface.

My main worry was the D-side flange rubbing against the seal, which is not a good thing at all.

So now I have matching gaps on both sides. Will keep an eye on them to insure no leakage, since i have the gear box out I could always take proper measurements using a straight edge.