G50 LSD rebuild kit

[turboquattro]

Hello,

I have searched and cannot seem to find a rebuild kit for G50 LSD unit.
I am hoping to install one in my '87 and thought to have it rebuilt (myself).
Anyone able to point me to a decent rebuild kit, would be appreciated.

Cheers

[turboquattro]

Also, here is the full P/N of the unit I have.

406 101 9137 981502 S20

Has an interesting ramp profile, not the usual V.

[Matt Monson]

Porsche classic has been stocking them as classic parts. Original numbers from pet are being used. Though they only make the frictions in 2.0.

[kevingross]

That's not a LSD from an '87 911, which had 40 / 40 ramps -- they would appear symmetric. It looks like one that came from a later 911-series car. The 406 number is a ZF part number, not Porsche, as you probably know.

I think you may have a 20 / 100 LSD from a 964-series C2. Most of the parts needed to rebuild it are available from Porsche, the exception being the 2.1 mm "outer plate" which recently became unavailable, and I guess the original 2.6 mm clutch discs per Matt's note. Take a look through the parts diagrams Porsche provides on their web site.

In a rebuild, I typically replace the clutch discs, other parts in the stack as needed. I measure the height of the Belleville washers (cup springs) and if they have lost height, fatigued, I replace them. The workshop manual will specify a desired delta between the assembled pack and the case height, and I'll swap in different thickness outer plates to get as close as practical to it. Check the two thrust washers: the versions with the pressed-in tabs are prone to fracture. If the 2.6 mm clutch discs are NLA as Matt mentions, I believe you can use the 2.5 mm clutch discs from the 944 Turbo S, or the 2.0 mm discs, adjusting the outer plate stack to get a good height.

Check the ramps for excessive wear where the pinions (cross shafts) ride. Check the break-away torque of the assembled unit, against the range specified in the WSM. I close up the unit with four M12 bolts and nuts for this test rather than torturing the poor little M6 allen screws.

Hope this is helpful. Good luck.

[dannobee]

Kevin's right. Here's an earlier G50 LSD. Notice the symmetrical ramp angles.



Notice the "40" at the tail end of the numbers. 40%

[Matt Monson]

Kevin,
His is a 4 plate, so uses 2.0 clutches . It is a 20/100 from turbo.

[turboquattro]

Any pros/cons using this 20/100 over the 40%?

Thank you
Martin

[kevingross]

Originally Posted by Matt Monson

Kevin,
His is a 4 plate, so uses 2.0 clutches . It is a 20/100 from turbo.

Matt, roger that! I cannot keep track of all the versions in my head. I tend to open 'em up, see what we got, and replace the old with the new. Cheers,

[kevingross]

Originally Posted by turboquattro

Looks like I was sold a cat in a bag. LOL
So, will this fit my G50-00?
Any pros/cons using this 20/100 over the 40%?

Thank you
Martin

Martin,

I would say first that it will depend on your intended use for your car, your skill level, and to some extent personal taste. With those caveats, there seems to be pretty broad consensus that the 20% on accel is weak sauce and has motivated many owners to step up to Matt's fine Guard Transmission LSDs.

[turboquattro]

I don't plan on doing any track time anytime soon, mostly back road spirited drives.

Thank you
Martin

[Matt Monson]

The lock up on throttle is adequate. It’s the 100% on braking that can be an annoyance, largely when backing the car up. Not the end of the world, and Porsche thought it was good enough for the turbo and the g50/10 in the RS.