Needed: HOW TO rebuild factory LSD.

cstreit · cstreit's Garage

Gang,

I've got a factory limited slip that pulled out of the racecar because I'm pretty sure the clutchs were failing. I'd like to tear it down and rebuild it...

Is there a "how to" on this anywhere?

pwd72s · 05:07 PM

Not as far as I know. But I do know a guy who DOES know "how to"...he did mine. Would you like his email? In his "spare time" he does do trans, and other, work for others, and a ZF unit could be UPS shipped from one coast to another. Why do I trust this guy so much? When he was going through my gearbox, I asked him about the Quaiff unit. He showed me my factory unit, then said he'd install a Quaiff (sp?) as a straight across swap if he wanted me to. It then dawned on me that he could have done just that, and I, with my limited driving skills, wouldn't have noticed the difference. Diogenese, (sp?) extinguish thy lamp...the BEST 915 gearbox guy on the west coast lives in Orygun, and he speaks the truth...his first name is Gordon...mentioned in case other NW guys would like to back me up...

Grady Clay · 03-03-2005, 05:17 PM

Chris,

There is no mystery here. "How to" is right here.

Pay particular attention to the order of the discs
Take a micrometer and measure each disc.
Report what you find.

We can fashion you the best ZF in the world, depending on your need.
You just started the LSD rebuild thread.

Best,
Grady

pwd72s · 03-03-2005, 05:25 PM

Chris? If Grady says he can lead you through the process? Trust him! I do!

beamonk · 03-03-2005, 07:17 PM

I am tagging along on this thread. I looked at some other threads and it seems the jury is out on this topic. I called Gary Fairbanks about this and he said it is rare to wear these out. I just don't see why not to go in it while it is out? Mine is sitting here looking at me!

afterburn 549 · 03-03-2005, 08:37 PM

All I know if is like most others in the world its not very hard

jluetjen · jluetjen's Garage

Chris;
Question one -- do you have the factory shop manuals and their documentation? Also 901/911 or 915? I'm pretty sure that it's similar, but before we all throw in our $0.02, it would most likely be good to know what the target is.

KTL · 03-04-2005, 04:17 AM

In case somebody wants to get started on their tech. advice, it's a 915 differential.

beamonk · 03-04-2005, 04:27 AM

Mine too !

Geary · 03-04-2005, 07:56 AM

According to Porsche, the friction discs should be changed every 30,000 street miles. The 915 LSDs are straightforward to work on, as the discs and plates are pretty standardized. (The G50 & later come in a number of versions.)

It's also pretty straightforard to update to 4 friction discs for track use, if your 915 LSD has only 2.

beamonk · 03-04-2005, 08:46 AM

My problem is how to crack this thing open, I am timid and don't want anything going flying across the room. I guess I need to track down the manual.

Geary · 03-04-2005, 01:29 PM

Hold the LSD together tightly with three 12mm (5/8") bolts/nuts, and THEN remove the two small set screws. Loosen the three bolts alternately just a bit at a time, and it's apart. It's quite simple from that point on.

Upon reassembly, just remember to use the three bolts to carefully pull the cover back down on the diff housing, before installing the two set screws. It's a good idea to slide the output flanges into the splines before reassembly, just to align housing & side gears as the LSD is going together.

KobaltBlau · 03-04-2005, 02:10 PM

This thread Rocks, thanks to 2 guys with 5 letter names starting with G!

ted · ted's Garage

I just had Jae at Mirage International rebuild mine.
San Diego ph# 1 858 581 1101.