Three quick axle questions

[BarryJB]

Greetings all, have scoured all the axle/CVJ threads here, and still have three questions. I am upgrading my 100mm CVJ axles to the later 108mm type (with frictionwelded stub axles) on my early '85 with a 915/68:

1. Is the Porsche/GKN OEM 108mm drive shaft (that has the non-serviceable outer CVJ and the cap on inner CVJ) shipped ready to install, i.e., with both CVJs pre-greased? I have a ticket in with our host on this. Concern is it seems likely they are, but I have read (not in Pelican forums) that it is wise to check (and add to if needed) the grease amount on new GKN factory-pre-greased axles anyway, even though this would involve removing the presumably sealed-on inner cap and outer boot clamp.

2. When a joint (drive/diff) flange is removed, does oil leak out unless one drains (all or some) oil from transmission first?

3. Is it necessary/recommended to replace the joint (drive/diff) flange seals when reinstalling flanges?

Thank you!
Barry

[DRACO A5OG]

1. it should be capped

2. you should drain it

3. you should change the seals, taking careful note of it's position in depth, they are not the same depth on either side. ALSO make absolute certain the seals are even and not cock eyed, it will wear them out quickly.

[BarryJB]

Originally Posted by DRACO A5OG

1. it should be capped

2. you should drain it

3. you should change the seals, taking careful note of it's position in depth, they are not the same depth on either side. ALSO make absolute certain the seals are even and not cock eyed, it will wear them out quickly.

Thank you Jim. 2 & especially 3, got it. 1st foray into this. Was suspicious as Bentley (pp 390-1 thru 390-3) does not mention draining oil anywhere obvious... but then there ARE seals )

Re 1: Understand axle inner should be capped, so forgive me for asking further... you are confirming that AFAYK the genuine Porsche/GKN axles are shipped ready to install, pre-greased, out of the box? And even if pre-greased, no need to check grease in both CVJs, based on suggestion (some vendor sites) factory was, um, occasionally skimpy on lube? This was never in doubt with the many replacement 100mm axle parts I've gone through, where were CVJs were always shipped dry.

vbr

[KTL]

They are shipped ready to install. But unfortunately the grease they use is cheap crap. This is going to sound stupid but here goes anyway. I would suggest pulling back the boots (or remove the inner CV) and clean out the grease so you can replace it with a high quality synthetic grease that will last. The reason most CVs fail is inadequate lubrication and that's primarily on account of the quality of grease. Use a high quality synthetic grease from the start and you'll not have to mess with them again for a long long time.

[DRACO A5OG]

Master KTL , answered

I did not know that GKN also used crappy grease, oh the joy, guess what I am going to do next week

[KTL]

Well my experiences are limited just hearing what others say and the handful of axle services i've done. But I feel like my beliefs are justified since one of the packets of grease I received in a recent GKN boot kit purchase leaked out and got the box all oily. My point is that if the grease got oily, it's likely an economy petroleum grease that can separate pretty easy. Good synthetic greases remain a uniform goop and don't separate. Plus they're just simply better at lubricating long term, just like most synthetic oils.

But this is all probably overkill since it'll take another 20+ years for the axles to wear out? I dunno. Maybe it's my pessimistic view of today's quality in everything. The original axles were built with better boots and better grease and were actually brand new parts. Whereas stuff made today is all about the bottom line, remanufactured and mediocre quality at best. We've seen new steering rack boots split within a few years, new CV boots split within a year, new rocker arms fall apart (follower pad), crappy quality of engine valves, shoddy engine bearing shells, crappy gaskets......... The list goes on. What a shame.

[uwanna]

Originally Posted by BarryJB

Greetings all, have scoured all the axle/CVJ threads here, and still have three questions. I am upgrading my 100mm CVJ axles to the later 108mm type (with frictionwelded stub axles) on my early '85 with a 915/68:


2. When a joint (drive/diff) flange is removed, does oil leak out unless one drains (all or some) oil from transmission first?

3. Is it necessary/recommended to replace the joint (drive/diff) flange seals when reinstalling flanges?

Thank you!
Barry

Barry,
I have replaced 100mm trans output flanges with 108mm several times, never drained the oil. I believe the static oil level is below the flange seal. In any case, I never lost any oil!
As to the flange seals, if yours are not leaking now, I don't think they will leak with the new flanges, at least mine didn't. YMMV
Good luck, and you are doing a great upgrade! No more loose CV allen bolts with
the 10mm bolts vs the old 8mm.
Regards,
Grant

[BarryJB]

OK then:

Originally Posted by KTL

They are shipped ready to install. But unfortunately the grease they use is cheap crap. This is going to sound stupid but here goes anyway. I would suggest pulling back the boots (or remove the inner CV) and clean out the grease so you can replace it with a high quality synthetic grease that will last. The reason most CVs fail is inadequate lubrication and that's primarily on account of the quality of grease. Use a high quality synthetic grease from the start and you'll not have to mess with them again for a long long time.

Crap. Cleaning off cheapo stuff and repacking with synthetic no fun. No this doesn't sound crazy, it makes more sense than "not enough" as basis for rumor about not just installing straight out of box.

Originally Posted by DRACO A5OG

Master KTL , answered
I did not know that GKN also used crappy grease, oh the joy, guess what I am going to do next week

Assume we will need to use either a new oetiker clamp, or, whatever the original boot clamp type installed is, maybe they will be reusable (not holding breath on that).

Originally Posted by KTL

Well my experiences are limited just hearing what others say and the handful of axle services i've done. But I feel like my beliefs are justified since one of the packets of grease I received in a recent GKN boot kit purchase leaked out and got the box all oily. My point is that if the grease got oily, it's likely an economy petroleum grease that can separate pretty easy. Good synthetic greases remain a uniform goop and don't separate. Plus they're just simply better at lubricating long term, just like most synthetic oils.

But this is all probably overkill since it'll take another 20+ years for the axles to wear out? I dunno. Maybe it's my pessimistic view of today's quality in everything. The original axles were built with better boots and better grease and were actually brand new parts. Whereas stuff made today is all about the bottom line, remanufactured and mediocre quality at best. We've seen new steering rack boots split within a few years, new CV boots split within a year, new rocker arms fall apart (follower pad), crappy quality of engine valves, shoddy engine bearing shells, crappy gaskets......... The list goes on. What a shame.

Good enough for me, and it jives with this: my mechanic (Jae Lee at Mirage) has ALWAYS given me packets of quality synthetic grease, wherever I'd bought replacement Löbro 100mm CVJs in past, along with a disparaging comment about the stuff that comes with them... more circumstantial evidence.

Originally Posted by uwanna

Barry,
I have replaced 100mm trans output flanges with 108mm several times, never drained the oil. I believe the static oil level is below the flange seal. In any case, I never lost any oil!
As to the flange seals, if yours are not leaking now, I don't think they will leak with the new flanges, at least mine didn't. YMMV
Good luck, and you are doing a great upgrade! No more loose CV allen bolts with
the 10mm bolts vs the old 8mm.
Regards,
Grant

I like that answer re not draining oil, and giving it a shot with existing seals (g/b rebuilt 1 year ago). No leaks at present, and not so messy to go back in with the 108 axle design if seal(s) leaked, anyway.

I’ve given up on finding/catching a new/used pair of the gryphon snot 85.5 thru 86 flanges, for reasonable $, but just recently discovered in a thread here that if you machine a few mm off the spline ends of the 87-05 joint (drive/diff) flanges (950 332 209 01), they fit and work fine. I found a used pair for $200 inc shipping, and have an expert machinist buddy. Can't find exactly how much to take off posted anywhere, other than "match length to the 100mm flange", so will do that, using the outgoing 100mm flange shaft/step/seal dimensions.

Biggest problem I had, since installing the 3.6, was not so much the 8mm bolts loosening (new bolts & hex bit most every time, and using the thick-flange boots seemed to stop that), it was the CVJs wearing out, even with the good grease, about as often as the rear tires (265 [Kuhmo XS RIP], or now 245 RE11's). I sucked myself into changing the 100mm CVJs out four times in some three years, on basis it was an easy job, instead of going to the 108mm axle in the first place. Live & learn. But, duh!

Thank you everyone. This site is such an amazing resource. Would never have even considered the 3.6 conversion without all the experience and wisdom here.

[uwanna]

Gryphon snot 85.5 thru 86 flanges, LOL very appropriate description! Sure glad I got mine back when you didn't have to pledge your first born for a pair! But then that was back in 1992 when I did the 3.6 transplant when there were no fancy
"kits" to solve all the install problems. Everything then was backyard engineering, but it still runs great today. I even added an on engine oil cooler, because nobody told me I couldn't!

[BarryJB]

Originally Posted by uwanna

Gryphon snot 85.5 thru 86 flanges, LOL very appropriate description! Sure glad I got mine back when you didn't have to pledge your first born for a pair! But then that was back in 1992 when I did the 3.6 transplant when there were no fancy "kits" to solve all the install problems. Everything then was backyard engineering, but it still runs great today. I even added an on engine oil cooler, because nobody told me I couldn't!

LOL back at you Grant, first born! Never thought of that!

Considered using 3.2 cooler w/3.6 after coming across awesome write up during 2-1/2 years research prior to 3.6 plunge—maybe you wrote that?! Decided extra (return side) filter was no bad thing, but one front active cooler wasn't cutting it, so squeezed in a second active fender cooler, L side. Cooling OK w/a 3.2 (radiator style) cooler & 8" fan each side, plus it retained stock look. Lot of fettling to clear FL tire, and relocate alternatives for vapor canister and washer reservoir in frunk. And so on.

A friend made CNC'd blocks from dimensions in another Pelican's post for offsetting pickup points on the reinforced (kit) rear engine bracket and welded it all up. Jae at Mirage here (San Diego) has done a bunch of these conversions, so he did all the engine/bell housing/flywheel/wiring/brain/fuel lines stuff. As a CA car, had to satisfy DMV ref, so keeping stock 993 cat w/tight bends allowed stuffing two short Magnaflow cylindricals over cat, clearing heat tube ok, w/center outs, extra heat shields and everything wrapped. Heat and AC both work great... after more mods.

But as you say, when we did this (c2010), most of the complicated & critical stuff was available in kit form from PM (and others), plus us late-to-it guys benefitted from all you early adopters' pioneering and maybe sometimes painful/$$$ experience. It was quite a journey, even so—can't imagine how challenging and satisfying it must have been to do it with just the idea, the intention, with nothing but empty toilet paper tubes, JB Weld, hairy string, wooden wedges and whitworth wrenches, back there in the early 90's.