Porsche-O-Phile

Long story short:

1. Pull out of parking lot.
2. Hear loud "clunk"
3. Notice engine power changes no longer result in response at the wheels
4. Slowly coast over to side of road (fortunately no traffic)
5. Notice transmission gear selector freely moves into any position (with or without clutch engaged)
6. Shut off engine.
7. Get out of car.
8. Look under car.
9. No fluid/obvious damage (good).
10. Go to rear of car.
11. Look under rear of car.
12. Observe driver's side axle hanging down, no longer connected to transmission.
13. Curse the Porsche gods.
14. Retrieve AAA card from passenger compartment.
15. Look under rear of car again.
16. Notice bolts holding rear axle to transmission have backed out.
17. Curse Porsche gods again (though less so, realizing this might only mean I need to re-install about 8 bolts and some grease - hopefully nothing too serious).
18. Call AAA
19. Get towed home.

Pics pending. Grr.

So check those bolts at the rear axles people.

924RACR

Yep. That's why I safety-wire all the ones on my racecar... after noting them backing out (despite using loctite). Never had a problem since.

Mike Murcia

I've been there, but I limped it home after putting in the 4 bolts that weren't bent. It's tough to get the bolts in without getting grease on the threads, but it can be done. Had you pulled the 1/2 shafts recently?

Porsche-O-Phile

No, that's the strange part. I've really done nothing on the back half of the car other than install a new fuel filter. At least I was going slow and when I finally rolled to a stop, the axle was just sagging down about 3". It makes me shudder to think what that kind of failure would do at highway (or track) speeds or if the thing had flopped down and "pole-vaulted" the back end of the car. That'd be ugly. I think I'll be safety-wiring all of them - that's a good idea.

KuHL 951

Retorqueing those bolts is standard maintenance any time I have the car on stands. They work loose everytime. I think I'll try the safety wire route for insurance. Any tips on the best way accomplish this.

924RACR

Lots of small drill bits and a drill press. Thankfully the allen-head bolts are easier to drill through than your typical hex-head bolt. Did I mention lots of drill bits?

Yabo

I swear theres a thread every month about these backing out. Has anyone tried loctite? and does that not hold either?

ibkevin

Thanks for the heads-up and I'm glad they didn't drop at speed. I have the parts for a boot R&R so I'll be doing the lockwire thing.

bearone

i would suspect that drilling holes would compromise the bolt.

have you ever tried an-aircraft hardware that is already drilled for safety wire?

TRWright

Yes this can be a PITA. I had 2 back out, which caused the other 4 to snap off inside the input shaft.

Jeff, do yourself a favor and switch them over to allen heads. Also be sure to get the highest grade you can find. . . Tighten them up everytime you change the oil. Call that a bit overboard if you will, but I was stuck 5 hours from home and I won't let that happen again!

Porsche-O-Phile

Sound advice from someone that's been there. I looked at those while I was lying under the car in irritated investagative mode last night and specifically remember wondering "what the f*ck is it with Porsche engineers and allen head bolts?"

I'm off to try and find some grade 12 metrics tonight.

Allen heads. Sheesh.

Allen head cam tower bolts = annoying, bad idea.
Allen head axle bolts = bad idea.
Allen head turbo bolts = REALLY bad idea.

Don't even get me started on "triple squares".

Mighty Shilling

it's the fender flares...

Naw, I've had this happen a couple times. not fun... but not as pooey as having a transmission grenade....

Porsche-O-Phile

Yea, just more annoying than anything. I swear I saw a smirk on the face of a dude the drove by in a 911 Carrera while I was waiting with the hazard flashers on, clearly broken down on the side of the road. Grr.

ibkevin

Good advice on drilling fastener heads , post #5.

Porsche-O-Phile

https://rennlist.com/forums/944-turbo-and-turbo-s-forum/221147-assembling-tial-kit.html



Good thread, btw.