Rear axle problem

[iplagolf]

Interesting day today. Took a road trip to D Patrick, the Porsche dealer in Evansville, Indiana. Left the lot, took the service road to the Lloyd Expressway. As I accelerated away from the red light the rear end let go and a thump, thump, thump as I coasted to a stop. Looked under the rear end and the left axle was sitting on top of the exhaust pipe. The six allen bolts were in the collar but were completely out of the transmission. I got the car towed back to the Porsche dealership. Here's the great part, mechanics on duty at 3:30 on a Saturday afternoon. Put the car on a lift and bolted it all back together. Greater yet, didn't charge me a dime! The mechanic told me in the 15 years he's been working on Porsche's he'd never seen what happened to my car happen on any other or even heard of it happening at all. I have never touched that area of the car. I was under the rear end mid week and saw nothing wrong. I'm putting it up on the jack stands in the morning to look it over. My question, why and how would this happen? All six bolts at the same time? Is this a good place for red loc tite? Any ideas. I'm just glad I wasn't doing 75 when it let go...Thanks, Fritz

[Guest765]

I had one bolt walk out on me and apparently it's more common than you think. Grease can get to the threads and vibration walks them out. Some people suggest some locking bolts for back there but from what I understand they are like ninety dollars - a total ripoff.

[Timmay!]

Someone was in the process of stealing your axles! LOL!
No, all 6 won't come loose at the same time without snapping some, unless you drive like a little old lady? Once you get down to 1 or 2 bolts holding the axles on, they're going to give. Was the dealership working on your car?
People often over torque those bolts. It's 33 ft lbs and no more.

[iplagolf]

No, the dealership wasn't working on the car. Interesting thing, the service MGR. asked me where I parked the car. I said, in my locked garage. He asked, you got anyone after you? Like someone would hijack or meddle with the car...Wife still loves me...Honey, you still love me, right? Well, she was in the car with me when it happened. I have no clue...Fritz

[SolReaver]

The CV bolts and dog ears have been known to come loose and I inspect mine yearly for tightness. Torque the bolts.....Drive for a few miles...re-torque and then "speed stripe" them to be able to tell at a glance if they are backing off. Most people think I am a bit obsessive....just imagine what would have happened if you had been at speed when those bolts let go and you will agree I am just careful.

While regularly inspecting the CV bolts, check your transmission linkage and make sure the funny little bolt with the wire is secure to the linkage.

[Guest765]

Its not like the car would have exploded just because he was at speed when it happened...

[wild man]

It's nice to hear a report of no damage every once in a while.


Moral of the thread:

The CV bolts should be checked every once in a while.

Maybe it's time to peg it as one of those WYAUT (while you are under there) checks.

[SolReaver]

I will agree that it could be a WYAUT item, but in my mind it is a safety issue. I know I am paranoid, however, IF it happens at speed and you are passing or trying to merge or cornering hard....Loosing power or a wheel locking up could make a big difference.

I drove a wrecker on the graveyard shift for a few years.....Please trust a paranoid old school mechanic when he says that life is short enough and crazy sh@t happens out there. No need to tempt fate. I have seen the aftermath of dozens of wrecks caused by less.

Just being broken down by the side of the road scares the junk out of me.

All I ask is a little quality time under your rides and the life you save...may be your own.

Likewise inspect brakes, wheel bearings, suspension, you guys know the drill... When you own a vintage sports car this is what you DO!

[wild man]

Originally Posted by SolReaver

Just being broken down by the side of the road scares the junk out of me.

I think there might be a little of that in all of us.

But since you were a tow truck operator and probably seenit all, a much higher degree of it must exist for you.

It happened to me once, a few months after I bought the 951. The right side inner joint disintegrated internally, but the parts stayed inside the boot. I wasn't on it very hard at the time. Since the TT operator was a friend of mine and I was less than 5 miles from home, the tow was a freebie.

The new axle shafts were Cardone remans that cost me about 80 bucks each. After installation, I kinda went out on a limb and injected (what I guessed was) an equal amt of heavier bearing grease into each boot after putting about 100 miles on the axles. Hopefully the new ones will never go out on me, with this extra insurance that I added. But you never know.....

[SolReaver]

You can always clean, and repack your CV's, while you have them out, you swap left fro right and vice versa to wear evenly. If properly maintained...they just don't wear out. Use the good CV bearing grease... not the junk that comes in the tubes with the kit.

[acorad]

It is a safety issue, if you were at speed and that axle was being flung around what besides the exhaust would it hit? Gas tank.

My bolts all backed out a few months ago until there was only one hanging on by a thread and it got sheared off. Major pita to get the sheared-off portion out.

[Rasta Monsta]

If you guys are worried about it, you can buy a set of very cleverly engineered locking CV bolts from Ideola's Garage. . .look up "Stage 8."

[SolReaver]

yes...you could use fancy bolts...OR you could just do the job right.

Clean the mating surface and threads, torque in two stage sequece with a drop of locker under the head NOT the threads. Road test, re torque and speed stripe. If done right, the stock bolts are fine IMHO. You can and should use new bolts of the correct grade if the old ones are worn. in fact I recommend using new hardware if the old bolts were bashed around by a loose CV or just for the hec of it as new bolts hold torque better. (cheap insurance)

The stage 8 bolts are a bit of overkill for the average driver...But, there is no such thing as overkill if you are racing...in which case you inspect regularly or you get hurt.

Inspect regularly. With the speed stripe the visual takes less than a min on each axle while it is up there. You should be inspecting the car at least once a year anyway. Put it on your yearly checklist. USE your yearly checklist.

This is a known issue.....The life you save.....

[iplagolf]

As you can see in the picture there was some damage to the dog ear. I'm going to try to "tap" it back into place. Knowing my luck it will break off. I see a, "drop the tranny and repair in my future." Any thoughts?

[SolReaver]

well, Minimal replace the bolts as they might have been overstressed. First "tap" the flange into shape as best you can. Next check the mating surface clearance with plastigage or paint and a light torquing to see if you have any gaps serious enough to worry about. The bolts keep the friction on the mating surface. You will have to take it apart and make a judgment call. If you have a bit of time...WYAUT pull the other shaft and think about swapping them around.

Your call as to whether you want to do serious tranny work. If you aren't racing and don't mind inspecting on a regular basis I think you can prob get buy for now. Again..your car...your call

Clean, assemble, torque, drive, torque again and speed stripe. The locker goes under the head but not on the threads. Use weak locker or just paint. you want to work fast or use slow drying stuff.

Give us some pictures of your nifty speed stripes...they really help the car go faster...really...

[iplagolf]

Biggest concern is water and grit getting in. Will be going where this man has not gone before. Me and Clark's, we can do anything! Worst case, what parts am I going to need? Since the tranny is going to be out, check out the clutch? Car has 85,500 on it. Seems solid. Ideas? Thanks, Fritz

[SolReaver]

on second thought...Before "tapping" just check to see if the mating surfaces and the bolt alignment is good.. I retrospect I am wondering if the 'Tapping" might do more harm than good. you would be putting impact force on a bearing at a funny angle...so..use discretion and if it isn't really broke don't fix it...just take it apart, clean it and put it back together.

[iplagolf]

Question, why wouldn't the mating surface and bolt alignment not be good? I do intend to replace all of the bolts and check the dog ear bolt holes for "buggered threads." Clean it all up and re-grease. It seams there is a rubber boot needed here to seal the collar and stop the grease throw off as seen in the picture. Large heat shrink? Fritz

[SolReaver]

why wouldn't the mating surface and bolt alignment not be good?
* I would hope it IS good. I don't know how bad it will look when you take it apart. I was advising you to check these things.

It seams there is a rubber boot needed here to seal the collar and stop the grease throw off as seen in the picture. Large heat shrink? Fritz

## IIRC it is a gasket. You will want to replace it...they are cheap. Formagasket works too. You may need to use a bit of gasket sealant as a filler. IF you have thrown a bit of CV grease about it may be time to rebuild the CV or at least clean and repack. Once you get it apart you will have a better idea.

Suggestion: take a big clamp or a couple of clamps put together and "crush" the flange back while GENTLY "tapping" You can prob get enough shape back to get a seal with minimal gasket Goo.

I figure the job will take 4 hours and 3 beers start to finish. piece o cake.

[iplagolf]

There's a gasket? I thought it was a lands and groove type of thing. High and low ridges with grease in-between. I need to look at a break down to see what I'm dealing with.