My name is KC Moore, and I have a problem...
 

I have a problem with breaking axle shafts on German cars. I just this last weekend broke the left half-shaft of my '74 911. On New Years' Eve, I broke the left half-shaft on my '93 BMW 318i. What's the deal? Are these just like the weakest part of German cars? I haven't driven these cars any different than my previous Honda or Nissan cars, and they never had any problems.

I'm about to order a new half-shaft for the Porsche, but wanted to get some input as to what I can buy that would be more robust for my '74, if anything. Are there any newer, stronger, 930-type parts that will bolt right on? Has anyone else had this problem before?

Sincerely,

German car destroyer.

I wonder if they are designed to break instead of damaging your gearbox. We had 60's and early 70's Land Rovers and they were that way.

Uh, what, may I ask, were you doing when this happened? I'm thinking it wasn't "Pulling out slowly.":D :D

pic...
 

Well, I was just slowing down to a stop sign when it finally gave out, but I have a feeling that the stop-light burn-outs had a hand in it. The sad part is, when it came out, it took the left heat exchanger and throttle linkage with it.

http://www.sunflower.com/~kcmoore/shaft.jpg

http://forums.pelicanparts.com/uploads/he2.jpg

Hmm, shouldn't be an issue. I have heard that BMW's are always in the shop, so that would explain that problem(and the fact that it's not a Porsche), and your other car is almost 30 years old, maybe it was just it's time. These cars are pretty robust, unless you are trying to match the magazines 0-60 times and launching really hard you shouldn't have a problem with normal half shafts. Many people have put much more powerful engines in early cars. I hear more about transmission problems than half shaft problems.

Old age...
 

That's true...this car is old. I guess I should expect some failures, especially after putting in new rings and head gaskets, and a performance muffler. I'm not real worried about replacing the half shaft, because it's pretty cheap, but now I have to get headers sooner than later, and somehow make a bracket to hold the throttle turnbuckle since the other one was ripped out of the tranny housing. Oops.

front wheel drive cv's will click and clack on corners a long time before they break. most vibrate like the dickens when they are worn.

i thought i popped one last night in a loaner 944 (f'in junk mobile).

the guy that works on my cars had the 72 axle cvs machined for bigger balls. (cannon axles which moved from knoxville to nashville).

where are they breaking?


oooh . carnage pictures. tell your insuance guy that you ran over an animal and see what he says.

we used to hulk up on the parking/rear brakes and smoke the tires off the rims on the front drivers in the younger days. $700 bill from the honda dealer for two front half shafts put a stop to all the fun.

Re: pic...
 

There's your answer. These cars are not made for "burn-outs", engine and trans directly over drive wheels provides too much traction for this. The Germans never figured owners like you into their design parameter, something about them being more impressed w/ great road cars than ones that do party tricks. :cool:

KC,
Is it broke or did the bolts just back out? Mine backed out on me and almost gave me a heart attack. I was sitting at a traffic light and got the green. I was actually going to pull out slowly when just as the car began to move, BANG! It let go at the wheel. I was very lucky to be at a stand still or it would have been more like what you encountered.

Warren(Early S man) swears on replacing the washers and NOT re-using them. They are not worth the risk. I bet he pipes up with the part number.

Right Warren?

Hmmmm does the phrase "preventative maintenance" come to mind? You just can't buy a 30 year old car and not expect to give it a thorough going thru before you decide to go out and abuse it. Expect more of the same unless you are willing to put forth the time and money to bring the car up to safety specs.

...
 

Well, after further inspection, it looks like the bolts did indeed back out, but when they did, the drive axle spun around and whacked the heat exchanger and took out the throttle linkage, thereby ripping the boot and releasing all the grease. I'm gonna replace the whole thing anyway, just to be safe.

As for the insurance, I only have liability because no one around here will insure a 28-year-old car with full coverage.

I'm really surprised at some of the other comments concerning my driving. These cars were designed to be driven, and driven like racecars, not Studebakers. For those of you who drive your Porsches slow and cautious, shame on you...you should have bought Mercedes.

Oh, we have guys here who drive anything BUT slow & cautious...Mike Marshall, Jack Olsen, well, the list goes on of guys here who track their cars...TRACK is the key word here...and you know, I doubt any of them like to do "burnouts". But if your car would pass tech, I'm guessing they'd be willing to show you the fast way around places like Mid Ohio, Thunderhill, Laguna Seca, and others. If burnouts is your thing, I'd suggest buying a car designed to do them... rant over...

I deffinately would not replace the whole thing, meaning the half shaft, that would be over kill in my book. i'd replace the CV joint and make sure that you torque the bolts right and make sure that they are the right length.

Paul

Re: ...
 

I've seen lots of loose 911 CV bolts. The threads have to be totally clean and then tightened in a star pattern.

These car were designed to be driven, even raced, but drag race starts on these cars is simply abuse because they aren't designed for it. The clutch will slip before the tires will. In the case of pre-'72 cars with their 901 transmissions, 1st gear hangs off the end of the mainshaft. As a result, drag race starts in first may may snap the end off the mainshaft.

-Chris

Same thing happened to me about a year ago, but two of the bolts sheared off in the trans hub. Now CV inspection and checking the torque is part of my monthly maintenance routine. This just happens all too often.

...
 

Here are some clips of people who disagree with the rest of you.

http://www.sunflower.com/~kcmoore/911burnout.mpeg
http://www.sunflower.com/~kcmoore/911burnout2.mpeg
http://www.sunflower.com/~kcmoore/0-160.mpeg
http://www.sunflower.com/~kcmoore/modena.mpg

"Here are some clips of people who disagree with the rest of you"

Justifying stupidity doesn't make it right. Very few cars were designed for the abuse of a burnout, it appears from your comments about a similar problem with a BMW that you do not own one of them. But what the heck, its your money, abuse away but you may want to migrate towards a Mustang or such

Dude, you need to get a ride in a track prepared 911 by a fast driver on a scary track sometime, that will shut your ass up in a hurry. Without even doing any burnouts. :rolleyes:

I used to judge a performance car by its ability to roast tires, when I was about 16-18, yeah, the less traction the better the performance, right?

Once again, these cars became famous for not breaking in hard core endurance racing situations, like 24 hour flat-out races, but the right idiot can break anything.

We've helped you through some pretty mind-boggling ignorance already on this board, what's the use if you won't listen? :cool:

EDIT: I apologize for the tone of this post, but I am going to leave it up so that everyone can see an example of how not to address a fellow BBS member.

Hey KC....is your car actually *running*?
Last time we heard, I thought you timed it to run on 3 cylinders(?)

Anyway, drill the bolts and safety-wire them.
Enjoy the burn-outs. You'll be asking us about a clutch next.
;)

I repacked my CV's a couple of months ago (okay, only 1K miles). Past weekend I checked the axle bolts and was able to tighten the right side (300+ foot-pounds or me hanging on the cheater bar 2 feet out). All the CV bolts were at torque spec - the G50 bolts are a little bigger and torque tighter.

Like Paul says, it's something on the annual check list...

The bolts backed out on mine a few years ago and did the same thing, a big bang coming out of a parking space, breaking my starter off the motor. I attribute it to pulling my motor and trans out myself a couple of years prior. Speaking to some Porsche mechanics, those bolts must be torqued properly, and really tight, or they will back out. It's supposed to be fairly common knowledge. I just tightened them like normal when I put the whole thing back together. Nevertheless, I just bought all new bolts and washers, and replaced them all, and torqued the hell out of them the second time around. Double check them a few months later to make sure they are still tight.

burn outs......I don't know what to say. Sounds like a Corvette guy in out midst. Big Daddy meets Ferggie...sad. the old man is probably lookin down on you sayin. " I hope his axle snaps"

Nevermind.
 

Okay. I just want to get something clear before I make my pact to never post on here again. I don't make a habit of doing burnouts, or even try to. I simply "got on it" a little too much last weekend after installing the new muffler. I'm sure NONE of you perfectionists have EVER made the tires chirp.

Yes, the car is running, and running well. I learned a lot from SOME people, while taking it in the crotch from others. No matter how smart or skilled I might become in this world, whether it's in my computer field or working on my 911, I can honestly say I'd never call anyone an idiot or stupid for making a mistake due to ignorance of the situation.

I think it's sad how most of you are so quick to criticise and how quickly you forget that you were once in my position.

Hey KC, don't let them get you down. I've noticed more vitrol on the BBS as of late, must be something in the water...

Common Knowledge? I gotta check my CV bolts I had know idea.

You got whacked by lots of people (myself included) about the cam timing. You deserved it. But this? I think the winter weather is getting to some of these people. There are also unnamed curmudgeons who aren't nice to very many people.

During a road trip, the bolts in one of my CVs let go just like yours. Inexplicable. It destroyed the cooler on my 915 euro trans and parked the car for a month while my wrench scratched his head trying to figure out how to fix it without ordering a cooler.

Burnouts? Hell, we've all done at least one.

'that will shut your ass up in a hurry'
'We've helped you through some pretty mind-boggling ignorance'
'Justifying stupidity...'

While I don't necessarily subscribe to burnouts being my thing, and sure, I agree they aren't the best way to care for your car, and that tracking your car is seen as the 'mark of a real driver' around here, still the fact is not everyone holds the same view. That's cool. Everyone can hold a different point of view. We should all be able to accept that. But abusing people and challenging their sanity because they don't do what you do is...well.... :rolleyes:

The guy asked what the knowledge of the people here thought might be causing him problems. The answer seems simple enough, given his admission of doing stop light take-offs. No need to flame him though!

Don't forget many people think that spending heaps on a 911 then putting it into a wall at a race track is not their idea of sanity either.

I just hate to see people here getting flamed and driven away. Its like the HP junkies who always get crap nearly every time they post (although its changed a little over the past few months). People like Merv and Juan are posting a lot less and thats a shame. They were really pushing the envelope of performance and research. They are equally true pioneers of 911 development and that should be applauded. Sure it may not be going around corners smoothly and quickly but all the same it a love for the marque and all that it can be......my rant over and flame suit on!

Opinions are one thing, abusing people because they see things diffrently from you is another...chill out!

oh bugger.......

I typed that last post an hour ago but couldn't send it because I want time to think it over. Obviously I took too long and the inevitable happened.....he's off.

That's a shame.

I'm on KC's and expathk's side. No-one pedals these cars like an old lady on a bike... Unless you bought the car to admire it sitting in the garage. To me, the greater car abuse is running it on a track. I'd rather run it hard on a country road for 10 minutes than toast it on a track for an hour. My humble opinion. Notice I didn't even use the terms "stupid" or "ignorant".

Ok my hang up is no insurance or rather not full coverage . I prefer to protect my rides the best possible way. I am 27 with a 914-6 and 911s and yes I have done a burnout once or twice but thats not were its at. Going fast at an auto cross or whipping some corvette out on the track is were it counts. I would tend to agree with staying away from the burnouts and drive the car the way it was meant to be driven. Besides a porsche doing a burnout is kind of dumb as compared to a LS6 chevelle doing one.

Ben
75 914-6 (2.7)
77 911s (3.0)

Ever notice the guys at a CART race pushing the car away from a pit stop? And every season, some guy pops the clutch after a stop, and poof! vanishing driveshaft peices! Driveline shock needs to be managed carefully. Nature of the beast.

Burnouts? Not my cup of tea, but that doesn't mean I haven't "tried" them!

To me, the bottom line here is that some guys are road racing their P cars, some are tracking them, and it appears some, (at least one!) does the occasional burnout.....and to me, all is good with the world. As long as the posers aren't driving them I'm happy!

OK, I apologize to KC and anyone else whom I might have offended with that post. Sometimes my Irish temper erases my manners for a bit, and I should restrain from typing. As has been said before, internet communication leaves a lot to be desired sometimes and I must choose my words more carefully.

Funny thing is that I do not dislike KC in the least, he seems like a nice guy and probably fun to party with. (Though I kind of doubt that he feels the same way about me). And furthermore, I have a soft spot for muscle cars and tire smoking, but 911s are not the cars to do it in. Our cars are every bit as much fun as any overpowered Detroit iron, just a different flavor. I reacted to the insinuation that anyone who advises against 5000rpm clutch popping from a standing start does not "drive these cars as they were intended". That is ridiculous, and a track session would change that mind, but I could have said it nicer. So, sorry once again about that.

And I did learn something myself from this thread, I am going to check the torque on my CV bolts from time to time. Take care, :cool:

KC Moore,
Don't let it get to you. I got the sharp end of the stick here before. I left for awhile. But the plusses outweighed the minuses, so I came back. Let them make fun. Ignore them. Big Dogs don't have to bark at Small Dogs.

apologies accepted.
 

Here's a video clip of what I do with my Porsche. Unfortunately I don't have access to a track or have the time for it. Most of this video was shot during work hours, because I travel all over Kansas to fix computers for my company.

http://www.sunflower.com/~kcmoore/porsche_test.wmv

It's 20 megs, so 56k people will want to dl'it at night.

And none of the CART guys or IRL or NASCAR or...... Ever spin the tires when leaving the pit. That's right, nice smooth takeoff, no slip and slide...
And lets not forget the smooth and silky transition in torque during shifts...

Just souds like a maintenance issue. If PV hadn't jumped on it, it prolly woulda backed out on the interstate, or god knows where...

I really like the safety wire idea. I wouldn't have thought of it.

KC can do what he wants. Personally I did one burn out in my P-car and that was immediately after having to replace the half shaft after three bolted sheared off and the axle dropped. It was for test purposes. I would much rather feel the acceleration from second through 4th. But that is just me.

CART, F1, IRL, NASCAR, sure those guys do burn outs leaving the pits. But they're not driving 20+ year old cars and the cars are gone over with a fine tooth comb after each run. So when you see these guys shearing drive shaft components with new top $$$ parts, you know the drive train takes abuse. When the parts are 20+ years old you can't expect them to hold up.

The price of dropped axles is the cost of off-the-line rapid acceleration.

that's a really cool video KC.. and stick around, sure there might be some bad apples but that doesn't make the whole batch bad.

Cool video!

I can vouch for the Irish temper :)

We didn't get knicknamed the "fighting Irish" for nothing?
Always punch first, then ask questions.... hard to get that out of your system. Denis you're a bad boy! But a man for apologizing!
When us Irish do spout off it's not intended to be personal, please don't take it that way...... right Eric?
HAH HAH HAH HAH, Just messin with you Eric? Hah HAH hah

You guys are so, so harsh.

Yeah, popping the clutch and doing burnouts is hard on the car (I never do it - I don't want to pay for my fun). I figure KC probably already knew that.

Every time I've been to my local Porsche races, I watch 30 of them drop the clutch on the start line for each race. Each driver training I've been to, I've watched people running a figure 8, tyres spinning, bouncing off the rev limit, etc. The cars are fine.

I don't do it, but I'm willing to bet the 911 is not really any more fragile (the 901 gearbox aside) than most... doesn't RarlyL8 do this sort of stuff semi regularly?

(edit) Just watched the video (which is all class!) and KC doesn't do anything most Porsche owners I know don't do all the time. The "burnout" at 1 min is only squealing the tyres a little - its not a 6,000rpm clutch dump.

You should have seen the disgusting abuse I give (gave?) the BMW all on the basis it is a race car....

By the way, I really have seen a broken axle (on a '73 Lotus Elan +2). It had been converted to proper CVs and axles (not the dodgy Rotoflex it originally had) and one of the axles sheared - there must have been a weak point. Owner was doing exactly what KC did at the 1 min mark...

Love the video KC.