Broken Drive shaft

will lyons · Jan 13, 2008

Hi guys

After returning from a great day out at the NEC pistonheads Autosport show and 2 miles from home I pulled out of the filling station a Little harsh but not too much as I thought then bang the offside drive shaft has snapped completely in two 1987 220 T

question is

are all drive shafts for manual cars the same
there is no drive to the nearside is the car fitted with LSD

gears engage correctly and i can feel the box driving but no power to either wheel obviously one side is broken but the other is fine or ..... has something more sinister happened in the diff part of the gear box as I did think the nearside wheel would power it seems I can get a replacement for about £50 and a couple of hours to remove and refit If I can find one I am hoping to have it done in the day

Wil

geoffbateman · Jan 13, 2008

Sounds like the diff is doing exactly what it should. With the drive shaft broken the broken side will rotate at double speed and the side with the wheel on will not turn because of the resistance. My guess is that you have a normal diff, not LSD. However I would not run in this condition for any more time than absolutely necessary. My guess is that if you replace the broken driveshaft all will be well as long as there was no other damage caused internally as a result of the failure.

Diver944 · Jan 13, 2008

PET shows the drive shaft for a Turbo is different to a Lux though they are the same either side.

You can look at PET online here:

http://www.porsche.com/uk/accessoriesandservice/classic/genuineparts/originalpartscatalogue/originalpartspdfcatalogue/

Take a look at the diagram in Section 5, illustration 501-10

will lyons · Jan 13, 2008

I have found one for the S2 would this be the same for the turbo or is it correct to assume the S2 would be the standard drive shaft as is the lux on the PET

will

Guest · Jan 13, 2008

ORIGINAL: geoffbateman

Sounds like the diff is doing exactly what it should. With the drive shaft broken the broken side will rotate at double speed and the side with the wheel on will not turn because of the resistance. My guess is that you have a normal diff, not LSD. However I would not run in this condition for any more time than absolutely necessary.

?? He can't "run in this condition" at all. If a drive shaft has snapped, the car won't move an inch.

zcacogp · Jan 14, 2008

If a drive shaft has snapped, you will have half a drive shaft flailing around underneath the car, causing huge damage to everything in sight.

Given that it isn't sounding like the car is being put through an industrial mincing machine, I'd guess that you DON'T have a broken drive shaft.

You may have completely lunched a CV joint, but I have never heard of sudden, total failure of these items.

Will - I'd get someone with some mechanical savvy to have a good look at the car, as soon as possible.

Oli.

Guest · Jan 14, 2008

Even if you can move and have a LSD don't! you will knacker the clutches in the diff

will lyons · Jan 14, 2008

Oli
It is a broken drive shaft I have been very lucky as it has snapped in the middle and I wasn't travelling very fast or high revs as I had only changed to second gear I let the clutch out a bit sharp so obviously the torque and friction grip of the tyre was too much for it but thanks for your concern it is much appreciated

It contained itself very well I now have a replacement which I will do tomorrow and post some pics on titanic of the broken one. I see in your site info youre a dab hand at these pitty you're so far away

Wil

zcacogp · Jan 14, 2008

Will,

Good that there is so little damage. I still struggle to see how a broken drive shaft can not cause major damage at any speed - due to the drive from the gearbox - but there we are.

Changing them will be pretty easy. Two points to note.

1. Make sure you have the right size spline drive, and that it is correctly inserted, before trying to remove the six bolts on each CV joint. You may well find there is crud in the heads of the bolts - a bit of WD40 is great to clean them out. (Mangle the splines in one of the bolts and the job becomes a TOTAL nightmare.)

2. When you are removing the CV's from the driveshaft, you will need to strike them pretty firmly with something heavy to get them to shift. A plastic mallet is the classic, but I have found that a metal hammer can be better (it gives a better 'shock'.)

Getting CV's off is messy, and the moly grease gets everywhere. Don't skimp on it when you re-assemble. GKN always used to sell tubs of the stuff, and one could be a good investment. (Cost a fiver or so - not much.)

Oh, and when you re-assemble, make sure you do those bolts up tight.

Oli.

geoffbateman · Jan 14, 2008

ORIGINAL: muddy

ORIGINAL: geoffbateman

Sounds like the diff is doing exactly what it should. With the drive shaft broken the broken side will rotate at double speed and the side with the wheel on will not turn because of the resistance. My guess is that you have a normal diff, not LSD. However I would not run in this condition for any more time than absolutely necessary.

Click to expand...

?? He can't "run in this condition" at all. If a drive shaft has snapped, the car won't move an inch.

Sorry for the ambiguity of the comment. It was just that he had been running the engine and engaging the gears, naturally without forward motion. To run a diff at 100% differentiation like that is not a good idea.

will lyons · Jan 14, 2008

Thanks Geoff.

It was only to diagnose the problem for AA recovery before they would send out a flatbed for it and at very low revs in each gear for piece of mind I had not screwed the gear box, I will know better tomorrow evening when I have replaced it but I understood your comment completely

Wil

will lyons · Jan 14, 2008

Here you go Oli

A picture for you very fortunate as it snapped only one inch away from the CV joint on the gearbox the other side obviosly did fly around until I stopped which was only a few feet.

wil

Guest · Jan 14, 2008

Certainly lucky the thrashing end did not take anything else out. When you have the bits off the car, I would be interested to see a close-up (macro) shot of the fracture. If it is a fatigue failure they usually start from a scratch or notch and you get a characteristic 'wave' pattern radiating out as the crack spreads progressively.

zcacogp · Jan 15, 2008

Will,

Indeed very lucky - had it gone any further from the gearbox, you would have had a big problem. And had it snapped while you were travelling you would have mangled a fair bit of the underneath of the car, and the suspension, and probably locked the wheel and quite possibly lost control of the car! You are a lucky person!

I'd be be interested in the beech marks as well - as per Muddy's comments.

Oli.

Diver944 · Jan 15, 2008

Blimey Will, you always looked such a gentle driver too [

]

That is the first pic I've seen of a broken 951 drive shaft, though you hear a few stories from the highly tuned US cars that do a lot of drag strip work. Apparently there is a GKN motorsport driveshaft for our cars that is very strong for super powerful race cars - don't know if it's available over here

zcacogp · Jan 15, 2008

ORIGINAL: Diver944

Blimey Will, you always looked such a gentle driver too []

Interesting - what does a gentle driver look like? [

]

Super-duper motorsport driveshafts probably come with super-duper motorsport pricetags. I'd guess that, given broken driveshafts are not frequent occurances, Will was unlucky in that it broke (and then very lucky in the mode of breakage!) It does make you wonder how it did happen tho'. An existing (manufacturing?) crack, which has rusted and extended over time? Someone careless in changing a CV joint sometime in the past managed to stress the end of the driveshaft? I notice it snapped at the end, where the shaft constricts and is shaped, which will be a natural stress-focus. Bet it's something like this ...

Oli.

will lyons · Jan 15, 2008

Interesting Oli

I checked history and it has had all 4 CV joints replaced by one of the independents I will not post it here but tell you when we next meet in case it was a problem, this was May 02 at a cost of £321.00 with 3 hours labour. How quickly did you do yours [

]

its not how long it takes though if the job is done properly as I am sure yours are with the detail report you gave [8|]

I had noticed over the last few days some ever so slight noise from the rear I had suspected a wheel bearing it was not the same noises I had heard from my old lux and it didnt go when slowly changing gear so not the usual whiny gear box noise, I wonder if the run back from the NEC had anything to do with it breaking ? temperature of CV and heavy pull away who knows I will post the close up pics when I have it removed and iif anybody wants the offending item to examine they are welcome to it.

Wil

will lyons · Jan 17, 2008

Its DONE phew !!!! everything seems ok and not as long to do as I thought it would be for me.

I have only moved a few feet after completing replacement I can now confidently reveal it was MASSIVE CORROSION

I am about to upload some pics to show how much almost 1/4 way through in what must have been a small crack initially hidden by the cv joint boot cover the replacement was a complete used unit but aas the cv joints I have are quite new I think I am going to change them over in the summer pics to follow shortly Now what did Oli say it may have been looks like you were correct again Mr Parker very well diagnosed [8|]

I can enjoy again and enter cotswold rally now its fixed thanks for all the help guys look forward to seeing you soon
Wil