Half-shafts

Post by **dunketh** » Fri Sep 16, 2005 3:12 pm

Hi, I've got a 1966 moggy - a 'new' one buy morris standards I guess!

I remember reading somewhere that the weak spot in the half shafts is where there's apparently a 'step' down to the cut splined bit in the box end. Mine don't have a 'step' here - the spline is just cut straight into the shaft. Is this right?

Also, is it worth fitting hardened shafts as a pre-emtive fix - rather than replacing standard ones when/if they break?

Also, how weak are standard shafts? There seems to be a lot of conflicting opinion about this..

I know thats a fair few questions for one post but I'm new to minors so thats my excuse!!

thanks
jon

Post by **KirstMin** » Fri Sep 16, 2005 4:16 pm

Well my 1966 didn't have any problems with standard half shafts in the last 15 years of me driving it and the 20 years before that of my parents before me. On a standard 1098 engine with 48bhp I cant see HOW it's possible to break them - i did my fair share of trying in the first few years of my licence

. Ive recently upgraded to a 1275 engine and put toughened ones in that are apparently good for 70bhp or so. After that it depends on how hard you drive.

Post by **Willie** » Fri Sep 16, 2005 5:54 pm

There was nothing at all wrong with the original half shafts, it is
just that many of them have done many many thousands of miles
and all mechanical things eventually wear out!! The ridge you mention
would be found on the actual splines and is a consequence of the
splines rubbing on the planet wheel in to which it fits....again normal
wear and tear. The same half shafts were used in the Riley 1.5 cars
and were quite capable of handling the increased power AT THE TIME.
If you happen to see the pronounced ridges on the splines then you
have been warned, and NEVER swop them over to the other side!

Post by **bmcecosse** » Fri Sep 16, 2005 9:09 pm

I did break one many years ago - but I was autotesting the car at the time - with massive rear axle tramp !

Post by **Peetee** » Fri Sep 16, 2005 9:16 pm

It's worth checking your halfshafts for visual wear as even a mildly modified 948 can break worn shafts. I believe a standard shaft can cope with 70bhp and a hardened one 100bhp.
Eliminating axle tramp will go a long way towards preserving halfshafts as too will running standard width tyres. It is the torque of the engine or more specifically the resistance created by the grip on the road (tractive effort) that twists the shafts and causes failure.
I raised the comment some time ago about the right angle cut on the spile of the halfshafts. I suggested it was a stress raiser and should have had an additional 45° face or radiused cut.

Post by **KirstMin** » Sat Sep 17, 2005 9:53 am

Peetee wrote:It's worth checking your halfshafts for visual wear as even a mildly modified 948 can break worn shafts. I believe a standard shaft can cope with 70bhp and a hardened one 100bhp.

that's interesting because as I understand it from others on this site the hardened ones will cope up to 70 or so and not 100. But I guess they would cope with whatever bhp if you drove with a light foot. Not bmcecosse by the sounds of it

Post by **plastic_orange** » Sat Sep 17, 2005 11:43 am

I used to break half shafts with great regularity on my MGB engined minor (highly tuned - reputedly 130 bhp - before dynos were the norm) which had a Riley 1.5 axle. I always took a spare diff and shafts with me when I ventured any great distance - ie car meets in south of England. When I ran out of Riley parts, and just before I changed axle to Capri 3 litre, I used minor shafts and never broke one!! I think this is because they probably had a bit more reserve of strength left in them compared to the riley which obviously had more power and torque and therefore fatiqued them more. If you are seriously worried, then I suggest upgrading to Ford - it's not hard or expensive.
Incidentally, my wife's minor with mildly tuned 1100 totally exploded a riley diff resulting in a ruined axle casing, so it's really down to luck.

Pete

Post by **rayofleamington** » Sat Sep 17, 2005 1:04 pm

so it's really down to luck

yes! I've abused a lot of Minors and never broken a halfshaft!

Post by **aupickup** » Sat Sep 17, 2005 1:32 pm

nor me

Post by **Willie** » Sat Sep 17, 2005 4:35 pm

I had a less than six years old Traveller which I used to tow a large
boat full of diving gear to Scotland from London and back and a
shaft snapped three weeks later!

Post by **Cam** » Sat Sep 17, 2005 11:24 pm

I've never broken one either, but if you need more poer handling capacity then as Plastic_Orange says, upgrade to a Ford unit. The Mk2 Escort one I have has RS2000 halfshafts and can apparently handle 170 BHP! So I have plenty in reserve.

As an aside, my grandad bought a brand new Ford Anglia and snapped a halfshaft almost straight away! After that, he vowed never to have a new car again.

He never had a Ford again either!