Lotus Elan and Lotus Elan Plus 2 Forums

Hi All
Looks like I have broken a billet shaft,is this a first or has it happend to others. This shaft was fitted in 2018 when I noticed one of my original shafts was not an updated stronger one.
Any ideas on how to remove the broken part with a diff insitu. Will have to investigate further today to see if diff needs to come out. Should have left well alone.

soory to read that : if/when convenient please post photos to document the failure for future reference (also mention the circumstances : use, tires, upgraded engine etc.)...

I’m no mechanical expert but I’d have thought it would be possible to do tge job with the diff in situ. Once you remove the circlip you will need to somehow give the shaft a bit of a whack to get it out of the diff. Doubt you’ll have much room so you might have to rig up something to extend the shaft away from the diff to give you a chance. Maybe you’ll be lucky attaching a pair of molegrips and tapping on them until it pops out.

Putting a replacement back should be easy by comparison.

When you remove the spider end with the bearing, examine the fracture. If it is a clean break, you may be able to remove the splined stump with a strong magnet.

However, if the break is in the splined section, It will most likely break into two conical faces, with a mass of triangular bits of teeth falling into the diff oil, which will have to be removed, if they have not already damaged the diff gears.

+1 to what Foxie said.

I've done this job before and it is possible, providing the break is just 2 pieces.

Roger

Panic over guys

Feel embarrassed due confusion between me and my helper there is no breakage

sorry but I am much happier,

Great to see the quick responses and help Thanks

I was following this to see why and how a billet axle could break. Thanks for the update.

What made you think it was broken?

I had one break. No idea of where it was from or how old it was. I replaced it with a later OEM one in good condition. No trouble since then.

I removed the broken section with the diff in the car. Slide hammer to remove the bearing and rest of the shaft, and to remove the good one on the other side. Then used a drift to knock out the broken bit. It was a clean fracture and no extra bits to try and find. I did flush the diff with fresh oil to be safe. Bit of a pain, and the only time the Plus 2 has left me stranded in 5 years.

Slight topic drift, but as an Electronics guy, I never understood this 'billet' business.

I thought the strongest parts were made by forging, as the grain boundaries followed the shape of the finished part as the forging process 'squished' the material into the correct shape.

If you start off with a solid billet (which I guess is advertising code for stock bar material), then machine your part out of this, then you are cutting across grain boundaries, which surely must be weaker than a forging.

Is the term 'billet' used to differentiate the part from an item that has been cast? I can sort of see that it is harder to control the quality of a cast part than something that started off as a uniform slab of material.

Thanks,

Andy.

Andy,

As an electronics guy you are extremely well informed. Items that are forged are just as you say, and the forging has directional properties, of course the grade of material used also has an effect.

Richard Hawkins

While not an engineer, I have some knowledge in this field. I think the important bit is understanding where the most highly stressed area is. The spline teeth are the the highest stressed (where they end engagement with the diff female spline), but are not easily forged. The root of the spline and the adjacent small diameter shaft is next in line. The grain
of a HRS billet runs along the axis of the base material so is aligned with the spline, and reacts similar to a forged piece. Fully forged would be slightly stronger due to the grain following the teeth, but not economically feasible for a low production part.