[kwaku415]

My brother has a 2014 535ix and took it to the shop to get the front right axle replaced because I found out the CV Boot was torn after seeing the axle shaft seal in the driveway. I made him stop driving after seeing the shaft seal in the driveway. I bought the axle off FCP Euro with the bolt and axle shaft seal. I know 100% that the axle shaft fits. I got in a car accident recently and I can't work on it myself. The mechanic replaced it but used the old bolt and didn't install the new axle seal. Not my car so not sure how much he drove or how hard, but I drove it the next day or 2 and it was making a lot of noise take it back to find out the axle snapped. Just trying to see if anyone would know why and if it was the driver's fault or the mechanics. Wouldn't the differential leak when the axle seal is off causing it to lock up?

[ChiltiCoatl89]

To clear things up, originally it was only the CV boot that was torn? and before it got replaced, the Axle itself was not broken correct? I would not put any of it on your brother and would check the install from the mechanic and check other hardware surrounding the Axle for sure. Sounds like possible improper installation, (Thankfully FCP Euro will replace the part if all else fails on your end.)

[kwaku415]

Yes, only the CV boot was torn the whole axle was not broken and was still intact. The mechanic was trying to say I bought an aftermarket axle that didn't fit, which I knew wasn't the case. I bought the GKN one which is what BMW uses and have the same brand axles I have on my 3 series which hasn't been changed since the factory. My brother eager to drive his car and not being aware of my warranty gave into whatever replacement they were using ($150 total for the 2nd axle ��*♂️) without telling me first. Didn't matter anyway cause that one snapped a day later also. To add, I still even have the axle bolt and shaft seal that they didn't use from the first one. Also, the differential and everything around it didn't leak or throw any codes.

[ChiltiCoatl89]

Any update on your COA (Course of Action)?

[kwaku415]

Originally Posted by ChiltiCoatl89

Any update on your COA (Course of Action)?

I spoke to the mechanic one last time just asking questions, and he ended up admitting that he doesn't have the proper lift that allows him to spin the wheels when it's in the air and we'd probably have to take it to the dealer. (Shouldn't have taken the job if he couldn't handle it) I gave my brother my opinion and said if it wasn't broken to begin with and it broke twice after that they're probably the culprit, and he needs to stop treating his beamer like his old Mazda cause he told me he topped up the oil twice. He has a friend with an F10 and got this mechanic who does European cars and we got in contact. But after a look at the engine bay and testing the engine mounts, I noticed his OFHG was leaking told him about it and how catastrophic it could be and he probably brushed it off. To be fair he's not the best when it comes to maintenance. The belt snapped and you know what comes with that. Got quoted 1500 for the installation of the axle and inspection of the oil pan and everything that comes with a shredded belt. So yeah, the axle is the least of our worries now but, I'm getting the warranty replacement from FCP Euro. I appreciate you for your help, when this is all over I'll let you know the actual reason.

[kwaku415]

Originally Posted by ChiltiCoatl89

Any update on your COA (Course of Action)?

No pieces of belt got into the motor and he didn't charge for the axle he said the previous mechanic didn't tighten it all the way.

[ChiltiCoatl89]

If you can get that Engine back 100%, Highly recommend he installs a Crank guard, its about 70-150$ bucks depending on who makes it and they also have crank bolt capture, so the belt will never get inside again! The Tech should have known to have torqued it to spec! why didn't he tighten it all the way in the first place?

[John H.]

Make sure to order a new axle bolt, as they are one-time use only.

Yeah, find a new tech to work on your vehicle.

Yup, GKN is OEM.

[Unspec]

The wheel does not need to spin to install an axle properly. You can do axle replacements with a normal jack. My bet: mechanic did not properly torque the bolt for the axle. It's quite a hefty torque spec, and due to not having the BMW repair manual the mechanic just gave it a couple of hits with an impact and called it tight enough rather than properly torquing it. Due to direction of spin of the wheels, the bolt then loosened on its own since it did not have the proper torque (this is why Porsche center locks on the passenger side are lefty tighty righty loosey). That then introduced play in the splines, and every time your brother accelerated the axle's wheel-side splines essentially hammered against the splines of the suspension carrier. Axles are not designed for this kind of shock forces and and eventually the shock fatigued the axle enough to just snap.

I would look into replacing the entire suspension carrier to be honest, since if my theory is correct, the carrier's splines are likely damaged as well due to this hammering.

Also as a quick aside, GKN is not OEM. It is OE, a step above OEM. OEM means they directly make parts for BMW, but not necessarily the literal part. OE is the exact same part that would have been used by BMW during assembly, but with the BMW logo removed. In terms of replacement parts hierarchy (and thus price tbh), it goes:

1. Genuine
2. OE
3. OEM
4. Aftermarket copies