[zole2112]

Yes, I owe an update.
When I went to install my axle this time I found the axle support bearing bracket was broken. When i went to replace that I found that 3 of the 4 bolts were loose so I suspect that this was at least part of the root cause of this failure. In addition I found that my camber was off on that side as well, it was off in a positive position but I can't say exactly how much, I adjusted this back to match the other side at neutral. I will be getting an alignment in spring. In addition I changed my motor mounts, they were not what i would call bad but slightly softer than the new ones so that would mean more movement than stock so I think changing them was a good thing.

All of this aside, when i found that broken axle support it makes me wonder if it had a crack ever since I had my accident, destroyed the right front, and it allowed play in the axle although I didn't notice it before.

So at this point, since I found at least 1 other guy with an xDrive that is lowered more than mine, I believe that there were a combination of factors that led to my issues and I have addressed them all.
check post #58 https://f30.bimmerpost.com/forums/sh...1495834&page=3
I also found another thread with a guy who blew out 3 axle cv joints like me, the consensus over there was motor mounts. https://www.e90post.com/forums/showthread.php?t=1256676

In addition I found a video on youtube from Kies Motorsports where he blew out an axle on his xdrive F30 when he tried modding with F80 control arms which affected camber significantly.

Lot's of info there. I feel pretty good about where I am now, the last failure occurred after 4 months of no issues and that one was pretty clearly due to the support bearing bracket breaking. As soon as it's warm out I will be putting it on a lift to inspect it again and to collect some more measurements to compare to the spare axle that i have.

[alexng72]

Originally Posted by zole2112

Yes, I owe an update.
When I went to install my axle this time I found the axle support bearing bracket was broken. When i went to replace that I found that 3 of the 4 bolts were loose so I suspect that this was at least part of the root cause of this failure. In addition I found that my camber was off on that side as well, it was off in a positive position but I can't say exactly how much, I adjusted this back to match the other side at neutral. I will be getting an alignment in spring. In addition I changed my motor mounts, they were not what i would call bad but slightly softer than the new ones so that would mean more movement than stock so I think changing them was a good thing.

All of this aside, when i found that broken axle support it makes me wonder if it had a crack ever since I had my accident, destroyed the right front, and it allowed play in the axle although I didn't notice it before.

So at this point, since I found at least 1 other guy with an xDrive that is lowered more than mine, I believe that there were a combination of factors that led to my issues and I have addressed them all.
check post #58 https://f30.bimmerpost.com/forums/sh...834&page=3
I also found another thread with a guy who blew out 3 axle cv joints like me, the consensus over there was motor mounts. https://www.e90post.com/forums/showthread.php?t=1256676

In addition I found a video on youtube from Kies Motorsports where he blew out an axle on his xdrive F30 when he tried modding with F80 control arms which affected camber significantly.

Lot's of info there. I feel pretty good about where I am now, the last failure occurred after 4 months of no issues and that one was pretty clearly due to the support bearing bracket breaking. As soon as it's warm out I will be putting it on a lift to inspect it again and to collect some more measurements to compare to the spare axle that i have.

How high are you actually from the ground to your fender?
I'm 25" from the ground and haven't had any issues since i lowered it.

[zole2112]

Originally Posted by alexng72

How high are you actually from the from to your fender?
I'm 25" from the ground and haven't had any issues since i lowered it.

I'll have to measure it when I get home but I have 255/35/19 tires which are 26" and I am about 1" above that so I should be at a fender height above the wheel of about 27" with the center of my hub at 13". The difference between the 2 is what determines the length between the hub and the differential.

If you don't mind and you get a chance could you measure the height of the bottom of your differential from the ground and also give me the height of the center of your hub? I'll do the same. Then I can compare the 2.

As we lower the car the differential drops while the center of the hub stays constant unless you change tires/wheels. What I'm interested in knowing is the length of C in my drawing. As I lower my car further the difference between the differential height and the center of the hub gets greater, shown as B. As B increases, C increases as well (remember A squared + B squared = C squared).
As C increases in length the point where the CV joint, tripod bearings, rests moves out away from the differential.

Ok, anyway, what I want to know is at stock height where do the tripod bearings in the inner CV joint sit. If I know that then I can calculate where they sit as I lower the car.

[alexng72]

Originally Posted by zole2112

I'll have to measure it when I get home but I have 255/35/19 tires which are 26" and I am about 1" above that so I should be at a fender height above the wheel of about 27" with the center of my hub at 13". The difference between the 2 is what determines the length between the hub and the differential.

If you don't mind and you get a chance could you measure the height of the bottom of your differential from the ground and also give me the height of the center of your hub? I'll do the same. Then I can compare the 2.

As we lower the car the differential drops while the center of the hub stays constant unless you change tires/wheels. What I'm interested in knowing is the length of C in my drawing. As I lower my car further the difference between the differential height and the center of the hub gets greater, shown as B. As B increases, C increases as well (remember A squared + B squared = C squared).
As C increases in length the point where the CV joint, tripod bearings, rests moves out away from the differential.

Ok, anyway, what I want to know is at stock height where do the tripod bearings in the inner CV joint sit. If I know that then I can calculate where they sit as I lower the car.

I don't mind doing for you but I don't know if i can get under the car to measure from the diff though. Your post is very interesting since we're looking at it from the view of engineers. I'm in school to be an engineer too and having someone like you to have a conversation makes me so excited haha. Anyway, I'll try my best to get the measurement and I'll post it up asap.

[Marlinman]

Wow, that's great information! Sticky material! Thanks.

I wonder if I should take a look at my motor mounts now.

[zole2112]

Originally Posted by Marlinman

Wow, that's great information! Sticky material! Thanks.

I wonder if I should take a look at my motor mounts now.

How many miles on yours?

[zole2112]

Originally Posted by alexng72

I don't mind doing for you but I don't know if i can get under the car to measure from the diff though. Your post is very interesting since we're looking at it from the view of engineers. I'm in school to be an engineer too and having someone like you to have a conversation makes me so excited haha. Anyway, I'll try my best to get the measurement and I'll post it up asap.

Thanks man, I'll be measuring mine but I may wait a few weeks until it gets warm unless I can get on the lift again in the meantime then I can measure it inside a nice warm shop lol.

That's cool you're going for engineering, my son is in his junior year for Mechanical Engineering too. I've discussed this many times with our top ME at work, he's into working on cars as well so I love having his input.

[Marlinman]

Originally Posted by zole2112

How many miles on yours?

sitting just below 105,000 miles currently

[zole2112]

Originally Posted by Marlinman

sitting just below 105,000 miles currently

I figured to change them anyway before installing my turbo. They are not expensive and pretty easy to change if you have a lift. I have 88k miles on mine

[Insane435]

Did you get an alignment after install? When you change the height of the car, it needs to be aligned.

[zole2112]

Originally Posted by Insane435

Did you get an alignment after install? When you change the height of the car, it needs to be aligned.

I did not. I know, dumass move. I was going to have it done but I procrastinated and then it was winter. I will be getting it done in the next month as soon as it warms up.

[Insane435]

Originally Posted by zole2112

I did not. I know, dumass move. I was going to have it done but I procrastinated and then it was winter. I will be getting it done in the next month as soon as it warms up.

That could be your problem, when you drop the car, the camber changes, although now that i think about it, i dont think you can change front camber.

[zole2112]

Originally Posted by Insane435

That could be your problem, when you drop the car, the camber changes, although now that i think about it, i dont think you can change front camber.

I will definitely be getting an alignment as soon as I put my summer tires on, I am so sick of snow and ice. I have an adjustable camber plate on my coilovers so that's good. It'll be interesting to see where the camber is now vs spec. I set the camber in the neutral position on the plate but I don't know what the translates to exactly.

[Insane435]

Originally Posted by zole2112

I will definitely be getting an alignment as soon as I put my summer tires on, I am so sick of snow and ice. I have an adjustable camber plate on my coilovers so that's good. It'll be interesting to see where the camber is now vs spec. I set the camber in the neutral position on the plate but I don't know what the translates to exactly.

I see. Yea that could very well be your problem. Too much negstive camber will break them. Just like when people put on f80 control arms, it breaks the axles.

I think getting an alignment to spec will solve your issue. Best of luck!

[zole2112]

Originally Posted by Insane435

I see. Yea that could very well be your problem. Too much negstive camber will break them. Just like when people put on f80 control arms, it breaks the axles.

I think getting an alignment to spec will solve your issue. Best of luck!

Thank you!
I saw the Kies Motorsports vid where he intalled the f80 control arms on his F30 xDrive and immediately blew out his right inner CV joint. I want to be confident that I find the root cause before installing my turbo this summer although I saw absolutely no indication that my torque level with the stock turbo had anything to do with the axle failure.

[Insane435]

What tire sizes do you have?

[zole2112]

Wheels are 19 x 9.5 with 20mm offset, Tires are 255/35/19 all around.

Without my stiff suspension I was rubbing the rear tires on big bumps, the front had no issues with that size. There is about 3/4" between the struts and the tires in the rear, in hindsight I could have went with a larger offset and then used a spacer to move the tire out to maybe 3/8" from the struts and it would have tucked a bit more under the rear fender

[Jayeshwar]

hey guy I need some info on how to deal with this problem. for the past week I ran thru 3 front axle passenger and driver, and on airlift performance bagged on my 2013 BMW 335i xdrive f30, is there any better possible solution? is custom axle a better choice for bags? please help me thanks

[zole2112]

Originally Posted by Jayeshwar

hey guy I need some info on how to deal with this problem. for the past week I ran thru 3 front axle passenger and driver, and on airlift performance bagged on my 2013 BMW 335i xdrive f30, is there any better possible solution? is custom axle a better choice for bags? please help me thanks

How low are you? My axle was blowing out at the inner CV joint passenger side only but it ended up being due to a cracked bearing support which allowed the CV joint to dip low enough to allow the tripod bearing to pull out of the joint. Motor mounts can cause this if they're bad as well. If you're too low, which is what it sounds like since you blew out both sides, I think the only answer is to get a custom axle that is longer than the stock although I don't know how much longer since I haven't gotten my lift yet and am just about to finally start building my house.

[Jayeshwar]

Originally Posted by zole2112

How low are you? My axle was blowing out at the inner CV joint passenger side only but it ended up being due to a cracked bearing support which allowed the CV joint to dip low enough to allow the tripod bearing to pull out of the joint. Motor mounts can cause this if they're bad as well. If you're too low, which is what it sounds like since you blew out both sides, I think the only answer is to get a custom axle that is longer than the stock although I don't know how much longer since I haven't gotten my lift yet and am just about to finally start building my house.

tire to fender low right now, that what am thinking too do right to get some custom work done on the axle but in am in Toronto region, there not a lot of custom auto shop out here, but thanks for your input appreciate it

[Musashi]

Originally Posted by zole2112

Axle blew yet again. driving slow, about 15 mph immediately after turning a corner, just crazy. I am having a custom length axle shaft made and will be moving to that.

Has anybody else out there lowered their F30 xDrives? I can't be the only one to have done it.

Yes, Dinan springs F R 3/4" max as intended to prevent axle issues.. Done 2017... Zero issues but I stayed within spec...Both Dinan and BMW were clear ref axle risk for anything lower than 1.5"....

[zole2112]

I just realized I didn't come back to report the root cause of my issues. I found that I had a cracked bearing support on the Right Side axle which allowed the support to sag down enough that the tripod bearing was slipping out. After changing the bearing support I did raise my car some, I am leery of lowering it back as low as I had it before since I don't know how much tolerance there is when you hit 1.5" as Musahi mentions so I've been lowered about 1" since changing out my bearing support. No issues since then.