355 Ball Joint Failure on 6k Mile F355

WOW - You are lucky a spark did not ignite all those magnesium shavings from the wheel! Pretty car.

 

OEM ball joints don’t have the castled nut with the pin. That’s a factory part.

 

In order to re assure 355 owners that typically these front ball joints are very strong when at correct torque, the one that remained on the lower arm when the hub shown detached from the 355 in an accident, looked as good as new when I checked it, the hub failed first in that scenario.

I have a used front ball joint somewhere, when I find it I will take a pic to see how normally waisted the shaft is at the point where it attaches to the ball.
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Here you go - you can see the narrowing of the threaded portion


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Glad your safe!

That’s some interesting pictures. Been a long time since I did metallurgy, but I’d go with a fatigue failure from lack of tension.

Be good to get a metallurgy guy to have a look at that.

 

While you're under there, look for anything that looks like accident damage. Maybe the body shop forgot to tighten a nut.

sjd

 

Sorry to hear about what happened (and glad no one was hurt), but an interesting thread for sure.

I was checking your car out at LRP on Sunday; a rubino 355B with 6000 miles isn't something you see often! Hope you're back on the road soon.

 

Edited my reply as your pics had me intrigued so I went off hunting.

Both the damaged and spare hub I have here are circa 23mm, so either the collar is a press fit into the hub and is missing from both of these and still attached to the old ball joints or there were changes during the life cycle of the 355,

Next stop is the eurospares website to see if they list different part numbers for the ball joint depending on year, or if they list a collar.

A pair of hubs I previously fitted to a car accepted replacement ball joints so either I was lucky to match everything up without realising or there were changes.

 

In looking at your picture it appears the collar is still in the passenger side hub and the failed side collar is seized to the broken stud of the joint.

 

You are probably correct but the failed side also looks to have been machined to properly fit that collar. I also had looked at the parts drawings and nowhere does it show a collar. Weird one for sure.

 

According to the eurosprares website there were a number of revisions to the knuckles on the 2.7 versions during their life and then 2 types for the 5.2 versions depending on whether for Bosch abs or Teves sensors fitted.

The two in my pics are from a 96 spec 355

Interestingly there is only one part number for all versions in relation to the ball joint, so I guess it just means the threaded part slides further up depending on which hub is fitted/width of hole in the hub.

No inserts listed for any of the hubs.

Also interesting is that eurospares sell a pattern ball joint which has a castle nut!

Sounds like you have one spec hub on one side and a revised version on the other, probably just using up stock at the time when it was assembled.

The hole in the hub pic does look smaller on their website as if a collar is fitted.

Given that all the other significant holes in the hubs do have inserts/collars though it would seem like the hole for the ball joint would also have them.


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This is bizarre, it looks like you have 2 slightly different uprights, and rather than source the correct ball joint for each, an adapter was made to fit the same ball joint on both sides - and there does not appear to be enough shoulder on that nut to properly hold the thing together, unless there was a (now lost) washer under it. The odd part is, on a 6000 mile car with no known work in that area, it appears to have been a factory boge, but you'd think they'd just grab a matching upright or another ball joint as opposed to machining an adapter bushing....What year is the car?

 

Pete, there is only one ball joint available for all the 355s its been superseded though twice for some reason, but its the only one available for all the cars
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If you look at the picture Paul500 posted of the hub the three holes do look like there is some form of pressed in collar (especially in the hole at the top of the hub). Could account for there not being any separate listing for it in the parts manual. Could it be to prevent seizing of the stud to hub due to different metals since the joint is a replaceable item? Just speculating.

 

There is a collar inserted on the wheel hub for the lower ball joint, upper ball joint and the steering tie rod.

In the pics the OP posted the sleeve is still in the steering knuckle and the broken ball joint had the sleeve still on the shaft.

When I removed my lower ball joint with a press one of the sleeves came out the other stayed put.

I have my steering knuckle out right now and the upper replacement ball joints came with new sleeves to press in.

 

last 6 of the vin? I can check mine if it's close and see what's on there, mine is 100329.

 

Could be that the collar is inserted before machining. Are there machine marks on the collar that came out with the broken ball joint?