Front wheel bearing collapse

[freddyuk]

Has anyone had a complete front wheel bearing collapse ie. the outer bearing race has disappeared leaving the brake disc "floating" and held in place by the caliper???

This just happened to me on my E300 TD and nothing showed up on the warning lights. We had a loss of brake pressure but no other indication. I assume there is a dual brake system otherwise the car should have pulled violently to the nearside where the disc was floating off the stub axle. The outer bearing and nut has gone!

This could have been catastrophic??

Many thanks

Freddy

 

[Arnie]

...well, I'm afraid that there are no warning lights for the bearings; you must rely on good and regular maintenance, to keep them greased and adjusted.

 

[freddyuk]

Bearing failure

Sorry you misunderstood me - I do not expect any warning of a lack of maintenance. This was a fully maintained car wich effectively lost half its front bearings. The only sign we had was a punture and the brake pedal going to the floor but it could be pumped back up.The air had got into the system because of the fact the disc was wobbling.
I cannot give any other explanation but it was NOT lack of maintenance and we must have driven for some considerable distance because the first sign we had was the front tyre puncturing as it had rubbed through the inner tyre wall on the suspension!
I replaced the wheel and did not notice any other problem.
When we got home (another 200 miles) the brake problem arose.
I had the tyre changed and it was when i bolted the wheel back on that i noticed it was still loose after i had torqued the wheel nuts. I found the whole disc loose.
We then realised that the failure must have occurred some time before and we had no idea. No viabration and no brake pull to one side.If the caliper had given way on the motorway then i guess we would not be here now.



Freddy

 

[landover]

YOU MUST HAVE HEARD SOME SORT OF NOISE .IF THE BEARING AND OUTER NUT WHERE GONE. THIS SORT OF DAMAGE DOES NOT OCCUR WITHOUT NOISE. :wink:

 

[freddyuk]

Bearing collapse

Well please trust me if i had noticed anything or suspected anything like that i would not have driven up the M4 and then round the M25 at 70 mph!!
There was no noise that we could hear and no vibration.
There was eventually some loss of brake pedal pressure.

There should not have been any braking on the front near side wheel as the disc was just spinning so how come ? You would have noticed that surely. I assume there is a dual curcuit??

I am mystified.

Freddy

 

[Arnie]

This is very unusual as bearing failures usually make themselves heard long before complete failure occurs. Was it the original bearing or had some work been done recently, perhaps with overtightening of the bearing? It would require the inner cage to fail for the outer race to come off, and this could be due to lack of grease or overtightening. Normal wear would normally give more warning.

The reason you needed to pump your brake pedal more is that a wobbly disc would have pushed the caliper pistons further in, away from the disc surface, therefore requiring a couple of pumps (with little resitance) on the pedal to bring them back into close contact with the disc.

 

[jberks]

Presumably the disc and caliper would have remained attached, just not had any effect on braking. So why the loss in pedal pressure if the hydraulics were ok and the pad was still around the disc? I presume the ABS kept you out of a ditch when you braked, though with no braking on the nearside, I would expect it to pull to the offside. Did the ABS not go mad ?
It is harder to tell than a wheel is becoming detached than you would imagine. I always though that the steering would go and the car would shake, but when a muppet didn't tighten the bolts on my escort front wheel years ago, the effect was very subtle, despite half an inch of play. I only noticed when I got an odd rumble, which less mechanically minded people would have ignored. On a merc its probably almost unnociable. Guess its the centrifugal and gyroscopic forces.