Cracked tunnel behind bearing carrirer

[stgdz]

Cat probably knows about the cracks when you fix the driveshaft and it's likely the reason they don't put it on. There is likely to much variation that can happen on a manuf line, they probably proved this with validation testing.

They then likely rationalized not putting it on would be better than putting it on. The driveshaft becomes sacrificial at this point but the rider can still stop. They can't stop if the caliper rips out of the tunnel.


My method is used for torquing was the following
1)torque to 20lbs and do that at 90-180-270-360 degrees
2)torque to 25 and do that at 90-180-270-360 degrees
3)torque to 30 and do that 90-180-270-360 degrees

At the 180 and 270 torque sequences I could feel the screw pull the fingers in ever so slightly.

 

[stgdz]

Oh and Mike what are you sticking the dial indicator on at the rotor? Is it the spot behind the clip?

 

[Richard Hodgins]

I go and forth on this, the shaft saver vs not and the sacrificial driveshaft design. From what I have gathered, I dont think I have ever seen a worn shaft leave anyone stranded?! I would imagine a cracked tunnel would be disastrous though!
I had a 2013 Procross with 25000kms that had the original shaft in it. It was worn to hell of course and the bearing was still good, had been changed once or twice and just thrown on the bad shaft before I got it. I have never seen one break though because of the shaft being worn.

That being said, I also have a 2019 XF9000 with 20000kms. Shaft saver since 1000kms and on original shaft, no wear on it. Will have to check tunnel (although checked it at 17000kms and no cracking etc).
At the end of the day, we want to find the best reliability. Obviously top gear fix is mandatory, but with the driveshaft wear, not really sure it contributes to better reliability one way or the other (shaft saver or having a worn shaft).

The brand new 2022 I picked up actually had anti-seize on the shaft where the bearing rides!

 

[Yamarus]

As a result, it turns out that it is better to remove the wedge from the shaft, even if there is wear on the shaft, in order to avoid a much greater catastrophe - a tunnel rupture. Let it be better to have a gap between the shaft and the bearing?

 

[STAIN]

it is now repaired stronger than original and without the secondary hole

I think that other large hole is there to cool the caliper.

 

[Gman25]

I think that other large hole is there to cool the caliper.

Hmm thats a good point but if you are not a on the brake type guy wonder if its needed? Guess i could drill 3 smaller holes instead of one big one to help with cooling? Thoughts?

 

[stgdz]

Yeah the caliper fits in that hole and you will need to cut it out or the Caliper will be out of alignment

 

[STAIN]

Hmm thats a good point but if you are not a on the brake type guy wonder if its needed? Guess i could drill 3 smaller holes instead of one big one to help with cooling? Thoughts?

These brake systems hold a very small amount of fluid. I would find a way to cool it.

 

[KnappAttack]

You are corect the caliper was moving up and down and cracked the chassis it is now repaired stronger than original and without the secondary hole drilled through tunnel.
I showed cats design to a senior rngineer at bmw and he was disgusted by cats poor desin and engineer, i then showed him the rest of cats poor engineering and he could not believe their engineering team has not been fired for putting out the same crap year after year and not fixing any of it

I've been saying this forever.

Doo has the same design and has no problems at all. Their bearing is pressed on the shaft and the caliper is a tight fit on the bearing. Its not rocket science, but they fail year after year on fixing the issues, so we fix it with the aftermarket.

 

[KnappAttack]

Oh and Mike what are you sticking the dial indicator on at the rotor? Is it the spot behind the clip?

I clamp it on the running board in the big cutout. Zero runout every time I install a wedge. I have NEVER seen a tunnel crack with the wedge installed properly, but people just can't seem to get it right for whatever reason or they think its "good enough". They either don't care to do it right, or they don't know how to do it properly so total failure is the result. You can tell someone how to do it only so many times and they still f-it up. Gets old and I hate the stupidity of it all myself. Defiantly can't trust certainly dealers to do it properly for sure.

 

[Turboflash]

Not sure how that was done? Forward hole is mates with the cast boss on the housing to center it and the rear hole is where the shaft comes through. How was one hole eliminated?

 

[Turboflash]

I go and forth on this, the shaft saver vs not and the sacrificial driveshaft design. From what I have gathered, I dont think I have ever seen a worn shaft leave anyone stranded?! I would imagine a cracked tunnel would be disastrous though!
I had a 2013 Procross with 25000kms that had the original shaft in it. It was worn to hell of course and the bearing was still good, had been changed once or twice and just thrown on the bad shaft before I got it. I have never seen one break though because of the shaft being worn.

That being said, I also have a 2019 XF9000 with 20000kms. Shaft saver since 1000kms and on original shaft, no wear on it. Will have to check tunnel (although checked it at 17000kms and no cracking etc).
At the end of the day, we want to find the best reliability. Obviously top gear fix is mandatory, but with the driveshaft wear, not really sure it contributes to better reliability one way or the other (shaft saver or having a worn shaft).

The brand new 2022 I picked up actually had anti-seize on the shaft where the bearing rides!

How could the bearing still be good if the shaft was "worn to hell"? The shaft was spinning inside the bearing and wearing the ID of the bearing. No way the bearing ID didn't get bigger.

 

[stevewithOCD]

How could the bearing still be good if the shaft was "worn to hell"? The shaft was spinning inside the bearing and wearing the ID of the bearing. No way the bearing ID didn't get bigger.

I think he means the "Ball Bearings" were good & tight most likely cuz they never spun like they were born to do

 

[Turboflash]

Ok, even it that's true, bearing is still toast. ID is worn big time.

 

[Kevin]

Very interesting read everyone !
I just install a wedge yesterday and didn’t like the fact that the rotor no longer floats a bit.
I will take it out and reinstall
Thanks for all the great info