Agile Off Road Front Shaft

[Tazzieman]

I wonder what % of owners can actually physically crawl under to check their CV joints. Without their own joints tearing or dislocating.
Or knocking their prescription goggles off.
I suppose one advantage of a lift is it's slight easier if you are "large boned"
Nonetheless I doubt whether many chaps are slipping under the machine on a weekly basis.
So perhaps someone can market Propshaft Cam with infrared sensor?
It's a thought; I'll admit not a great one.

 

[Tom109]

I wonder what % of owners can actually physically crawl under to check their CV joints. Without their own joints tearing or dislocating.
Or knocking their prescription goggles off.
I suppose one advantage of a lift is it's slight easier if you are "large boned"
Nonetheless I doubt whether many chaps are slipping under the machine on a weekly basis.
So perhaps someone can market Propshaft Cam with infrared sensor?
It's a thought; I'll admit not a great one.

I may think about a lift. I have the space for it and I’m not getting any younger. Just last weekend a small magnetic shop light slipped down under the engine on my Wife’s Defender Trophy. Removing front-/mid-skid plates and underbody cladding was a chore, even with the wheels on 8-inches of cribbing.

 

[AFdude412]

Inspecting these ‘boots’ has become part of my daily routine on the trail. Were the “micro cracks” visible and/or detectable by touch? Can you provide any photos so that we can all know what to look for?

TIA,
Bill

I’ll have to draw back under there and get a few. I’ll post back soon.

 

[AFdude412]

Inspecting these ‘boots’ has become part of my daily routine on the trail. Were the “micro cracks” visible and/or detectable by touch? Can you provide any photos so that we can all know what to look for?

TIA,
Bill

It's pretty minor. Looks a little dried out. This pic is from my front CV on the front shaft. But all are showing it in some fashion.

 

[C-Mack]

Curious if the occasional application of 303 Protectant could help keep the boots somewhat supple without being overly sticky and attracting dust?

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• Keeps surfaces looking newer and lasting longer
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• Helps repel dust, lint and staining
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[Dokatd]

Weather checking is not the issue. Plus the stock part has a light coating of some kind on the boot that may look like it has cracks but it's just the film on the rubber.

The failure comes from constantly extruding the boot by pinching it. This happens over time and is not visible from the outside. You will only know you have a problem when the boot has actually torn. It's a dramatic thing not something subtle you have to get up close to see. Now it may be that the tear is on the top of the joint and hidden from view but if you are paying attention you will see it.

Again, the tears or cracks are dramatic. You won't need your readers to see the damage. And the damage leading up to failure is not visible from the outside of the joint.

And finally, if your joint is glowing orange then the boot probably failed some time ago and you just missed it.

 

[Tazzieman]

Nice thought, but the boot is a fairly hard plastic substance and not what you'd call supple. Once it gets a little crack like leather you can't magically heal it.
I just noticed early failure of mine.

 

[Dokatd]

Nice thought, but the boot is a fairly hard plastic substance and not what you'd call supple. Once it gets a little crack like leather you can't magically heal it.
I just noticed early failure of mine.
View attachment 7917222

Yep, you have some damage for sure.

That said, the rubber is pretty supple once you get it off and feel it. But you are right, a rubber spray is not going to help.

 

[agcheck]

It would seem to me that a multiple double Cardan driveshaft is the correct solution here. Does anyone know if this has been considered or tested?

 

[Dokatd]

It would seem to me that a multiple double Cardan driveshaft is the correct solution here. Does anyone know if this has been considered or tested?

View attachment 7917505

Been done, and it vibrates. Double DC shafts are not great for full time 4wd. The centering ball is a bit of an achilles heal for the DC joint.

 

[Zimm]

Weather checking is not the issue. Plus the stock part has a light coating of some kind on the boot that may look like it has cracks but it's just the film on the rubber.

The failure comes from constantly extruding the boot by pinching it. This happens over time and is not visible from the outside. You will only know you have a problem when the boot has actually torn. It's a dramatic thing not something subtle you have to get up close to see. Now it may be that the tear is on the top of the joint and hidden from view but if you are paying attention you will see it.

Again, the tears or cracks are dramatic. You won't need your readers to see the damage. And the damage leading up to failure is not visible from the outside of the joint.

And finally, if your joint is glowing orange then the boot probably failed some time ago and you just missed it.

I’m still trying to decide if “extrude” is being used properly here. I’m not picturing it in the typical definition of material being forced thru something. Please describe what is you see happening to the boot when you say it is being extruding.

 

[Dokatd]

I’m still trying to decide if “extrude” is being used properly here. I’m not picturing it in the typical definition of material being forced thru something. Please describe what is you see happening to the boot when you say it is being extruding.

The boot is basically being rolled through two rollers and extruding the boot making it thinner.

Roller #1 is the drive shaft itself.
Roller #2 is the boots metal collar.

Not enough force to bruise but just enough to work the boot over time thinning it out. Eventually it gets thin enough that the boot tears apart from the rotational speed.

You will see a distinctive crease or ridge at the folding point where the extrusion pressure is the highest. See the radial ridge in the pic below. Thats not there when the boot is new. You can even see the machine marks from the shaft imprinted in the rubber boot.

 

[Tom109]

The boot is basically being rolled through two rollers and extruding the boot making it thinner.

Roller #1 is the drive shaft itself.
Roller #2 is the boots metal collar.

Not enough force to bruise but just enough to work the boot over time thinning it out. Eventually it gets thin enough that the boot tears apart from the rotational speed.

You will see a distinctive crease or ridge at the folding point where the extrusion pressure is the highest. See the radial ridge in the pic below. Thats not there when the boot is new. You can even see the machine marks from the shaft imprinted in the rubber boot. View attachment 7917515

Is this conditional or physical contact? Is the rubber boot thicker than the gap between Rollers #1 & #2? If Yes, then that collar must be modified.

 

[Dokatd]

Is this conditional or physical contact? Is the rubber boot thicker than the gap between Rollers #1 & #2? If Yes, then that collar must be modified.

Contact is conditional. As the suspension extends to its fullest extent. The folded rubber boot is thicker than the gap between rollers.

I have a plan B or maybe it was plan C that involves slight modification of the boot and collar. But I need to make some dies to do that and I'm not certain it will work due to the necessity of bolting down the boot and joint. The joint is already designed to allow access to the bolts and provide the maximum amount of angle. Unfortunately we exceed that angle with stock suspension.