Front Drive Shaft Update

[jvkintheusa]

What does not kill us makes us stronger! Another tool to add to the pack list.

Yeah mine is starting to look like a mobile garage

 

[jvkintheusa]

Do we need to put anti-seize on The mating surfaces when installing the front drive shaft?

 

[pmatusov]

Do we need to put anti-seize on The mating surfaces when installing the front drive shaft?

YES!!!

 

[255/85]

Or what about an “accordion” bellow - kind of like a toilet plunger. Multiple rings in the bellow.

I seem to remember someone trying an additional accordian boot (in Europe?) but the results were poor. A different boot design would be great if it worked.

RCV Performance (<-- this is a link) has a possible solution in their axle shaft boots that maybe hasn't been suggested here. The boots are external to the "bell'' of the CV. AFAIK they require constant additional lubrication but are considered suitable for exposed uses unlike, say, a traditional Birfield used in Land Cruisers, etc. They can handle a fair amount of angle.

It would require a complete redesign of the transfer box CV and wouldn't be cheap.

 

[Lexx]

What do you guys think about Owl Vans theory that these torn CV boots are due to the boot being pinched during installation, especially when lift kits are being installed? I wonder if this could even happen at the factory when they're building the Grenny?

 

[CrazyOldMan]

What do you guys think about Owl Vans theory that these torn CV boots are due to the boot being pinched during installation, especially when lift kits are being installed? I wonder if this could even happen at the factory when they're building the Grenny?

I’m kinda more inclined to think this has to do with the rubber composition and maybe @Zimm ’s point about no give/flex capacity on the material. So tearing from pulling - not pinching. But I don’t know.

 

[jvkintheusa]

I saw that video and I'm not completely convinced although when I compare the shaft angles between a non-lifted grenny and my 1.7 Eibach lift, the angle looks about the same. Not sure about a 4" lift.
Regardless, I'm removing my lift and keep the 275 tires.

 

[Zimm]

ultimately, I think we have learned these cv's are intended to accommodate movement from center line, but not necessarily live far off the center. Which, up 'till now, I didn't know.

 

[Zimm]

I saw that video and I'm not completely convinced although when I compare the shaft angles between a non-lifted grenny and my 1.7 Eibach lift, the angle looks about the same. Not sure about a 4" lift.
Regardless, I'm removing my lift and keep the 275 tires.

Yea I'm with ya, when you draw out the angles and distances, it does not appear like much, but I'm also betting the impact the angle has on failure is plotted on a curve that spikes, not a straight line.

 

[Dokatd]

What do you guys think about Owl Vans theory that these torn CV boots are due to the boot being pinched during installation, especially when lift kits are being installed? I wonder if this could even happen at the factory when they're building the Grenny?

The "boots being pinched at install" theory is fine and all, but it's only an accelerant. I have installed many Grenadier shafts at this point with 100% no pinching upon install and they all still failed.

And as for material and stretching etc. these boots are super supple and compliant. Once I started checking for it I have clearly seen evidence of the boot being pinched/squeezed in operation. I have the evidence from several joints on my desk as we speak. Being lifted just makes this condition easier to meet. So stock trucks get away with it for longer because they don't live as close to the extent of travel. But lifted trucks are always about 2" closer to max. Either lifted or non lifted trucks running on smooth roads without undulations will likely see 100k before a boot fails. But add in daily bumps, humps and jumps and you quickly loose mileage per boot. The bellows shape is inconsequential.

 

[CrazyOldMan]

The "boots being pinched at install" theory is fine and all, but it's only an accelerant. I have installed many Grenadier shafts at this point with 100% no pinching upon install and they all still failed.

And as for material and stretching etc. these boots are super supple and compliant. Once I started checking for it I have clearly seen evidence of the boot being pinched/squeezed in operation. I have the evidence from several joints on my desk as we speak. Being lifted just makes this condition easier to meet. So stock trucks get away with it for longer because they don't live as close to the extent of travel. But lifted trucks are always about 2" closer to max. Either lifted or non lifted trucks running on smooth roads without undulations will likely see 100k before a boot fails. But add in daily bumps, humps and jumps and you quickly loose mileage per boot. The bellows shape is inconsequential.

Similar failure pattern for OEM and aftermarket?