Front drive shaft broken

[Tazzieman]

LR put them in the rear diff end on Discovery 1’s and RRC’s. Most were replaced with u-joints at the first opportunity.

They don't like to flex up and down.The Guibo rubber couplings are standard on old Mercs, Fiats, Saabs, Alfas etc...even on the rear half shaft of the Porsche 917/935 with up to 1000hp.
FYI

 

[Commodore]

I recall reading that. I’ve seen some pinions rather erect. I think the ring gear at speed is tossing copious amounts lubricant up and over. Ever wonder why they take the time to shape interior in a channel? It aids in directing the fluid up and over the top and not just splashing outwards to the side. I honestly don’t think a few deg of angle is going to prove to be life or death to the pinion, if it was, this was designed on the razors edge of reliability.

I 100% agree with you on each point. So when are we going into the front axle business together? We should do it somewhere in the middle of the country to save on shipping.

 

[C-Mack]

Curious if cutting and turning the axle in order to lift the pinion up if any new problems will be created in the process such as pinion clearance to oil pan or other major components during axle articulation?

 

[Commodore]

Curious if cutting and turning the axle in order to lift the pinion up if any new problems will be created in the process such as pinion clearance to oil pan or other major components during axle articulation?

I haven't really studied it but I doubt it would be a clearance issue.

 

[Dokatd]

Curious if cutting and turning the axle in order to lift the pinion up if any new problems will be created in the process such as pinion clearance to oil pan or other major components during axle articulation?

Considering we are only talking a minor change I doubt it would be a problem. But I haven't looked at it too hard yet.

 

[Tom109]

Well, when it rains it pours. The other shop just came back and said they do not believe a DC will survive with the current angles. They said the only viable option is a Rzeppa joint like we have. But of course the boot will remain the limit.

So........that's that I guess. At least for now.

What exactly did they say?

1990's coil-sprung Land Rovers (without corrected swivels) could run a single-DC front prop shaft and manage to last a reasonably long time. However, I would probably prefer to replace a Rzeppa rather than rebuild a DC joint...

 

[AFdude412]

Not sure if this has been addressed already and thinking outside of the box here, but maybe there's different aftermarket solution via a custom front axle, like Dynatrac, Currie, Dana, etc? Could they correct the angles in their production?

It's an expensive route, but just thinking...

 

[Dokatd]

What exactly did they say?

1990's coil-sprung Land Rovers (without corrected swivels) could run a single-DC front prop shaft and manage to last a reasonably long time. However, I would probably prefer to replace a Rzeppa rather than rebuild a DC joint...

They specifically said the DC would not handle the angles. I sent them all the angles of my driveline. They then said the Rzeppa can handle more angle than the DC. Which is accurate by the books. But they qualified it all with the Rzeppa boot is maxed out so failure is eminent.

Not sure if this has been addressed already and thinking outside of the box here, but maybe there's different aftermarket solution via a custom front axle, like Dynatrac, Currie, Dana, etc? Could they correct the angles in their production?

It's an expensive route, but just thinking...

Certainly an option. Not as cost effective if we can get a core axle to cut and turn. Someday we will see a Gren on 60's but that might be awhile. I suspect Ineos will correct the front pinion angle some day. They likely will run through their first batch of axles before though.

 

[Zimm]

Not sure if this has been addressed already and thinking outside of the box here, but maybe there's different aftermarket solution via a custom front axle, like Dynatrac, Currie, Dana, etc? Could they correct the angles in their production?

It's an expensive route, but just thinking...

There is no volume or parts commonality with anything they have on the shelf. You're talking swapping front and rear and who knows what would go on with the ABS. Cut and turn the stock housing is by far the best option.

 

[Commodore]

They specifically said the DC would not handle the angles. I sent them all the angles of my driveline. They then said the Rzeppa can handle more angle than the DC. Which is accurate by the books. But they qualified it all with the Rzeppa boot is maxed out so failure is eminent.


Certainly an option. Not as cost effective if we can get a core axle to cut and turn. Someday we will see a Gren on 60's but that might be awhile. I suspect Ineos will correct the front pinion angle some day. They likely will run through their first batch of axles before though.

It does appear that the Rzeppa isn’t maxing out its working angle mechanically but rather the boot is ripping and that leads to failure. Axle half shafts on independent suspension trucks run Rzeppa joints at more acute angles without failing BUT they use a large external boot instead of the small captive one that we all have. I’m wondering if there is a boot that we can slide over the existing Rzeppa and fill with grease. That way it won’t matter if the inner captive boot rips and spills grease. A larger boot with bellows will handle the repeated flexing much better that that tiny captive boot. Obviously this is why they are used on front axle half shafts that need manage both suspension travel AND steering angle inputs constantly. Hell, I wonder if this isn’t going to be the “new CV” that we are promised for the 2025 model year.

Something like this:

 

[Dokatd]

It does appear that the Rzeppa isn’t maxing out its working angle mechanically but rather the boot is ripping and that leads to failure. Axle half shafts on independent suspension trucks run Rzeppa joints at more acute angles without failing BUT they use a large external boot instead of the small captive one that we all have. I’m wondering if there is a boot that we can slide over the existing Rzeppa and fill with grease. That way it won’t matter if the inner captive boot rips and spills grease. A larger boot with bellows will handle the repeated flexing much better that that tiny captive boot. Obviously this is why they are used on front axle half shafts that need manage both suspension travel AND steering angle inputs constantly. Hell, I wonder if this isn’t going to be the “new CV” that we are promised for the 2025 model year.

Something like this:

View attachment 7887690

Problem is RPM's. Half shafts spin much slower than driveshafts. The larger boot would likely induce some vibrations. It also wouldn't retain all the grease in the joint. The joints get loose primarily due to lack of grease when the boot fails. Dirt etc doesn't help either of course.

 

[Commodore]

Problem is RPM's. Half shafts spin much slower than driveshafts. The larger boot would likely induce some vibrations. It also wouldn't retain all the grease in the joint. The joints get loose primarily due to lack of grease when the boot fails. Dirt etc doesn't help either of course.

How about redesigning the existing boot and retainer. What we are looking for is a high speed CV with a larger and more flexible boot.

We currently have something like this:

And we need something more like this:

I'm going to drop by my local custom driveshaft shop and get their thoughts.

 

[Commodore]

Perhaps it is worth reaching out to these guys and seeing if they would be interested in designing an improved boot.

Drive Shaft CV Boots | High Performance Components | Race-Tec

Race-Tec is a leading supplier of high-performance Drive Shaft CV Boots for the world's most challenging power transmission applications, contact us today on 023 8024 6986 to discuss the requirements for your drive shaft boots.

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Take a look at the attached pdf's.

 

[C-Mack]

Agreed a much tougher boot design would be better but the OEM style is designed to keep the grease as close to the CV bearings as possible (except when it splits open of course) where as a ribbed design would work as a collection point for the grease and not allow it to find its way back into the CV joint.

Maybe on the diff end where the boot would sit higher grease could move back into the joint but on the transfer case end the boot would always be lower than the joint therefore the grease would tend to sit in the boot.

 

[Jhellweg]

Apologies if this approach has already been discussed, but my INEOS dealership who did the Eibach install lowered the differentials, presumably to improve the angle. These are the installation notes from them:

“Removed front and rear driveshaft couplings at differentials to avoid stressing joints. Lowered differentials and replaced springs with spring tool. Reassembled and adjusted front thrust adjustment bolts to maximum value forward.”

Potential improvement? This was for the 2.5/1.2 lift but I had them swap for the 1.7 because I prefer the stance and tow often.

 

[Dokatd]

Apologies if this approach has already been discussed, but my INEOS dealership who did the Eibach install lowered the differentials, presumably to improve the angle. These are the installation notes from them:

“Removed front and rear driveshaft couplings at differentials to avoid stressing joints. Lowered differentials and replaced springs with spring tool. Reassembled and adjusted front thrust adjustment bolts to maximum value forward.”

Potential improvement? This was for the 2.5/1.2 lift but I had them swap for the 1.7 because I prefer the stance and tow often.

They did not do what you are thinking they did.

 

[Jhellweg]

They did not do what you are thinking they did.

Good to know. Would you mind expanding?

 

[Tenac]

Good to know. Would you mind expanding?

Meaning they supported the driveshaft and then lowered the axel down to swap the springs. Basically the exact process one should take to do this, some shops try to save time and leave everything connected and that is what stresses the angle of the driveshafts. I've been checking mine often since my lift so far about 1500miles to indication of damage to the rubber covers.

 

[Jhellweg]

Meaning they supported the driveshaft and then lowered the axel down to swap the springs. Basically the exact process one should take to do this, some shops try to save time and leave everything connected and that is what stresses the angle of the driveshafts. I've been checking mine often since my lift so far about 1500miles to indication of damage to the rubber covers.

Appreciate the explanation. And here I am thinking they had introduced a differential drop for our IGs. Well I’ll be keeping an eye on the boots and hoping the 1.7 lift isn’t too much of an extra strain to put me at risk—so far so good

 

[C-Mack]

I think the “maximum adjustment forward” statement on the paperwork means they dialed in maximum caster after the lift to help with the steering but in effect this lowers the pinion even more adding additional angle to the cv joints. That’s what I’d be more worried about as the cv joints boots are already stressed now they are even more so. Nice of them to baby the driveshafts during install, which is the right thing to do, but now the front is set to run in a condition that will shorten the cv boot life.