High angle Rzeppa joint available?

[waren]

Wondering if anyone with a lifted explorer/ranger has found a source for high angle Rzeppa joints like those available for the JK Jeeps from terraflex.

Considering a superlift and wondering if there is an alternative to the SL/RC double cardan shafts.

 

[Blown]

Here's some research: http://www.ijmerr.com/v4n1/ijmerr_v4n1_1.pdf

I didn't read it, but have run double cardan joint drive shafts with no problems. Those Rzeppa joints are likely pricey.

 

[waren]

Wow that is an awesome paper thanks!

I’m sure the rzeppa is expensive ... my hope was less than a dual u-joint shaft.

Really wondering if it would be possible to use a JK rzeppa ...

 

[imp]

Wow that is an awesome paper thanks!

I’m sure the rzeppa is expensive ... my hope was less than a dual u-joint shaft.

Really wondering if it would be possible to use a JK rzeppa ...

Here is how the real Rzeppa design works. Not found today, to my knowledge except via specialty or aftermarket. You might want to look into first-year Oldsmobile Toronado which used big ones, which rarely failed, cannot say anything about maximum angle, however. The first Ford Fiestas, 1978-1981 had pretty big ones, too. We put 200k + miles on three of them with never a cv failure.

 

[waren]

So I reviewed the paper above, I don’t believe it’s comparing the rzeppa joint to the double cardan cv joint.

I assume ford (and Jeep) use the rzeppa joint on the front driveshaft as it likely offers less vibration than the double cardan joint at factory angles.

What I don’t understand is why the rzeppa has such a short life in increased angles when lowering the front diff (superlift, RC, RCD). I assume the angles are still well within the operating range of the rzeppa joint.

I wonder if the issue is that the factory joints are dry and worn into a certain angle of operation and then that angle is changed causing prompt failure. If this is the case simply rebuilding and maintaining fresh grease may offer longer life.

How to rebuild cv style cardone ( front drive shaft )

Well, I did it... myself!:D I followed the instructions in this I will advise, thought, that you get all of the specialty tools needed such as the band clamp tool listed in the video and use a snap ring pliers! I tried getting around these two tools only to extend my time from what should...

www.explorerforum.com

It seems that the replacement Dana joint (expensive) is sold out on RA, only cheaper aftermarket joints are available. Any experience with the quality of the aftermarket joints?

I was also reminded here

Driveline Geometry 101

Driveshaft Angle Explained This video will demonstrate the proper angles for a drive shaft in a stock Jeep or Truck and how the rules change when you add a suspension lift. The video below demonstrates what is happening to the shaft at different angles, how improper angles can cause speed...

4xshaft.com

That the double cardan joint really needs the u-joint at the other end of the daft to be operating as close to 0 deg as possible. I have a double cardan shaft on my lifted full-size Bronco and changed the ujoints often. Likely due to the rear pinion not pointing up enough.

I assume that the available lift kits (for ranger and 2nd gen explorer) do not rotate the front diff either so the double cardan likely isn’t a perfect solution there either.

At this point all theoretical, I haven’t lifted yet, just want to have a plan for the known issue of the front driveshaft. I could replace the rzeppa joint around 20x for the cost of the double cardan shaft so that’s the default plan I guess.

 

[waren]

Quick update the dorman part number for the joint is 932-201. Dorman actually has fairly decent technical data on the CV joints including;

spline count 26
spline diameter 1.051”
spline length 1.297”
bolt circle 3.596”
bolt size M8x1.25
housing OD 4.206”
housing depth 1.394”

Using this information I was able to confirm that no other CV joints that dorman offers appear to be a match spline count or bolt size and circle. Which answers the question could the high angle CV joints available for jeeps be used on a 2nd gen explorer ... they cannot without modifications.

 

[imp]

The double cardan joints used for many years on luxury cars, cadillacs and lincolns, definitely did not allow as much angularity as a rzeppa cv, or even a single cardan joint. Their purpose was to eliminate vibration.

Rzeppas don't just wear out prematurely. Like any such device, remaining lubricated adequately and sealed properly to prevent entry of dirt gave very acceptable life.

I had 3 vehicles with rzeppas which each exceeded 300,000 miles without service or failure.

 

[Josh P]

The rzeppas that were on my Grand Cherokee didn't last 200k miles. I replaced the front drive shaft with a double cardan. The boots kept ripping in the axle CV joints so they got replaced with u joints.

 

[waren]

Hmm that totally makes sense. this it probably is the boot ripping that is killing the joint ... not the angle of operation on the joint itself but the angle and motion on the boot that cracks fails and then takes out the joint.

Oh and totally agree the double cardan can be an excellent choice I just want to avoid $600 on a custom shaft if I can.

 

[Josh P]

I'd try and avoid a $600 price tag too. Might find a driveshaft from a different vehicle that might work. For example I had a B2 that needed a rear driveshaft and the front shaft from a 1st get explorer fit perfectly. My WJ grand Cherokee, I used a front shaft from a ZJ to save over $200 on an aftermarket unit.

 

[410Fortune]

I will only install Spicer lifetime U joints in my personal rigs
The lifetime joints are what ships in our driveshafts from the factory
They are non greaseable
They will last like a stock U joint

I refuse to install greaseable U joints ever again, they fail very very quickly.

 

[CDW6212R]

You might consider making the front driveshaft with an older Explorer shaft, and new parts as well, to build one. This one was about $200 for me, plus the two used shafts I took to the shop to work with.

 

[waren]

Interesting ... I was hoping that the rzeppa joints were standard like u-joints and I would be able to source an improved design if changing drive line angles due to drop brackets. I read a post somewhere that the superlift or Rough Country Shaft damaged one owners transfer case. I assume because the front diff pinion was not sufficiently parallel to the driveshaft.

Since I don’t want to mess with the front diff angle I think the rzeppa should in theory be better ...

maybe the real solution is to set the pinion angle parallel to the t-case and get rid of the CV all together. The front diff is stationary so set the angles right and this should work.

 

[waren]

I took some rough measurements today.

The front driveshaft is 1deg down to the front diff

The rear driveshaft is 7deg down to the rear diff

All good until I noticed the CV joint on the front shaft seemed to be to be at a much greater angle than 1deg. So I measured the output flanges on the transfer case which is 5deg down towards the rear.

So the actual unjoint angles;

on the rear driveshaft are about 2deg each.

on the front driveshaft the ujoint (at diff) is close to zero the operating angle of the cv joint is about 6deg.

With a 4” lift

The rear driveshaft angle would increase from 7deg to 12deg with unjoint angles of 7 deg (recall the tcase is 5deg down)

Assuming the no change in pinion angle front driveshaft angle increases to ~7.5deg the angle across the unjoint is 6.5deg and the angle at the CV is 12.5deg.

These are rough calcs are based on rougher measurements, but the failure of the factory CV joint is less of a mystery to me. In addition to the increased CV operating angle the lower ujoint angle of 6.5deg also increases stress on the OE CV joint as the shaft accelerates and decelerates.

I expect the rear driveshaft ujoints will operate vibration free albeit with a shorter lifespan.

My plan for the front is to try and rotate the pinion up to equal the angle of the driveshaft. Pointing the pinion up to 5 deg above horizontal should change the driveshaft angle from 7.5deg to 5.5deg ... aligning with the pinion (within half deg) and reduce the angle across the CV from 12.5deg to 10.5deg while also significantly reducing the accel/decel introduced by the lower ujoint. Admittedly I am not sure how I will do this, I think lifting the pinion by ~1” will do it.

 

[CDW6212R]

The front diff/housing is mounted with a bracket that has three bolts holding them together. I have had one of those brackets off one time, to see how much extra movement there might be with the bolts loose. I think they may be able to shift a small few degrees, tilting the pinion shaft up or down from stock. I would begin there, see how much play is in that big bracket and the bolts when loose. If that can do what is needed, you may have to remove the diff, depending on if the holes can be altered to help or not.

 

[waren]

Exactly my plan, I’ve been through this drill after a few suspension mods. Once after swapping a cobra IRS into a mustang. Suddenly I had so much vibration the rear view mirror was blurry on the freeway. In that case the IRS pumpkin (significantly lighter than the solid axle) resonated badly. The much heavier solid axle (in terms of weight to be accelerated by imbalance). I messed with bushings and pinion angle with some improvement.

I was baffled the driveshaft angle should have been the only thing that changed ... I gave up ... months later I replaced the tires and wheels with freshly balanced new rubber at a price I couldn’t resist ... smooth as glass. The remaining imbalance was the tires which although equally imbalanced before and after the swap weren’t out of balance enough to get the solid axle into resonance ... but more than enough for irs pumpkin. Lesson learned.