Jump to content
snoopy2x

Steering Bellcrank Shaft Wobble and Eventual Failure

Recommended Posts

This past weekend I visited my brother-in-law, Fred, who owns a 1967 V6 CJ5.  This is the first time I'd done so since rebuilding the original Ross steering gear for his jeep earlier this year, and I was very much looking forward to driving it. 

When I did so, I noticed that while the steering wheel had significantly less play than it did before the gear rebuild, it was definitely not as great of an improvement as I'd expected to see (i.e. quite a bit less of an improvement than I'd experienced after rebuilding the box for my own V6 CJ5).   After his rebuilt box was installed, the play at the edge of the steering wheel was cut approximately in half from what it had been - from about 5" to 2-1/2" or so.  When driving it, I also noticed that the steering wheel did not return to center following a turn on its own without a little "help" from the driver.  

We took turns looking at the steering linkages while one of us turned the wheel back and forth within the free play area to try to determine where the "slack" was.   It quickly became clear that the bottom end of the steering bellcrank shaft, which had been recently worked on by a friend of Fred's who also installed the rebuilt steering gear for him, moves side to side about 3/32 of an inch or so when the steering wheel is being turned back and forth.  (This struck me as potentially dangerous, as if that shaft were to fall out while the jeep were being driven, the steering would immediately be lost altogether.) 

The bellcrank shaft bracket is stable / stationary while this sideways movement at the lower end of the shaft is occurring.  This bracket was replaced by a previous owner at one time, as it is bolted, rather than riveted, to the frame. 

To further complicate the question, we are not sure if his jeep would originally have had the 7/8" diameter bellcrank shaft, or the larger 1-1/8" shaft.  This change was made sometime during the 1967 model year on the V6 CJ5s.  The serial number indicates that my '67 CJ5 was built in August 1966, and it has the smaller 7/8" diameter shaft.  Fred's was built in Nov. 1966.  Based on the visible end of it, the shaft that is currently installed appears to be a 7/8" shaft....but I could be wrong about that.

Unfortunately we did not have time to take the bellcrank assembly apart and attempt to find the problem while I was there, nor did we have the replacement parts in hand that may be required to fix it -  so he is in the process of finding a local mechanic to help him repair it.    

I'm wondering if anyone on this forum has any thoughts about the potential causes of the side to side movement of the end of the bellcrank shaft.  Is it likely improper installation, a worn shaft or bracket, or something else?  Also, is it is possible to tell which would be the correct shaft diameter for Fred's jeep based on the bellcrank support bracket that's installed?

The photo below shows the current bellcrank setup in his jeep:

1.5772e56cc0c2a_FredsBellcrankAssy.thumb

Share this post


Link to post
Share on other sites

Snoopy2x...Important subject to share, time-honored bellcrank wear and the need for either a rebuild or repair.  I rebuilt a Jeep bellcrank for the first time in 1969 on my 1950 Jeep CJ3A.  The Jeep was only 19-years-old at the time, and if still rolling today with its original steering, it would likely have at least one, maybe two more bellcrank rebuilds.

You've noted the bellcrank pedestal replacement, and this points to a concern about the bore size and condition of that casting.  If offshore built, who knows, it could be out of specification.  The amount of play you describe is excessive, for sure, but does not account for the difference between a 7/8" and 1-1/8" shaft size.

I would check the O.D. and I.D. of the bellcrank kit parts.  If a caged bearings type, the bearing size could be wrong.  Check the shaft diameter, bellcrank bore size and the bearing part numbers.  Look up the bearing by number for its I.D./O.D. size.  If not a quality bearing, don't depend upon the size being correct to specification.  

There are at least a half dozen bellcrank repair kit methods and parts.  Machining tolerance could be off on the shaft, or the bearing spacing over the bellcrank's bore could be incorrect and allowing for wobble.  If the bearings are a pair (or sometimes three) caged needle/roller type, they might be installed in the bellcrank bore too close to center.  The bearings need to support the bellcrank near the outer ends of the bellcrank bore.  (A factory shop manual or rebuild kit instructions describe the correct position of these bearings.)  If not, there could be wobble.

Some things to consider...

Moses

Share this post


Link to post
Share on other sites

I was evidently not completely clear in my initial post - sorry for any confusion I may have created: 

The bellcrank does not appear to be wobbling on the shaft, so I don't think the bearings are the issue in this case.   The problem is that shaft itself, for some reason, is moving somewhat inside the support bracket .   This movement can be seen at the end of the shaft when the steering wheel is turned back and forth.  

I suspect this movement of the shaft in the bracket may be what is causing the steering wheel not to return to center following a turn as easily as it should.  When the end of the shaft moves side to side slightly while the bracket remains stable, that movement in turn creates pressure / friction on the spacer washer above the bellcrank - which I think may be the reason the steering wheel needs a bit of "help" to return to center after a turn to the left or right. 

Does that make more sense?

Share this post


Link to post
Share on other sites

Plenty of sense, snoopy2x!  Two issues:  1) wobbling bellcrank shaft in the support bracket and 2) a bellcrank washer creating bind when the shaft moves out of center or tilts.

I can't see the bottom of the shaft nor the nut that secures the shaft.  The design looks different than the traditional frame supports.  Is there a pinch bolt that secures the bellcrank shaft within the support bracket?  The typical vintage Jeep CJ uses a bellcrank shaft that is clamped into the support bracket by a horizontal pinch bolt, lock washer and nut.  The support bracket's clamping area has a vertical slit that allows the casting to pinch together and cinch around the bellcrank shaft.  When the pinch bolt is secured properly, the bellcrank shaft should be rigid in the support bracket.

Here's the OE service manual schematic for the CJ bellcrank, circa Kaiser/Jeep Corporation era.  This is a generic, universal illustration but representative of the four-cylinder and earlier Jeep V-6 models.  I use PDF for clarity, zoom-in on the bellcrank assembly diagram and parts nomenclature to see the "usual" layout:

Kaiser Jeep Era CJ Bellcrank Illustration.pdf

Note the parts listed and their orientation.  Does Fred's '67 Jeep CJ-5 V-6 frame support and bellcrank assembly look similar?  If so, make sure the parts and parts orientation are correct.  This includes proper orientation of the chamfered washers and other parts.

I've also included the actual factory service steps surrounding the bellcrank rebuild, including a support bracket replacement with bolts instead of rivets, similar to the replacement done on Fred's Jeep CJ.  There is another diagram of the bellcrank parts layout here:

Kaiser Jeep Era CJ Bellcrank Rebuilding.pdf

Note the sequenced parts assembly procedure and the tightening sequence for the bellcrank shaft and pinch bolt.  There is considerable torque on the pinch bolt nut to stabilize the bellcrank shaft.  Make sure the bellcrank is assembled in proper sequence and torqued to specification.  These rebuild instructions also describe the placement of the bearings in the bellcrank bore.

Once you have the bellcrank working properly, if there is still hesitation on the return-to-center after corners, check the front axle's caster angle and also the closed knuckle axle housing's spherical ends for too much wiper seal drag.

Moses

Share this post


Link to post
Share on other sites

I think I found the bellcrank bracket used on Fred's jeep, which appears to be a 7/8" shaft bracket that's listed as a takeoff part at Willys Jeep Parts (number 807009  https://www.willysjeepparts.com/Bell_Cranks_B.htm  - photo below).  Fred's going to take a close look at his bracket this weekend to verify whether or not it is in fact the same one.  

If it is the same part, given that he'll have to transport his CJ5 a good ways to get it worked on by a mechanic he found who has experience with older jeeps, I'm going to encourage Fred to go ahead and buy one of these brackets (after verifying with the seller that as a takeoff part, it is in good, usable condition), along with a new 7/8" shaft kit, including all new bearings, etc. (like  http://walcks4wd.com/bell-crank-kit-78-2a-3a-3b-cj5.html ).  Fred already has an NOS bellcrank that was just installed a few months ago. 

This way, along with a printout of the .pdfs from the manual that you were kind enough to provide, the mechanic will have all the information and major parts in hand he might possibly need to rebuild the bellcrank assembly, and hopefully solve the problem.   

Will let you know the outcome of this situation. 

Thank you so much for the benefit of your jeep wisdom, Moses!

 

2.577554dd0d644_BellcrankBracket807009.J

Share this post


Link to post
Share on other sites

Good approach, snoopy2x...No photos are from an angle that would show the vertical split in the bracket at the pinch bolt.  Can you confirm whether this bracket has a compression slit?  

Moses

Share this post


Link to post
Share on other sites

I had a conversation with Fred last night, and asked him to check the pinch bolt to ensure that it is there and that it's tightened to the proper torque.  I'll ask him to take a photo of his bracket showing that bolt, and the compression slit that should be there as well.

In addition, before he orders the takeoff bracket, assuming he decides to do that, he should as you suggest confirm that it has a compression slit.

Share this post


Link to post
Share on other sites

Here's Fred's photo of the rear of his current bracket showing the pinch bolt and compression slit.  

He will need to check the torque on that nut and the top shaft nut, but assuming they are both are tightened to spec....given the current wobble at the bottom end of the bellcrank shaft....could there be any other cause for that wobble besides wear on the shaft, and/or in the cylindrical shaft receptacle inside the bracket?

Incidentally, the bracket on my 1967 CJ5, which was built in August 1966, a few months before Fred's jeep, has the same 7/8" dia. shaft bracket (though mine still has the riveted original). 

 

3.5778890742d19_Fredsbellcrankbracket-re

Share this post


Link to post
Share on other sites

Thanks for sharing this photo, snoopy2x...Have Fred follow the tightening sequence found in the shop info PDF (above).  The image clearly depicts the slit and compression pinch bolt, which the manual states should be 50-70 lb-ft. torque.

As for a wobble beyond loose hardware, shaft wear or a worn bracket bore, the only other issue would be bad tolerances on the bellcrank shaft's diameter.  You share that this should be either 7/8" or 1-1/8" diameter.  If the shaft's diameter is smaller than the bracket bore, the pinch/compression slit would not be able to compensate enough to secure the shaft.  I doubt this is the case.  Assuming that the pinch bolt is at least snug, you can see that the slit is still spread some; this would not be likely if the shaft were too small in diameter.

Note that the slit does not run to the bottom of the casting.  The lower opening to the bracket should be close to the shaft's diameter.  (That section does not compress.)  Wear at the bottom or any other area of the bracket's bore could create a wobble.

Note:  Verify whether the bellcrank bearing kit requires a spacer (similar to the early design depicted in the first PDF uploaded above).  The bearings may require solid support between them when torque is set on the bellcrank shaft nut.  Otherwise, there could be wobble at the bellcrank.  This would not account for a bellcrank shaft that wobbles in the bracket, but any work at the bellcrank should include accounting for the right parts and using the correct assembly sequence.

Moses

Share this post


Link to post
Share on other sites

 

April 8, 2018 (almost 2 years after initial posts above)

My brother in law Fred had a significant failure occur in his 1967 CJ5's steering system today.  It could easily have been catastrophic if it had happened while he was on the road, instead of minutes later as he was pulling the jeep into his garage.   He was extremely fortunate, to say the least. 

The shaft of the same steering bellcrank pictured above (in 2016) literally fell out onto his driveway this afternoon, immediately disabling the steering.   Based on his photos below, it appears that the pinch bolt that clamps the mount around the bellcrank shaft must have loosened itself over time - possibly to the point that it actually fell out(?) - and the nut on the top of the shaft likewise worked itself loose.  Once both were gone, the shaft dropped out of the mount. 

Fred and I had been concerned about this possibility, as mentioned in the first post in this thread a couple of years ago.  In an effort to ensure that preventative measures were properly taken, Fred subsequently had the frame mount replaced and the bellcrank assembly re-installed by a local mechanic who supposedly had experience with older jeeps.  Given what just happened, however, it's highly questionable whether or not that work was performed correctly.  

Fred sent these photos he took earlier today:

 

Freds-bellcrank-shaft-failure-1.jpg

Freds-bellcrank-shaft-failure---2.jpg

Freds-bellcrank-shaft-failure---3.jpg

 

Needless to say, Fred's a bit shaken up by this (and so am I!)   If you have any questions, I'll be glad to relay those to him and post his answers.

 

- Do you have any thoughts in terms of forensic analysis?  

- Also, is there anything you would recommend be done in order to prevent a recurrence, beyond what you already suggested above? 

 

I'm wondering if Fred should consider upgrading to one of these modified bellcrank assemblies:  

 

....or one of these similar modified bellcranks by one of the Early CJ5 site members:

http://www.earlycj5.com/xf_cj5/index.php?threads/steering-bellcrank-rebuild-qusetion.129680/#post-1395299


 

Share this post


Link to post
Share on other sites

snoopy2x...Very glad that Fred is safe!  This was a serious parts or installation issue...

Is there a castellated nut and drilled hole at the top of the shaft?  Is this a self-locking nut or a castellated nut?  A castellated nut with cotter pin installed properly generally will not loosen.  A self-locking nut is up for grabs, it could loosen, especially if the shaft rotates back and forth—like if the pinch bolt and nut fell out first.  That's reason enough for a castellated nut and cotter pin.

Of course, the pinch bolt nut needed proper torque, and the bearing and shaft fit-up must allow the pinch bolt's center line to center with the notch in the bellcrank shaft.  It would be most unusual for the pinch bolt and shaft top nut to come loose simultaneously.  It's likely that the pinch bolt came loose first.  The shaft nut worked loose after that.  Time sequence for the shaft nut loosening once the pinch bolt came loose would be anyone's guess.  My guess:  Not long with a self-locking nut; longer with a castellated nut and cotter pin.  (The cotter pin would be sheared.)

Note:  If the washers are the correct O.D. and were installed properly, the shaft cannot drop through the bellcrank with the nut in place.  If the washers are either the wrong O.D. or omitted, the loosening of the pinch bolt/nut would enable the washers and nut to drop through.  There is a top washer(s) in Fred's photo above.  Note the reference to the chamfer on the washers, they must face toward the bellcrank.  This is important.

In the PDFs provided at June 29, 2016 above, there are two bellcrank assemblies illustrated, along with detailed installation steps.  Note that the parts and their orientation/sequencing are different between the two bellcrank kits/designs.  Looking at Fred's photo of July 2, 2016 above, the parts look like the later style bell crank design shown in FIG. O-9.  Is that correct?  There is a possibility that either the wrong "kit" was installed in the mount, or the parts were not sequenced properly.  There are subtle detail differences between FIG. O-1 design and FIG. O-9 designs.  Were chamfered washers provided in the kit?  Aftermarket parts and kits often miss such details: The chamfer is for alignment.

Since parts fell out, did some get lost?  Can you confirm whether the kit is right for the bellcrank design and mount—or whether all pieces were installed correctly?  The pinch bolt aligns the assembly and its parts vertically.  The shaft nut secures the stack of parts.  Once again, you're dealing with early V-6 models and the need to determine which parts sequencing applies:  FIG. O-1 or  FIG. O-9.  The design dictates which bellcrank kit applies. 

In addition to parts sequencing and determining whether the replacement parts match up with the bellcrank type, you need to determine if the parts alignment and sequencing allowed the top nut to tighten properly.  The pinch bolt is straightforward in its fit:  The shaft notch must center with the bolt centerline.  If so, the shaft aligns vertically with the bellcrank mount.

Of course, the hardware torque needs to be correct.  If the parts fit or orientation is not correct, these torque figures would be moot.  Parts out of sequence, the wrong parts or kit, wrong spacing distances, all of this could add up and loosen the top nut.  A misaligned  (not centered) pinch bolt could also loosen.  

If you can find all of the pieces that fell off, measure their vertical stack height.  Compare this with the the two bellcrank illustrations and Fred's bellcrank mount.  Determine which parts kit, parts sequencing and parts spacing would be necessary.  See whether out-of-sequence parts, improperly installed parts or a wrong stack height led to the loosening of the pinch bolt and/or top nut.  If everything seems correct, and if the top nut was a self-locking type without a cotter pin, the issue was likely an improperly torque'd pinch bolt that fell out.

Footnote: If the washers were chamfered, see if there are signs that they were fitted incorrectly.  This could allow hardware to loosen as well.

Moses

Share this post


Link to post
Share on other sites

I just spoke with Fred, and he had a (different) mechanic put the jeep up on a lift today to try to figure out exactly what caused this failure.   It appears that the mechanic who installed the mount and bellcrank assembly a couple of years ago made two separate mistakes during the installation.

First, no cotter pin had been installed through the castle nut at the top of the pin.  In fact, the mechanic who looked at the jeep today had to slightly grind some of the "crenelations" at the top of the castle nut in order to make them wide enough to accept even a small-diameter cotter pin.  

Second,  the previous mechanic had also overtorqued the pinch bolt to the point that it stripped the threads.   Though the bolt was still in place, because the threads were stripped inside the nut, it was no longer capable of maintaining the necessary tensile "pinching" force on the pin across the slot in the mount.

As far as the parts used in the 2016 installation, the bellcrank was NOS. The bellcrank shaft kit used was one that should have been (to the best of my knowledge) the correct version for Fred's jeep.  His is an early 1967 CJ5 built in November of 1966.  Here's a link to the rebuild kit he bought (note the narrow slots in the castle nut):  https://walcks4wd.com/bell-crank-kit-78-2a-3a-3b-cj5.html 

I don't know for sure whether or not any parts were lost, but from his description it sounded like Fred still has all of them.

Moving forward, Fred has decided to have a modified double tapered-roller-bearing bellcrank (like those linked to above) machined and install it as soon as possible.  His reasoning is that this mod will not only add a greater margin of safety, but will also result in a more easily maintainable bellcrank assembly that's less likely to loosen over time and cause unwanted play in the steering system.

Fred certainly realizes that he was very, very lucky indeed that the bellcrank pin fell out when and where it did.  The consequences could have been truly disastrous if it had happened at speed and/or in traffic, which he had been very shortly before it failed.   That someone was looking out for him seems, to both he and I, to be quite obvious!

Share this post


Link to post
Share on other sites

Sounds consistent with what I envisioned...No cotter pin and no pinch bolt force.  That will do it!  Very glad that Fred is okay.  Your vintage Jeep CJs are gems and need to stay on the road—literally and figuratively!

Share this post


Link to post
Share on other sites

Your comment about self-locking nuts above got me to thinking about the shaft nut in the kit Fred used.  Looking at the images shown in the link ( https://walcks4wd.com/bell-crank-kit-78-2a-3a-3b-cj5.html ), I wonder if the shaft nut that came in this kit, which visually correlates with Fred's description of having very narrow cotter pin slots, could actually have been intended by its manufacturer to be a self-locking nut, rather than a castle nut? 

Here's an enlarged image of the nut shown in one of the photos on the link:

 

Bellcrank-rebuild-kit-shaft-nut.jpg

Share this post


Link to post
Share on other sites

snoopy2x...Looks like a self-locking nut that does not require a cotter pin;  the slots are not for a cotter pin although a small pin might indicate when the nut is trying to loosen.  An asset with a cotter pin is its safeguard function.  If the castellated nut starts to loosen, and if this process is witnessed in time, you can see that the nut is trying to back off and shear the pin.

Note that in the Jeep manual's FIG. O-9 image and parts legend, you see a factory self-locking nut ("Stollock Lock Nut" in the legend description).  If the pinch bolt is secure, this nut would not be subject to the rotational back-and-forth that could loosen the nut.  Arguably, and even in factory thinking, a self-locking nut suffices when the shaft is secured by the pinch bolt/nut and the bellcrank mount's clamping force.  The failure in this case points to the stripped pinch bolt threads and nut that did not secure the bellcrank shaft.  The rotating shaft eventually loosened the self-locking nut. 

In your tapered roller bearing aftermarket conversion kit image, you can see a castellated nut.  Castellated nuts with cotter pins are common on safety items like steering linkage, including the tapered tie-rod ball stud at the bellcrank.

I personally like the castellated nut on steering linkage and safety related parts, as you can see nut creep during a vehicle inspection.  By design, the castellated nut and cotter pin are a last safety resort.  There is always a tensioned/stationary backup when a castellated nut is employed:  either a tapered stud (think tie-rod ends), a secured shaft (think Jeep bellcrank shaft), or a keyway indexed thrust washer in the case of front wheel bearings on a traditional 2WD spindle or common trailer hubs.  (The backup thrust washer has an index tab that aligns with a keyway to keep the washer from rotating.)  The castellated nut is subject to load but not subject to rotational force. 

The castellated nut (or a self-locking nut in this case) should never be subjected to back-and-forth force;  if it is, you can expect the cotter pin to shear and the nut to come loose—or the self-locking nut to back off as it did in this case.  For the bellcrank shaft, the pinch bolt/nut and clamping force of the bellcrank mount are engineered to prevent the bellcrank shaft from rotating.  The castellated or self-locking nut should stay put.  The cotter pin is a safety backup.

When reassembling this bellcrank bearing and shaft, make sure the washers are installed in the factory orientation...If the bellcrank shaft has a cotter pin hole, I would use a properly graded castellated nut (must be an automotive application nut with the correct tensile and sizing) and a cotter pin.  If there is no cotter pin hole in the shaft and you use a self-locking nut, make sure the nut is new and properly sized/graded.  Self-locking nuts are not designed for multiple use.  This nut wiggled loose and must be replaced to hold a torque setting.

Moses

 

Share this post


Link to post
Share on other sites

Thanks very much, Moses, and I've sent Fred a link to your excellent analysis above.  I asked him if the threaded part of the bellcrank pin that came with the kit had a hole drilled through it to accept a cotter pin, and he said it did.

I can understand his and his mechanic's confusion. While the bellcrank pin has that hole, the self-locking nut (which resembles a castle nut, but has narrower slots) would not allow for the installation of a cotter pin through it without modifying the nut by widening the slots.  It sounds like maybe the manufacturer of the bellcrank repair kit he purchased started out including a castle nut that would allow the insertion of a cotter pin, then switched to a self-locking nut at some point during production - but did so while continuing to provide bellcrank pins with a cotter pin hole drilled through them.

In any case, Fred has already purchased an NOS bellcrank and the Timken tapered roller bearings needed to have a custom bellcrank machined, like the ones shown in my post on the 8th.  That custom unit will likely be installed later this month, and will hopefully permanently solve the issue.  

Share this post


Link to post
Share on other sites

snoopy2x…There may be another reason for the switch to a self-locking nut: Maybe a castellated nut will not index properly with the aftermarket shaft’s cotter pin hole.  Compare the location of the cotter pin hole on a stock/OEM bellcrank shaft with the aftermarket shaft's cotter pin hole location.

Moses

Share this post


Link to post
Share on other sites

That's an interesting thought, and is certainly a possibility.   I don't know that Fred or I have an OEM bellcrank shaft to compare to the one from the kit, but maybe another member reading this does, and could provide a comparison.

Thank you again for your help with all of this, Moses! 

 

 

  

Share this post


Link to post
Share on other sites

×
×
  • Create New...