whining front or rear pinion bearing on BN6

[bighealeysource]

Hey all,
Good news first, took second place in the 100-4 and 100-6 class for Healey's at yesterday's British Car Days at Charleston, SC. Lost to a BN2 !!!! We had 126 LBC's show up for our clubs's 26th BCC days so great event on a beautiful day down here in the Low Country. Club is British Car Club of Charleston.

Now maybe bad news- I believe I have managed to finally figure
out where I am getting a whining noise - other than me about something not going my way - that really manifests itself under power as opposed to coasting at speed. As a friend of mine explained, when you are just coasting at speed and still in gear of course, your drivetrain is not under as much strain as when you are accelerating or under power at speed. Seems to make sense to me and is exactly how the whining noise appears. We think it is one of the bearings on the pinion as not coming from the axles or wheel bearings. IS this possibly normal or should I be concerned ? I very routinely check the rear end oil to make sure it is not something stupid like that. I replaced the front pinion bearing oil seal a few months but did not replace that bearing or the rear one. Both were replaced when rear end assembly was rebuilt. Any thoughts or advice ?
Thanks,
Mike

 

[57_BN4]

Hi Mike,

I recently pulled down two diffs, one 3.54 and one 4.11 and both the pinion nuts were varying degrees of not-tight. The 3.54 was literally finger tight and the 4.11 was tight enough to require a breaker bar but needed very little effort. The nut should be 140 lb-ft which is almost twice what the head studs are done to. A normal size rattle-gun won't get it that tight.

If the noise has started recently then I'd guess the nut is not tight after replacing the seal. Further, the preload on the pinion bearings is set by thin shims behind the front bearing and on my 3.54 a shim had broken up from being loose so if I had just tightened it, the bearings would have been overloaded. The correct procedure to check the bearing preload involves a complete strip down but a diff specialist may be able to check it in-situ.

If your diff has 'whined' since being rebuilt then the pinion/CW mesh is probably not right. Setting up a quiet diff is a black art imo!

Andy.

 

[bighealeysource]

Hey Andy,
You might have hit the nail on the head. I tried to get 140 pounds on that nut when I put it back on but my home made breaker bar was bending when I put more than 100# on it so that's about as tight as I got it. And, whining probably has got worse over the last couple hundred miles which would probably coincide with the nut perhaps getting looser. That is a relatively easy check as opposed to having to replace a bearing so will do that asap. Is this is the case it is more of a nuisance noise due to that nut not being tight enough or will it damage that bearing beyond use ?
Many thanks,
Mike

 

[Superwrench]

Mike, Usually when the seal goes bad it is because the bearing is going bad and causing movement that ruins the seal. Under power it has a load on it and you won't hear it. When you are coasting it frees up and you will hear the noise from the wear. Hope you get it corrected without much trouble. :hammer:

 

[fordtrucks4ever]

Bearings that are making any noise, especially if getting noticably worse are due to total self destruction. Under preload on bearing of any rear end, it takes very little time to completely destroy the ring, pinion, bearings and housing. When it fails the rearend will usually lock up solid without any real warning. IT will happen anytime anywhere. Its like doing a brake check without tail lights in front of a semi tailgating you at 60 mph. Not a pretty picture. I would seriously find out what the noise is before you become a statistic. I have experienced two rear end failures. One vehicle was in tow and literally melted the teeth on the pinion before locking up.

 

[bighealeysource]

Youch !!!!!!!!!!!! I am planning on dropping the drive shaft, tightening the
nut to the required 150 lbs and will see if that takes care of the problem.
I'll let everyone know what I find out.
Thanks,
Mike

 

[GregW]

tightening the
nut to the required <span style="font-weight: bold">150 lbs</span> and will see if that takes care of the problem.

140 ft/lbs. I saw that you posted that earlier, just a friendly reminder.

 

[Bob_Spidell]

Also, unless your e-brakes work better than mine you'll need someone standing on the brake pedal to keep the diff from turning.

If you're doing this on jackstands be SUPER careful.

 

[bighealeysource]

Thanks Bob ! I'll have a friend helping me and have made a 1.25 inch angle iron
tool to bolt to the flange after dropping the driveshaft. Will then put 140#
on it. Other one I made was too think and it bent with the application of the
100#+ of force on it. Will be on jackstands but will be careful.
Regards,
Mike

 

[Bob_Spidell]

... have made a 1.25 inch angle iron
tool to bolt to the flange after dropping the driveshaft ...

Excellent idea.

 

[Randy Forbes]

... have made a 1.25 inch angle iron
tool to bolt to the flange after dropping the driveshaft ...

Excellent idea.

Yes, many ways to accomplish this.

This happens to be at the opposite end of the driveshaft, but it works just the same...