Repacking Front Wheel Bearings

[shorn]

When repacking front wheel bearings (BJ8, wire wheels), would one recommend extreme pressure grease? Also, would there be any reason to change the shims around the distance piece if there was no end float prior to the repacking. I will, of course, check end float anyway, but I would think it should be the same if the same bearings/races are reused.

 

[Keoke]

Hi Shorn, sometimes its ok to reuse the existing shims and sometimes it is not, best to have shims on hand just in case the distance piece tolerance causes a change in the shim settings. Just be sure the grease is rated for diskbrake applications.---Fwiw---Keoke

 

[vette]

Hello Shorn, Keoke is right, it is good to have extra shims available. But as most of us, if we take somethng apart on our Healeys and we don't have what we need it is just an overnight or so to get the part. I have found that when you repack bearings with the same set up as you had previously, that they are usually alittle tighter than before because the fresh grease is taking up some space where the old grease was filling and was probably alittle thinner from heat and wear. That's why we repack them. Having said that, I inspect everything before I use it over again. if it shows any signs of heat or wear or cracks it must be replaced. I have repacked my front wheel bearings now twice in three summers of use. Putting about 3000 miles per summer on it. I'm still using all the same parts, shims, spacers, bearings, and races, that have been with the car since way before I bought it. I have used the same periodicity of maintenance on my Vette for the past 20 years. Haven't lost a bearing yet. /ubbthreads/images/graemlins/yesnod.gif

 

[shorn]

Did mine this morning. The shims were in good shape and were reused. Bearings and races were ok, but the grease had dried out some. Cleaned the bearings and repacked. It took about an hour and 30 minutes for the drivers side, most of the time devoted to getting the mangled cotter pin out. Other side went smoother. I am headed from Seattle to Seaside, OR. this weekend and wanted to make sure I didn't have bearing problems on the way.

 

[vette]

Sometimes i spend 'alot' of time on each bearing set-up. i clean everything, including the hub spotless. If your grease was looking dry, the proceedure was definately due. Hope you have a good trip.
Dave C.

 

[anthony7777]

im doing mine now,i had 5 shims on l/s used new bearigs and races,put back together,had to leave out 2 shims-.003&.005 to get cotter pin in,book says 'must not back off nut to line up pin'no mention of torque speck for nut?,do not put grease in cup!will cause overheating!book only shows 3 shims but at one time mine probably needed more,had to make up new 'backplate setpin lock washers'as they were missing,

 

[anthony7777]

perhaps its my aviation backround,but why would anyone reuse an inexpensive bearing and race when its such a pain to get to?reuse an oil seal?'as my italian great grandma usta say 'imanotinkasoo!especialy when its been used several times befor?are you testing its failure perameters?ya,ya if it aint broke etc,etc bull!ever see a bearing failure?not pretty!and dangerous,and dont ever blow compressed air over it to clean it spinning the bearing,youll never play a musical instrument again or ever be able to pick you own nose!dry bearings can and do explode,makes a neat sound though,always error on the side of being safe,come on man-love you guys!!!!!!!!1

 

[John Loftus]

[ QUOTE ]
no mention of torque speck for nut?

[/ QUOTE ]

The factory workshop manual(BJ7 - BJ8) says, "40 to 70 lb/ft. Latitude for this reading is given so that the nut may be aligned with the split pin hole in the stub axle."

Also, I like to set up the outside bearings dry, no grease on the shims and bearings until I get the right thickness of shims. Then grease, torque and drive.

Cheers,
John

 

[Dave Russell]

General comment,
The somewhat strange & seemingly complex front wheel bearing shimming, adjusting, tightening procedure is largely due to the marginal structural strength of the stub axles. They were originally designed for a somewhat sedate Austin sedan. Denis Welsh Racing claims that 50% of the AH stub axles that they have examined are cracked.

The spacer along with the shims, allows the spacer to be put very tightly in compression. Eg. 40 to 70 ft lbs of torque on the axle nut, without causing side loading & binding on the bearings themselves. This compression allows the spacer to effectively become a part of the axle & to add greatly to the structural diameter/strength of the spindle.

A real PIA to setup correctly but worth the effort. Most cars were designed with spindles that are large enough to have sufficient strength without the spacer, shims, & very tight axle nut. Thus the more usual procedure to tighten the nut a bit & back off until the cotter pin fits. A few folks have suggested tightening the Healey spindle nuts in the same way. In doing so, they are giving up a considerable part of the spindle's structural strength.
D

 

[shorn]

Dave,
Thanks for the enlightening explanation regarding the spacer and shims. I guess I had not really thought about them adding necessary strength to the under engineered stub axle, but it certainly makes sense.

 

[shorn]

Anthony,
My service manual indicates the bearings should be repacked at 6,000 mile intervals. If that is done, I would not expect to have to replace the bearings/races for several repacks. On the other hand, if my Healey were flying at 30,000 feet, I might be more cautious.

 

[vette]

Anthony, when was the last time you had a bearing failure on your SUV. Do you get it repacked often??? Realisticly, bearings do take alot of punishment. Keep them clean, greased, and adjusted properly and they last a long time. I can tell when a bearing needs replaced. Here is the $64,000 question, which Dave Russel has already offered a realistic explanation. the Question is, ' If the Healey has a tapered roller bearing, like most American cars of the 50's & 60's, (and it does) why then does it need a spacer and shims??? While the American cars just adjust the nut for alittle preload.... Times up, as Dave Russel mentions, it will add strength by providing a system of components to share the load. Here's another reason. "Precision" , you will get a much more precise load adjustment on the bearing. With the shims set up properly the bearing will have no end play at all, and will also have no risk of too much preload, ie tight bearing. The method of backing off the nut to align the cotter pin just creates end play. You don't have to do that with a Healey. How 'bout all those cars of the 60's running around with loose front wheel bearings. Hmmm, they lasted along time too. must be able to take a heck of alot of punishment. /ubbthreads/images/graemlins/cheers.gif
Dave C.

 

[Dave Russell]

[ QUOTE ]
How 'bout all those cars of the 60's running around with loose front wheel bearings. Hmmm, they lasted along time too. must be able to take a heck of alot of punishment. /ubbthreads/images/graemlins/cheers.gif
Dave C.

[/ QUOTE ]
Most of the cars of the 60's had spindles designed large enough that they didn't need extra support. Also most 60's cars were not built with racing in mind as was the Healey. The Healeys were designed to a low budget limit, so they used as many parts as possible out of the existing parts bins. The front suspension was largely borrowed from the Austin A90 sedan. Surprisingly few of these "borrowed" parts were not up to the task.
D

 

[vette]

Gotcha Dave. When I started repacking the front wheel bearings on the Healey, my first thought was why do I need these shims and spacer. i put them back in but kept thinking, just remove them and tighten the bearing like you would most other cars. They are tapered rollers, and would take a preload to keep the play at a minimum. then it came to me, the shims allows a much more precise adjustment. If your going to race a car, a precise fit on the wheel bearings would be a plus.

 

[anthony7777]

dave interrsting as always,i followed your advice 40-70 lbs/ft and found that it makes the hub very difficult to spin by hand once all is together and tightened,how much force should be needed to turn the hub by hand?should it spin very freely.require moderate force,or should it seem slightly diffichlt to spinn? i put the assembly together several times to make sure all the components were correct,but still find it 'slightly strenuous' to spin by hand.

 

[Dave Russell]

It is usually suggested to fit the bearings dry so that the grease will not interfear with the setting. Obviously, the bearings, spacer, & shims, need to be spotlessly clean. After the bearings are fully fitted, remove enerything, grease the bearings, & refit. It is even suggested to leave the seal out until final greasing & assembly.

If the hubs are hard to turn with the nut fully torqued, more shims are needed. You want to be at a point where the nut is torqued to final, the hub turns freely, but no noticeable play in the bearings. Very slight play would be better than not enough. The difference might be a single .001" shim. If there is too much pressure on the bearings they will overheat.

A lot of trouble, Especially working inside a small hole, but you only have to do it once. The setting should remain until the bearings are replaced. My car is still going on what I think are the original bearings after 40 plus years. I expect you can go considerably longer than 6,000 miles before repacking. Once the shims are fitted they shouldn't need any more attention unless you mix them up when repacking.
D

 

[anthony7777]

dave thanks,what i found happening durring assembly on the bench was that befor bolting up the brake calliper,the rubber seal for the dust cover was hitting the rotor enough to make it difficult to turn the rotor,once properly alligned the hub spun just fine,i replaced the bearings and races as mentioned ,and found that i needed to exclude one of the 5 shims .003 in order to have propper clearance.now its replace wheels,blead brakes,etc,etc.thanks again,anthony7777,63-bj7