• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

MGB MGB Wheel Bearing Video

Share this page

So, what was different or new about how he assembled the hub than how you've ever done it?

& I'm trying to figure out how anybody could put one together wrong? Unless they leave the shims out.....but, you really don't need the shims:

https://www.theautoist.com/spacers&shims.htm
 
I think it's nice for people to actually watch somebody do it. It is a lot clearer than reading the Haynes.
 
I just love his videos. They do illustrate things better than the manual. One thing that has me worried, I don't recall having the spacer described in the video. I have wire wheels, so I am not sure that it needs it. It has been many years since I have had the hubs off the car, so there may be spacers in there, but I don't remember taking out a spacer when I did the bearings. Maybe I should take them off quick and check.
 
Ron - read the tech tip on my website that I linked to in my answer...you don't need the spacers.
 
Thanks Tony, I figure the car has not had the spacer in there for since 86, so I really was not in a hurry to put one in there. I have never used shims as the video described, and those bearings must be 15 years old.
 
I just don't understand why anyone would skip the bearing shims. Regardless of whether or not the spindle will survive without them, they significantly increase the strength of a critical steering component. Is an extra ten minutes such a burden? I'm with Mr. Twist on this one. Assemble the car as it was designed.
 
Steve S said:
they significantly increase the strength of a critical steering component
Click to expand...

Gotta disagree there, Steve..they don't add strength, they allow you to apply torque.

Using or not using the shims is really a personal choice. With the shims you work to a torque spec, without them you don't.

The MG's design isn't unique to MG - but other cars with the same design do not use shims...the difference is MG specified a torque for the castle nut/cotter pin on the end of the stub axle where all other cars of the same design do not specify a torque for the castle nut/cotter pin.

Guess I'll quote from the tech tip: "To be in step with the rest of the world leave the spacer and shims out. Tighten the nut good and snug, turn the wheel a half turn or so, loosen the nut, and turn it right lightly until you feel it make contact. Wiggle the wheel and if you feel any play or looseness tweak the nut a little tighter until that play is gone. If the cotter pin hole doesn't line up back off to the first cut in the nut that will. Some spindles have two cotter pin holes, one vertical and one horizontal. Catch the closest one you can and insert the pin.

The reason for tightening the nut and turning the wheel the first time is to press any excess grease from between the rollers and the cup. When you back the nut off and re-set it lightly there will be a slight float, but you won't feel it. Sometimes you can after the car has been driven a few miles. Most cars have no cuts on the nut, but have a "tin" nut with cuts for the cotter pin that slips over the "real" nut. You have infinite adjustment with them. My MGB is the only car I ever worked on that had shims in there. No other car, trailer, tractor, or anything else had them, nor needs them, and the bearing, spindle, and hub configuration is the same as an MGB."

...& here's anther note on it:

"Those bearings are going to do exactly the same thing with or without the shims. Those cones don't float on the spindle either way, the angles on the bearings take care of that.

Look at this picture, study it a while, think about it. It all comes out the same with or without the shims, it's just that the conventional way of adjusting them is much quicker and easier. The taper on the bearings assure everything will work as it should, shims or no shims, so long as the preload or float is adjusted properly. The key word being properly, not precisely, this isn't rocket science you have a little leeway."

FRONTWHEELBEARINGS.jpg


John Twist is absolutely correct in describing the way they were installed/torqued at the factory...finding the correct shim combination when rebuilding them is the tricky thing, especially when you replace bearings since all bearings have minute differences in them from others.

Like Ron, many of us have run safely for years & years without those little spacers...
 
I will agree with Tony. Tapered bearings ~when properly loaded~ are fine without the need to go through the shim and spacer routine. Additionally: when actually doing it the spacer 'n shim way there is the possibility to damage the cups and rollers if the shimpack is too small and the nut is torqued to spec's. It'll "dent" the cup with the rollers and you've a brand new damaged bearing set. Better to do it by "feel" IMO.
 
Yep Steve you are spot on. Whether the car experiences excessive loading or not the spacer creates a loaded coll um which strengthens the Axel. The shims are required to offset manufacturing tolerances in the spacer to achieve zero end float and no binding of the bearing. However, to reinforce the Axel the unit should be torqued up tight.--Fwiw---Keoke
 
Keoke said:
However, to reinforce the Axel the unit should be torqued up tight.
Click to expand...

Guess I've gotta ask this question: If the specified torque is so important, then why do you either back off that torque or add to it to get the castle nut to align with a hole for the cotter pin?

Which brings a second question: If the torque is important, to maintain that important torque, do you add or subtract shims so that, when torqued properly, the slots in the castle nut align with the cotter pin hole?

Either the torque is important or the cotter pin is - both can't be.

....&, finally, how can those tiny, thin, multiple shims add strength? I would think, if anything, they are weak points.
 
Hi Tony, Most other British cars that use this same design allow a 20 Foot Lb range on the end torque requirement to allow one to align the castellated nut with the split pin hole. But finger tightening is a no no. The shims are under compression and just become a small extension of the spacer. consequently, you can achieve adequate torque on the nut and alignment with the split pin hole.--Fwiw--Keoke
 
So, loading the hubs without the shims or torque as in the tech tip on my site accomplishes the same thing as installing them with a +/- 20-lb torque rating..only, doing it without the shims actually provides more strength as the shims don't necessarily compress completely unless adequate torque is applied & inadequate compression = weakness not strength.

Again, I've gotta go back to many, many years of driving without problems by lots of MG owners who tossed their shims without incident as proof the shims/"so-so" torque rating is overkill.

Wish I could rate threads in the MG Forum as this is a good one!
 
No Tony, the 20 Lb torque range is in addition to the required torque range for the design. This simply says that the maximum specified torque - a maximum of 20 lbs is OK. This is because the additional 20 Lbs added pushed the required torque spec into its asymptotic range. Which says the stiffening of the entire assembly above the required design level with the additional 20 Lbs of torque applied is incrementally small and can be tolerated during assembly if partially reduced within that range to line the hole, castelated nut and the split pin up.---Keoke
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Gotta disagree there, Steve..they don't add strength, they allow you to apply torque.[/QUOTE]
The spacer, bearings, shims, etc all act as one unit. They are sort of an "outer spindle", stiffening the inner spindle through compression. If they are not compressed together they become a bunch of separate pieces, doing nothing to strengthen the spindle assembly.

The shims do not allow you to apply torque specifically. They simply allow you to achieve the proper torque without smashing the bearings, which is not possible without them. You will always run loose without shims unless you are extremely lucky with the size of the spacer.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Guess I've gotta ask this question: If the specified torque is so important, then why do you either back off that torque or add to it to get the castle nut to align with a hole for the cotter pin?[/QUOTE]
Because you aren't using shims. With shims, you do not back the nut off. You achieve the proper torque setting and insert the pin to keep it there.

Setting end float and lining up the split pin are separate jobs. Once end float is set and the nut torqued properly, you can shim the large washer to line up the castellated nut with the hole. Alternatively you can file or sand down the nut or washer to line it up. A belt sander makes this job very quick and easy.
 
Steve S said:
They simply allow you to achieve the proper torque without smashing the bearings
Click to expand...

& that is the only thing the shims do!!

They don't add strength because they are never fully compressed - & neither are the bearings fully compressed (were they, they wouldn't turn freely)...thus, the bit about "The spacer, bearings, shims, etc all act as one unit. They are sort of an "outer spindle", stiffening the inner spindle through compression" is a fallacy: as an entity, they are never fully compressed!

I think a person can shim or not shim - & either way, if set up correctly, is okay.....some of my cars have shims, some don't...I just finished my '74-1/2 GT before I left, taking the hubs apart for the first time since it left the factory...one side had 2 shims, the other had 3...neither have shims now!

Discussions like this are what makes a thread like tihs one so valuable.
 
Well, bit of a difference here.

Let the battle lines be drawn!

I will come down on the side of Doc and Tony. Why, experience.....

Also a little input on the torque thing. MB's were heavy into the torque setting on 107's and up to 119's. Even made it such a high priority that if the hole did not line up with the specified torque you were to install new washer(s) of varying thicknesses. So theoretically you would be going back and forth to the parts counter a number of times to get the proper washer. One day I asked the Special Services Advisor, who came out to look at the EGR problem that the M classes were having when they first came out. Special services advisor is MB's field engineer designed to travel from dealer to dealer investigating and resolving technical problems.

He told me, tighten to lockup, back off to pin opening. recheck in 1000 miles. This was one of the MB tech specialists. They no dummies.
 
The engineers at Abingdon were no dummies either, and they used shims for 56 years.

* Using shims makes for a stronger steering spindle.
* A stockpile of all size shims will cost a couple dollars.
* Installing them takes only a few extra minutes per hub.

The job is done once every several years on a daily driver, and once per lifetime in a Sunday driver. I just don't see the point in leaving them out.

I'm not trying to argue the point, I honestly can't understand the reason for skipping such a minor step in a much larger job.
 
Steve S said:
and once per lifetime in a Sunday driver
Click to expand...

An aside but true, Steve...like I said, my '74-1/2 GT just rolled over 85,000 documented miles..I pulled the hubs for the first time this summer & they'll probably never be pulled again in my lifetime....& the only reason I did it now was because it needed brake pads & I figured what the heck & rebuilt the stub axles and calipers while I had the front end jacked up.

Steve S said:
I honestly can't understand the reason for skipping such a minor step in a much larger job.
Click to expand...

It could take a couple times pulling everything after torqueing things up to get the right 'float' (too tight so add a shim or too loose so take one out, change sizes a couple of times, etc.) & even that's no big deal...I just don't see a real need for them.

Plus, its a great discussion!
 
I never thought this would go to these lengths. I guess my DPO pitched the spacers on my car years ago, as I pulled the hubs this afternoon to clean and repack the bearings. There was no problems with them, so I just repacked and reassembled the hubs. They seem good to go for another fifteen years or so. Unless I put on my drilled and slotted rotors /bcforum/images/%%GRAEMLIN_URL%%/smile.gif
 
Back
Top