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MG MGA - Play in front wheel hub re-visited..

This's driving me nuts..
I posted earlier about this, got a lot of helpful responses and, keeping them all in mind, went to work and the problem still remains.
The right front wheel has slight play in it, whether I push/pull at the 12 and 6 o'clock position or the 3 and 9 o'clock position.
I put new bearings in; the problem remained.
Everything inboard of the hub is rock-solid; steering knuckle (stub axle), swivel links, steering, everything; none of these components show any play whatsoever when I push/pull the wheel as described above.
The only play is in the hub relative to the stub axle.
When I take the wheel/tire off, and use my finger to push at the 12 o'clock position of the brake disk, it results in about a half a millimeter of play (top, where my finger is) going inward, while the bottom correspondingly goes outward.
If I screw the castellated nut onto the stub axle all the way as tight as it will go, without regard about cotter key concerns, the problem remains.
When I do pull or replace the hub off/onto the stub axle, it does so with the resistance one would expect. Ie: There's no evidence there to suggest that the stub axle has worn to a point where the bearings would have any play relative to the stub axle.
Strangely though, if I place a puller onto the hub like I would do if I were getting ready to pull it off the stub axle, and tighten it only finger tight, the play is no longer there.
All the components are in place; distance washer at the base of the stub axle, large inboard bearing, distance piece, small outer bearing, washer, and castellated nut.
I've also noticed there's a very, very tiny amount of corresponding play at the left front wheel also.
Before investing in a used 1600 hub and/or a new distance piece, distance washer, etc., I thought I'd throw it out to you guys; what do you think's causing it?
Thanks..
L.R. deOlazarra

LR. No way to know what is causing it. You have provided the observed symptoms, but no information on which to make any form of determination as to cause.

Any play at the stub axle will translate into greater play the further from the center line of the stub axle you go. Basic physics. And the further outwards you go, the greater the leverage that will be applied to the stub axle.

You need to measure everything in the hub assembly, crosswise. (Measure at one point, then take the measurement at 90 degrees to the first measurement to determine if things are measuring the same on both planes.) Outside of the stub axle where the spacer and bearings fit. Inside and outside diameters of the bearings along with the thickness of the bearings. Inside and outside diameters of the spacer along with its thickness. Distance from the rear of the stub axle to the end of the stub axle. Depth of the threaded area of the stub axle. Length of the spacer between the two bearings. Thickness of the washer between the nut and outside bearing. Depth of the bearing recesses inside the hub and the diameter of the holes for inner and outer bearings.

All of these measurements, then, need to be compared to a known good set to see if there are any differences, and, if so, whether the differences might be the cause of the perceived problem.

The fact that, when you put the hub puller on and tighten it finger tight, the movement goes away, might indicate that the problem lines somewhere in the tolerances within the long axis of the stub shaft/hub assembly--i.e. something is too thin. But, without taking a series of measurements and comparing them to known good systems, nothing can be checked out in a systematic manner. You might wind up, through trial and error methods, covering up the problem rather than correcting it. Better to work in a systematic manner and find the root cause of the problem.

Les
Les Bengtson

Are you aware that ball bearings come in different grades? This relates to the movement between the inner and outer races.
Do you know what grade yours are?


Mick
M F Anderson

Some websites of interest.

http://americandad.biz/ts/gradechart.htm

http://en.wikipedia.org/wiki/Ball_(bearing)



Mick
M F Anderson

Mick is right on. I had the same prob with SKF 6304 and 6306 bearings from the local supplier. I had to re-order to a "normal" fit vs a C3. This cured the slop. Ask your bearing supplier for a closer fit. There are about 5 different tolerances, depending on end use.
Art Pearse

http://www.ntnamerica.com/pdf/2400/brgclear.pdf

See table 6.3 but should say micrometres, not mm.
Art Pearse

Bearing inner races should be snug on the stub axle. Once you tighten the nut securely the bearings cannot move on the axle anyway. Bearing outer races should be press fit in the hub. If the bearing outer race moves in the hub you need to replace the hub.

The inner race spacer should be exactly the same length as distance between shoulders in the hub, usually not a problem, but you can measure it to be sure. If these two lengths do not match, the bearings would be tight, not loose.

If all that is good, and it still wiggles, you need to replace a bearing or two (too much internal clearance, or worn out).
Barney Gaylord

I was told that bearings intended for use in an engine, specificaly, crankshaft mainshaft in a motorcycle engine, were not suitable for use in a wheel. This, I was told, was because engine bearings have more running clearance due to the fact that they run faster and are subjected to higher temperature than would be experienced in a wheel. Fitted in a wheel, such a bearing would give too much movement. So although a bearing may look and fit the same as the one you are replacing, it must be the correct one for that particular application. The reverse situation happened to a chap I knew a some years ago. He needed a new bearing for the crankshaft in his ancient motorcycle and managed to find one with all the correct dimensions. It wasn't long before the bearing was making awful sreaming noises and was found to be completely worn-out. Turns out the replacement bearing was a wheel bearing.
Lindsay Sampford

Thanks to all for your responses.
I had no idea there were different grades of bearings.
The bearings I have show "6306" on the inner and "6304" on the outer bearing.
Art; you changed from the above numbered bearings to something that addressed the problem. Do you recall what the nomenclature or numbers of the bearings are that eliminated the play so I'll know what to say when the supplier asks what I'm looking for. (I checked out your supplied .pdf file, but my ignorance of the subject made the contents incomprehensible). :)
A thought comes to mind; since I obtained the bearings from Moss which is a MAJOR supplier of Brit parts here in the U.S., there's got to be a lot of MGAs out there that're running around on these bearings, unless Moss changed their source recently. Can all these MGAs have play in the hub? Anybody with Moss bearings into jacking up the front and checking for play? Maybe it's acceptable or normal to have the play? The play is very slight; just enough to feel(and hear).
Again, thanks for the help and suggestions.
L.R. deOlazarra

L.R, I used SKF 6306 and 6304 bearings - that is the size number. Then you can specify a CN or a C2 clearance. C2 is the tightest CN is tighter than what you would put in an electric motor. C3 is what you get if you don't say. I used CN and found it was good. You should go to a commercial bearing supplier who can get you anything. I used Motion Canada, a part of Motion Industries. You should have no trouble locating a supplier in California. But first make sure your existing bearings are not sloppy fits on the spindle or housings.
Art Pearse

http://www.globalspec.com/local/2778/CA
Art Pearse

Thanks, Art; I'm SO much better clued in to what the nature of the problem may be. The GlobalSpec link saves me time too; appreciate it..
L.R. deOlazarra

L.R. I've been following this thread with interest because I have the same type of minor front bearing play in my 1600 after a complete restoration on the right side only. The left side is ok. I even replaced the hub with a brand new one and installed new bearings from SF, not Moss, and after about 500 miles the minor play returned. So it looks like SF and Moss use the same bearings. I didn't know that there were different grades of bearings and it looks like I would need to replace the bearing with a higher spec to get rid of the play. The car runs great and there's no sign of any play while driving so I'm going to leave it alone for the time being. Let us know if you replace your bearings and if it makes any difference.

Andy
Andy Preston

Ball bearings do have different internal clearances as mentioned, C3 being the most common "precision" bearing. The ABEC numbers cover component tolerances, but don't really say anything about the actual assembled clearance in a usable form. That is, you could have very close tolerance components, but the assembled clearances can be tight or loose as required. The C* used to be stamped on the race, but that appears to have gone away as tolerances got generally more accurate, resulting in more predictable assembled clearance as "standard".

Barney's comments are exactly correct, and in that condition the play is determined by the tighter of the two bearings. This is subject to tolerance stacking, giving more or less play in the assembly.

It is my belief that spacers were originally selected to suit the hub they were assembled with, but these matings get lost with time. If the spacer is too long, the outer race of one or both bearings moves out over time, again resulting in the tighter bearing clearance being the controlling factor in wheel play. If the spacer is too short, the bearings are preloaded, giving no play but possibly overloading the bearings. This gives the obvious strategy of shortening the spacer by a very small amount to preload the bearings in opposition to each other, effectively loading them as angular contact bearings - not to be overdone!

Note that as the hub heats with use, especially braking, the bearings will get tighter as the hub expands lengthwise. For this reason, the early specs for many brake assemblies called for C3 or "slack fitting" bearings, especially on alloy hubs, as motorcycles.

Bottom line is that if the bearings fit correctly on stub axle and hub, and wheel play is not actually causing a problem like knocking back disc pads, leave it alone.

FRM
FR Millmore

Sheesh; decisions, decisions.
In light of FR's comments, I'm going to slap it all back together and leave it as is. Then I'll take it up the local mountain, turn around and heat up the brakes/hubs about as hot as they're ever likely to get and see if the play been reduced or eliminated. If it has, fine; end of story. If not, I may still just leave it and check the play now and then for additional play; for all I know, the car's been like that since I got it 5 years ago-I only noticed it lately. If it gets worse, I'll know where to put my attention, thanks to the help on this forum. Cheers.. :)
L.R. deOlazarra

LR -have not read your earlier post but have you told us what the play is in the vertical/horizontal axis with the wheel on? Barney gives some advice on a range of acceptible tolerances and makes the point that ordinary ie non tapered bearings will tend to have some play. I went through this when rebuilding my suspension and because my previous car had tapered bearings with no play I kept trying to replicate this. I ended up fitting new hubs and bearings that produced less play but after about a weeks driving the play went back to almost what it was in the first place. I'm not saying you haven't got a problem but just bear in mind that most MGA's have some play in the wheels arising out of the hub/bearing set up.
J H Cole

As long as it is small enough to allow you to set the toe-in accurately enough.
Art Pearse

LR
Does this play result in a wheel shimmy when you drive the car? And if it does does it start to show up around 55-60 mph?
Gordon Harrison

Thanks for the comments, JH; nice to know.. that's not the first time I heard of wholesale new part replacement resulting in a fix, only to return to the previous condition after several hundred miles.
Hi Art.. I haven't been implementing any toe-in, instead aligning the wheels in a parallel configuration after reading the admonition & guidance outlines from various sources; the Haynes manual comes to mind for one, and other sources that I can't recall at the moment. I know there's two camps on this; the parallel setup seems to work ok for me.
Gordon; yes, I used to have shimmy and vibration at just about the speeds you referred to. Then, when getting the tires/wheels balanced, the technician declared he couldn't balance any of them because the wheels were out-of-round. That's where the shimmy came from. Turns out this isn't uncommon on MGAs. I like the original wheels, but where was I going to find a set that were guaranteed true? So I finally went to Moss and bought a set of Minilite replicas and put new 195/65-15 tires on them, resulting in better handling, no more shimmy, and a $1200 reduction in my bank account. Then Murphy's Law kicked in and I ran across a shop that specialized in trueing up wheels. They fixed all four originals and they're back on the car; no shimmy. (The virtually new Minilites/tires/lug nuts are for sale, dirt cheap, if anyone's interested).
L.R. deOlazarra

L.R. what shop did you use in Ca to true your wheels and how much did they charge. I'm thinking of putting my origianl wheels back on my car.

Andy
Andy Preston

Andy; go to www.stocktonwheel.com. They did all four wheels and bead-blasted them for about $350. There's also the shipping charge you'll have to pay to get the wheels to them. I primed them and used the Moss wheel paint for the final coats. The only downside is turnover time; it took upwards of two months for me to get the wheels back; they were apologetic though, indicating the long turnover wasn't the norm. They're located in Stockton, Ca.

-LR
L.R. deOlazarra

Also Valley Wire Wheel in Van Nuys and Pico Wheel and Tire in North Hollywood.
Steve Simmons

This thread was discussed between 01/01/2010 and 05/01/2010

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