57 replies to this topic

[MRA]

I NEVER hammer on the bearing! As explained earlier I use an old inner race as a spacer/drift, split (or alternatively, reduced in diameter by a couple of thou, which us extremely tedious unless you have a suitable grinder) to avoid it jamming in the hub. And, no bigger than a 4 ounce hammer.

 

But an old inner race is hard and can lead to damage on your new bearing, or small chips from entering the new bearing, either are detrimental to the health of the bearing, whereas softer material can at least be squashed and pushed out the way etc...  or fairly easily cleaned out.

[AlexMozza]

You can buy tools for fitting bearing races ect, not much money. A quick look on eBay should find some.

[tiger99]

Yes but when you need one NOW because the Mini is your vital daily transport, as mine were at one time, that is just not an option. But threaded rods and large washers were used quite frequently as substitutes for various official tools.

And intelligent use of the hammer, preferably softish, does not result in metal chips in the bearing. It seems that the skills of the old mechanics have been lost and people don't seem to believe that such primitive methods actually work. The next generation will not even be able to use a bearing insertion tool unless it is interfaced to their iDiotphone or iDiotpad.... Is that progress? We will all be driving Mercs with sealed bonnets soon... (Actually Brexit may save us from that horror, which is coming upon the EU.)

I will be getting a lathe once other higher priority tasks are complete, and then, not just to keep you guys happy, I will actually make some proper bearing insertion and removal tools. I do agree that when there is the opportunity to use such things they should be the tool of first choice. But lack of a tool should never leave anyone stuck with no way if changing their bearings, which is the only reason that I became involved in this thread.

[MRA]

I NEVER hammer on the bearing! As explained earlier I use an old inner race as a spacer/drift, split (or alternatively, reduced in diameter by a couple of thou, which us extremely tedious unless you have a suitable grinder) to avoid it jamming in the hub. And, no bigger than a 4 ounce hammer.

I was referring to this comment, as it appears you use an old bearing to tap in the new bearing, as this is 2 hardened parts together chipping can easily occur...... 

[tiger99]

I fully understand what you mean. The two races are kept in close contact which makes chipping unlikely. The hammer is most at risk of chipping, but before it was stolen I used one with a hard plastic face. It doesn't need the enormous "g" force of a sharp metal to metal impact to shift the bearing, more the dull thud of a lead shot filled non-bouncing hammer.

 

I am sure that the bearings are very hard indeed, especially Timkens, but that is accomplished partly by alloying elements rather than making them brittle by simple heat treatment. Otherwise, road shocks might cause the races to crack.

 

In adverse circumstances it is more important to get the job done than worry too much about things that usually don't happen. But in the course of a business or something like a full restoration the economics are different and I would not dream of doing it that way, I will need a press anyway for my future plans. But that would be of no help to someone who carries tools and basic spares, and has a bearing fail miles from anywhere. That is where the apparently primitive methods can be a real life saver, and why they should be known,

 

Last time I actually did a Mini that way, a Timken, boxed as Unipart, was about twelve quid and lasted the remaining life of the car. I have never had a premature failure of a bearing I have fitted. Not quite so successful with some other parts...

[MRA]

I fully understand what you mean. The two races are kept in close contact which makes chipping unlikely. The hammer is most at risk of chipping, but before it was stolen I used one with a hard plastic face. It doesn't need the enormous "g" force of a sharp metal to metal impact to shift the bearing, more the dull thud of a lead shot filled non-bouncing hammer.

 

I am sure that the bearings are very hard indeed, especially Timkens, but that is accomplished partly by alloying elements rather than making them brittle by simple heat treatment. Otherwise, road shocks might cause the races to crack.

 

In adverse circumstances it is more important to get the job done than worry too much about things that usually don't happen. But in the course of a business or something like a full restoration the economics are different and I would not dream of doing it that way, I will need a press anyway for my future plans. But that would be of no help to someone who carries tools and basic spares, and has a bearing fail miles from anywhere. That is where the apparently primitive methods can be a real life saver, and why they should be known,

 

Last time I actually did a Mini that way, a Timken, boxed as Unipart, was about twelve quid and lasted the remaining life of the car. I have never had a premature failure of a bearing I have fitted. Not quite so successful with some other parts...

 

In fact Timken are not as hard as cheaper brands because they use a better quality steel, cheaper brands using a lower quality steel will need to be hardened which due to the properties will in most cases be a fair bit harder.

 

I would suggest that in future if you are suggesting a bodge that you make that clear !

[tiger99]

It isn't a bodge except in the hands of incompetents. The technique has been widely used in industry for well over 50 years.

[MRA]

It isn't a bodge except in the hands of incompetents. The technique has been widely used in industry for well over 50 years.

 

Using a hard bearing to tap in another hard part is a bodge, defiantly NOT used widely in industry, and certainly not over the last 50 years, maybe the last 5 years by uneducated mechanics. 

 

You will not find it in any text book of repute or any training establishment !

 

But the technique which wasn't in question has been used since bearings were first invented, just not with 2 hardened steel parts together, copper, aluminium, brass anything softer would be used but never a hardened bearing onto another hardened bearing !

Edited by MRA, 21 November 2016 - 02:43 PM.

[tiger99]

The two hard parts do not impact each other. They are held in constant contact. It is the fairly soft hammer that impacts the old bearing race. And if it us as bad as you say I would have damaged several. That did not happen.

[foreverfixin]

I have just finished dismantling my drum brake front hubs. These were found to be equipped with roller ball type bearings. Using the dismantling procedure described in Haynes the bearing inner races were tapped out followed by the outer races, all for cleaning and assessment for potential reuse. tiger99 says, in the second post of this topic, that "these bearings always fall apart and are ruined when removed". So, my question is this - is Haynes completely wrong to suggest that the bearings can be reused if the components "are in a satisfactory condition"? I was fully intending to reuse the bearings as they are in excellent shape but after discovering this discussion I am left thinking that I ought to be buying new (which could be of lesser quality than those I already have). Dilemma! What does the panel think?

[Spider]

I have just finished dismantling my drum brake front hubs. These were found to be equipped with roller ball type bearings. Using the dismantling procedure described in Haynes the bearing inner races were tapped out followed by the outer races, all for cleaning and assessment for potential reuse. tiger99 says, in the second post of this topic, that "these bearings always fall apart and are ruined when removed". So, my question is this - is Haynes completely wrong to suggest that the bearings can be reused if the components "are in a satisfactory condition"? I was fully intending to reuse the bearings as they are in excellent shape but after discovering this discussion I am left thinking that I ought to be buying new (which could be of lesser quality than those I already have). Dilemma! What does the panel think?

 

If it were me, I'd be fitting new bearings while it was in bits. You can fit either Timken Tapered Bearings or a quality Ball Type, If the Bearing does let go, 99 times out of 100, it also does a fair bit of damage to the Drive Flange and usually the Hub too. Drum Brake Hubs are getting harder to find.

[foreverfixin]

Okay, new quality new bearings it is then. That means that, if it becomes necessary, I can chop off one of the inner races that remains stuck on the drive flange! Thanks Moke Spider for your prompt reply. Happy New Year.

[Spider]

, I can chop off one of the inner races that remains stuck on the drive flange! Thanks Moke Spider for your prompt reply. Happy New Year.

 

Remove the Inner Race from the Drive Flange for sure, but you might already find if it's like that, then the Flange is Cactus.

 

Happy New Year to you too , Cheers

[foreverfixin]

Right, in my last post I said that I would get new high quality bearings. Since then, knowing that it didn't matter if I damaged it, I've removed the inner bearing race from the offside drive flange using a bit of heat and a big pair of mole grips. The shaft of the drive flange was found to be in very good condition. However, there is some wear and pitting on the inner end of both flange shafts, enough to make me wonder if they should be reused. So, in addition to new bearings both sides it's now looking like new drive flanges also, which has had me thinking about dimensions . . .

. . . having studied Moke's cross-section of the complete drum/hub assembly I'm still not totally sure about this whole front wheel bearing thing. I realise that my new taper roller inners will need to be tightened somewhat into their outer races. This will result in the inner face of the drive flange squeezing the entire bearing/spacer assembly onto the CV? Now, whilst all that is going on, and this is where my confusion lies, is the inner end of the drive flange shaft meant to be simultaneously squeezed onto the CV by the same torque? If so, to achieve this, the dimensions of the drive flange shaft, hub casting and bearing/spacer assembly will have to be extremely accurate and I don't see how this can be. Surely there's got to be some tolerance somewhere? For example, it has been said that the width of the central register in the hub can vary between 10.20 and 10.40mm and also the total thickness of replacement bearing kits are not all the same.

Forgive me for rambling on, I hope what I've written is understandable. I'd like to have a clearer picture than I already have so that when it comes to reassembly I know what's what.

[Spider]

I'll need to re-read your post here to get my head around it all, however, I did pick up on this part of it;-

 

 and also the total thickness of replacement bearing kits are not all the same.
 

 

and herein probably lay some of the differences between quality bearings, like Timkens and some of the cheaper replacements.

 

I do know Timkens are held to some fairly close tolerances, however, this is also why the Timkens are a matched assembly that shouldn't be mixed with parts from another assembly. With each and every Matched Set for a Mini, they measure the Cones and Cups, then supply the matching spacer to give the correct Bearing Assembly Pre-load. They even engrave their size numbers on all the matching parts.