To lap or not to lap?

[steve.thomas]

Hi everyone,
I've got a problem with a loose rear hub on my Plus 2. I had new wheel bearings fitted and after approx 150 miles the hub came loose on the driveshaft - luckily i noticed it before the wheel came off. On inspection I could see no obvious damage to either hub, shaft or key and so reassembled with a new hub nut and torqued up. But there is still some play that can be felt by hand if rocking the hub on the shaft. I'm sure the play is between hub and shaft rather than anything else, and it is very easy to pull the hub off again which I don't think should be the case. I've looked thru the archives and there is a lot of mention of lapping the hub to shaft, but opinion seems split as to whether this is a good idea or not. Given my situation I'm going to be faced with a new hub and/or shaft so it seems I have little to loose. Can this be done with the shaft still on the car, as I'd rather not disturb the new bearings if possible. I'm not an engineer by background and cannot find any description of exactly how you perform 'lapping' - do you actually turn the hub thru 360 degrees or just back and forth close to it's final position? Is there any special cleaner to use afterwards to remove the grinding paste ?
Thanks for any advice.
Steve

[AussieJohn]

Was the hub distorted by heat or a "not so good" puller? Maybe another hub needed.

[andyelan]

Hi Steve

I personally am not in favour of lapping except as a last resort, particularly if you want to keep the bearings in place. If the parts were made correctly and are not damaged then it shouldn't be necessary.

There are a few things however that you should look at first as somthing must be stopping the hub correctly seating. Often I find the key is the problem as it has a tendency to push too far down the groove and ride up where the groove runs out. Check the fit of the hub on the shaft without the key and look for any burrs or polished high spots on the shaft. These need to be removed ceasfully with a stone. Often the edges of the keyway can become slightly raised or the hub can also build up a ridge around the area which was not in contact with the shaft these will need to be removed. Also the key need to be polished to remove any rust or burrs

As a guide, if you put the hub on the shaft and hit it with the flat of your hand, then it should not come off except with a light tap from a hammer. If you can pull it off by hand then somthing need to be done.

Hope this makes sense

Regards
Andy

[bob_rich]

Hi Steve

If you have a problem with the location peg or a few burrs on the peg or the channel these can be cleaned off as described in other posts. Once the peg and grove are checked and cleaned up To check if the fit is good ( once it does not rock which obviously is not good ) coat the shaft using one of the bright coloured marking pens used to highlight parts in documents. Fit and tighten up the hub fully then remove it. See how much of the marker die has been removed other post suggest at least 80% contact is required to confident. There are a lot of posts on this subject that should help.

The other thing I found is that the thick washer (3mm or 1/8") that goes under the 5/8" nut can bend and possibly bottom out preventing the full force being applied to the hub/shaft taper. I had new washer made up for mine and made them as thick as I could after checking the tolerance on my assemblies.

Hope this helps best of luck

Bob

[garyeanderson]

Hi Steve

I spent some time on the following post and the subsequent follow up to this problem last summer. Maybe ask Greg, as it is still fresh in his memory. There is a lot of good info on this forum if one is willing to read and filter out the garbage. There are 4 pages of talk on the following post, if you missed it please have a read and it some of the info may save you from doing things twice.


elan-plus-f13/replacing-right-rear-hub-key-t21071.html

[GrUmPyBoDgEr]

Hi Steve

I spent some time on the following post and the subsequent follow up to this problem last summer. Maybe ask Greg, as it is still fresh in his memory. There is a lot of good info on this forum if one is willing to read and filter out the garbage. There are 4 pages of talk on the following post, if you missed it please have a read and it some of the info may save you from doing things twice.


elan-plus-f13/replacing-right-rear-hub-key-t21071.html

Well done, that man!

[ecamiel]

This may be heresy but I used Locktite "Bearing Mount" for a trackside fix that worked for perfectly for years. I only redid it properly when I took everything apart for magnaflux.

Eric
64 S1 Hart

[ardee_selby]

This may be heresy but I used Locktite "Bearing Mount" for a trackside fix that worked for perfectly for years. I only redid it properly when I took everything apart for magnaflux.

Eric
64 S1 Hart

Eric,

Needs must and all that. From (http://rallyelan.com/previous-rallies/previous/) :

"The local lathe operator had shaped a new outer half for the shaft, cut the old shaft between the two bearings and welded the two together. The keyway was cut with the precision engineering technique of putting shaft in vice and applying angle grinder! It worked and the shaft has already done 2,500 miles of tarmac, desert, beach and washboard"

Quite astonishing (and not a mention of any lapping!)

Cheers - rd

[ardee_selby]

Steve,

You have a PM.

Cheers - rd

[steve.thomas]

Many thanks to everyone who responded with help and information - really appreciated. What a fantastic thing this forum is !!!

Today I've lapped the hub to the shaft and achieved a much better fit - as was suggested a light push with palm of the hand now requires a tap with a hammer to remove the hub. I bolted it up confident that the play would be eliminated - and I think it has been, at least between hub and shaft, but I can still feel some play which must be in the (brand new) wheel bearings. I believe this is the case as if I hold onto the brake disc it impacts the amount of play i can feel - which to me implies the play is in the shaft. Is it acceptable to have any discernable play at all in the wheel bearings ? If not I'm not sure what to do next.
Steve

[ardee_selby]

Steve,

I'm hesitant to say this

What was the scenario that lead up to the bearings being replaced? And when you said "I had new wheel bearings fitted..." I assume it was done by a.n.other. Correct?

So would you happen to know the condition of the shaft bearing surfaces, and bearing housings in the strut, after it was dis-assembled? I don't want to be a Job's comforter here, but what you describe doesn't sound right for new bearings.

Knowing what was done and, more importantly, how it was done could give us some clues.

Cheers and good luck - rd

[paddy]

I think some end float is expected, even with new bearings. Double check and see if the movement you are feeling is axial or radial wrt the shaft.

Paddy

[steve.thomas]

The background to this scenario is that I was replacing badly worn rotoflex couplings with Sue Miller CV joints, and while most of the rear suspension was apart decided to replace the n/s wheel bearings as they were very noisy - although they didn't have a lot of play in them. I took the complete hub carrier to a local Lotus specialist to replace the bearings as I don't have the correct hub puller or ability to press in new bearings etc. Therefore I'm afraid I can't comment on the condition of the shaft or hub carrier internals. I'm pretty sure there is more play now than before I started, but it's hard to say - I'm probably being more critical given that they're new components !!
Steve

[andyelan]

Hi Steve

Sorry to have to tell you this but I had the very slightest movement of the rear wheel, similar to what you describe, but fitting new wheel bearings completly eliminated it. There's now no movement of the wheel at all. I can't say I noticed too much of an effect on the way the car drove though, main issue was a knocking noise from the rear when driving on rough roads.

I would suggest rocking the wheel while someone is pressing the brake pedel. If the play disappears it would suggest the problem does lay with the bearings, possibly their fit in the housing. If the play doesn't disappear then that would sugest play in the suspension pivots.

One final point, do you have CV joints or rubber donuts in the drive shafts. I have found small amounts of play in the suspension / bearings can be masked by the tension applied by rubber donuts. I only discovered the play in my wheel bearings after I had switched to CV joints

Regards
Andy

[steve.thomas]

Just to close this thread out, here's an update on what has happened. I took the complete hub carrier assembly to Miles Wilkins at Fibreglas Services. He quickly identified that the inner bearing had been fitted the wrong way round and the inner circlip was missing, resulting in some play in the shaft. On inspection the thread on the end of the shaft was slightly damaged, so a new shaft and bearings were fitted. All this was done in about half an hour while i waited - great service! It's now back on the car and all play has been eliminated. Do I get the record for the shortest wheel bearing life - 150 miles !!

Thanks again to those who replied and to Brian for the telephone support - much appreciated.
Steve