Rear bearing endfloat adjustement

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Rear bearing endfloat adjustement

Postby Giniw » Thu 04.08.2016, 14:34

Hello Everyone,
A while ago I noticed that my rear wheels had quite a lot (?) of play in my own unexperimented opinion when pushing the wheel on the top (please see the green arrow on the enclosed picture)
Anyway, I decided I had to check and adjust the endfloat.
I followed the procedure (tightened to 25N.m, slackened the nut and tightened again with fingers) and it appears that there is exactly the same feeling when jiggling the wheel.
I guess this could be normal after all, but I am curious to know whether that sounds OK to you, too? :poke:
Thank you in advance!
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Re: Rear bearing endfloat adjustement

Postby lotusflasherman » Thu 04.08.2016, 19:17

Just been checking mine. I fitted new hubs to take removable discs, & new bearings, several months ago and you had me wondering if I might need to re-adjust them... answer - No.
With the pads prised clear of the discs, I can spin the wheel and it rotates several turns before it stops but there is no detectable lateral movement at all.

My technique is to put a socket on the nut so I can get a good grip by hand but I cheat and use finger and 'opposable thumb' :lol:, then I re-tighten by hand but how tight I go depends on where the next alignment of hole & slot for the split pin will be.

I'd recommend you to see if you can get the nut round to the next split pin alignment position without too much effort and see what that feels like. If the bearing is too tight the wheel will stop very quickly if you try to spin it - but make sure pads aren't dragging on the disc or you won't be able to tell.
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Re: Rear bearing endfloat adjustement

Postby Giniw » Thu 04.08.2016, 19:19

Thank you very much :)

lotusflasherman wrote:My technique is to put a socket on the nut so I can get a good grip by hand but I cheat and use finger and 'opposable thumb' :lol:
lol yes I did it exactly the same way :-D

then I re-tighten by hand but how tight I go depends on where the next alignment of hole & slot for the split pin will be.
The slots were almost perfectly aligned when the nuts stopped rotating when tightening with my fingers so I didn't go any further.

I'd recommend you to see if you can get the nut round to the next split pin alignment position without too much effort and see what that feels like.
The effort wouldn't be huge indeed as 25N.m is rather low, but as far I remember the wheel still spun more or less freely with the nut tightened at 25N.m (although I am not 100% sure here, I will have to check again)
FYI, when the bearing nuts were tightened to 25N.m I couldn't feel any play at all.

Are your bearings any different from stock since I understand you have after-markets hubs?
Last edited by Giniw on Thu 04.08.2016, 19:34, edited 4 times in total.
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Re: Rear bearing endfloat adjustement

Postby lotusflasherman » Thu 04.08.2016, 20:15

Giniw wrote:Thank you very much :)

lotusflasherman wrote:My technique is to put a socket on the nut so I can get a good grip by hand but I cheat and use finger and 'opposable thumb' :lol:
lol yes I did it exactly the same way :-D

then I re-tighten by hand but how tight I go depends on where the next alignment of hole & slot for the split pin will be.
The slots were almost perfectly aligned when the nuts stopped rotating when tightening with my fingers so I didn't go any further.

I'd recommend you to see if you can get the nut round to the next split pin alignment position without too much effort and see what that feels like.
The effort wouldn't be huge indeed as 25N.m is rather low, but as far I remember the wheel still spun more or less freely with the nut tightened at 25N.m (although I am not 100% sure here, I will have to check again)
FYI, when the bearing nuts were tightened to 25N.m I couldn't feel any play at all.

Are your bearings any different from stock since I understand you have after-markets hubs?


Bearings same as OE and in fact I fitted new ones that came out of genuine Lotus branded bags as I had them, rather than bearings that came with hubs. (Also got couple of sets of 'pattern' bearings supplied by Chris Neil many years ago. )
Did 130,000 miles in my first SE and wore out two sets of rear discs so got quite practiced at fitting new discs. (Seems my rear brakes work!) First set came without bearings so second time I ordered discs and bearings and those discs already had them fitted.. :banghead:

When I slacken the nut I try not to disturb the bearing seating and re-tighten by hand 'quite hard' to find the next split pin position. If it comes 'too easy' I'll go for the next one... The manual says "If necessary, tighten further, the smallest amount necessary to insert the split pin." My 'engineering judgement' tells me if wheel spins freely but doesn't wobble it must be about right... :lol: If it wobbles, tighten a bit more.
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Re: Rear bearing endfloat adjustement

Postby Giniw » Thu 04.08.2016, 20:57

Thanks you very much.
The question is, will I be motivated enough to do that before my 430mi trip tomorrow? :lol:
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Re: Rear bearing endfloat adjustement

Postby Simon_P » Thu 04.08.2016, 22:10

There should be some play - It is a taper roller bearing!

You are adjusting the end float not removing the end float. Do exactly what it says in the manual and not a flat more.

If it doesn't wobble it is too tight. The bearing will warm up in use, as it expands it takes up the play.
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Re: Rear bearing endfloat adjustement

Postby Giniw » Thu 04.08.2016, 22:48

Oh thank you, too, I must admit I didn't think to the thermal dilatation effect! That makes sense.
That will be interesting to check again when it's hot.
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Re: Rear bearing endfloat adjustement

Postby lotusflasherman » Fri 05.08.2016, 03:23

It will expand and tighten slightly when hot but should still spin freely. If it doesn't it's too tight - but taper roller bearings in differentials are set up with big preloads and last for hundreds of thousands of miles - but they have the advantage of running in hypoid oil that gives better lubrication and cooling. If wheel bearings run too hot the grease runs out ...

Generally, for wheel bearings the ideal operating setting at operating temperature is near- zero to slight preload to maximize bearing life. Most bearings are set cold with slight end float but that's only between .001" and .007" so significant wheel wobble should not be present. This end float setting results in the bearing being as close as possible to the desired near-zero/slight preload setting when the unit reaches its usual operating temperature. If the bearing still has significant end play when at operating temperature it will shorten its life because it allows internal impacts that eventually cause the hardened surfaces to fail. Equally, if it always runs below expected operating temperature with end play it will have a shortened life.

Lotus went for the castellated nut and split pin holes that means you need to make a judgement of which hole and slot to go for... even when you follow the manual.
These days most manufacturers use a 'bootle cap' and split pin that gives more choice or use a stake nut which is locked just where it should be...

You might find this informative ...
Setting-Techniques-for-Timken-Tapered-Roller-Bearings.pdf
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Re: Rear bearing endfloat adjustement

Postby Simon_P » Fri 05.08.2016, 11:48

lotusflasherman wrote:Lotus went for the castellated nut and split pin holes that means you need to make a judgement of which hole and slot to go for... even when you follow the manual.


If you follow the manual you do not need to make a judgement - It is explicit... but then it reflects the combined knowledge of Lotus, GM, and SKF (or whoever supplied the bearings) followed-up with extensive endurance testing. They want you to have that much play.

Diff pinions and wheel bearings are completely different applications, that is like comparing petrol and diesel and saying they are both engines.

lotusflasherman wrote:Generally, for wheel bearings the ideal operating setting at operating temperature is near- zero to slight preload to maximize bearing life. Most bearings are set cold with slight end float but that's only between .001" and .007" so significant wheel wobble should not be present. This end float setting results in the bearing being as close as possible to the desired near-zero/slight preload setting when the unit reaches its usual operating temperature. If the bearing still has significant end play when at operating temperature it will shorten its life because it allows internal impacts that eventually cause the hardened surfaces to fail. Equally, if it always runs below expected operating temperature with end play it will have a shortened life.

I read that too, but you have confused axial play which you are setting, and the lateral play that you can feel on the outside diameter of the wheel.
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Re: Rear bearing endfloat adjustement

Postby lotusflasherman » Thu 11.08.2016, 18:09

Simon_P wrote:
lotusflasherman wrote:Lotus went for the castellated nut and split pin holes that means you need to make a judgement of which hole and slot to go for... even when you follow the manual.


If you follow the manual you do not need to make a judgement - It is explicit... but then it reflects the combined knowledge of Lotus, GM, and SKF (or whoever supplied the bearings) followed-up with extensive endurance testing. They want you to have that much play.

Diff pinions and wheel bearings are completely different applications, that is like comparing petrol and diesel and saying they are both engines.

lotusflasherman wrote:Generally, for wheel bearings the ideal operating setting at operating temperature is near- zero to slight preload to maximize bearing life. Most bearings are set cold with slight end float but that's only between .001" and .007" so significant wheel wobble should not be present. This end float setting results in the bearing being as close as possible to the desired near-zero/slight preload setting when the unit reaches its usual operating temperature. If the bearing still has significant end play when at operating temperature it will shorten its life because it allows internal impacts that eventually cause the hardened surfaces to fail. Equally, if it always runs below expected operating temperature with end play it will have a shortened life.

I read that too, but you have confused axial play which you are setting, and the lateral play that you can feel on the outside diameter of the wheel.


Been a bit busy to reply to this but .... Nope, I haven’t confused anything…

Taper roller bearings should operate with a true rolling motion with the rollers being in constant contact with both the cone and the cup. Indirect taper roller bearings (small ends pointing inwards) are adjusted by tightening a nut and locking it in position. Direct taper (small ends pointing outwards) are adjusted by a predetermined spacer between them, as on a Mini. When cold they may have very slight end play, axial play if you like, but should never have lateral play of any discernible amount or the rollers are losing contact with the cone or cup.

My first car, 50 years ago, was a Ford (100E) Anglia with drum brakes having integral indirect taper bearings so any work on the brakes ended with setting up the end float. Ford said 'tighten bearing to seat it while rotating wheel until resistance is felt and wind back nut checking end float with a feeler gauge between back of nut and hardened washer'. They said between 2 & 6 thou and helpfully stated it’s 3 thou between split pin positions. (I worked out that it’s actually 3.3 recurring for 30° on a 25 tpi thread). When I transplanted a 1996cc Essex V4 engine and 2000E gearbox into that I was working on the brakes quite often so became a dab hand at setting up end float. Changing the crownwheel and pinion from 4.4 to 3.77 to suit the V4, went to a Ford Dealer to get new pinion taper roller bearings. Storeman said 'I'm not sure if we stock that bearing' as he looked it up but then said 'Yes we do, it's the same bearing as the front wheel bearings ' ... so same bearing, different application, significantly different pre-load - that's the point I was making about preload they can take.

Shortly after I was using a Lotus 6 hybrid. It had torque tube rear axle but Triumph sourced front like the 7 so was using a Lotus 7 Manual for guidance. In the 7 Manual Lotus says 'Spin the road wheel and tighten the slotted nut to 5 lbs ft. Unscrew one flat to give .002 in. to .008 in end float on the hub". Now that's what I call explicit! (One flat is 6.6 thou).

In the Elan+2 Manual Lotus specify using a dial gauge to check end float of 2 to 4 thou to be achieved and in the Eclat Manual it’s 3 to 5 thou using a dial gauge, both of which are a bit tricky with increments of 3.33 thou, but the Scimitar GTE Manual, which used the same front suspension as the Eclat, tightened to a higher torque and said go back 1 flat but did warn about doing it cold because clearances reduce significantly when hot.
Now all those applications are for front wheel bearings that suffer heating by the front brakes so a bit of cold end float is necessary as they tighten when hot.

The rear brakes on the M100 don’t seem to get very hot at all and the M100 Manual (DD Page 11) says "Slacken the nut, and re-tighten using fingers only. If necessary, tighten further, the smallest amount necessary to insert the split pin" so they are being set up with no end float… that’s zero, zilch, nowt… The judgement part is what is 'necessary' - do you use the first hole, when it's not really finger tight, or the next opportunity 30° clockwise which will wind it in 3.3 thou (on a 25 tpi thread, which I believe is what the Elan M100 has).

How strong are your fingers anyway? What is ‘finger tight’? To me the “If necessary, tighten further” implies that a tool may be used to get to the next position if fingers won’t quite do it…
Anyway, as I said in an earlier post, wheel should always spin freely, particularly when hot, but no end float, and certainly no lateral play. If you have any your castor and toe in/out will be going outside limits… and the MOT man won’t like it either.
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Re: Rear bearing endfloat adjustement

Postby Simon_P » Thu 11.08.2016, 21:15

Phil,

I don't know where to start!

You give several references, where you define the amount of axial play (end float) but then you say:
lotusflasherman wrote:but no end float, and certainly no lateral play.

If there is axial play there will be lateral play which will be magnified by the ratio of the diameter of the bearing to the diameter of the wheel so you are going to feel it when you rock the wheel.
lotusflasherman wrote:and the MOT man won’t like it either.

The MOT test section 2.6 Rear Suspension and Wheel Bearings section 2. checks for movement "....asses the amount of play" with a reason for failure of "2.1 Excessive play in a rear wheel bearing,indicating severe maladjustment or wear."
so unless it is severely maladjusted or worn he really won't mind. It doesn't say "no Play"

lotusflasherman wrote:... so same bearing, different application, significantly different pre-load - that's the point I was making about preload they can take.
Good, you agree that they are completely different applications - Tighten your wheel bearing as tight as a diff pinion and you will do about 3 miles before it gives up.

Heat in bearings is caused by friction in the bearing - quite a lot by churning grease and loads if you overtighten them.
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Re: Rear bearing endfloat adjustement

Postby lotusflasherman » Fri 12.08.2016, 06:40

but getting back to the nitty gritty ... M100 = no end float, no preload, all you have to do is find the sweet spot ... :-D
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Re: Rear bearing endfloat adjustement

Postby Simon_P » Fri 12.08.2016, 20:29

Lotus Elan Manual V6 Section DD Page 10
DD.6 HUB BEARINGS
Each rear hub is supported on two roller bearings which are adjustable for end float.

If there was no end float they would have to give a preload figure, because there are n number of torque settings that have no end float.

So follow the manual and you will adjust the end float, and you should correctly just be able to feel the play when you rock the wheel - If you can't discern movement it is too tight.

Worn roller bearings will exhibit more play as the rollers wear barrel shaped by a tiny amount.

I know someone who successfully sued a Lotus Main dealer for adjusting out the play on M100 rear bearings and it was when it was a current model. They did about 5 miles before the bearings seized.
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Re: Rear bearing endfloat adjustement

Postby Simon_P » Fri 12.08.2016, 20:51

Since you wont take it from me I have found this:
Below the Timken technical note specifically for wheel bearings rather than generic taper bearings.
Vol2Iss1_Proper_Tapered_Bearing_Settings_English.pdf
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Re: Rear bearing endfloat adjustement

Postby Simon_P » Tue 01.11.2016, 13:06

looking through the service bulletins ...

For anyone adjusting the end float on their rear bearings

See
Service bulletin 1994/03
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Re: Rear bearing endfloat adjustement

Postby Brit-Car-Nut » Tue 01.11.2016, 14:22

For those that don't know that the service bulletins are in with the manuals (link below), here is 1994-03

Rear Wheel Bearing Adjust.jpg
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