Calculating Front Hub End-Play

[RAC68]

Calculating Front Hub End-Play

OK, maybe my memory is getting a little shadowy and the things I just put down seem to disappear, later to turn up exactly where I remember putting them down, but I usually remember what I have done to my Healey…no matter how far in the past.

Finding excessive end play in the left front, today I decided to determine what thickness the shims in place are and calculate the extent of the endplay and shims needed. I wanted to do this in anticipating of receiving new outer bearings and to prepare for their installation. Well, having done this task around 3 decades ago, I could not remember how to measure the end play.

Raising the car and removing the wheel, dust cap, caliper, and cotter pin, I torqued the castle bolt to 60 PSI and pushed the hub back as far as it would go. I then inserted the tail extension of the micrometer to the tab washer and rested the rear foot of the micrometer onto the outside lip of the hub. Registering the micrometer at 0 when fully pressed back, I then pulled the hub forward and took the reading.

Is this procedure correct and is there an easier way to determine end play for a shim calculation?

I appreciate that 0 end play is the acceptable nomenclature, however, is there an acceptable clearance (i.e. +/- 0.002-0.004)?

Thanks all,
Ray (64BJ8P1)

P.S. I was asked recently, “Why do you own a Healey?” “Mental health” was my reply. “It always gives me something to think about.”

 

[Keoke]

I appreciate that 0 end play is the acceptable nomenclature, however, is there an acceptable clearance (i.e. +/- 0.002-0.004)?


NO !!--It is not a nomenclature ,it is a requirement.

When you fail to get zero end play at the specified torque, you fail to load the axel spacer which stiffenes the axel.

 

[EV2239]

Usually taper roller wheel bearing are assembled with a tiny bit of play which disappears when they heat up in use, so slightly slack is less risky than too tight. However if there has been excessive end float as with your car Ray, I'd be inclined to strip the bearings out, clean it all up and make sure there's no wear and that they're not loose on the stub axle etc before reassembly and shimming to the book.

 

[Keoke]

Usually taper roller wheel bearing are assembled with a tiny bit of play which disappears when they heat up in use, so slightly slack is less risky than too tight. However if there has been excessive end float as with your car Ray, I'd be inclined to strip the bearings out, clean it all up and make sure there's no wear and that they're not loose on the stub axle etc before reassembly and shimming to the book.

Follow the insurrection manual it knows exactly what it is doing.-

 

[Bob_Spidell]

This is blasphemy, I know, but I shim until the hub turns freely, and there's just the slightest, perceptible bit of end play. Yes, I do it by feel, but I've only been doing it that way for 120K miles so who knows. More often than not, 0.030" give or take a thou or two of shims is about right.

 

[Keoke]

This is blasphemy, I know, but I shim until the hub turns freely, and there's just the slightest, perceptible bit of end play. Yes, I do it by feel, but I've only been doing it that way for 120K miles so who knows. More often than not, 0.030" give or take a thou or two of shims is about right.

Well I recon how if you stay on the Carriage ways and do not do long high speed drives or drive hard.
,you may get away with it.

However. at Breckenridge we had an out of town car come in with the bearings set up loosely. The bearings froze to the axle and exploded. Roger Moment worked on that car and at least got it to rool on to a trailer to be towed home.

 

[RAC68]

Hi All,

Bob, both wheels have two original shims each with the following measurements 0.0295 and 0.005). Your 0.30 seems a very close approximation.
Keoke, I understand that encapsulating the sub-axel under stress increases its rigidity and strength, however, the manual keeps using the term “excessive” end-play which seems to infer there is some acceptable level. Additionally, the manual may have a good description of how to measure end-play but I haven’t been able to find that part of the document…the reason I asked.

Is my approach to measuring end-play appropriate or is there a better way?

Ray (64BJ8P1)

 

[dougie]

This is blasphemy, I know, but I shim until the hub turns freely, and there's just the slightest, perceptible bit of end play. Yes, I do it by feel, but I've only been doing it that way for 120K miles so who knows. More often than not, 0.030" give or take a thou or two of shims is about right.[/QUOTE

Bob -

I'm with you, it's all about feel. I pull the front hubs a couple times each race season for inspection on my '57 racer and have always re-installed them using the "feel" method. At 125+mph down the straights at Road American, the steering wheel feels pretty smooth and my car tracks nice and straight. I do use some pretty exotic racing wheel bearing grease as well.

 

[Keoke]

Dougie

In your case I think that is quite acceptable since the earlier cars had stronger axles.

 

[EV2239]

Well I recon how if you stay on the Carriage ways and do not do long high speed drives or drive hard.
,you may get away with it.

However. at Breckenridge we had an out of town car come in with the bearings set up loosely. The bearings froze to the axle and exploded. Roger Moment worked on that car and at least got it to rool on to a trailer to be towed home.

I'm sure you're wrong and the reason I say this is that we deal with quite a few R-R & B with taper roller front wheel bearings that are set up with a 2 thou feeler under the nut and washer retaining the inners. Cold they have a little bit of play, and hot not. Otherwise the design is just like the Healey but bigger.

People who don't realise this and take out all the play end up with overheating bearings, grease everywhere etc, so I'm pretty sure that if they were tight enough the bearing would freeze and do as you describe.

Ash

 

[Keoke]

R-R & B with taper roller front wheel bearings that are set up with a 2 thou feeler under the nut and washer retaining the inners. Cold they have a little bit of play, and hot not.

Otherwise the design is just like the Healey but bigger.

I see no Problem here:


I think that any assembly design that is larger and stronger than the later Healey cars could use your indicated method

As to heating:
There is no heating of the bearing as the preload is borne soley by the inner ,race. When setup properly the wheel is just as free as a lark..

 

[EV2239]

What I'm saying is that it's safer to set them a tiny bit loose than a tiny bit tight, because they tighten up as they heat up and eventually overheat when they're too tight. For this reason, not just R-R & B but other cars using taper rollers advocate a small amount of play when cold. I hope this is clear and sorry if I wasn't the first time.

 

[Genos2]

Having done hundreds of tapered (roller) style wheel bearings over the last 40 years, I agree that most that do NOT use shims use the prescribed .001-2 thou clearance, but with our Big Healeys, where the axle nut is torqued to a specified setting, clearance must be set w/proper shimming otherwise you cannot achieve proper torque of axle nut. Factory Knows Best! cheers

 

[EV2239]

Having done hundreds of tapered (roller) style wheel bearings over the last 40 years, I agree that most that do NOT use shims use the prescribed .001-2 thou clearance, but with our Big Healeys, where the axle nut is torqued to a specified setting, clearance must be set w/proper shimming otherwise you cannot achieve proper torque of axle nut. Factory Knows Best! cheers

Agree totally, but once shimmed and torqued a tiny bit of play is safer than a tiny bit tight IMO.

 

[BoyRacer]

First, the early front stub axles not stronger than the later BJ8 stub axles. Just the opposite, the early (100-6 and 3000 thru the BJ7) stub axles have less material in them and they are prone to cracking. The BJ8 stub axles have much more material and are stronger.
Secondly, the axle nut should initially only be tightened to 40 ft lbs. That is so that it can be tightened a bit more if necessary to line up the cottter pin with a slot in the castellated nut.
Thirdly, to obtain the correct end-play of approx .003 to .004, you start nipping things up to 40 ft lbs with enough shims so that you have excessive end-play. The you measure the end-play (usually with a dial indicator) and then you know how much shim you need to eliminate. Zero end-play will burn up your bearings. Too much end-play and things can get loosey goosey.....and then some people will advise you to move the front of your rear leaf springs inboard to prevent the "wandering".

 

[RAC68]

Rich,

Your posting seems to clear a number of confusing and counter statements but I really do not want to misunderstand. When I posted this question, I hadn’t performed this task for about 3 decades and did not expect a discussion but a flat statement clarifying a defined procedure.

Originally reading the manual (more then once), such statements in the manual as “when play in the hub bearing becomes excessive” followed by reassembly statement (5) “…Reduce the number of shims to eliminate end-float, while still allowing the hub to rotate freely,…” seem . The first seems to indicate that some shim-calculated end-float (as you have indicated 0.003-0.004) should be present while the other indicates NO end-float should be present.

As Bob has indicated, the original (2) shims on my Healey were 0.0295 and 0.005 and produced what I felt was excessive end-float. By eliminating the 0.005 shim, end-float was eliminated with a very small drag present (I am assuming is being caused by the grease) at a torque of 70 PSI. Since I am waiting for new outer bearings and races, this was a rehearsal for the final fitting and all will be redone. So, this has become important as I do not want to address this again in my lifetime.

How/where do you place the dial indicator to measure end-float? I
s my understanding correct?
Should I move the front leaf spring mount inward to compensate (only kidding)?

Ray (64BJ8P1)

 

[steveg]

I re-shimmed my front end in March 2013 after adding BJ8 spindles and discs. Would like to add to the mix:

Suggest getting a shim kit from Moss.
Norm Nock's book (p.57) has a full page instruction on this: he says to shim the bearings before packing with grease. You won't get a proper feel with the grease in place.
The idea is to add too many shims, then remove them until no drag with no* end float is present, tightening to 40 lb/ft each time. My translation of no*: barely perceptible end float.
Note the combination of the vertical and horizontal axle holes with the 6 slots in the castellated nut gives the ability to adjust in 1/12 turn increments. (If I recall correctly the axle is 16 tpi, so 1/12 turn should be about .005" increments.)
There should be no drag at the final torque of 70 lb/ft maximum.

When bearings are packed and everything's buttoned-up, suggest a short drive followed by a re-check.

 

[Keith_M]

Rich,

As Bob has indicated, the original (2) shims on my Healey were 0.0295 and 0.005 and produced what I felt was excessive end-float. By eliminating the 0.005 shim, end-float was eliminated with a very small drag present (I am assuming is being caused by the grease) at a torque of 70 PSI. Since I am waiting for new outer bearings and races, this was a rehearsal for the final fitting and all will be redone. So, this has become important as I do not want to address this again in my lifetime.


Ray (64BJ8P1)

I did this 5 years ago, so my memory is imperfect, but I seem to recall that I determined the appropriate shim thickness with just a light coat of engine oil on the bearings. This removed any drag associated with the grease and made the disassembly/reassembly process less messy, so it was easier to try different shim combinations.

 

[HealeyRick]

Advice from an expert:

 

[RAC68]

Steve/All,

The shim kit from Moss indicates BJ8s from 2704 and my BJ8 is prior. I was also told the MGB shims would work for my BJ8P1. Does anyone know if that is true and which Kit I should order?

Thanks,
Ray (64BJ8P1)