To Shim or Not to Shim?

[Wylecoyote]

I need to replace the front wheel bearings on my 100/6 and have read elsewhere that some people, quite knowledgeable people, are suggesting not to bother fitting the various shims that are available.

As a layman with no knowledge of stress factors on stub axles, etc., I'm just wondering what other owners views are on this.

Cheers Phil

 

[Healey Nut]

Shimming takes the play out of the bearings so they properly seat and run properly in the bearing races , shim them too tight you will have noisy wearing bearings . Too sloppy and you get wheel wobble and bearing wear .

 

[Bob_Spidell]

There's an ongoing debate about whether or not the spacers, and shims, are even necessary. No American cars of that era had them, to my knowledge, and I don't think any new cars do. The debate--including actual physics--includes whether or not the spacers add strength to the stub axle and some Healey owners have found their cars, purchased used, didn't have them. I'm of the "If the BMC beancounters didn't think they were necessary the cars wouldn't have them" school of thought (my BN2 had/has them, so if BMC found them unnecessary they had a chance to omit them over model changes). Early BJ8 stub axles were known to crack, and Austin did beef them up on later cars, mostly with a larger radius at the base of the spindle (which also has its own spacer). Note also the spindle has a lengthwise notch and the flat washer that goes under the castellated nut has a 'tit' on it so it doesn't rotate. Repop flat washers are poorly cut and I had one spin on me and I thought for sure the bearing had disintegrated (the noise stopped after a few miles when the washer got wedged). The manual gives a torque spec--40-70lb-ft IIRC--but now I torque the holy snot out of them (you aren't going to snap the spindle, though you could destroy the threads I suppose). If you don't use the spacer you can't torque the nut that way; my father, a former auto shop teacher, showed me to tighten the nut to where you can just slide the flat washer around with a screwdriver (won't work with the Healey flat washer, as the I.D. is close to the O.D. of the spindle).

I've installed several sets of bearings, with new races natch--and a couple sets of hubs--on two Healeys and have found "0.030 of spacers give-or-take a thou or three works well. I used to use a micrometer to set end float, something like "0.003 IIRC, but now I just set them so there is just a smidge of end play, and never had an issue over thousands of miles.

 

[red57]

I advocate using the spacer and shims. I think not using the spacer and shims is a form of laziness but I'm not sure it actually strengthens the stub axle. However, by tightening onto the spacer it does mean the inner races cannot spin/rotate. And, after setting up the shim stack you can pull the hub to re-grease/inspect or any other reason and reassemble and the end play will be consistent.

When setting the shim stack you want to oil the bearings with light motor oil to protect the bearings but no grease yet and without the seals in place because they will cause a slight drag and mask the feel of the bearing clearances.

As others have said, you want free spinning w/no drag and no extra movement in/out or side to side.

There is no pre-determined amount of shims, every bearing and axle/hub will have slightly different dimensions so each will have different shim requirements.

After you get the setting you want, remove & clean the bearings and then grease with your favorite axle bearing grease, install the seals and then install the hub and tighten the nut.

The torque range of 40 to 70 lb-ft is there to allow you to align the cotter pin holes in the spindle and nut.

 

[dougie]

I agree with Dave and have used this method on my vintage racer for 20 years with never a problem under high performance conditions.

 

[Randy Forbes]

Shims & spacers here too.

Always.

 

[Michael Oritt]

In response to his question in less than 48 hours Phil received great and helpful responses from five highly knowledgeable and experienced BCF members.
This forum is a wonderful asset and in the future I hope that new members will continue to come along and share their input.

 

[Wylecoyote]

Many thanks for the info chaps,
here is what happened. I did fit some spacers( .006) but after torquing up the nut to around 40 everything locked up so kept adding until had .012 and then torqued to 70, backed off a bit to get pin in and all spinning freely. I am worried because I seem to have had to add quite a lot compared to what members are suggesting, ie no shims or .003 or there about?

 

[red57]

As long as you have 40 or more torque and the hub spins freely and without excess play with lightly oiled bearings with no seal installed, you are good.

As I said in Post #4 above: "There is no pre-determined amount of shims, every bearing and axle/hub will have slightly different dimensions so each will have different shim requirements." Just because one guy needed .003 doesn't mean everyone needs .003. These are machined parts (bearing races, rollers, stub axle, hub, etc.) and each part has it's own dimensional tolerance + or - so changing out any one of these elements can change the shims required.

 

[Wylecoyote]

Cheers everyone,
now onto the next issue.. Water pump!!! will be back soon
Phil

 

[Wylecoyote]

Good Morning all,
I noticed car was getting really hot, so checked thermostat and sure enough it was stuck. What is advice re running without a thermostat. ie in a British summer, can be hot and car only goes out in sunshine!
More worrying whist fiddling with thermostat I noticed a small crack in the casting of the water pump. No water is coming out but I can see inside it as crack is about 10mm long and 3mm wide. I was thinking just put some JB weld in or am I looking at some bigger failure if pump not replaced?

 

[Bob_Spidell]

Is the 'crack' on the underside of the pump? If so, it's a 'weep hole' and is there to let you know when the seal is failing. No need to plug.

Side note: I've been through quite a few water pumps on two Healeys and have not seen the body of a pump crack (plenty of other issues, though).

 

[Randy Forbes]

The consensus on running without any thermostat fitted is that the water will pass through the radiator too quickly, not allowing sufficient transfer of heat.

Never had any problems running with a thermostat fitted in some of the hottest states in the US (California, Louisiana, Ohio & currently Florida) and rarely rises above the t/stat set-point (180*, IIRC?). That includes using a regular type & the OE-type "bellows" style, which mine's been running for at least the last decade-decade and a half (I didn't notice any difference when "the correct" bellows was fitted). I DO have an auxilary thermostatically controlled electric fan in addition to the engine driven fan.

If you DO insist on running without a thermostat, then I recommend you take an old thermostat and "gut it" of its valving action, and use it as strictly a restrictor plate to slow the flow of coolant through the radiator.

 

[Wylecoyote]

New thermostat on order, thanks for reply it makes sense to fit one regardless of weather.

Re the water pump, the crack is on the top looking down at casting. will try to get a photo