Lotus Elan

Elan S4-Continuing to Unravel the Mystery - Front Hubs

PostPost by: ricarbo » Wed Dec 24, 2014 11:19 am

Unlike modern cars, the front wheel bearings have to have a bit of slack. The best way to set this is to use a dial indicator on a magnetic stand that sticks to the upright. When I serviced mine last, I noticed the bearings had been spinning on the stub axle, so I used Loctite to fix the inner races to the stub axle, but it makes more work when changing the grease as you have to careful to clean all the old stuff off.
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Richard
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PostPost by: denicholls2 » Wed Dec 24, 2014 3:46 pm

You appear to have no experience with greasable (vs. permanently lubricated) wheel bearings. As nobody has suggested this before beyond "checking", I'll jump in.

With 25 years since last doing, your bearings are junk by default. They might be OK, but replacements are cheap and you won't have to do this again for about 20,000 miles if you just replace them. Both sides, inners and outers, four bearings total, two different sizes.

If you don't replace, you still must repack. SKIP THIS AT YOUR PERIL, it's probably more important than which side your hubs are mounted on.
1. Soak the bearings in your favorite grease-dissolving solvent. They should be clean and shiny and have no evidence of scoring or overheating (blue) on any of the rollers. Remove all traces of dirt and grease.
2. Examine the races that are pressed into the hub. If they are also pristine, you can leave them and save some effort. Any scoring or visible wear on the portion traveled by the rollers and they need replacement. They press out with a drift from behind. If you remove them, I strongly recommend replacement, new races come with new bearings so if you need to replace the races you get new bearings too.
3. If you buy new bearings, pick up here. You should still pack new bearings, I've never found them to be properly done as shipped. This is the fun part.
4. Using high-temperature grease designed for disc brakes (I like white lithium), grab a bearing in one hand and a glob of grease in the other. Getting your hands well into it, press the grease into every nook and cranny of the roller cage. (A tool is available to do this, but less effective, wastes more grease and not nearly as much fun.)
4. When well-packed but not over-greasy, you are ready to reassemble.

Other noteworthy items: The old bearings are wear-matched to the races, so if you don't replace, be sure to swap their sides too to keep the bearing with the race.

Carefully follow the correct procedure for reinstalling the castle nut. I've found on these Triumph parts there is only one correct answer -- too loose and there's too much play, too tight and there's too little. Too tight is worse than too loose because it will cook your bearings pronto, but too loose and it will fail any good inspection.

Repacks should be done at least every 20,000 miles. Which is why this assembly comes apart so easily.
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PostPost by: englishmaninwales » Wed Dec 24, 2014 4:15 pm

ricarbo wrote:Unlike modern cars, the front wheel bearings have to have a bit of slack. The best way to set this is to use a dial indicator on a magnetic stand that sticks to the upright. When I serviced mine last, I noticed the bearings had been spinning on the stub axle, so I used Loctite to fix the inner races to the stub axle, but it makes more work when changing the grease as you have to careful to clean all the old stuff off.
Regards
Richard

I find the the current generation of MOT testers don't know that there should be a tiny bit of slack in the bearings of these older hub designs. Pre MOT, my Elan and Caterham ( same Triumph set up ), I take up all the slack and then re-adjust after the MOT. I must admit I don't use a dial gauge, but adjust for free play by feel, with the wheel refitted, and recheck after a few hundred miles.
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PostPost by: elanner » Wed Dec 24, 2014 6:04 pm

Another interesting thread.

Dumb question time: Can the play be detected by hand? I've noticed that if I rock a wheel lightly, or quite firmly, then there's no obvious play in my front suspension. But given a vigorous rock I can feel some play. I've never spent any time trying to track it down (ball joint, trunnion, bearings?) because as soon as I get the wheel off I can't feel any play at all.

So I'm rather waiting for it to get worse to the point that I'll be able to figure out where it's coming from. Hardly the finest engineering approach, I realize, but I don't have a DTI and I have plenty of other things to work on! :-(

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PostPost by: oldchieft » Wed Dec 24, 2014 9:46 pm

Get another person in the car, check the play at the wheel.

Then get the helper to put the brakes on hard, check the play again and the movement that is remaining is in the suspension.

The play that is removed is the play in the hub.

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PostPost by: LI-599 » Wed Dec 24, 2014 10:45 pm

Thanks denicholls2 for the comprehensive instruction on replacing/repacking front wheel bearings. I will go and check the free play on my S4 DHC today. The only comment I will make is DO NOT use petrol(gasolene) to wash the old grease out as it will cause the new bearings to fail very soon.
Merry Christmas to all.
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PostPost by: elanner » Thu Dec 25, 2014 9:45 pm

Jon,

Got it. That's clever. Thanks!

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PostPost by: oldchieft » Thu Dec 25, 2014 10:17 pm

elanner wrote:Jon,

Got it. That's clever. Thanks!

Nick


The old tricks are the best

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PostPost by: jbeach » Fri Dec 26, 2014 6:15 pm

Thanks denicholls2, Jon, Greg Z, Frank, and everyone else.

Nothing is easy, it is? I am, however, a huge believer in doing things correctly once. So I'll be replacing my front bearings when I switch the hubs from side to side, drilling a hole for easy removal of my cotter pin, etc.

Now, back to installing and bleeding my newly-rebuilt clutch slave cylinder - this afternoon I'm fabricating a heat shield from a piece of insulated aluminum cookie sheet...kind of a pain, but it beats sitting at my desk practicing law!

All my best,

John
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PostPost by: englishmaninwales » Fri Dec 26, 2014 11:56 pm

LI-599 wrote:......... The only comment I will make is DO NOT use petrol(gasolene) to wash the old grease out as it will cause the new bearings to fail very soon.
Merry Christmas to all.


Hmmm.... Done that for years and never suffered a bearing failure, despite extensive abuse on the track. What detrimental effect does the petrol have on the bearing surfaces to cause premature failure?

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PostPost by: ricarbo » Fri Jan 02, 2015 4:49 pm

Although using a dial gauge enables you to have confidence that you have the end float specified in the manual (2 to 4 thousandths of an inch), an alternative is to tighten the nut firmly to seat the bearings, then slacken it to the first position which enables the split pin to be installed. You could, in theory, put a feeler guage between the nut and the washer, but I think that would be difficult because it is all in a recess. You will definitely be able to feel the slackness if you try to lightly rock the hub. Clearly different from wear in the suspension.

It is important not to overpack grease into the void in the hub between the bearings. Some say half full, some say one third full. I use Castrol LM. The theory is that the grease melts under pressure, turns to oil which flows into the packed grease, melting a little of that which then gets on to the bearing surface - a sort of recirculating arrangement. Overpacking apparently stops this, leading to bearing failure.
Regards
Richard
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PostPost by: LI-599 » Sat Jan 03, 2015 4:15 am

Hi again, I guess the advice about not using petrol to clean out the old grease was given to me when I tried to get warranty from the bearing supplier after bearings failed within a year. I had dropped one of the bearings so washed the dirt(and grease) out with petrol. Could have been a furphy then.
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