924Board.org

[ryoji]

I replaced both inner and outer bearings, repacked grease and tightened cast nut over 300lb-350lb . There is still a play for both the right and left. Acturally there was not before change and there is now.

What did I do wrong do you think? Packed too much grease? Defected bearing --- which is hard to believe on both side? It got to be something I did wrong!!!

Could somebody give me a suggestion?

Thanks
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R.I.P.:a 924 ITA race car

[ryoji]

bump
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R.I.P.:a 924 ITA race car

[Smoothie]

Tough to guess what's wrong. I think you can safely rule out "too much grease" though.
What are the part numbers off the packaging for the items you installed?
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[ryoji]

Outer bearing 113-501-277A
Inner bearing 113-5.1-283

Both are looks the same as old ones.
Both bearinging need to drive in by hummer and/or puller so it is very tight fit.
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R.I.P.:a 924 ITA race car

[Smoothie]

Those are the right parts as long as the "5.1" is actually "501" in that second number.
They're straight, rather than cone-shaped bearings, so a slight amount of play might actually be normal. If you're sure all the parts are on in the correct sequence and as you said it's torqued to over 300 ft-lb, then there might not be a problem. I think I have a slight bit of play in my own rear wheels. The only question would be "How much is "slight" and how much is acceptable?". If I stumble across a spec for that, I'll let you know - otherwise, I suspect you're ok.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[ryoji]

Mmm. My tech inspection guy marked it Failure for the track outing. I got to do something on it.
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R.I.P.:a 924 ITA race car

[Smoothie]

I had a look at mine again and get no play if I grab the tire front and back and try to rock it back and forth horizontally. On trying to push in-out, I'm not noticing any play either. -But on grabbing top and bottom and pushing top while pulling bottom and vice-versa (a vertical rocking motion), there is slight play. I tried my best to get a measurement with a dial indicator (a clumbsy procedure) and measuring about an inch down from the outer diameter of the tire, measuring on the sidewall of the tire, I get .005" play on the left wheel and almost .010" on the right wheel (five one-thousanths of an inch and ten one-thousanths). (This was done with the rear of the car jacked up and the wheels off the ground.)
What kind of play are you seeing? - Up-down, side-to-side, in-out, all?
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[ryoji]

There is no play if I grab the tire front and back. It is because of brake caliper. Once I take out the caliper, there is almost the same amount of play as grabing the tire top and bottom.

I know the tech inspectors check by holding tire top and bottom; not sides.

I think it is originated by bearing of inner racer and roller; which is by design???
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R.I.P.:a 924 ITA race car

[924RACR]

I had the same problem, possibly with the same tech inspector? He was giving me all kindsa crap on it. I finally managed to get to go out, but the wheel bearings did turn out to be bad - destroyed themselves during the race, but blew the motor (last year, May, Beaverun GTS Challenge race) before I lost a wheel.

I then had to replace the bearings. But I still seem to recall having some play. I'm still not entirely sure on this one. There may be an issue as a result of having a worn spacer between the bearings - you know that tube that the axle slips through, it more or less just sits in there? The length of that may be an issue. That's my guess, anyway.

I think if you end up driving on bad bearings, it may damage that tube for overall length, resulting in too short a spacer tube. This can I think then result in damage to the next set of bearings, because you don't get enough pre-load on the bearings.

I'm wondering if I need to start using a proper bearing press on them. Still, that's $250 for the tool, but I'm probably going to have to pony up the cash for it. I think the hammer method may be OK for street cars, but not for racing.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[gohim]

The problem is probably bad spacers.

When you replace the wheel bearings, it is recommended that you replace the spacers as well.

I has never seen any steel trailing arms where the bearings fit was so that tight that you needed a hammer to seat them.

Seems to me that you could set them safely with a long threaded rod and a couple of big washer/spacers (holes should be only large enough to allow the threaded rod through). I would think that the threaded rod from a spring compressor would work perfectly.

[924RACR]

Yeah, that's a good point, gohim. What I think would be gained from using the fancy expensive press, hopefully, would be the similar ability to press the old bearings out smoothly and cleanly.

Of course, if I were smart, I'd just freeze the bearings before I install them - they'd probably drop right in then! I never have the foresight to plan that far ahead.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[ryoji]

When I move up and down on the edge of the wheel shaft, I can see the small space between the inner racer and roller bearing. That small movement becomes the recognizable play.

I think the only possible stopper of the play is that the inner spacer pressed tight between the wheel shaft and the inner bearing and the spacer prevents any shaft movement other than rolling.

Then it come down to your suggestions of "not banged enough by hummer" or "spacers".

Who sells new spacers?
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R.I.P.:a 924 ITA race car

[924RACR]

Well, that is another possibility I didn't think of, that you might have a worn stub axle - if the play is in the fit between the stub axle and bearing, not in the bearing itself?
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[John Brown]

I think this is simply manufacturing tolerance and MAYBE hub becoming egg shaped or, (hub or axle or both) wear but that can only happen if the bearings 'spin', in which case you should see galling. I have not found an egg shaped hub (yet) but all my steel arms have play.

The inner ball bearing indeed uses differenct thickness large circlips to retain it. If you visualize the setup that really only sets axial play. I maintain that if it is at all reasonable you will never feel axial play by hand. And, I have never seen anyone try to check it by pulling the wheel out and then pushing it in.

The outer roller bearing 'floats' in the hub and on the axle. It's location is only set by the spacers. Whatever play exists between the outer roller bearing and the axle and the hub is fixed and no amount of new spacers or torque will change it. This is where the play comes from on these steel arm rear suspension. BTW, 300 to 350 is way over spec on the 924 and way more than you need. All you're doing is stretching the axle.

I have trouble with the spacer changing things. Unless the new spacer moves the outer roller bearing out to a tighter section of axle and/or hub then the spacer will have no effect.

Visualize or sketch the setup. The high torque on the axle nut attempts to make a solid stack of the spacers and the 2 bearings inners races. That stack has is held axialy by the outer race of the inner roller bearing. The inner roller bearing is retained by the hub ridge on the outer side and the circlip on the inner side. Even though/if the stack behaves as a solid piece whatever play exists in the ball bearing itself and/or the retention of the roller bearing outer race, will both be magnified to allow the unit to 'rock' which will show up as radial play at the outer bearing/wheel end of things.

That leaves the out roller bearing to really set the limits of radial play that we perceive as wheel movement. By it's nature the roller bearing is not adjustable.

Hey, they should have used a tapered setup. The aluminum arms use two of the large ball bearings. Still not optimum design IMHO. But apparently it works (better). Mostly just because the bearings are much larger and they definitely are a press fit.
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John
80 931 - #931 44Cup
99 Escalade - tows track cars
gone but not forgotten: original 924.org car - 82