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-   -   Front hub spindle dimensions (http://forums.pelicanparts.com/porsche-911-technical-forum/535863-front-hub-spindle-dimensions.html)

chris68 04-09-2010 08:14 AM

Front hub spindle dimensions
 
Hi All,

I want to check the wear on my front hub spindles. Can anyone advise original shaft diameters at inner and outer bearing positions plus the spacer ring dimensions?

Thanks,
Chris

rusnak 04-09-2010 08:41 AM

I will look later today in the photo file, but I think you can dimension the bearing inner race and compare to the spindle.

chris68 04-09-2010 09:39 AM

Thanks Rusnak,

I could use some inspiration on this. My front wheel wobble is driving me nuts.

The IDs of the bearings are stated as 31.75mm and 19.05mm. I assumed a 'locational clearance fit' between bearing and spindle. This results in a max difference between spindle and bearing diameters of 0.034mm (0.0013") for the small one and 0.041mm (0.0016") for the big one.

However, it would be nice to know for sure the original dimensions for spindle and spacer ring.

My car is 42 years old now, and there's a bit of spindle wear but it doesn't seem enough to constitute the wobble I'm getting. I'm confident the wobble is at the hub because it dissappers when I put the brakes on.

Cheers,
Chris

burgermeister 04-09-2010 04:39 PM

Wobble? While driving?

A worn spindle manifests itself (on my car anyhow) by the wheel having some play when you rock it at the 12 & 6 o'clock positions (front end jacked up) no matter how tight you adjust the wheel bearings. I recently made an attempt at fixing mine by electroplating some copper on the worn part of the spindle until the inner race was a pretty tight fit again. I'll see how it holds up.

Not sure this is your problem though ...

vonsmog 04-09-2010 05:07 PM

Have you tried changing the wheel bearing yet? I had a wobble in my rt. front and repacked the bearing today. But I just ordered new bearing from our host for both sides. The race is tight on the spindle, but I think my bearing are just shot. maybe the races in the hubs are just shot. These bearing are not that big, for the size tires we now put on these cars.

chris68 04-10-2010 06:58 AM

The bearings are new so shouldn't be the problem.

I took a micrometer to the spindle and measured the OD (in the vertical axis) at both bearing faces. They were both 2 thou' below the ID stated for the bearings.

Is this too much?

Cheers,
Chris

burgermeister 04-10-2010 07:52 AM

.002 seems like a lot of play. My car had about that much, and it was definitely noticeable when rocking the wheel back & forth. But I never had a wobble while driving as a result - I could only tell with the front jacked up and by grabbing the wheel at 6 & 12 and rocking it.

chris68 04-10-2010 08:26 AM

Thanks Burgermeister,

Mines the same, wobble at 12 and 6 o'clock. Less at 9 and 3 o'clock. Looks like I'll have to look out for better struts.

Was your car ok to drive like this? I'm wondering whether I'd better lay it up until I can improve things. Shame, the weather has just started to pick up in the UK :(.

Cheers,
Chris

burgermeister 04-10-2010 04:12 PM

Car is fine to drive. I took mine on track like that too. Just required an explanation at the tech inspection as to why the wheel bearings are adjusted correctly despite the play in the wheel.

You can try electroplating the spindle - caswell plating sells a cheesy kit for $40 that will do the trick. Not sure about the long term durability though, as I just plated mine 100 miles ago ... then again, there is little to loose - it's not going to make it worse :)

chris68 04-11-2010 12:39 AM

Burgermeister,

I saw your post about plating the spindle, interesting ...... Can I ask, did you consider hard chrome or cobalt before choosing copper? Also, did you use brush plating, was it easy to get a uniform finish and did it take long to build up the surface?

Like you say, I can't make it any worse!

Cheers,
Chris

Flieger 04-11-2010 12:15 PM

I thought that the necessary activation chemicals (acids) for hard chrome resulted in Hydrogen embrittlement in the base metal.

burgermeister 04-11-2010 05:23 PM

I considered zinc or copper, as both are supposedly fairly easy to plate at home without nasty chemicals. Not removing the struts to send them out was a requirement for me!

The spindle does not appear to be hardened, so hard chrome seems unnecessary. I don't know anything about hydrogen embrittlement, but based on Flieger's comment I'd make myself smart before sending spindles out to be chromed.

I did not have difficulty getting a uniform finish. It took 30 - 40 min / side. Keep things warm with whatever means, or it will take a lot longer!


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