Problem with Refurbished Hollow Wheel

[matthewb]

Hi chaps

DOES ANYONE KNOW HOW AND/OR WHO COULD CLEAN-OUT MY HOLLOW SPOKE FRONT WHEEL?

I bought my 993 C4S second-hand - two and a half years old with 45k - from an OPC.

I had my wheels reburbished about 2 years ago. During the process, it was discovered that one of my front wheels was not a standard solid spoke wheel (as the other front and the two rear wheels are) - it was a hollow spoke 'Technology' wheel.

I decided that I should replace the front hollow spoke wheel with a standard-spec solid spoke wheel to balance things up - there is a couple of kg difference. However, no solid spoke wheels were available at the time although a good-condition hollow spoke wheel was - so I now have two hollow spoke wheels (993.362.136.00 - ET52) at the front.

Once on the road, however, wheel wobble became apparent at around 55 mph (with the problem occuring again, I assume, at around 110 mph). I had the wheels rebalanced. Still wobbled. Had wishbones replaced (bushes were a bit worn). Still wobbled. Had forum discourse with Maurice (didn't mention to him that one of the fronts was a reburbished hollow spoke wheel - didn't then realise the significance of this) who recommended having them rebalanced. Gave up.

Some days OK. Some days not.

Then I read the article in the latest club magazine on hollow spoke wheels. Eureka. Of course. The valve hole probably hadn't been sealed when the wheel was being reburbished and the blasting medium (sand, glass beads, whatever) had therefore got inside the hollow spoke and rim spaces, and was freely moving around inside. This would account for the ineffectiveness of repeated wheel-balancing.

Recently things have been a bit better. I think some sticky gunk or scrod must have got inside the wheel, securing the blasting medium in one place thus making wheel-balancing feasible. Still not happy, though.

PLEASE - DOES ANYONE KNOW HOW AND/OR WHO COULD CLEAN-OUT MY HOLLOW SPOKE WHEEL?


I hope the following information is useful and complements the aforementioned Porsche Post article...
[blockquote]Hollow Spoke "Technology" wheels (smooth back):
993.362.136.00 - ET52 - 19.95 lb (front)
993.362.140.01 - ET65 - 23.36 lb (narrow body rear)
993.362.140.00 - ET40 - 25.13 lb (wide body rear)

Solid Spoke "Turbo-look" wheels (ribbed back):
993.362.136.01 - ET52 - 25.57 lb (front)
993.362.140.04 - ET65 - 29.32 lb (narrow body rear)
993.362.140.03 - ET40 - 31.08 lb (wide body rear)
[/blockquote]Thanks
Matthew

 

[dommorton]

Seems a bit unlikely there would be enough beads in there to cause an imbalance, but surely the best way to get them out again is the way they went in?

Take the tyre off, take the valve out, and give it a good shake.

 

[clyde]

ORIGINAL: dommorton

Seems a bit unlikely there would be enough beads in there to cause an imbalance, but surely the best way to get them out again is the way they went in?

Take the tyre off, take the valve out, and give it a good shake.

But it's going to take quite some time, so do it over an old carpet or something similar because, as your arms and fingers weary, you're bound to drop it at least once []

 

[IndischRot]

Glad you found my article useful - do post back with how much material is found in the wheel. I assume it's been checked for run-out or other damage?

 

[vitesse]

Mathew,
Surely the phrase is "Nihil Carborundom Illegitimus"[]
If the detritus is awkward to fall out,I would use an air suction pump made from one of those cheap Schultz type spray guns-add a longer piece of tube -rubber or plastic onto the suction input-remove the small nozzle,insert small tube into the valve opening & apply air pressure to the gun-follow 'elf & safety guidelines.

Cheers,
Colin.

 

[matthewb]

Nihil Carborundom Illegitimus

Hi Colin

Thanks for the suggestion.

WRT the quote, it would appear there are many variants. It's also rubbish, i.e. pseudo Latin - see http://en.wikipedia.org/wiki/Illegitimi_non_carborundum

 

[matthewb]

Hi Felix

I'll certainly let you know how much crud comes out. Perhaps you will be publishing another piece for PP with this info and the wheel part-numbers I detailed in my original forum post.

WRT to Colin's post, I was wondering if high pressure water might not be more effective - of course, you'd have to make sure you got all the water out!

Sorry to sound ignorant but what exactly do you mean by "run-out or other damage"?

Cheers
Matthew

 

[pse_SC]

Probably better still to fit 2 x Non Hollow Spokes to match the rears on yours... I am concerned about this very problem, as I would like to get my Hollow Spokes (all 4!) refurbished soon - it's worrying that someone has done this to the wheel without knowing enough about it's makeup[&:].

 

[geolab]

here is the reply I posted two years ago, good luck

The material used for blasting flows easily.
Place two empty tires on top of each other, and place your wheel on top at a 45* angle the spokes
facing up. Now with a rubber hammer, tap all around while turning the wheel, WITHOUT tapping on the front
not to scratch the wheel.
Settle the wheel with the valve opening at the bottom of the wheel.
Now if you shake the wheel, the sand will go out from the valve opening, FROM THE BACK.
Do not try to let sand out from the front.
If inspected closely, you could see that the opening from the back has grooves to let anything inside to flow out.
After doing the tapping and emptying proceedure a couple of times, place the wheel on the balancing machine Without the tyre and test.
The material is heavy, so a small quantity is a lot of weight inside.
I had a difference of 5 ounces. when emptied, I had around 0.176 ounce balancing per wheel after...

 

[IndischRot]

ORIGINAL: matthewb

I'll certainly let you know how much crud comes out. Perhaps you will be publishing another piece for PP with this info and the wheel part-numbers I detailed in my original forum post.

WRT to Colin's post, I was wondering if high pressure water might not be more effective - of course, you'd have to make sure you got all the water out!

Sorry to sound ignorant but what exactly do you mean by "run-out or other damage"?

The part numbers were in the first half of the article published the month before. But that portion of the article is almost word for word the same as http://www.porscheclubgbforum.com/tm.asp?m=112688

I would try the dry shake/tap method posted just above - no point in adding more material into the cavity than is already there.

Run-out or other damage simply refers to the wheel being out of round from damage caused by potholes and the like - a shop should be able to put the bare wheel onto their balancer and spin it very slowly to see if there are any issues.

 

[matthewb]

Many thanks to all responders - some very useful info.

Cheers
Matthew

 

[matthewb]

Hi Felix

I had a look at Maurice's article as you suggested. Most interesting. How embarrassing. I'll see if I can find last month's issue - goodness knows how I missed part-1. At least we both published the same wheel pn details!

Cheers
Matthew