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MG MGF Technical - MG alloys deflating at bead

Hi I am having problems keeping some of my tyres inflated despite having them re seated. I have decided to have the tyres taken off so that i can smooth down the beads.
Any advice please on what to put on the beads to stop this problem re occurring?
Thanks
F.J. Holland

I have my regular T1-Rs fitted by my local independant garage who treat the bead sealing section with what they call mastic - but is in a bucket open to air so it isn't real mastic. When they change them the old stuff just peels off and a healthy smear of fresh is applied before seating the new tyre. Thus I am leak free on original wheels with over 150,000 miles on them.
I am sure it can be requested from tyre fitting chains.
deyual

Thank you for that information I will ask my local tyre fitter about that.
I have just finished rubbing down the wheels and have them smooth around the bead seating area. I was wondering if I should spray some lacquer onto the smoothed areas - is that a good idea?
F.J. Holland

Hi F J, my front right was deflating at about 6 PSI per week and I was constantly inflating to keep at the correct pressure. The car had been layed up for about 3 weeks and was nearly down to the rim. I took the wheel down to my local Kwik Fit, they checked for a leak, reported back that they couldn't find any and tried to sell me a new tyre. As the MG is layed up at the moment I brought the wheel back with the same tyre attached, kwick fit didn't charge.
The wheel has been on the car for about a month now and the tyre has remained at the correct pressure since.

How does that work??
s a miller

Apart from the obvious cause of leakage, a badly fitted tyre, the other problems are corrosion between the paint and the metal under the bead area and porous wheels due to MGR's famous quality control. I had leaking wheels refurbished which included shotblasting and repainting (actually power coating). The problem was cured for a couple of years but is slowly coming back.
Brian Highe

Just had a front tyre refitted due to rim leak on a wheel that had been repaired about 5 years ago. It had had to be powder coated, so doesn't match the other three which were new on less than twelve months before. I was losing 1 or 2 psi/week and will be keeping a beady eye on them all! As far as I know, all that was done was a clean-up and refit.
Mike Cunningham

Thanks to everyone for the replies!

We had a tyre fitter in today to do a tyre on a lorry so had a chat with him about the problem. Basically, he agreed that to sand back the bead areas and to give them a protective coat of lacquer was the way forward. He said that should sort the problem but gave me some rubber solution that his company use on suspect rims. Said to take it to the fitting station when taking the tyres back and to get them to apply this to the bead. Apparently, not all fitters use this rubber bead seal as it is quite expensive.

He was absolutely certain that this would solve the problem-will let you know but fingers crossed!!
F.J. Holland

isoflex liquid rubber paint?

IF - the porosity is in the wheel flange / bead, something like the above, might help the sealing of the tyre to to bead

IF the porosity is in the hub ( the part inside the tyre, then, something specific for the material, like this, would be my first choice..

http://www.impco-inc.com/stuff/contentmgr/files/6d3b497b35904b12be7cc55550e50055/misc/alumiseal_tech_datasheet.pdf

http://www.plantservices.com/vendors/products/2011/Impco-AlumiSeal-methacrylate-compound.html

i guess it depends on availability.. but isoflex is available in hardware stores, though impco is a usa product, it must have a counterpart available in the uk.
N.J. Simon

The use of aluminium filled varnish is commonly used to seal porosity in aluminium castings however the need for a vacuum chamber does not make it a DIY job.
Removal of the air from the porosity causes it to fill with the varnish.
Geoff F.
Geoff Farthing

i understand... Geoff, so i looked up methacrylate and its derivatives, as i sensed that there are very similar compositions for crack sealing.. and it turns out that MMA is common in all kinds of coatings... one of which is epoxy resin.. and its derivatives, another is floor paint and concrete crack sealers..

the absence of air, isnt hard to achieve..ptfe tape would do it on a wheel hub..

And for example super glue is a common derivative... its a cyanoacrylate, and one specific application is to use baking powder as a core..
http://en.wikipedia.org/wiki/Cyanoacrylate

i dont think it would be difficult to liberally dust the clean wheel hub with baking powder, and then slowly but surely - paint it with super glue... :)

learning that technique has given me all kinds of ideas for fixing things, i have not considered before, since both baking powder and superglue are easily and cheap to source.
N.J. Simon

I also had mine blasted and refinished. still ok 2 years later but have been warned the problem will eventually reoccur. had all 4 done for £100 however so figure that was a good deal.
Leigh Reid

This thread was discussed between 12/11/2011 and 09/02/2012

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