OT car: slow leak, alloy wheel refurbishment?

[Adam Funk]

One tyre (right rear) has a slow leak: I pump it up to 30 PSI, and two days (~ 90 miles) later it's about 26.5 so I pump it up again. Our normal tyre place (usually pretty good) resealed it twice (at no charge since they had put the tyre on) then said if that didn't work we might need to get the wheels refurbished and gave the name of a company in the area. (The wheels do look grubby.)

My wife took the car to the wheel place, reported what the tyre man had said, and the wheel man said something like "sure, we can refurbish them, £50+VAT each" after a cursory look. No mention of any guarantee that it would work.

This place would put loaner wheels on our car for a week while fixing ours, then swap them back.

Anyone know how reliable this is likely to be?

Thanks.

[Harry Bloomfield, Esq.]

Adam Funk has brought this to us :

It should be absolutely reliable, if done properly. There are two possibilities..

1. Alloy corrosion has worked its way down the sealing lip between tyre and lip. That should be all cleaned off and repainted to provide a good as new sealing surface.
2. The alloy itself might be porous, rather unusual, but paint should fix that too.

Finally and extremely unlikely, the wheel might be cracked and will be scrap.

[Andy Burns]

I put four new tyres on yesterday, it took them close on 2 hours, they said they'd had to wire-wheel corrosion from all the rims and paint them with "goop" that then has to go tacky before they can fit the new tyres ... no extra charge, but he said they'd rather do it upfront than have me come back in a week saying they they keep losing pressure ...

[Dave Plowman (News]

If properly done, it will sort it. But depends what paint they use. You can make them look pretty and hold air quite easily. But the best coating, which lasts longer, is more expensive.

[Bob Eager]

The problem I had, years ago, was that the lacquer on the wheels started flaking.

I had them all 'done' (one at a time) and they were fine until I sold the car some years later.

[Dave Plowman (News]

If the wheels have corroded on the rims, that sealer gunge ain't going to be that long lived - or wasn't here.

[Thomas Prufer]

You could, of course, dismantle the wheels and drop them in a tub of water and see where the leak bubbles...

(This is excellent advice to give; I myself would not take it. Grubby work, car wobbly on a jack, tub of suitable size not readily available, hence bathtub full of rubber marks and brake dust... yech.) Maybe a squirt bottle with soapy water? Because refinishing the wheel won't help if it's a leaky valve stem.

Thomas Prufer

[Andy Burns]

We'll see, it's not as though he upsold me to having it done, and it took quite a bit of his guy's time doing it.

No sign of any corrosion from the outsides of the wheels, I did have a hell of a job getting one wheel off the hub a fortnight ago due to alloy on steel corrosion. All wheels have all been off the car twice in the last couple of years, for new tyres and brake pads.

[Harry Bloomfield, Esq.]

on 05/11/2021, Andy Burns supposed :

I apply a tiny smear of copper grease to the interface between the two.

[Andy Burns]

It did cross my mind that I'll pop them off and do that ... had to drive it round waitrose car park with the nuts finger tight and slam on the brakes a time or two to get it loose.

[Brian]

Harry?s advice is good just adding to his comments.

Alloys do tend to lose air in colder weather - at least that is my experience across numerous cars. Not nearly as much as you are seeing but, for example, while I check my tyres in the summer, I don?t ever need to top them up. I do sometimes in the winter. With steel wheels, I don?t see this difference.

You may have damaged a wheel - a pothole, caught a kerb etc. This isn?t always obvious if it is on the inside edge. I caught a pot hole and damaged a wheel and saw the same as you. The damage wasn?t visible with the wheel on the car - at least unless you were under it.

They can ?roll out? such damage - if it isn?t too bad, possible without even refinishing the wheel I believe.

I assume you?ve had the tyre off and checked?

Ditto the valve checked? I had a valve fail years ago.

As Harry mentioned, a porous wheel is possible but if they are quality wheels this is unlikely unless they were abused at some point - so the protective layers were removed.

[Dave Plowman (News]

If you have set the pressure on a warm day, it will read lower on a cold one.

Something wrong there then.

Assuming the tyre is OK, the most likely cause by far is corrosion to the rim. Allowing air to leak out there. Happens with old steel wheels too.

[Michael Chare]

New inexpensive alloy wheels would not cost much more. I can't check the exact price without knowing the vehicle. Steel wheels would be cheaper.

[Adam Funk]

Right, that's not gonna happen in this house.

The tyre place has checked the valve stems (among other things).

[Sysadmin]

Put a tube in.

[Steve Walker]

Not a good idea. Both wheels and tyres can have rough surfaces not designed for tubes and can cause sudden failure.

A friend ended up spinning backwards into a motorway central reservation barrier, when she suffered a blowout, a week after a tyre place bodged a repair by fitting a tube.

[Adam Funk]

Thanks.

[Adam Funk]

Is that why tubes aren't (generally) used now?

[The Natural Philosopher]

Yes. Tubes are capable of extremely rapid deflation - from 'OK' to 'bloody dangerous' can be less than a second. Tubeless tyres tend to leak more slowly - usually long enough to 'get you home'.

Of course that discounts the eco-hippy sticking a knife through the sidewall of your 4x4. Thereby increasing your carbon footprint.

[Dave Plowman (News]

Not sure of all the reasons, but tubeless have been the norm for many a year. A radial tyre tend to squirm more than ancient tyres - the tread saying fairly constant, and the walls flexing more. Which might lead to more rubbing between tyre and tube?