Bailey Unicorn wheel recall

[xtrailman]

Apparently the unicorn problem is solved by greasing the bolts and increasing the torque.
The problem is said to be heat related.

Details should be on the Bailey web site.

 

[Bri2]

Ray, just read the Bailey web update and under NO circumstances should any form of grease be used. They are issueing a new type of bolt which has a dry lubricant. From there web, copa slip etc should not be used. All new Unicorns will be fitted with the new bolts.
Its all here http://www.bailey-caravans.co.uk/information-centre/latest-news/newsitem.php?recordid=229

Bri

 

[xtrailman]

Thats right dry lubricant

 

[Surfer]

It shoudl never have happened in the first place! Perhaps if they gave a caravan a proper road test prior to mass production and then a proper PDI afterwards, we would not be reaidng about this. It seems that every time I read about a wheel coming off a caravan, it is a Bailey but maybe I am wrong.

 

[Dustydog]

Does the Al-ko chassis have any part in this?

What is so special about a Bailey Unicorn chassis, hub and wheel?

Dry lubricant? Never used it in my life. Is there something else going on here that dry lubricant is trying to mask?

I think I'm turning into a Victor Meldrew Dog.

 

[admiral1757]

Sorry Surfer, our van was written off and not a Bailey but using the Aklo chassis and ATC a la Unicorn, I was told that Chinese manufactured Hubs were involved but not on our Brand

 

[xtrailman]

As the problem is heat related, why isn't there a recommendation for extra cooling?
The most obvious would be larger brake drums, or longer cooling fins.
Perhaps Bailey knew heat could be a problem, hence the larger 15" wheels.

 

[WatsonJohnG]

We had a wheel come off our Ace Award Nightstar after suspected tampering but it was also on the same Alko chassis with the 15in wheels and we did have also trouble with the brakes malfunctioning although the van was fully serviced and obsessively checked for wheelbolt torque
Makes you wonder

 

[Royston]

Nobody has explained to me why isnt the nearside wheelhub fitted with with left handed thredded bolts, this would stop the nuts from unwinding.
My gas bottle is fitted with them , so what is the problem.

Puzzled Royston.

 

[Pinto]

We had a wheel come off our Coachman VIP after we fitted the steel spare where an alloy had been. This was only after about 3 miles. We queried it and coachman said there should be no problem and we were right in using the alloys bolts and nuts on a steel wheel, but my husband wasn't sure at the time as he reckoned old landrovers had to have different bolts and nuts if steel wheels were fitted to where alloys had been. Opinion reckoned it was because the holes in the spare had slight rust damage and as we travelled the hole got bigger. Where is the spare carried ? Under the van where it gets all the sh*t going off the road. It had been torqued up correctly and everything.Thakfully we were coming slowly off a roundabout so damgae but no writeoff.

 

[GrahamDerby]

The old Transit vans used to have that, it used to be fun watching people try and change a wheel when they didnt know.

 

[Lutz]

From the information I can glean out of the Bailey bulletin, it would appear to me that it's more a problem of the bolts suffering from hydrogen embrittlement caused by zinc plating rather than too much friction in the joint. Hydrogen embrittlement would cause the bolts to break rather than loosen. If it were simply too much friction in the thread causing the bolts to loosen because of inadequate pre-load, then this would be a generic problem affecting all similar designs and not just Unicorn models. The 'dry lubricant' that they refer to is actually also a form of zinc coating but one which doesn't suffer from the drawback of potential hydrogen embrittlement.

 

[xtrailman]

Lutz
Most of the wheel detachments were due to the bolts dropping out, so to speak.

 

[Lutz]

You mean that the bolts actually unscrewed themselves rather than breaking? If so, then why has it only happened on one model range? If they broke, then the problem could be put down to poor quality control on a particular batch of bolts on the part of their supplier. But if they are becoming unscrewed, lots of other caravan wheels are attached by the same method and they aren't afflicted by the same trouble. Unicorn models aren't the first to use zinc plated bolts so there must be more to the issue than meets the eye. I therefore have a sneaking suspiscion that Bailey are either deliberately or unknowingly covering up the real root cause because, without further information, the explanation that they give just doesn't tie up.

 

[Sproket]

If bolts are falling out the problem could be that the female thead has cut big when being tapped, if so they really need to use a calibrated go / nogo thread plug gauge to check the female thread and then replace the hub if they are the proved to be the problem, bear in mind that the tap will have cut hundreds if not thousands of threads before being replaced, also if the pcd is not correct that will also cause a problem.
The nogo side should not enter the thread, if it does the tap has cut over size...............

1 So either the pcd on the hub is out..
2 So the pcd on the wheel is out
3 Or there are problems with the gauging of the threads, all three can be quite easily measured on a Coordinate Measuring Machine
4 Or there are problems with the bolts ?

Watch how a CMM works

They dont just start falling out without a good just cause.........

 

[Lutz]

If it were simply a dimensional problem as you suggest, Sproket, then it would be solved by replacing the bolts with ones of the right thread size and not by using bolts with a different surface finish, as Bailey are doing. It must therefore be a material problem rather than a dimensional one.

 

[xtrailman]

I do know that i was unhappy with the side to side play in the bolts, i reported this on the CT forum, before the recall.
I was also less than happy that to find part of the black finnish "attached" to the alloy wheels (from the hub), when i removed them for balancing.
It took quite some time to carefully clean the mating surfaces.

And the wheels took 130grams and 135 grams to balance!

Personally i don't see the bolt replacement as the answer to the problem.

Also some 200 wheels a year are reported to become detached each year, according to posts on the CT forum. So the problems are across all makes, but as Bailey had ten reported cases in a very short period of time, hence the recall.