frightening experience.

[Lutz]

We haven't been told the make of the towbar. I have heard of cases where some towbar manufacturers were not supplying necessary reinforcements for the chassis frame at the locations where the towbar is bolted to the chassis or where reinforcements were supplied but not fitted, possibly because they were awkward to install and therefore simply left off. That could account for elongated bolt holes and consequently a loose towbar. After prolonged shaking a loose towbar could, in turn, cause the hitch stabiliser pads to disintegrate.

 

[otherclive]

We haven't been told the make of the towbar. I have heard of cases where some towbar manufacturers were not supplying necessary reinforcements for the chassis frame at the locations where the towbar is bolted to the chassis or where reinforcements were supplied but not fitted, possibly because they were awkward to install and therefore simply left off. That could account for elongated bolt holes and consequently a loose towbar. After prolonged shaking a loose towbar could, in turn, cause the hitch stabiliser pads to disintegrate.

Witter as described in post above from the OP. I had a Mondeo mk1 with a towbar fitted by Ford technician and they did not install support tubes that prevented the rectangular body section compressing as the fastenings were torqued up. It started to clunk en route from Scotland.

 

[Jcloughie]

We haven't been told the make of the towbar. I have heard of cases where some towbar manufacturers were not supplying necessary reinforcements for the chassis frame at the locations where the towbar is bolted to the chassis or where reinforcements were supplied but not fitted, possibly because they were awkward to install and therefore simply left off. That could account for elongated bolt holes and consequently a loose towbar. After prolonged shaking a loose towbar could, in turn, cause the hitch stabiliser pads to disintegrate.

Yes, as OC said, bespoke made and fitted by Whitter. See #5 and 15. Isn’t it strange that JLR can’t supply a bar unless fitted in a newly supplied vehicle? I would have thought it would be a listed spare part. If not, how would someone manage if they had one damaged in a rear end accident? Also, don’t bars need to be type approved?

John

 

[Lutz]

Yes, as OC said, bespoke made and fitted by Whitter. See #5 and 15. Isn’t it strange that JLR can’t supply a bar unless fitted in a newly supplied vehicle? I would have thought it would be a listed spare part. If not, how would someone manage if they had one damaged in a rear end accident? Also, don’t bars need to be type approved?

John

The type approval only covers the towbar assembly itself and the location of the attachment points, not any reinforcements or modifications that may be necessary to the chassis.

 

[ProfJohnL]

On the issue of loading I have done several thousand miles uk and Europe with this set up. Always loaded the same. No stability Issues. Checked nose weight before setting off. 70 kg. The van wasn’t snaking wildly. It was more like when a wagon overtakes closely but with no vehicles nearby. I reacted immediately by easing down the speed otherwise I am sure it would have started snaking...

I am not disputing you have manged so many miles with no prior incident, and that is great news, However the point of concern I had is your report of how on this occasion you began to detect some instability at around the 60mph. It seems likely this may have coincided with the failure of the hitch.

The damage you have described to the hitch of the dislodged friction pad raises the possibility the damping effect of the hitch had been reduced, and as such it allowed the snake you began to detect to arise.

If you outfit is prone to snaking when the friction pads are not operating it means your outfit is inherently unstable at normal UK motorway speed limits., and more crucially you out has come to rely on the action of the stabiliser to make it drivable. This is not good practice as no out fit should rely on addition stability systems to make it drivable.

I strongly suggest you should review your loading regime to improve the unassisted stability. It may not need much, but It is so very easy to allow nick-nacks, the odd torch or magazines to be unwittingly added to a caravan, and they all can begin to unsettle what was otherwise a good plan.

Please double check.

 

[Dustydog]

Good point Prof but as Clive pointed out the ATC should have halted the snake.

 

[ProfJohnL]

Good point Prof but as Clive pointed out the ATC should have halted the snake.

Well that depends on how big the snake had become, It may not have grown to the threshold point to trigger the ATC.

Caravan instability does not begin instantly. it builds up, and a good driver should be able to notice the early signs and may be able to take early enough action to bring it back under control before systems like ATC actually start to take action.

But as I pointed out previously no one should have an outfit that relies on either the friction damper or ATC to make it towable. Both of these accessories should be considered to be like a seat belt safety additions, just in case things really do start to go pear shaped.

If as the OP's case the failure of one of these device has apparently led to the outfit showing its true stability status and in this case it raises concerns, and it certainly suggests the loading should be reviewed even if just for peace of mind.

 

[Dustydog]

The OPs weight ratio is good.
The OP has used the same set up for two years with no problem.
I‘d like to hear his thoughts on loading and the nose load being used. Did he deviate from his normal loading?
I wonder just how great the snake was? A lot of you will know that section of the M5 is a notorious caravan “snake” black spot.
Peoples perception of a snake are very different.

 

[otherclive]

The OPs weight ratio is good.
The OP has used the same set up for two years with no problem.
I‘d like to hear his thoughts on loading and the nose load being used. Did he deviate from his normal loading?
I wonder just how great the snake was? A lot of you will know that section of the M5 is a notorious caravan “snake” black spot.
Peoples perception of a snake are very different.

He did say that it was the initiation rather than a full snake, more akin to a truck passing by, and by rapidly easing off it brought the outfit under control. #15

 

[Dustydog]

He did say that it was the initiation rather than a full snake, more akin to a truck passing by, and by rapidly easing off it brought the outfit under control. #15

Thanks. Not a full blown snake. I guess we’ll never know if was the slowing down or the ATC or the dickie towbar assembly or possible loading
or the M5 hill😉

 

[Hutch]

Hutch which screw are you thinking of?

This video might help some folk to understand the Alko friction pads. Although the video doesn't show the rear friction pad being replaced.

View: https://youtu.be/ruxzwVYutkQ

 

[ProfJohnL]

...
The OP has used the same set up for two years with no problem.
...
Peoples perception of a snake are very different.

I cannot understand why some people are questioning the sensibility of carrying out a loading review following an incident of instability.

Being blunt about it, It really doesn't matter how long a particular loading practice has been incident free, the fact that an incident occurred on this journey proves the outfit is suspect, and even though a mechanical failure has arisen, the nature of the failure has exposed a weakness of the outfit which is actually close to being inherently unstable than the driver had previously suspected.

With that information, is it wise to ignore the possibility the loading regime is not ideal and mask it by simply repairing the mechanical fault? or should the underlying instability be addressed by reviewing the loading regime, as well as repairing the mechanical failures?

I agree that what might be described as a snake by one person may not illicit the same description from someone else. Humans are generally very poor at describing experiences consistently yet alone being able to express the detail of an experience to another, (Don't get me started on Audiophiles and audio perfection).

Regardless of the accuracy of the description, the most sensible approach has to be check everything including loading to try and improve the safety margin of the outfit. There is nothing to be lost, but there could well be a safety margin gain.

 

[Hutch]

I would think that Witter would like to be appraised of this problem as the tow bar has certainly had a problem, and is more than likely to have been a major factor contributing to this incident.

 

[Dustydog]

I cannot understand why some people are questioning the sensibility of carrying out a loading review following an incident of instability.

Being blunt about it, It really doesn't matter how long a particular loading practice has been incident free, the fact that an incident occurred on this journey proves the outfit is suspect, and even though a mechanical failure has arisen, the nature of the failure has exposed a weakness of the outfit which is actually close to being inherently unstable than the driver had previously suspected.

With that information, is it wise to ignore the possibility the loading regime is not ideal and mask it by simply repairing the mechanical fault? or should the underlying instability be addressed by reviewing the loading regime, as well as repairing the mechanical failures?

I agree that what might be described as a snake by one person may not illicit the same description from someone else. Humans are generally very poor at describing experiences consistently yet alone being able to express the detail of an experience to another, (Don't get me started on Audiophiles and audio perfection).

Regardless of the accuracy of the description, the most sensible approach has to be check everything including loading to try and improve the safety margin of the outfit. There is nothing to be lost, but there could well be a safety margin gain.

I believe most of us did agree with your loading point. I even questioned if the OP had deviated from his loading norm! Surely that fully supports your scripts🤔

 

[Buckman]

Well that depends on how big the snake had become, It may not have grown to the threshold point to trigger the ATC.

Caravan instability does not begin instantly. it builds up, and a good driver should be able to notice the early signs and may be able to take early enough action to bring it back under control before systems like ATC actually start to take action.

But as I pointed out previously no one should have an outfit that relies on either the friction damper or ATC to make it towable. Both of these accessories should be considered to be like a seat belt safety additions, just in case things really do start to go pear shaped.

If as the OP's case the failure of one of these device has apparently led to the outfit showing its true stability status and in this case it raises concerns, and it certainly suggests the loading should be reviewed even if just for peace of mind.

You are correct, but unfortunately I think many people rely on the ATC or stabiliser keeping the outfit stable instead of loading correctly.

 

[Buckman]

The OPs weight ratio is good.
The OP has used the same set up for two years with no problem.
I‘d like to hear his thoughts on loading and the nose load being used. Did he deviate from his normal loading?
I wonder just how great the snake was? A lot of you will know that section of the M5 is a notorious caravan “snake” black spot.
Peoples perception of a snake are very different.

I think the issue was between J12 and J13 as that is where we had a very bad snake due to tram lines in the road. I eased off and then accelerated gently which brought the outfit back under control. No ATC back in 2005.

 

[Dustydog]

I think the issue was between J12 and J13 as that is where we had a very bad snake due to tram lines in the road. I eased off and then accelerated gently which brought the outfit back under control. No ATC back in 2005.

Actually the worst bit is nearer the downhill stretch between Worcester and Tewkesbury, but any long downhill in open areas are worse than they look . Hence the advisories!

 

[Buckman]

Actually the worst bit is nearer the downhill stretch between Worcester and Tewkesbury, but any long downhill in open areas are worse than they look . Hence the advisories!

Not much of a downhill on that stretch of the road as it is reasonable flat except for the short distance just after Strensham services where there is a slight downhill grade.
Are you perhaps thinking of the stretch of road between Bromsgrove M40 / M5 and Droitwich turnoff as numerous caravan accidents on that stretch of road?

 

[Dustydog]

Not much of a downhill on that stretch of the road as it is reasonable flat except for the short distance just after Strensham services where there is a slight downhill grade.
Are you perhaps thinking of the stretch of road between Bromsgrove M40 / M5 and Droitwich turnoff as numerous caravan accidents on that stretch of road?

Yes, but the South bound bit after the M42 /M5 junction. I think that’s the one you meant, typo 😜😜

 

[Buckman]

Yes, but the South bound bit after the M42 /M5 junction. I think that’s the one you meant, typo 😜😜

Yep that is the stretch which is before the Driotwich turnoff and not Tewkesbury. I think the issue is the wind that causes outfits to start snaking?

 

[Dustydog]

It is a very deceptive piece of road. The decent doesn’t look steep. The terrain looks gentle. A real trap😢

 

[ProfJohnL]

It doesn't matter where it happened. It's the fact it happened that's important, and the problem is investigated and resolved in the most sensible way.

 

[Buckman]

It is a very deceptive piece of road. The decent doesn’t look steep. The terrain looks gentle. A real trap😢

We better not discuss this any further otherwise our knuckles will be rapped!

 

[Dustydog]

We better not discuss this any further otherwise our knuckles will be rapped!

🤬🤬🤬

 

[Hutch]

Look back at the problems with the friction pads in Alko tow hitch and then the tow bar of the Jaguar E pace which is an early Version. The Profs ideas are good but maybe should be dismissed, ,think outside of your exprtices as a gas engineer, Traore is not inexperienced and his replys should be respected.