Removeable towbar on LR Discovery 3

[DomDom]

I have a small issue with the removeable towbar on my Landrover Discovery 3 working loose on a journey. Last weekend we got back and when I unhitched I found the towbar was able to move from side to side about an inch and a half. To say I was a little concerned is a massive understatement and I was struggling to understand why it was like this.

Anyway, looking back, since we changed the tintent for a new Elddis back in January I am getting the towball work loose and this never happened on our old Swift. Thinking about what might have been causing it, possibly the difference between the Alko and BPW chassis or hitch head, then it dawned on me, the BPW with the Winterhoff head is new and thus so are the friction pads whereas the old van was 8 years old and I had never changed the pads.

So, last night I tried out the theory and took the van out for a run. 30 miles with the friction head fully closed - result was a loose towbar. On the return journey I left the hitch head friction part unlocked (snapped down to lock the ball in the socket and didn't push down the friction setting) and the bar was still snug & tight when I got back.

So, from this I am wondering if the friction pads are too tight or if I would be better off with a ATC system instead (can't remember the BPW equivalent). I wouldn't normally worry but the bar was very loose in the socket when using it, to the point where I was worried it was close to coming out. The one saving grace is that the LR has a massive eye cast into the chassis for the breakaway cable so at least this isn't just looped over the towball.

I also spoke to a pal who tows his van with a Ford F150 and the american style towbar which has a ball bolted on. His ball comes undone if he uses the friction head despite having lock washers and doing it up to 200nm with a torque wrench. Clearly these things impart a great deal of force on the towball.

Obviously if the worst was to happen and it came adrift, aside from the immediate danger to other motorists, I imagine I'm going to have a massive fight with the 2 insurance companies who insure the van and the car.

Your thoughts please.

Dom

 

[Lutz]

Removeable towbars are normally of a spigot type which is inserted into a socket and is then locked. It is difficult to imagine that such a design could work itself as loose quite as much as you describe without some serious fault, either in the design or in the choice of materials. But maybe your towbar is of a different type and you can explain in more detail where the clearance occurs that allows an inch and a half movement.

The towbar manufacturers are fully aware of the forces that can occur due to an AlKo or Winterhoff type coupling because these are defined in international standards, so it seems very strange that the design from a reputable manufacturer could develop such a problem.

 

[Bazz1]

Hi Dommonic, you dont say how old the Tow Bar is. I would be having a word with the supplier/fitter and the manufacterors. As Lutz as said they should all know the forces that are present from this equipement, and it should be servicable. May be something the maufacteror has over looked. At least get it checked out, Bazz.

 

[DomDom]

Thanks for this chaps. OK, the towbar is the genuine landrover part which is designed for Discovery-3 and RR Sport.

Trying to describe the design is difficult but it is basically a taper (wedge) which fits into the socket on the chassis and then a spring loaded locking pin (also tapered) moves into the chassis at about 45 degrees to the wedged part. (upwards) The swan neck is cast on to the end of this wedge.

Removal is by means of a rotating knob which (I guess) operates a rack & pinion thus pulling back the locking pin and allowing the wedge to drop.

It is the pin which is moving back under load and this allows the wegde to partially drop out of the chassis which then leaves it a loose fit and this is what is allowing the sideways movement.

I've tested the pin using a G cramp in the vice and unless the knob is unlocked with the key it will only move back about half an inch so it probably cannot come out completely as long as the knob is locked when on the car. But to be honest I was worried enough to book it into the dealer on tuesday for a more thorough investigation. I also checked the various LR forums and I am not the first to report this although there do seem to be varying interpretations of "Working loose" from what I have (OMG type loose) to a slight movement. Tuesday will tell hopefully.

 

[DomDom]

Not sure how to post a picture here but there is an image of the thing at



The blue arrow points at the pin which releases the main pin when the bar is inserted.

The red arrow points to where the main locking pin comes out of.

 

[DomDom]

Not sure how to post a picture here but there is an image of the thing at



The blue arrow points at the pin which releases the main pin when the bar is inserted.

The red arrow points to where the main locking pin comes out of.

Aha, HTML code works then

 

[Lutz]

I'd have the towbar seen to immediately by a dealer. There is something seriously wrong with it if the wedge that you refer to is allowed to partially drop if it was previously properly locked in place. If you have towed for any significant distance with a partially dropped towball you may have damaged it or the socket further and the whole assembly may have to be replaced.

 

[JTQ]

As you say you have searched various Disco forms you might be aware of this one where this was discussed.

http://www.disco3.co.uk/forum/topic41342.html
And importantly a defect found in a particular case. See final entry: -

"Problem solved

Took car to stealers today and demonstrated problem by comparing my towball with a couple of others on forecourt. The release lever on my towball could be moved down about a quarter turn making the whole towball quite slack, on the others the lever could not be moved at all.

Result, new towball supplied under warranty (original supplied new with car March 07).

Stealer also took the opportunity to carry out some recall work on the car, they were a bit vague on what was involved! Something to do with brake servo pipes.

I am a happy man "

I also have the Disco3 and now have towed over 30,000 miles. My towbar also just perceptibly slackens and I cant see how it can do anything else given the down loads it sees. But this is just the slightest slackness; it can be felt and heard but hardly seen.

As a design it must be adequate as the same receiver and tongue features in the Australasian market rated at 250 kg noseweight , with the same 3500kg towing limit.

Your plan to see the dealer is essential.

 

[DomDom]

I'd have the towbar seen to immediately by a dealer. There is something seriously wrong with it if the wedge that you refer to is allowed to partially drop if it was previously properly locked in place. If you have towed for any significant distance with a partially dropped towball you may have damaged it or the socket further and the whole assembly may have to be replaced.

Hope the socket isn't damaged then, that would mean a new chassis

 

[DomDom]

As you say you have searched various Disco forms you might be aware of this one where this was discussed.

http://www.disco3.co.uk/forum/topic41342.html
And importantly a defect found in a particular case. See final entry: -

"Problem solved

Took car to stealers today and demonstrated problem by comparing my towball with a couple of others on forecourt. The release lever on my towball could be moved down about a quarter turn making the whole towball quite slack, on the others the lever could not be moved at all.

Result, new towball supplied under warranty (original supplied new with car March 07).

Stealer also took the opportunity to carry out some recall work on the car, they were a bit vague on what was involved! Something to do with brake servo pipes.

I am a happy man "

I also have the Disco3 and now have towed over 30,000 miles. My towbar also just perceptibly slackens and I cant see how it can do anything else given the down loads it sees. But this is just the slightest slackness; it can be felt and heard but hardly seen.

As a design it must be adequate as the same receiver and tongue features in the Australasian market rated at 250 kg noseweight , with the same 3500kg towing limit.

Your plan to see the dealer is essential.

Yes, I found that one last night and it was the one which prompted me to call the dealership. Looks like there might be a design change on the towball itself or maybe a fault which requires a new one. Will report back.

 

[Bazz1]

Hi all, just another spanner in the works. If there is play in the tow ball then it will be an MOT failure. A number of tugger freinds have the the Pin + Ball type for differant trailers and if theres any slackness in the fitting then they have been failed. I gather the age of vehicle we are discussing hasnt reached the stage that it requires an MOT, but just something else to consider. Bazz.

 

[DomDom]

Hi all, just another spanner in the works. If there is play in the tow ball then it will be an MOT failure. A number of tugger freinds have the the Pin + Ball type for differant trailers and if theres any slackness in the fitting then they have been failed. I gather the age of vehicle we are discussing hasnt reached the stage that it requires an MOT, but just something else to consider. Bazz.

Bazz, vehicle is of MOT age now (4.5 years) but the towbar is not testable if it's not fitted at the time of testing. Mine never is, it's only fitted when I need it. (too many banged shins)

All Discovery 3's and RR Sports have the socket built into the chassis so whether or not the car is a towcar is an unknown quantity at MOT time.

 

[Wendy-Norfolk]

Hi Dominic, we've got a similar situation with the removeable hitch on our LR Discovery 3, there's a little bit of play up and down, rather than side to side.

It's been like this for a couple of years now, as we are only aware of it on uneven/bumpy road surfaces, we don't see it as a problem - the hitch is perfectly secure!!)

 

[Wendy-Norfolk]

Hi Dominic, we've got a similar situation with the removeable hitch on our LR Discovery 3, there's a little bit of play up and down, rather than side to side.

It's been like this for a couple of years now, as we are only aware of it on uneven/bumpy road surfaces, we don't see it as a problem - the hitch is perfectly secure!!)

OH is going to check the play just to be on the safe side!!

 

[DomDom]

OH is going to check the play just to be on the safe side!!

I've been checking mine over regarding some information on the Disco3 forum.

Tell OH to fit the towbar and lock it removing the key as well. Then see if the green knob can be pulled and turned. If it turns AT ALL, the locking pin is moving back and the bar will drop and give quite a bit of movement. This is the problem with mine I think and LR are going to check it out on tuesday.

 

[DomDom]

OK, went to see the dealer yesterday and the DP plus 2 techs all looked at it. One of the techs is a 'vanner with a D3 and he confirmed that I am not the first to have this issue. He also confirmed that the green locking knob should not turn at all when the unit is locked, which mine clearly does.

I demonstrated how loose the towbar can become by fitting it, locking it, removing the key and then turning the green knob 1/4 of a turn. The bar dropped by about 3/8 of an inch and could be moved from side to side by about an inch and a half. It would not come out completely which is reassuring but all agreed it should not do any of this. Locked SHOULD mean locked, not partially locked.

Anyway, upshot is they've ordered me a replacement towbar which I shall test when it arrives (thursday) and the matter has been reported back to Land Rover by me just to cover any future issues which might arise (like needing a new chassis because of a damaged socket)

Will report further once new part arrives.

Dom

 

[ed1]

OK, went to see the dealer yesterday and the DP plus 2 techs all looked at it. One of the techs is a 'vanner with a D3 and he confirmed that I am not the first to have this issue. He also confirmed that the green locking knob should not turn at all when the unit is locked, which mine clearly does.

I demonstrated how loose the towbar can become by fitting it, locking it, removing the key and then turning the green knob 1/4 of a turn. The bar dropped by about 3/8 of an inch and could be moved from side to side by about an inch and a half. It would not come out completely which is reassuring but all agreed it should not do any of this. Locked SHOULD mean locked, not partially locked.

Anyway, upshot is they've ordered me a replacement towbar which I shall test when it arrives (thursday) and the matter has been reported back to Land Rover by me just to cover any future issues which might arise (like needing a new chassis because of a damaged socket)

Will report further once new part arrives.

Dom

hello dominic, will be checking ours, had 2 on 2 disco 3s, never noticed a problem, but will definately have a better look, thankyou for the info

 

[DomDom]

Finally I managed to get back to the dealer today. New towbar supplied and we tested it. Locking mechanism works fine on the new one and the old one has been returned to Land Rover for inspection. Happy days again.