Jump to content

Re Torquing Towbar Bolts


Bob From Dunstable
 Share

Recommended Posts

Had a Witter detachable fitted to my new CX5 in February by a specialist National fitting service and had towed about 2000 miles with it. I was getting ready to set off three weeks ago when fitting the tow ball into the receiver I noticed that I could pull the entire tow bar up and down by about 10 mm.

 

Several of the bolts securing the tow ball to the car had come loose, one in particular the nut was so loose I could tighten it with my fingers. I tightened the bolts as best I could and went on holiday. I checked them again before towing home and they needed a little tightening again.

 

I had the fitting company back to check them yesterday and he found some bolts not up to the required torque and tightened them. Apparently some are 85 nm and some 95nm.

 

Obviously I asked why bolts had come loose and his answer was that tow bar bolts should be re torqued every 700 miles. When I said that my two previous tow cars a MB 320 cd and a Freelander 2 had never required the tow bar bolts re torquing he said that they wouldn`t as they are "a different class to the CX5 and have more solid fixing points".

 

This is a first for me and I can`t help thinking that the bolts weren`t torqued properly in the first place and the comments made by the fitter are just a smokescreen.

 

Anyone have any experience or knowledge of this ? From what they have told me checking the torque on the tow bar bolts will have to be added to the list of regular maintenance.

 

Bob

Mercedes Benz E220 AMG Line Auto Estate and Bailey S4 Unicorn Cadiz

Link to comment
Share on other sites

Sounds a load of rubbish to me having to check them every 700 miles.

I can, however, understand an initial check after a few hundred miles as the towbar settles in.

Edited by JanandJay

Willerby Avonmore previous kit VW Splitty Camper,Ford Transit Camper, Commer Highwayman, Sprite Alpine Caravan, Rapids Export Folding Caravan, Fiat Autosleeper Harmony, Ci Granduca Motorhome, McLouis Glen 432 Motorhome, American RV Trail-Lite twin slide outs 8.2ltr petrol/lpg, Lunar Solaris Limited Edition Caravan.

Link to comment
Share on other sites

I had to tighten mine after only 1 year and towing no more than 500 miles, I was surprised I could spin the bolts round with ease, only 3 bolts were tight at about 30 lb/ft, I have only covered 4,000 miles in the year I have had the car, but I will be checking again in a years time. I do wonder if it was tightened correctly initially.

 

May be the 700 miles the OP mentioned is the towing miles and not the tow car mileage.

 

As the security of the tow bar and its electrics are now an MOT check, it is no hassle to check, better to spend a few mins checking instead of an MOT failure

2013(13) Sorento KX2 2. 2 Diesel Manual, (With smelling clutch) Glittering Metal (Metallic Grey) dragging a 2020 Coachman VIP 520 with a Powrtouch Evolution Motor Mover (Towing @ 80. 0%) :)

 

1288275170_2019VIP.jpg.775f2d8ce7b26db242e04a2e77903cd0.jpg

Link to comment
Share on other sites

Wouldn't you think that if this was a problem and bolts did frequently need retightening that the towbar fitting companies would offer a checking / maintenance service.

It would make sense from a safety viewpoint and they would make a few extra £'s and save their reputation.

Strangely they don't - so I'm not inclined to believe that this is a frequent issue.

Having said that I don't recall the towbar fitter using a torque wrench when he fitted my one so I'm gonna recheck after a few hundred towing miles.

As Bob said, issues are caused as probably not torqued up correctly in the first place.

Edited by springtime

Willerby Avonmore previous kit VW Splitty Camper,Ford Transit Camper, Commer Highwayman, Sprite Alpine Caravan, Rapids Export Folding Caravan, Fiat Autosleeper Harmony, Ci Granduca Motorhome, McLouis Glen 432 Motorhome, American RV Trail-Lite twin slide outs 8.2ltr petrol/lpg, Lunar Solaris Limited Edition Caravan.

Link to comment
Share on other sites

Contrary to this, I have had towbars swopped and

the fitter has had to grind bolts off!

I have never actually seen a fitter use a torque wrench

on anything smaller than a 24mm bolt like all skilled people

they use ring and open ended spanners and their experience

the same as I did in my engineering trade.

I think your people lacked experience and accordingly put you at risk.

Just my opinion

Link to comment
Share on other sites

Extract of witter tow bar fitting states

 

Recommended torque settings: M8 - 27Nm, M10 - 53 Nm, M12 - 95 Nm, M14 - 150 Nm, M16 - 214 Nm

 

I do not believe anyone has "sufficient experience" to know when they have tightened a bolt/nut configuration correctly when nyloc nuts are used, without a calibrated torque wrench. If an accident did occur which the police investigate and find it to be the tow bar fitting causing the incident, then the fitter would not have a leg to stand on legally. So anyone who fits any bolts/nuts configuration who do not use correct tools are not IMHO professionals and do not deserve to be trading.

2013(13) Sorento KX2 2. 2 Diesel Manual, (With smelling clutch) Glittering Metal (Metallic Grey) dragging a 2020 Coachman VIP 520 with a Powrtouch Evolution Motor Mover (Towing @ 80. 0%) :)

 

1288275170_2019VIP.jpg.775f2d8ce7b26db242e04a2e77903cd0.jpg

Link to comment
Share on other sites

Very interesting! I also have a Witter detachable and towards the end of last season I experienced pronounced knocking. I had a look underneath but could find nothing obvious. First trip out this year the knocking drove me potty, so when home I got back underneath. One side of the towbar was OK while the other was hanging on with one bolt only and no nut at that!! Took the car into the dealer that same day and they dealt with it there and then.

 

No problem since, so I suspect that the bolts on that particular side were never tightened/torqued properly in the first instance.

Edited by PaulCWren
Link to comment
Share on other sites

Yes Bob my towbar came loose this year, I've been away since and the bar remains tight.

 

A NTTA workshop fitted mine but I think next time I will use a fitter that has the use of a ramp.

All the bolts were loose on mine except the four on the receiver.

Luckily where I was on holiday the farmer had a ramp for his own vehicles and tightened them up for me.

 

I later took it back to the NTTA workshop and had them checked with a torque wrench, I can't say if they used one initially.

All they said was bring it back after some use and if the bolts are found loose they would contact Witter.

 

I also had the cross member bolts come loose on a Xtrail, which is bar to bar if you know what I mean, so nothing to do with the solidness of the car.

Edited by xtrailman
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...