Mercedes ml 320 towbar issue

roosky

Hi all

I have an 06 ml320 that had a genuine Mercedes towbar fitted to it.

Long story short it broke away from the jeep body shortly after so got a mechanic weld it back up and strengthen it.

The weight of the trailer pushes down the back of the jeep and is breaking the tow bar away from. The jeep, has anyone had this issue before and has anyone sorted it.

Jeep is class to pull but towbar set up is too weak, mechanic said it’s designed like a car not a jeep

Wold be pulling a livestock trailer approx 3.5t..... would have pulled a lot heavier with old landcruiser and never had an issue

Thanks

Dirty Nails

roosky wrote: »

Hi all

I have an 06 ml320 that had a genuine Mercedes towbar fitted to it.

Long story short it broke away from the jeep body shortly after so got a mechanic weld it back up and strengthen it.

The weight of the trailer pushes down the back of the jeep and is breaking the tow bar away from. The jeep, has anyone had this issue before and has anyone sorted it.

Jeep is class to pull but towbar set up is too weak, mechanic said it’s designed like a car not a jeep

Wold be pulling a livestock trailer approx 3.5t..... would have pulled a lot heavier with old landcruiser and never had an issue

Thanks

I'm assuming it's the jeep chassis thats collapsing rather than the towbar?
There is towing weight & nose weight. I'd say nose weight is only about 150 kg,you'll see it on the towbar cert plate. Either the ball is set too high or the load is too far forward. The joys of cattle,you can't tell them where to stand You might have to put a gate in the trailer.
Also,I think that ML hasn't a separate chassis like the land cruiser.

TrailerBob

Don't see too many MLs in front of a cattle box.. horsebox maybe, but a very different load strain. If you look at the set up on a ladder frame jeep, landcruiser, pajero etc, the towbar is mounted on essentially a piece of heavy box steel that is connected to the chassis legs with 4 bolts on each side. I don't imagine the ML has such a set up, and as such, the nose weight is killing it as suggested above. The ratings really only tell half the story, as they are usually set with static loads in ideal conditions.

Eg, the 90 series landcruiser I have is officially rated to tow 2.8 ton, but in its design is capable of more, and is rated higher in other markets

roosky

Thanks for replies, now im not a mechanic but im passing on what he found.

So he reckons the set up is different to a landcruiser or trooper etc in that the tow bar is actually connected to the body not the chasis and is breaking the body like you can physically see the back bumper sunken.

He has welded it a few times and put in supports and said there is little more he can do but its annoying because its a great jeep to pull and i dont want to have to change it

Buffman

The towball limit (downward weight on the hitch) is what's being exceeded and breaking it. A quick google suggests the towball limit on those is 135kg which I guess the cattle trailer is exceeding.


Found a video of them being installed. It doesn't look like towing was a priority for Merc when they designed the ML. There seems to be very little to support the towbar.



I'd say without major structural engineering work to strengthen it, you're looking at getting something more suited to towing.



https://www.youtube.com/watch?v=evQtuz0h_os

https://www.youtube.com/watch?v=evQtuz0h_os

TrailerBob

That plate is attached in place of the factory bumper bar, which is part of the rear crumple zone I would imagine, an area specifically designed to deform under load. It would be fine with lighter or better balanced trailers, but you can't balance a cattle box very well, even with gates, the shifting weight is just too high in relation to vehicle weight (upwards of 1/2 ton each). I have towed a tri-axle cattle box with 4 on board a few times and I don't love it.

roosky

I have a 12x6 sheep trailer with decks, sorry was saying cattle trailer but same thing.....only difference is that there is no movement of animals, they are well packed.

When the trailer is on and loaded the jeep isnt even that pushed down on springs but you can see its bending the back bumper down

I was hoping someone might say that there was some way to like bolt the tow bar up further up the chassis or something

zg3409

Beware if a towbar breaks it may cause fatalities.

DIY repairs may fail and then welder/owner may be liable for reckless danger.

There are multiple limits to towing. Firstly does your driving licence include towing? If not you are limited to a small trailer.

The car (varies by exact model) has a Max towing allowance. The towbar has a Max rating. The trailer has a Max rating. The total weight of car + trailer has a Max rating.

The height of the towball versus height of hitch on the trailer needs to be matched with a Max nose weight. You can use a bathroom scales and some books or something to measure it.

Depending on towbar you can sometimes get a plate or hitch to raise towball or lower it to match trailer.

In your case the towbar has failed multiple times and I expect it has been regularly overloaded. The hitch on the trailer may have been damaged and the ball on the car may be dangerously worn. This is asking for trouble. As others have said get a vehicle with a massive toe rating, and make sure nose rating is at sensible amount. Ensure all safety device such as safety chain, breakaway cable, breaks on trailer are all working. Correctly. There are trailer servicing specialists that have spare parts and the knowledge. Many a person have been killed by trailers not attached correctly or disconnecting. A warn ball can easily cause a detachment.

Wishbone Ash

roosky wrote: »

I have a 12x6 sheep trailer with decks, sorry was saying cattle trailer but same thing.....

In fairness to you you didn't say 'cattle, you said 'livestock' and the others referred to cattle.

Wishbone Ash

roosky wrote: »

....Jeep is class to pull...

Pulling is easy. What's it like for stopping?

roosky

Wishbone Ash wrote: »

Pulling is easy. What's it like for stopping?

100% its a great jeep all round but this towbar issue has my heart broke....we have strengthened it so it cant physically pull off the jeep but its breaking downward if you get me

TrailerBob

I think you've answered your own question in a way.. the back end of the ML simply can't handle the trailer, even if the engine and gearbox are happy. You mention previous ownership of a landcruiser and dare I suggest its a direction to look again. If you'd hate to miss the luxuries of the Merc, then a late (05-07) 100 series Amazon is affordable and has all the goodies.

greasepalm

And thats why Land Cruisers can do the business .

selectamatic

TrailerBob wrote: »

a late (05-07) 100 series Amazon is affordable and has all the goodies.

Unfortunately they're not really what you could call affordable compared to a 06 ml320

Op if ya brought it to someone who's experienced in fabrication (making trailers that sorta thing) they might be able to brace things a bit better or come up with some solution for it upon inspection.

roosky

Ya so to add to the story...the Merc is my fathers jeep but he does no mileage as he is retired, I have my car for day to day and use the jeep when towing so it’s a great set up because I don’t need to be driving a jeep that’s hard on diesel all the time...the merc won’t be sold as its dads and he wants to keep it so I would be going changing my car for a jeep which has its own issues as you can imagine.....thanks for all feedback

TrailerBob

As it happens, I was getting diesel this morning and across from the pumps is the mart, and did a quick tot up of what was in front of the livestock trailers that were queueing to get in..

Nissan Navara x 1
Mitsubishi L200 x1
Ford Transit tipper x1
Toyota Hilux x 2
Toyota Landcruiser x 14

Certainly the only real choice in the Tullow area anyway..

CJhaughey

Mercedes are what are known as Lifestyle vehicles, fine for towing a caravan occasionally but not suited to heavy towing demands.
Comfortable and luxurious definitely but not the same league as a working 4x4.

eastie17

I sympathise but your looking for trouble with this setup. Combination of having to break hard coz there’s something large coming against ya, few bumps on the road at the same time and that trailer could be coming in your back window or worse.

MF290

Did you even get to the bottom of this? The ml320 are all rated for 3500kg braked trailer weight. Saw one passing the house the other day and the trailer looked to be nose down.

roosky

MF290 wrote: »

Did you even get to the bottom of this? The ml320 are all rated for 3500kg braked trailer weight. Saw one passing the house the other day and the trailer looked to be nose down.

Ya so the issue is that the tow bar mounts onto the body of the jeep not directly to the chassis so not as strong as other designs

ralphie

roosky wrote: »

Ya so to add to the story...the Merc is my fathers jeep but he does no mileage as he is retired, I have my car for day to day and use the jeep when towing so it’s a great set up because I don’t need to be driving a jeep that’s hard on diesel all the time...the merc won’t be sold as its dads and he wants to keep it so I would be going changing my car for a jeep which has its own issues as you can imagine.....thanks for all feedback

Apart from the towbar issue,how do you find the ML320 as a general farm runabout.Has it been mechanically reliable and is it manual or automatic?

roosky

ralphie wrote: »

Apart from the towbar issue,how do you find the ML320 as a general farm runabout.Has it been mechanically reliable and is it manual or automatic?

A brilliant jeep, it’s an automatic, my father had it from new before it became the farm jeep ....over 260,000 miles on it and has been trouble free....CV joint and a few wear and tear bits that went but that’s to be expected.

I made the jeep commercial back a in 2015 and it’s a big spacious jeep for bags or meal or what ever you need to haul.

ralphie

roosky wrote: »

A brilliant jeep, it’s an automatic, my father had it from new before it became the farm jeep ....over 260,000 miles on it and has been trouble free....CV joint and a few wear and tear bits that went but that’s to be expected.

I made the jeep commercial back a in 2015 and it’s a big spacious jeep for bags or meal or what ever you need to haul.

Thanks for the feedback.I was considering buying one of these as a farm runabout,bags of meal etc.I would be doing very little towing as a guy with a Landcruiser and big box does that for me.
I was always hesitant about buying one especially an automatic.

roosky

ralphie wrote: »

Thanks for the feedback.I was considering buying one of these as a farm runabout,bags of meal etc.I would be doing very little towing as a guy with a Landcruiser and big box does that for me.
I was always hesitant about buying one especially an automatic.

I have been told that if something major goes they are very expensive to fix so bear that in mind.....I was told by my mechanic that if the gearbox or clutch or something went it wouldn’t be like worth fixing