Rascally Wabbit

After spending way too much time reviewing what has been posted here & elsewhere, decided the hitch for me is the OEM. $900.+ smackers is a whole lot of coin, so decided used. Well, the big piece popped up for a pittance so I grabbed it. WOW! 48 lbs. of bumper brace & hitch made by Westfalia. Original bumper brace, sans hitch, weighs only 13 lbs. My question is what other pieces do I need beside wiring? Has anyone purchased the kit & still have a parts list or instructions available? Or perhaps some other source? Any information is appreciated!

formerjeepguy

If you want to stay OEM, then I understand that there is a larger cooling fan, an new brake light controller, and the wiring itself. There is also some ECU recoding or setting adjustment.

I went to the dealer and asked to buy the wiring component and they would not sell them to me saying that the only way I could get them is to buy the kit. I wonder if the answer would have been the same if I had asked to buy the parts with the part numbers in hand.....

Rascally Wabbit

The cooling fan requirement has been dropped, possibly because it is now standard. The trailer wiring harness, actually two, are now available. So the question is what else is included in the kit, especially any extra reinforcements. In this diagram, item #26 & #27 are side reinforcements which run inside the body frame where the beam attaches to the body.
http://www.genuinemercedesparts.com/...gramCallOut=27
When I swapped out the beam this week, the reinforcements were not there from what I saw, definitely nothing attached to the bumper brace. The same reinforcements are shown in the accessory hitch diagram so I am wondering if these are included in the kit. If not, then perhaps this is why the USA market vehicles have lower limits on the OEM hitch than in other markets. Just wondering... Anyone else have information, please?

Rascally Wabbit

Did some more poking around on the other website & stumbled upon this.
http://www.benzworld.org/forums/x204...-towbar-2.html
The picture of the kit, made by same company as the OEM hitch, shows the two additional braces which I am wondering about. Also very interesting is the aftermarket hitch bar which replaces the OEM bumper bar does not have the curved reinforcement! The OEM hitch does have the bar in addition to the curved reinforcement!

formerjeepguy

Do you know the part names/numbers for the wiring harness(s)? I would like to use the OEM wiring with an aftermarket hitch.

Rascally Wabbit

Here is a link to the parts diagram which shows both harnesses, items #30 & #310.
http://www.mbpartsworld.com/showAsse...roduct=8051602
Your VIN # will be needed to determine which harness is correct for your vehicle. Not cheap but they are designed to integrate with the factory system. Note in this diagram that the parts for the hitch are for both the Euro & USA style of receivers.

formerjeepguy

Perfect. Thanks you.

Koenig1

I guess I don't get it??? $900. Insane! That said, I realized before purchase that I needed a hitch, so that was one of the options required in my search. If I was to add a hitch today, well... most reputable hitch companies provide both hitch and 'plug & play' electrical connections for at least half of that! Some provide a better (2") adapter rather that the 'antiquated' 1.25" draw bar. I would not hesitate to mount one of these up with a little beforehand searching. Plenty on here have fitted up 'aftermarket' hitches with good reviews. These vehicles will pull/handle most trailers just fine.... unless you're planning to pull a flatbed with a bulldozer!

Rascally Wabbit

I hear what you say but I have looked at how the aftermarket hitches install in comparison to the OEM installation & there is no comparison. Crazy price? Absolutely but we chose to buy a Mercedes & not a Chevy. That is why I am piecing one together for about half the price of the accessory kit. Almost there too. There are ways to work around the small receiver.

bop11

When you say "No Comparison" are you referring to looks? The ability to remove the draw link does eliminate the look of a hitch. Of course beauty is in the eye of the beholder. As a structural engineer, I don't like the look of the OEM hitch. I had a similar unit on a Range Rover Sport and it was very weak in torsion. In the MB, the actual draw link is slid upward into a receiver using an approximate 2" long round tube. A pin keeps the tube from rotating along with some triangular pieces. After some wear this may make the hitch weak in rotation. The "tube" provide rotational stiffness in the front to back plane about a pivot parallel with the axles. On the RR this meant that a bike rack hung on the receiver when loaded with bikes would almost hit the ground when going over a railroad track or a cross road with a crown due to component deflection. This was true even though the RR had a much beefier and longer insert part. Looking at the picture in the link above, it also appears that all of the drag tension from pulling a trailer will be translated into a twisting torque on the new cross member (10). No wonder it is so costly and heavy. The resultant moments on the parts 150 and 160 will try to bend those. Pulling down on the rear of those link will try to rotate the vehicle about the rear axle reducing the weight on the front of the car during acceleration. And reversing the action during braking.
Curtis and other hitches use a direct pull link on the rear cross member which eliminates rotational torque across the vehicle from the trailer pull. The large, long tubes to the bumper beams provide torsional stiffness about the front to back axis. The same bike rack that use to give my Range Rover hitch fits, now is not challenged by crossing the same intersections and railroad tracks. The two inch receiver is fairly deep to reinforce it when a ball unit is installed. Speaking of ball units, they can be any of an assortment for different tongue heights if you intend to tow several different trailers of racks.
So if you like the looks of not having a hitch OK. Just remember that because it is expensive does not make it better! It also might not make it worse, but Curt and Draw-Tite and Reese have been in the hitch business along time and provide great value and security for the buck.

Rascally Wabbit

@bop11, the link I provided does show the type of hitch you describe but actually the OEM hitch for the USA is a standard fixed 1 1/4", direct pull type receiver as found in most aftermarket hitches. Not certain why MB chose to utilise that diagram but it is interesting that it shows the two different types of receptacle for the trailer wiring, one for the Euro & one for the USA. I do appreciate your comments from an engineering viewpoint which is rarely available. And yes, I heartily agree that the price does not dictate quality.

bop11

Thanks for the info. MB seems to do so many things with much engineering thought, I am glad to hear of their attention even in this instance.

magus

U-haul uses the Curt hitch. Hitch, wiring harness and install is $479. They say 2 hours of labor. Seems a reasonable price for an aftermarket solution.

Rascally Wabbit

Wow, has it been four years plus already? In that time, bought another house, renovated it, bought a Cherokee XJ & renovated that too, moved into the first, sold other house and so goes life. I obviously have not pressed the speed of the search for the two rails which reinforce the special OEM trailer hitch but I did check EBay from time to time. Last week, a salvage yard had a set for sale or make offer. I responded with an offer which was accepted. I now have them & very pleased. Next is to source the cap screws, likely grade 8 shouldered. Total cost is less than $500.00 which was my goal. Major tear down to install as we all know but at least I have the first experience some where in my head. And out here in the southwest nothing rusts!