I wanted to know what is involved in installing a towbar on an SLK R170. I found many comments where most of them asked "can I do it?" and the replies would discuss legal technicalities or where to buy them. Since I could not find any that actually talked about what is involved in installing one, I reckon it might be useful for me to make a contribution.
So today I installed a towbar on my 2001 R170. It was fairly simple once I figured out where it would go, and how to get the muffler out of the way. If I did a second one, it should take less than an hour. If a shop did it, it should take 30 minutes max.
The towbar was advertised on a NZ auction site, and the VIN number showed it came off a 1999. I don't know who manufactured the towbar, but it fit perfectly behind the bumper and is precisely aligned with the body. In hindsight, I should have sprayed it a matching silver rather than black, but otherwise I am pleased.
This is only to be used for a bicycle rack. Except for the right hand bolt that goes through the tow eye, the other five bolts go through boot (trunk) sheet metal. In my opinion, such a mounting is too weak to tow anything of substance but should be OK for a couple of bicycles.
Also, as a bike rack, no wiring is needed, avoiding the question of what happens when one taps into computer sensor wiring.
Installation was very simple:
- Wire brushed and repainted the towbar with black zinc anti-rust paint.
- Jacked up the rear of the car, muffler side.
- I was not sure how the rubber muffler hangers were supposed to be removed, so after the usual tools in the garage did not do the trick I took a very large flathead screwdriver, heated it in a vice using a gas welder, and bent the tip 95 degrees to fashion a hooking, pulling tool to remove the two rubber muffler hangers. It worked well both in removal and reinstall.
- Disconnected the grounding strap (10 mm)
- Pushed the muffler out of the way, held with a rubber bungee cord to give me room to work.
- Unscrewed the two nuts (8 mm) holding the heat shroud in place and moved the shroud out of the way.
- Used some blocks of wood to hold the towbar near the car (too heavy for one person to hold and install).
- The right hand side (starboard side) bolts to the towing eye. Bolt that first, but allow wiggle room.
- Place a jack under the middle and slowly raise the towbar into place.
- Make sure that the muffler heat shroud clears the bar by pulling it over as you jack it up.
- When the left side is near the bottom of the car, drill a pilot hole using a small drill bit in a hand-held battery electric drill.
- Open up the boot (trunk) and drill a 1/2" or 13 mm hole where the small hole was made. Spray with anti-corrosion paint.
- Presuming you aligned it right, put the upper brace (a large piece of flat steel with three bolt holes in it, and put a large bolt through the plate, hole and town bar below. Tighten, and if it looks aligned:
- Repeat drilling & painting the other two holes.
- Remove the spare tyre (so you don't drill a hole in it).
- Drill two pilot holes from the bottom, then drill the two large holes from above, paint the raw exposed steel and bolt in.
- Spray anti-corrosion paint on the nuts.
Relatively easy job.