540iT trailer hitches and towing cross country?

[joekitch]

i still have more to spend, i'll probably have a shop cut the bumper support with a proper cutting wheel, marking off where they need to cut, that'll be like an hour of labor so like $80
the tesla hitch is $112 from them directly
the wiring will be like $40 for a bypass relay kit
so all in that'll make the whole thing ready to tow $727.
Not cheap, but it'll look great and work great and will make this thing even MORE practical

[philly98540]

Pricey but it's the best stuff.

I got by for about $200 but I got a lucky low price on the hitch and did all work myself.

[joekitch]

Thing is, i don't actually need the tesla hitch. the 50mm euro ball will work perfectly find with the 2" cups on most medium size trailers (2 inches is 50.8mm after all), lots of audi guys have confirmed this.

also, it came in last friday and i took several pictures but didn't have the time to upload, here they are.


That was a lot of plastic wrap


IMG_20180303_171408.jpg



The tow bar itself is kind of dirty with some surface rust but everything is included (bolts, screws, keys) and it'll be easy to clean up, maybe put some rust proof on there



IMG_20180303_171424.jpg



The little door in the lower valance. it's EXTREMELY SATISFYING To pop it off and on.



IMG_20180303_171911.jpg



Here's that bumper support thing by the way, i can totally understand now why it's important to have this, it will keep the opening from being floppy with the notch cut out of the bumper carrer



IMG_20180303_172125.jpg



Took me a minute to figure out the installation for the hitch, you have to put the key into the the dial thing on the side and turn said key, then pull the dial OUTWARDS then rotate it all the way around to put it into the "unlocked" position, at which point you can shove it into the towbar and it'll lock in super securely



IMG_20180303_171436.jpg

[philly98540]

Nice stuff!

[geargrinder]

Cool. The cover and hatch setup very tidy indeed.

I'd be very tempted to replace those rusty steel bolts. The obv have some locking tabs on them that would probably not survive the removal process but you could figure out an alternative... safety wire or just plain red loctite probably.

[joekitch]

i'm actually having a bear of a time finding bumper support cutting marks or measurements

Closest thing i have is this schmiedmann listing for an oem cut bumper support, thankfully it seems to line up with some holes on the metal i can use for aligning where to cut the notch
https://www.schmiedmann.com/en/bmw-E...t=B51128193200




as for the rear portion, there's that old gunsmoke article about towing where he marks how much to cut away, which is to say basically all of it
http://www.gunsmoke.com/cars/540i/hitch/index.html







either way this is all on pause until i get my miata running again to use as a daily while this guy's under the knife

[geargrinder]

LOL. ITYS. Scotto want to ring in with advice? Any pixorz?

[joekitch]

i'm...not quite sure what you told me so, but, i could easily just hack away willy nilly but i'd like to keep things relatively OEM, especially since with the bumper insert the opening location and size is pretty specific

[geargrinder]

Yes it requires cutting. Major cutting. You pull the bumper, separate the cover and the metal support core, then have to do some rather extensive chopping of the aluminum support beam core...

I believe I also warned you elsewhere in your other threads or on email, but not gonna go dig that up...

[DHoang]

[joekitch]

I believe I also warned you elsewhere in your other threads or on email, but not gonna go dig that up...

oh i was fully aware of that, i'm just trying to find specific measurements of the front "notch" so i can cut it accurately
i thought your itys was referring to that

[joekitch]

beginning the tow bar install process, got the bumper support out of the bumper and swapped the lower diffuser section, now on to de-rusting the towbar and cutting the support
cutting it will end up being a chore and also dangerous though...
it's very hard to keep it in place on the garage floor since it doesn't weigh much, so as i'm cutting it, it's slowly sliding away.

[joekitch]

I've been making steady progress. bumper cover is cut and mounted (used some tires to keep the thing in place while cutting it). It's a good thing i cut off a ton of the central support material since i ended up being a little close to the large center bolt on the top of the tow bar fouling on the carrier.

Also went over all the harsh edges with a grinder and then with a brass brush on my power drill to make them less hand slicey

One thing concerning me, it feels like the hitch it going to foul on the edge of the hole in the diffuser, since i did a partial test fit and it was rubbing against it before the hitch was even fully installed....maybe once everything's fit together that issue will go away but...


IMG_20180410_204702.jpg


IMG_20180410_204654.jpg


IMG_20180410_204246.jpg

[joekitch]

Uh oh, some problems have arisen...

the tow bar and bumper are on the car, and as far as i know they're installed correctly. the little black L bracket sits on the inside and acts as a sort of lateral brace, which agrees with the pdf i found for installing the tow bar

e39 touring tow bar install.jpg

IMG_20180412_210530.jpg
IMG_20180411_180922.jpg




i put the bumper carrier, now cut, back on the bumper and put all the pop rivets back in, everything seems to align just fine




IMG_20180412_204157.jpg



HOWEVER, once the bumper and carrier are back on the car...well...not so good
for one thing, the hitch can't actually get into the port, it's fouling on the opening in the diffuser, like the diffuser hole is too low. i measured the difference and it's 17mm, phew! I can actually cut a notch into it, it'll just make the little "hide door" that goes over the opening not fit -quite- as well, but i can live with that. My bigger concern is WHY there's such a difference? all this should be fitting just fine?


IMG_20180412_211549.jpg


Continued in the next post (5 image limit)....

[joekitch]

In addition to the above, there's now this consistent panel gap between the bumper and the rest of the car. I held the bumper up as hard as i could while tightening the nuts which hold the tow bar to the body of the car, but even so this gap is still here...but why?



IMG_20180412_213408.jpg




Cutting a notch for the hitch is easy and pretty inconsequential in the long run, but this gap along with the 17mm difference might point to me having installed something wrong...or the tow bar being the wrong one for this car, which would be very very bad


One alternative i just realized, there are two smaller and one very big bolt holding the actual hitch attachment point to the towbar proper, i wonder if i could take those out, add a 17mm spacer to the hitch attachment point, then get longer bolts of the same size/type, effectively shifting the hitch point down ward without compromising its structure..

[geargrinder]

My thoughts...

• Re: the panel gap, I think its clear the towbar and bumper mounts are just not pushed up high enough. Maybe its because of your POR job (nice idea BTW, GG approves) not letting things slide around enough. I would try slight loosening those bolts, then gently using a floor jack under the tow bar to push it up firmer than you can do w/ your hand. I'd be pretty sure that'd sort out your panel gap, which is not large.
• However that doesn't explain the hitch attachment mis-fit. Because that 17mm is between the bumper support/cover and the tow-bar, regardless of where the towbar mounts on the car, that's still going to exist (aka you could have / should have mocked all the parts up together off-car before you put the towbar on the car, and it would have shown you the same thing... I might have setup a 2x4 screwed to a bench or couple sawhorses, and bolted the bumper mounts to that so I could fake the whole thing out in the open...)
• Imagonnaguess this is a sedan vs touring problem. Because the rear bumper cover does occupy lower space on the Touring I believe (which is why the touring rear bumper is always superior looking anyway ). It may be that either:

1. You have a sedan towbar and the touring bar somehow has a dip in it or some other feature to sit lower... or...
2. The touring vs sedan hitch attachment is different and extends down lower (a deeper "J" shape...)

Re: Your idea to space the hitch-receiver down lower... mmmmm.... maybe. How big are these trailers you're going to run all over creation with? You'll probably be increasing the sheer force on the bolts with a spacer in there, and for sure increasing the twisting torque on the towbar. I'm guessing that the "J" of the hitch is designed to more or less put the force from the hitch directly on the middle of the towbar, and if you lower it, it will have some angular leverage. If you're just running around town with a light open trailer and a couple lawnmowers and a cooler of beer back there, then its probably no big thing. If you're hooking up a massive 5th wheel or tuna-fishing boat and going up and down the Rocky Mountains, it might not be the best idea to mess w/ the factory geometry.

BTW if you go that spacer route, resist the urge to use stainless fasteners if you replace the bolts. Stainless is not good for a high-stress, high-sheer application like that. Use high-grade steel. You could also have a metal shop section the towbar with 2 simple cuts, and drop it down 17mm, then weld it up with some plate reinforcement. Would probably take not more than an hour if you had a welder, a metalcutting bandsaw, and some scraps of steel.

[joekitch]

i am going ti be doing a cross country trip with a 5x8 enclosed trailer so thats rather serious
the towbar is touring specific, i actually looked up the exact model by Oris and it does fit the touring HOWEVER this MIGHT be an issue with the msport touring bumper, maybe.
also looked up more ebay listings for touring vs sedan towbars to look for visual differences but they were minor, nothing to do with the "height" of the hitch socket

either way, cutting a bit out of the hole in the diffuser would be a muuuuch safer and easier solution
ill see about cutting the notch but leaving the plastic in there with a flexible hinge so i can swing it back into place when the hitch is not installed

[ChronoGN]

I am currently installing an used Bosal Towbar from Schmeidmann on an e39 touring also.
I am drawing a schematic to wire up the 7pin connector right now and I found this useful.
http://mixedwiki.com/install-7-pin-t...-bmw-x3-e83/2/

[joekitch]

oh that's right, i haven't wired up the trailer connector yet, still need to find out the color coding of the wires i need to splice and where to locate them.
for america it's just a simple 4 pin thing, which need brake lights, left/right turn signal, and reverse lights i think

[ChronoGN]

oh that's right, i haven't wired up the trailer connector yet, still need to find out the color coding of the wires i need to splice and where to locate them.
for america it's just a simple 4 pin thing, which need brake lights, left/right turn signal, and reverse lights i think

Not if you want trailer brakes and reverse light.
7 pin to 4 pin adapter is cheap. I will just get an adapter if I want to pull a small trailer. I'm installing a 7 pin since I plan on pulling a 4500lb RV.

Edit: Here is another useful piece of info I found for wiring your trailer connector. All the pin outs for E39 A3 Light Module.
http://www.bmw-planet.net/diagrams/r...o/E39_PA3H.htm

[joekitch]

Completely forgot to show an "After" shot, the hide-away option is incredibly slick
this is it with the door removed

IMG_20180413_160900.jpg





and with the door in place it's legit hard to tell there's anything there at all




IMG_20180413_160825.jpg




a more head-on picture



IMG_20180413_160535.jpg





I mean, shoot, that's STEALTHY

[computiNATEor]

Nice job!

And I know you weren't asking, but...

Your plastic belt line trim has obviously faded (whose hasn't at this age?), and I can't recommend Solution Finish enough. It does a beautiful job bringing back a nearly-permanent dark matte finish to faded plastic trim. I used it on my father's sidesteps on his Tundra, and he loves the brand-new and non-greasy look.

It's the last 10% that matters

[joekitch]

Got the trailer wired up, the modulelite goes on the left side of the cargo area where the cd changer would go in a sedan, the 10 gauge black wire to the battery (through the included 10 amp fuse holder, of course) and the little green wire to the right turn signal go across the cargo area. The positap connectors lock in VERY securely and have a super stable connection to boot.

i didn't realize the e39 is classified as a "Two wire" brake light setup, since the brake lights are illuminated as the turn signals (3-wire means a dedicated turn signal bulb) so i connected the red "stop" line on the modulite to the brake light signal line on the car. this caused the left light on my trailer to not illuminate, whenever i turned on the left blinker, the right light would blink instead, hah.
Once i un-tapped the red line everything worked totally fine.
i'll upload pictures of the wires later.

Also did a little spin around the neighborhood with an open face 5x8 800lb trailer in tow, the ball works fine with american hitches even over bumps

So i'm essentially 100% ready for the road trip

[scottieducati]

Glad you got that all sorted, my progress stalled once the bar itself went on. Wasn't too worried about the modulite wiring, but this will be a nice reference! Good luck on your trip and report back!

[joekitch]

err, what do you mean progress stalled?
also, one important thing to mention is the specs state to re-check all the bolt torques after a couple hundred miles of towing, since they can wiggle a bit as they "Settle in" and you want them to be really locked in there