BMW 535xi Touring E61 Tailgate Hydraulic Strut Popping off the Ball Joint - Set Screw Repair

My BMW 535xiT is my daily driver - use it for going back and forth to work every day and running all the errands to keep the household running. So - the tailgate and back window get lots of use. The car was manufactured in September, 2009 and now has 175,000 km on the odometer, and since BMW hasn't inported the 5 series touring to North America since 2010 - it looks like I'll be hanging onto this car for a while longer. The 3 series touring is too small, I'm not an SUV kind of guy, and I'm not ready to go to a Mercedes E series wagon just yet...

The completed set screw repair - neat and flush. 

So - about 6 months ago the hydraulic strut in the tailgate stopped lifting all the way to the top of travel - it started sagging and making ominous noises. So - I took the time to dig out the hydraulic pump and reservoir, replace the fluid with the BMW service kit, change the 10mm strut ball and get the tailgate functioning well again. I wrote about all that here.

Well - it took about 3 weeks until the hydraulic strut started popping off the ball - you can see the state of the bottom socket on the hydraulic cylinder here, there was finally enough wear that it wasn't going to stay in place.

This is not good....

This isn't good either....

So - just to keep the socket engaged, I cut a piece of styrofoam to jam in behind the strut to try to keep it in place - that worked fairly well for about a month, then the strut would pop off about every time I opened the tailgate, and it was time to make a more permanent repair.

There was a good discussion on the 5series.net forums, the idea that I decided to try out was a set screw. I did a bit of research and found some really nice ball tipped set screws and decided to try them out. 

5mm ball tipped set screws

So - I ordered a lot of these set screws and set out to do the repair.

To drill and tap a 5mm hole - you need a 5mm tap, and a 4.2mm tap drill bit

First step is to dismount the strut from the tailgate - you need to remove the plastic trim on the left side of the window. There's a small clip you need to get out of the way to get the trim off. 

Lift the trim underneath the window to get this clip out of the side trim.

Removing the lower half of the left hand tailgate trim - once this is removed, you can remove the hydraulic strut. 

With the hydraulic strut removed, it was time to set the hole placement for the set screws, and drill two holes - one on each site. I put a small sheet of plywood on top of the security screen - was very useful to support the strut during the machining.

With the strut removed, it's easy to rotate to drill and tap the set screw holes. The plywood makes a good work surface.

I aimed the drilling to intersect close to the steel circlip. Very important to use a pilot drill to locate the holes properly - a pilot hole of 2.5mm would be perfect before drilling out to 4.2mm which is the tap drill size for a 5mm tap. 

Drilling each side of the strut base. 

The first hole on the top side - this hole walked a bit because I didn't use a pilot drill hole - don't make the same mistake I did...

Aim for the steel ring clip...

With the first hole tapped to 5mm - testing out the set screw. 

With the holes drilled out to 4.2mm tap drill size, it was very easy to tap the holes - this is a fairly soft steel part and it cuts well. 

Strut replaced, and the set screw does a great job holding the strut in place. The bottom set screw is easily accessible.

To access the set screw on the top side - its easiest to access with the window open and the left side trim off.

A dab of blue Loctite will hold the set screw in place, keep it from backing out. 

In case anyone is interested, I've created an eBay listing to sell the surplus set screws from the lot that I had to purchase - you can purchase the set screws here at eBay listing 183298383219.

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BMW E61 5 Series Wagon Hydraulic Tailgate Lift Repair

Today I spent about 5 hours repairing my hydraulic tailgate actuator. There lots of discussion about this issue on the forums, I thought I would add some photos from my experience to help those considering or performing this repair.

Correct oil level should lie within the "X"
You can see the oil level is quite low - about 25mm below 

What was wrong? The hydraulic system sounded like it was straining to lift the tailgate. Did not sound normal. The tailgate wasn't lifting up all the way - was settling back down about 10cm lower than normal. And - the hydraulic actuator on the right side of the tailgate started popping off the ball joint - when that happenned, the lift would not operate normally and had to be reset by hand.

So - did some research, and then ordered the following parts:

1. Pressurized gas cylinder for the right hand side of the tailgate.
2. A pair of new 10mm ball joints
3. The hydraulic repair kit from BMW - which includes some hydraulic fluid and a bunch of small parts.

Then - I got started.

If you are going to top up the hydraulic fluid - start by opening the tailgate, closing the tailgate, then opening the tailgate again. This bleeds the system.

Start by supporting the tailgate with something solid - like a painting pole

I started by switching out the right side gas pressurized strut. I removed the old one - it just pops off the ball joints with a bit of gentle force.

E61 Gas Pressurized Struts - New on the Right, Old on the Left

I then took a bathroom scale and measured the force of each strut compressed about half way. The old strut had a force of 96 pounds half compressed. The new strut has a force of 138 pounds half compressed - a little over 40 pounds different. This may explain part of the reason why the hydraulic system sounded like it was straining. Replacement struts are not that expensive, even from the dealer. The new OEM strut even comes with a dab of grease inside the ball joint so that it is ready to install. Check yours - make sure it is greased to protect the ball joint from wear during opening and closing.

Old vs. new ball joint for right hand side gas pressurized strut.
Not bad condition overall. 10mm diameter ball.

With the gas strut changed - I then turned my attention to the left hand hydraulic side. I began by popping off the hydraulic actuator and trying to replace the ball joint.

Left hand ball joint - rusted and frozen in place

It was jammed, and I stripped the hexagon faces trying to remove it dry. So then I soaked it with penetrating fluid, and got onto it with a pair of vice grips.

Penetrating fluid helped a lot. Vice grips tore up the ball joint, but it ended up finally coming out. 

So - I decided to top up the hydraulic fluid while allowing the ball joint to soak in penetrating fluid. Every 10 minutes or so over 3 hours I added another squirt of penetrating fluid. On to the hydraulic system.

Hydraulic pump is just underneath the left rear access panel. The radio module is Sirius satellite Radio. 

Start by removing the left rear access cover - it just unclips and comes off. Next, remove the radio module if you have one - 4 screws hold the radio module to the bracket, then 4 screws hold the bracket to the car. I didn't bother removing the radio wiring harness, I just let it hand from the back of the car during the repair.

Hydraulic pump exposed - correct oil level runs through the X - you can see the level is quite low.

There are 2 nuts holding the bottom of the hydraulic pump bracket, this comes out with a 10mm socket. The upper part of the bracket is held by an 8mm hex head screw - comes out well with a 1/4" drive socket and short extension. 

Upper bolt removes with 8mm socket, short extension. 

By the way - make sure you have a nice 1/4" drive socket with a fairly light mechanism - you'll thank youself. The folding handle is really convenient in these tight spots.

Once the bracket is undone - you go underneath the bracket and remove 3 nuts holding the pump to the bracket - 6mm. 

Once the pump is freed from the bracket - reach up to the top and free the hydraulic lines from a small clip, and free the electrical harness from a zip tie clipped to the bracket. Once these are free - the pump is free to descend. You'll also need to remove the electrical connections - one plastic connector, and two individual wires that connect to the motor underneath a black plastic circular cover over the motor. 

Motor power connections under the black plastic cover. 

Then you can continue following the BMW instructions. I drained all the oil from the reservoir into a small pan.

Draining the oil from the reservoir. 

The drain plug is a small metal plug in the very bottom of the plastic reservoir. You don't need to (or should not) remove any of the hydraulic plugs from the pump. Then you can refill the reservoir. If you purchased the BMW kit - you'll have a new drain plug complete with O-Ring to reseal the reservoir.

Installation is the reverse of removal. Redoing the electrical connections is a bit tricky. Once the electrical connections are replaced - test the tailgate before bolting everything in. It might saving you having to remove the pump a second time to check the motor connections (from my experience...).  

BMW repair kit contents. The bottle of oil has a nipple the same size as the drain fitting on the reservoir - very nice. 

Then I went back to removing the left side ball joint. Three hours of penetrating fluid loosened it up - it was still very difficult to remove.

Chewed up the old ball joint removing it with vice grips. New 10mm ball joint on the right. 

Use lots of anti-seize on the new ball joint - might save the next owner of the car a lot of trouble. 

Socket at the end of the hydraulic actuator needs cleanup. 

So - I cleaned up the socket end of the actuator - toothbrush and penetrating fluid to get all the rust and crud out of the socket. Then I blew it dry with a bit of canned air, and filled it with waterproof grease. I popped the socket back on the new ball and it held.

Cleaning out the socket. 

Completed repair. I put a small section of stiff rubber fuel line next to the actuator, just to give it a bit of support to help it keep from popping off again. I'll update the post if this works. 

So - about 5 hours to do this repair from start to finish. The topped up hydraulic system works nice and smooth - like new - no sound of straining. The tailgate now closes and locks with a firm click. All good. 

The culprit - worn ball joint - chewed up by removal with vice grips. 

Update - 2 Years Following the Fluid Top Up

I use the car daily, use the glass window typically daily, and the liftgate hydraulics multiple times a week, several times an outing. So - the liftgate sees regular service. After about two years - my hydraulic strut developed a leak at the rod seal, and eventually the oil loss was enough to prevent the liftgate from going to full extension. I just recently replaced the hydraulic strut, and rebuilt the pump. I've completed a new post on the pump rebuild at this link. I'll do a new post on the cylinder replacement as soon as possible.

Sources and Links

The replacement 10mm ball and fluid kit was sourced from my local BMW dealer - Park Avenue BMW in Brossard. Total cost was in the order of $200.

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BMW 535xi Touring E61 Tailgate Wiring Harness - SenCom Repair Kit Installation

My BMW 535xi Touring is a 2010 model manufactured in March, 2009. Almost 6 years old with 120,000km. Last summer my remote locking failed – and it wasn’t the diversity antenna module under the rear spoiler, so I suspected wiring issues. I took it to the dealer to have them check it out – and they charged me about $500 to re-splice about 6 broken wires on the right side hinge harness. Since they didn’t insert a repair section – I was sure that this problem was going to reappear, and from what I’ve learned on the forums, I decided to try out the Sencom repair harness kits – with silicone insulated wire for better protection from repeated flexing, particularly at low temperatures.

Melted rear window defroster ground wire (far left) and cracked tailgate lights / locks ground (far right)

This fall – at the onset of winter – I noticed my rear window defroster wasn’t working. I suspected a broken wire in the defroster circuit, so I knew it was time to get at the harness repairs.

I ordered the kits through Autoteilemann.de – very quick and easy and the DHL shipping they quoted included all the taxes, duties and brokerage charges. It took about a week to receive the kits. I ordered 3 to be able to do a complete harness replacement – left and right. There is the kit for the right side harness, and 2 kits for the left side harness – one for the electrical wiring, and one for the antenna cable and windshield wiper fluid tubing.

Left side SenCom Kits Antenna Cable and Washer Tubing - P/N ANT0612 (left) and Tailgate Harness P/N 2016062 (Right)

The kits came with everything required for installation – all the butt crimp connectors, heat shrink tubing where required, new terminals for the defrost attachments on the rear window, terminals and terminal housings for the antenna cable splice and diversity antenna amplifier attachments, washer fluid tubing and barbed tubing splice fitting, and the rubber boots for the tailgate wiring pass through on the left and right sides of the rear window – pre-installed on the wiring loom.

Crimps, Antenna Connectors and Shells, Heat Shrink, Tubing Connector supplied by SenCom with the Left side kits

In preparation for the job – I only had one tool which I needed to add – a crimper for the very small insulated crimp connections. I picked this up at an electronics supply store. Otherwise, for tools, I used a Klein stranded wire stripper (red handled) for all the wire stripping, and an insulated channel lock multipurpose crimper for the standard red, blue and yellow insulated butt crimp connectors.

Crimper for very small gauge crimps (Top left), Klein Wire Stripper (Top right), Channel Lock Crimper for standard Red, Blue, Yellow Crimps (Bottom)

 I heat shrunk all the connections under the rear spoiler around the diversity antenna amplifier to ensure no moisture would get at any of the connections, so the heat gun came in handy there. When doing both sides – you’ll have about 120 wires to strip over the job – so make sure your stripping tool is sharp and in good condition.

I followed the Sencom video on Youtube to guide me through the process – very thorough. Here's a good tip - when the instructions come up in the Youtube video in german text - use your iPhone or Android Google Translate App to translate this text immediately - I was really surprised at how well this worked. The translation was never perfect, but you could get the idea fairly quickly.

Google Translate App is your friend with the German language text in the SenCom video

Start by opening the tailgate and opening the window glass first, then by disconnecting the battery negative post. I waited for the car to go to sleep mode prior to disconnecting the battery – about 10 or 15 minutes. I placed some small rags in the catch for both the tailgate and the window to prevent them from latching during the job.

Rags under the window and tailgate latches will help keep you moving - so you don't have to manually unlatch these if you accidently let them close. You'll be opening and closing the glass and tailgate many times during this repair, especially if you're doing both sides.

I started on the right side – removing all the trim panels per the Sencom video exposing the harness between the tailgate and the windows. I also made sure to let the car warm up in the garage overnight - so that the plastic and wiring wouldn't be cold and brittle.

A trim removal tool will help keep you from breaking the plastic.

When it came time to remove the curved black wiring supports in the hinge – I used a piece of wire coat hanger to push the pins out of the plastic clips retaining the wiring supports – makes removing these clips much easier.

Mini screwdriver worked on the outside hinges to remove the locking pin of the clip holding the black wiring guides

A short piece of wire coat hanger was flexible enough to get at the inside hinge pins - where the screwdriver couldn't access

The trim removal tool was perfect for removing the clips once the locking pin was pushed out

Removing the wiring guides was a bit tricky - using a rag to help protect the paint was a good idea when coaxing the wiring guides out from inbetween the tailgate and glass hinges. It can be done without loosening the bolts on the metal hinges.

Removing the black wiring harness guides - protect paint with a shop rag

Plastic storage container for keeping trim hardware in the order of removal - makes replacing the hardware much easier as you put everything back together in reverse order

Cut the old harness, splice in the new harness on the right side at the tailgate – then remove the speaker in the roof just ahead of the window hinges to access the harness on the inside of the car.

Carefully separate the OEM cable boot from the cable wrapping, and slide up and out of the way

Cut the harness - 10cm / 4" of free cable gives you lots of space to perform the splices

I upgraded the larger gauge splices (blue size) with heat shrinkable crimp connecters that I had on hand

All cables crimped on the right side talegate harness - and waiting to test. Note the number labels on some of the wires to uniquely identify the conductors in the SenCom harness that have the same gauge and color

Pull the old harness through the hinge area, cut the old harness out leaving at least 6” of the old harness to give you space to make connections in the speaker area. Pull the new harness through the wire boot underneath the speaker area, and make all the splices in the speaker area.

Both right side SenCom harnesses pulled through the body cable boot up from behind the inside rear speaker - I used electrical tape on the SenCom harness to make pulling the harness through the boot go easier. Then I removed the electrical tape to perform the splicing

Then go on to do the same for the harness running under the rear spoiler in the diversity antenna amplifier area. The connections under the spoiler are where I ran into a slight issue – one of the wires is brown with a very thin blue line – I mistook it as a ground wire and didn’t track it in my splicing. I had to go back, cut the splice I had done inside the car to identify this wire to the other end of the harness in the diversity antenna area.

Right hand side cable splicing in the speaker opening.

Harness Splicing Complete on the Right Side

A good trick for working with the factory harnesses after you've removed the adhesive tape wrap - is to remove all the residual gum from the wires with Goo Gone before starting the splicing. This will help keep your hands clean during the crimping.

All the ground wires – straight brown with no stripes in the factory harness – can connect to any other brown wire of the same gauge in the harnesses – you don’t need to match them to the same ground wire exactly. Otherwise – obviously – all the colored wires need to be connected correctly. The Sencom harness has a series of wires of the correct gauges but some wires are duplicates and you’ll need to track the duplicate colored wires with a continuity meter – so that you can identify them individually and track the connections. To get this straight – for each harness I cut and spliced – I wrote out a list of every wire – primary color and stripe color, and matched it with a particular color in the Sencom repair kit – e.g. Red wire no. 1, Red wire no. 2., White wire no. 1., White wire no. 2. Then when I made the matching connections at the other end of the harness – it was simple to get everything matched up correctly.

With the 2 harnesses completed on the right side – I moved over to the left side and followed the same method for the tailgate wiring harness, then did the diversity antenna cable / washer fluid circuit / defroster ground wire harness. This is where I found that my defroster ground wire had completely melted through.

To splice the antenna cable – Sencom provides you with a matching pair of male and female OEM style RF connectors – which were fairly straightforward to install. You have to strip the antenna cable in three stages – the outer cable insulation, the inner shield wire, and then the signal conductor insulation. I judged the strips and cuts based on the old connector – and on the female conductor, you need to crimp on a special, tiny, female signal conductor pin. A bit tricky. I managed to get this right – eventually proven by good radio reception and lots of channels when I got everything back together and tested.

Preparing the OEM side Antenna cable for crimping the RF connector

Female terminal crimped to the center core signal wire

Shield Body Crimped over the female terminal / ready for the plastic terminal housing

Female RF Connector with Female Signal Conductor - Gold Color

Once everything was reconnected – and prior to reinstalling any wire guides or trim panels, I reconnected the battery and tested everything. Signals, brake lights, parking lights, reverse lights, license plate lights, defroster function, radio, central locking, cargo cover release, tailgate release, window release. Everything worked perfectly the first try. No fuses blown.

Test all functions prior to re-installing the rear spoiler, or replacing any of the harnesses or trims.

So then – I disconnected the battery again just to avoid any possibility of a short circuit while replacing wires, and tucked away the wires and reinstalled the trim. The wire guides next to the hinges were a bit tricky to get back together, but I got everything clipped together and tightened the guides with a set of pliers so they would hold together firmly. I touched up any small scratches on these guides with a black Sharpie, so I looked like new when it was all back together.

I pulled the new harness through the boots in the roof just forward of the hinges so that there would not be too much slack in the harnesses ahead of the hinge wire guides – so the harness would not be able to be pinched in the hinges. Then I double checked the opening and closing of the tailgate, window and made sure the harnesses were moving freely without pinching. Then – tucked the splices up underneath the speaker openings, replace the speakers and trims, and reconnected the battery.
So – with the repair completed, I noticed that my remote locking / unlocking range became much better. I was down to being able to lock or unlock the car within only about 10’ of the tailgate. If I was at the front of the car, I couldn’t even unlock it. The broken ground connection for the defroster circuit may have been the cause of the lack of range of the remote locking circuit.

Conclusion

Radio reception was excellent, with lots of channels and maybe more channels than I had before (better reception?). It also seemed like comfort access was working a little bit better as well.
Repair time – about 12 hours total. 4 hours the first day, and 8 hours straight the second day from start to finish. Hopefully I won’t have to go back into this for the entire time that I own this car. This is clearly a design deficiency, hopefully BMW corrects this in future variants it builds with tailgates. 12 hours is a lot of time to spend on this – but I love the car and hope to keep it for a while (hopefully until BMW imports a future 5 series touring to North America….)

SenCom Wiring Harness Kits

Right and Left Side Wiring Harness Part Numbers

Left Side Antenna Cable Part Number

4 Year Update

I've been running this repair for just over 4 years now - and it's been solid. No futher issues, no problems with any of the tailgate lighting or functions. Rear window release and defrost still working great. All good. Impressed with the quality of these kits. 

Sources and Links

The Sencom kits were a bit expensive to have shipped from Germany with duties, taxes, brokerage, etc. but the kits are excellent quality. I can confirm the kits work fine with North American vehicles (535xi Touring LCI e61) with one spare conductor on the right hand side, and one spare antenna cable on the left hand side. Thanks to Sencom for supporting us with a quality repair kit and an excellent instruction video. Thanks to everyone on the various BMW forums for your support, I've gotten lots of good feedback on this post and I appreciate it.

Sencom 2016061 on eBay
Sencom 2016062 on eBay
Sencom Ant0612 on eBay.

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