BMW E61 Hydraulic Liftgate Pump Rebuild

The liftgate hydraulic pump in my 2010 BMW 535xi Touring lost hydraulic fluid level about 2 years following a quick fluid level top off. This time, there were two issues: i) bad seals on the liftgate cylinder; and ii) failure of the seal in the hydraulic pump accumulator piston, leading to leakage below the pump. 

I'll do a writeup on replacement of the lift cylinder separately. This post describes the replacement of seals and o-rings in the pump assembly.

BMW Hydraulic Liftgate Accumulator bore, piston and spring following dissasembly

When your liftgate starts struggling to reach the full open position, troubleshooting is fairly straightforward. The pump is located in the rear compartment, directly below the liftgate cylinder on the left hand side of the car, attached the left rear fender. To access, remove the left hand rear storage compartment door, then remove any audio components hindering access. Be very careful disconnecting the fibre optic connections on the audio components.

BMW Hydraulic Pump - low fluid level, fluid weeping from the accumulator (left side of pump)

Once you can see the pump, you'll note the "+" sign on the side of the plastic fluid reservoir. The oil level should be in the center of the "+" sign. In my case, the fluid reservoir was nearly empty, with traces of hydraulic fluid dripping from the accumulator housing (to the left of the fluid reservoir). 

Unfix the pump, lift to show bottom of accumulator and fluid weeping from vent hole

There are some gymnastics required to unfix the pump. Some can remove the pump without removing the left rear cargo area trim panel. If you're removing the pump for a rebuild, it may be easier to take the time to remove the trim panel. 

Once you have the pump removed from the car, and the hydraulic lines to the cylinder disconnected, you're ready to work on the replacement of seals. In the photo below, working clockwise from 12 o-clock, you have the motor top right. You have the mechanical pump mid right - between the motor and reservoir. The reservoir is bottom right. To the left of the reservoir is a hydraulic accumulator (a piston and spring designed to maintain hydraulic pressure, which holds the liftgate in the open position without the motor / pump running.) Just above the accumulator is a valve body, where the hydraulic lines connect and where the pressure sensor (top left) connects. 

Right side: Motor, pump and reservoir. Left side: Accumulator, valve body, and pressure sensor.

Removing the pressure sensor is straightforward. Remove the two hex head cap screws, and pull the pressure sensor straight up. The pressure sensor is sealed with a single o-ring - 9mm x 2mm. (All o-rings mentioned in this post are described by inside diameter (ID) then thickness. For outside diameter (OD) - double thickness and add to the ID.)

Pressure sensor with cap screws, and o-ring seal at base

I removed the motor, it is sealed to the pump with a single o-ring (41.6 x 2.4mm). I made no attempts to remove any pump components, I removed the pump, tried not to change the indexing of the drive spring, replaced the o-ring and replaced the motor. 

Motor removed. The o-ring stayed in the pump recess, it removed with a pick. 

In order to remove the accumulator piston, you need to split the two halves of the pump assembly. There are two long hex head countersunk screws which hold the two halves together. When you split the two halves, you'll note 5 oil passages which are sealed with small o-rings (4 x 1.5mm). Replacing these o-rings is very simple, just pop out of their recesses and clean any debris with a clean, lint free rag. 

Left and right halves separated - note 5 sealing o-rings.

Once you have the two halves separated, you can disassemble the accumulator. There are four hex head countersunk screws which hold the bottom plate to the accumulator body. Remove them slowly, and remove them equally (a few turns on each screw in rotation) because the bottom plate of the accumulator is under spring pressure. By separating the two halves of the pump, you ensure that the piston is at the top of the bore by removing any hydrostatic pressure remaining under spring tension. 

Accumulator piston removed from bore, note bits of piston seal disintegrating, dirty fluid

The piston will only come out of the bore with the two halves separated. Try to remove the piston square to the bore - to avoid the metal edges of the piston from scoring the aluminum bore. Same when replacing the piston, avoid rocking the piston in the bore, and insert squarely. The piston is a urethane U-cup seal, 35mm ID, 45mm OD, 7mm tall. 

Accumulator disassembled - piston, seal, spring, base and screws

Old accumulator piston seal on the left, new urethane U-cup seal on the right

New seal on the piston, old seal on the right

The final seals which are replaceable are the reservoir to pump seal which is a 39.4 x 3.1mm o-ring, and the reservoir drain/fill port, which is a 6.1 x 1.6mm o-ring. Reassemble in the reverse order of disassembly. Ensure that the accumulator is reassembled before assembling the two pump halves. 

After having rebuilt the pump, and disconnected / reconnected the cylinder hoses, you will need to bleed air out of the system. Reinstall the pump in it's normal location behind the left rear wheel well, but keep the reservoir off the pump. I used some 1/4" vinyl tubing to draw oil from my replacement oil can, and to reject oil and froth from the return line to an empty aluminum can. 

Bleeding the pump using vinyl hose. Note froth returning to the aluminum can. 

I used AeroShell 41 Hydraulic Fluid for this repair

Once the froth turns to a consistent air free oil flow, you can stop bleeding, remove the vinyl hoses, and partially replace the reservoir cup. I then refilled the reservoir using a syringe and vinyl hose to get the fluid level back to the "+" sign on the side of the reservoir. I used a regular stainless steel band clamp to hold the reservoir on the pump. 

Refilling the reservoir with the pump mounted in the car

Reservoir replaced, topped up to the correct level. 

I purchased extra seals when I completed this project, I'll put some seal kits up for sale on eBay for anyone interested in doing this repair.

I've made some repair kits available at this link. 

I've made some hydraulic fluid and refill kits available at this link.

Let me know if you have any questions in the comment section below. 

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BMW N54 E60 E61 x-Drive Oil Pan Leak Repair

If you have an X-Drive AWD BMW, the front differential is mounted to the side of the oil pan, and the right front drive axle runs through a sealed pipe through the oil pan. There are two aluminum covers which retain oil in the oil pan. I originally made a repair to one of these covers 2 years ago when I removed the engine to replace the turbos and do the oil pan and head gaskets. This repair failed almost immediately, and this post will explain why my original repair failed, and what I've done to make sure it doesn't happen again.

Right side of the N54 oil pan, with the right side drive axle and bearing support removed. 

Following my initial repair, the plate started leaking immediately. The engine had been reinstalled in the car, and the bearing support and drive axle already replaced, and the suspension bolted up and torqued. I didn't have the time or appetite to tackle the leak then, so I waited almost 2 years until I had a few other projects to work on to tackle this again. To start with, I removed the right side drive axle (half shaft) and the bearing support. Then, I removed the cover and discovered how little sealant remained between the sealing surfaces. The sealant remaining was brittle and was removed quite easily. I followed the sealant manufacturer's directions (wait 1 hour before applying full torque) but this delay is much too short to avoid squeezing out most of the sealant. This was my critical error.

Previous repair squeezed almost all sealant out of the gap between the sealing surfaces

 Clean up the mating surfaces. I use a plastic bristle brush, a plastic scraper, and scotchbrite pads soaked in brake cleaner to get the surfaces perfectly clean.

Plate cleaned up, old sealant removed, ready for re-sealing

I removed the bearing support and right drive axle without draining the differential fluid. I lost a very small amount of fluid through the axle tunnel, maybe 50ml or so (2 oz). I should top up the diff fluid when I complete the repair. Mating surfaces are clean.

Oil pan mating surface cleaned up, ready for resealing

 The last repair, I used a tube of sealant which I had on hand and was already opened. This time, I planned ahead, and made sure I had a fresh tube of new sealant for this repair.

Permatex Ultra Grey Gasket Maker

 Following manufacturers directions, I applied a 1/4" bead to one surface (the cover), and then assembled the cover with the fasteners, but not applying any torque. Just closing the gap to approximately 1mm, as evenly as possible on all sides.

Apply sealant to one sealing surface (not both)

1/4" 5mm bead of silicone, Circling the fastener holes (recommended in sealant instructions)

I waited 48 hours before applying torque to these cover fasteners - 2 N-m only. This seemed to compress the silicone nicely. I'll fill the oil pan with oil and check for leaks before replacing the drive shaft and bearing carrier - just in case I still have a problem.

Maintain a 1mm gap between sealing surfaces, wait 48 hours before torquing fasteners

The engine oil was refilled, and after another 48 hours, absolutely no sign of oil leaking from the plate. Looks like it will hold. 

Mate surfaces, but do not torque the fasteners. Tighten just until some sealant comes out of the gap

I've also found that I have a minor leak just above this repair - at the bed plate to block interface. A few drops of oil are seeping out around two of the bolt heads. To make this repair - the engine has to be removed from the car, and the bedplate removed (which provides access to the crank and crank bearings). This engine is at 205,000km now (approximately 130,000 miles) and this is a repair that I'd like to put off indefinitely. At least the oil pan to block gasket has held up nicely, no leaks so far. Same for the head gasket and valve cover gasket. 

If you have any questions, don't hesitate to ask in the comments below. 

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Shimming the Breville Smart Grinder BCG800XL for a finer Espresso Grind

I've been tuning up my coffee system for the past several months, coffee is a passion and daily espresso shots has been a routine of mine for many years. Check out my other posts on upgrades made to my Rancilio Silvia machine. Once I got my PID kit installed, I was able to manage temperature and shot time very easily. The next variable which I started working on was grind, and I found that I wasn't quite able to grind fine enough with my Breville BCG800XL grinder. Close, just not close enough.

Breville BCG800XL with Bean Hopper and Cone Removed

Off to the Internet! I found that Breville offered a free shim kit upgrade for this grinder. I called Breville customer service in North America, and found that my BCG800XL was discontinued. I owned this grinder for only five years. I initially thought about purchasing a replacement grinder, but I'm not keen about replacing things when they are still serviceable, and supporting the throw-away society. I decided to see what I could do to shim the grinder myself.

Use the handle of a wooden spoon to hold the burr from turning while removing and reinstalling the nut

Removing the burr is simple and takes approximately 10 minutes with one tool, a 10 mm wrench or socket. I removed the Burr and measured for washer shaped shims, and ordered some shims. 

Shims in place with Burr removed

When the shims arrived, I started by adding the 0.5mm shim. I could choke the machine a full 6 clicks from the finest setting, this shim was too thick. Then, with the 0.3mm shim, I found I could choke the machine at about 2 clicks from the finest setting. Perfect. My optimum grind is now 4 clicks from the finest setting, and I have several clicks finer to fine tune the grind if necessary.

Use the tip of a knife to ensure the shims are centered under the burr, before tightening the nut

Hint when removing and installing the burr - the nut holding the burr is REVERSE THREADED, turn right to loosen (not left). Also - I used the handle of a wooden spoon to jam the burr and keep it from turning while removing and reinstalling the nut.

0.3mm shim on left, 0.5mm shim on right

This fix will work for the following grinders (and possible others):

Breville Smart Grinder BCG800 

Breville Smart Grinder BCG800XL 

Breville The Smart Grinder Pro BCG820BSS 

The Breville kit part number used to be BCG800/116.1. 

I have spare shims available for sale on eBay at this link.

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Rebuilding BMW Transmission Oil Cooler Hose Quick Connect Fittings

I pulled the BMW E61 into the garage last week to sort out a few issues - rear axle CV boots leaking, oil leak, and low boost pressure. On inspection, I found a leaking transmission oil cooler quick connect fitting, which was spraying oil on the charge air duct from the intercooler to the intake manifold.

The upper (pressure side) tranmission oil cooler quick connect fitting is leaking

I did some research on the internet, could not find any articles about people rebuilding these fittings. This hose costs $170 - expensive to replace for a simple leak. I figured since it was leaking anyway, I would try to take it apart and see if there were replaceable seals. The part numbers of the hoses affected are: 17227570973, 17227571978 and 17227571985.

Once the connection is separated, I took a pick and very easily removed two regular o-rings from the female side of the fitting.

It was easy to remove two standard o-rings from the fitting using a pick. I was careful not to scratch the inside of the connector shell. Once I had the o-rings removed, I noted there were two spacers made from plastic - one green spacer deep in the fitting, and one gray spacer just above the green spacer.

O-rings removed from the fitting, see the green spacer and gray spacer just above. 

The old o-rings were squared off, and not very pliable. They held their out of round shape upon removal. I measured the old o-rings and then estimated what the original uncompressed size would be. They appeared to be standard metric o-rings, and a quick trip to the local o-ring supplier yielded some potential replacements. 

Old o-rings above, new o-rings below. Two per fitting. 

Next step was to stuff the new o-rings into the fitting.  To start with, I used a pick to push the green spacer to the bottom of the fitting, and lift the gray spacer to the top of the fitting. This leaves a groove the width of two o-rings to fit the first replacement o-ring. I stuffed the o-ring into the fitting using some needlenose pliers. 

Start by pushing the green spacer to the bottom of the fitting.

Then - insert the replacement o-ring using needlenose pliers. 

I used the needenose pliers to insert the o-ring into the fitting just above the green spacer, and then to hold one side of the o-ring in the correct position while I used a screwdriver to massage the o-ring into position. With the first o-ring in place between the green and gray spacers, use your pick to push down the gray spacer (and the first o-ring) against the green spacer. 

First o-ring inserted above the green spacer. 

Next step, insert the second o-ring just above the gray ring just as before. With both o-rings inserted, I closed the fittings, cleaned them carefully to remove all traces of oil, so that any new leaks would be apparent. Following a run-up - the two fittings I repaired were both well sealed. I created this simple schematic showing how the o-rings stack in the fitting. 

I've purchased spare O-Rings - if you would like to purchase O-Rings to repair your own fittings, click this link.

If you're careful with the plastic ring and don't break it when disassembling the connection, you may be able to repair it. One other tip - if possible, before disassembling, wash the hoses with soap and water, and get into the release clip side of the fitting with a toothbrush to get as much grit and sand out of the fitting. Blow water out of the release clips using compressed air, and this will make the disconnection a bit easier. Comment below if you have any questions. 

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Insteon On/Off Module Application - Preheating Rancilio Silvia Espresso Machine

The PID temperature controller operating instructions recommend a 45 minute warmup period prior to pulling the first coffee shot. This allows the temperature of the group head below the boiler to stabilize, which reduces water heating during the shot, and allows for quicker intervals between shots for the water temperature to restabalize.

I run an Insteon based home automation network, so I decided to install an Insteon plug in on/off module that I had available.

Insteon On/Off Module

The completed installation

These timer modules look quite contemporary

You could also install a mechanical or standalone digital timer. In my case, I wrote a very simple program in my Universal Devices ISY-994i home automation controller to switch on the pre-heat function at 5am, and shut it off at 9am. This will also help prevent the machine from being left on all day, and potentially triggering the 165C overheat trip sensor.

In use - works great - I make sure the machine is filled with water and the front panel power switch left in the on position at night, with a couple of coffee cups left on the warming tray. In the morning, I come downstairs, and the boiler temperature has stabalized and the group head is hot and ready for making coffee.

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Rancilio Silvia High Pressure Pump Hose Fitting Leak Repair

When I took my machine apart for the PID temperature controller installation, I noticed some calcified water drops underneath the high pressure hose of the pump, and some scale at the pump outlet where the connection had been leaking at the 90 degree elbow fitting.

Evidence of a slow leak at the high pressure outlet. Note the scale around the fitting. 

 I disassembled the pump and hoses, and cleaned the fitting and pump outlet with some scale removing C-L-R cleaner.

Pump and fitting disassembled nad cleaned. 

Scale removed using CLR cleaner

 With the parts cleaned, I decided to reassemble the parts using Pipe joint compound (Pipe dope). I like the pipe dope on high pressure applications because tape can tear and leave gaps in the threads. This compound is rated for 10,000 psi on liquids - more than enough for an espresso machine.

Pipe Joint Compound

Pipe Joint Compound applied to the threads of the stainless fitting.

Conclusion

Once reassembled, I performed a leak check, and there was no more leakage. All good. I'll need to pull the back cover off when I replace the rubber pump mounts - I'll report if there's any change.

Sources and Links

I hope you found this post useful. Feel free to ask questions in the comments section below. I answer all questions. If you're interested, you can help support this site by using the following links to Amazon.com in the United States. My go-to place for Rancilio Silvia parts in Canada is Espressotec.com.

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Rancilio Silvia Insteon Warmup Timer

I've been upgrading my Rancilio Silvia espresso machine. The PID temperature controller operating instructions recommend a 45 minute warmup period prior to pulling the first coffee shot. This allows the temperature of the group head below the boiler to stabilize, which reduces water heating during the shot, and allows for quicker intervals between shots for the water temperature to restabalize.

I run an Insteon based home automation network, so I decided to install an Insteon plug in on/off module that I had available.

Insteon On/Off Module

The completed installation

These timer modules look quite contemporary

You could also install a mechanical or standalone digital timer. In my case, I wrote a very simple program in my Universal Devices ISY-994i home automation controller to switch on the pre-heat function at 5am, and shut it off at 9am.

ISY 994i Program to shut the Rancilio Silvia Off at 9am Every Morning

If you look at the program folders - you'll note that I have a folder called "Home" - which only allows programs to run when the house is not in vacation mode. If we leave the house for an extended period, we'll set the house on vacation mode which runs automated lighting programs, and also prevents certain programs from running. In this case - the expresso machine will not pre-heat if we're not at home.

ISY 994i Program to shut the Rancilio Silvia On at 5:15am Every Morning

The automated shutoff program will also help prevent the machine from being left on all day, and potentially triggering the 165C overheat trip sensor when the boiler eventually runs out of water. This has happenned to me twice in about 10 years.

Conclusion

In use for two weeks now - it works great and I'm really happy with the upgrade. I make sure the machine is filled with water and the front panel power switch left in the on position at night, with a couple of coffee cups left on the warming tray. I also leave the portafilter in the group head to help keep the heat in the group head. In the morning, I come downstairs, and the boiler temperature has stabalized and the group head is hot and ready for making coffee.

Sources and Links

I hope you found this post useful. Feel free to ask questions in the comments section below. I answer all questions. If you're interested, you can help support this site by using the following links to Amazon.com in the United States. My go-to place in Canada for Insteon automation components is Aartech.ca.

 

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