Author: Steve Ball

Late model Sprinter / VW Crafter Front Wheel Bearing Hub Replacement


A noise that was unmistakably a wheel bearing in its last throws of life had grumbled away for a number of weeks before eventually becoming too loud for the driver to ignore and the van was bought in for attention. Once the front end was lifted it was easy to hear which side was the issue, simply by spinning the wheel a little and listening for the dry rumble of a worn bearing. On this occasion it was the offside or drivers side that required replacement.

Sprinter Crafter Hub Bearing Assembly - This would have to be removed and pressed into the cast hub carrier - Quite a job without serious tooling!

Hub Bearing Assembly – This would have to be removed and pressed into the cast hub carrier – Quite a job without access to some serious tooling!

The demands of the transport business dictate how this job is attacked in many ways. Speed of turnaround and the economy of ‘time off road’ are the most important factors and this job is one that if done in the manner described can be completed in under two hours – if you consider any other way, unless you have access to some serious pressing or tooling and a few unexpected new parts along the way, then the long-hand method is best avoided – believe me!

Used complete hubs are plentiful as they are interchangeable between Sprinter and Crafter models so its pretty much ‘anything will do’ as long as it is the correct side. You can pick up a used item with fitted ABS sensor (necessary as 99 percent of the time they will break on attempted removal!) for around £60 – £70 often cheaper, once you have located your spare part you are all set to sprint to the finish. The main issue in removing your own hub and pressing in a new £40 bearing is the difficulties and special press required. If you have to buy in the engineering expertise to press out and fit the new item for you, you can add another £30 cash tip to the job, plus your waiting time for them to do the job.. so the cost to keep you running is about the same – albeit with a used complete hub assembly and not new part. Add to that the possibility of the engineering shop breaking the ABS sensor, which would cost you another £40 plus to replace. Enuff said!

Sprinter-Crafter-906 Hub

Used replacement complete hub assemblies such as this one are plentiful and quite cheap to source for example from user vansevicesltd on EBay

So you have located your chosen spare part and are ready to install. Loosen the road wheel and jack the vehicle under the chassis subframe section that supports the wishbone eye bushes, get as far to the wishbone pivot line as possible as some of the steelwork that exists in that area, especially the U channel that runs beneath the engine, left to right, is only of light gauge and will collapse/bend on any attempt to support any weight on it.

Once the vehicle is in the air, remove the road wheel and wire brush the lower hub balljoint nut, steering track rod end nut and the two connecting strut/damper to hub bolts. Be sure to include all exposed threads, the cleaner they are the easier to remove. Spray penetrant and allow to soak.

Using a 30mm Hex socket and breaker bar undo the lower balljoint nut and run it off to just over the exposed threaded section. Use suitable packing beneath the joint to the ground with a short axle stand or wooden blocks and carefully lower the jack so a reasonable amount of vehicle weight is supported on the joint. Taking a heavy engineers hammer whack the casting to the front lower edge of the hub near where the taper of the balljoint is located, be sure not to miss and damage the boot gaiter or anything else that happens to be around. Usually two or three good blows will part the joint and once this is achieved, jack up the vehicle again to support its weight from the chassis.


VW Crafter

Use a 21mm Hex socket and breaker to undo and remove the steering ball joint nut, either use a lever type ball joint separator or the hammer method above to release that ball joint too. Undo the torx head recessed fixing that secures the brake disc to the rotating hub. Swivel the hub to gain access to the two caliper hanger to hub bolts. 21mm again and breaker will loosen these off, be sure to lever back the pads a little in the caliper to enable easy removal of the assembly off the brake disc. Removing the two hanger bolts completely, use wire to support the caliper assembly under the wheel arch out of the work area so that the brake hose does not get pulled or strained. Tap off the brake disc from the hub centre and place out of the way.

Ensure the ignition is off and key out before proceeding as any ABS sensor removal while ‘ignition-on’ could result in a fault code being set, possibly requiring clearing from the ECU. Best avoided if possible (extra time and money).

Using a 10mm socket remove the plastic nut just forward of the roll bar on the plastic arch liner, lever this out slightly and trace back the ABS sensor wire and unplug it from the connector block hidden behind. ABS is usually the lower of the two connectors, the upper one is the brake pad warning sensor wire.

Using a 21mm spanner to back the bolt heads, use the 21mm socket and breaker bar to loosen the two strut mounting bolts. Note at this point that the top bolt is a slot and the bottom bolt is a hole. This is to allow adjustment of camber angle of the road wheel and should be returned to its original position as much as possible. Normally the bolt head position is easy to relocate on the strut leg as it has left a clean area where it has sat, simply make sure you refit this top bolt to position on assembly. Drive out the two strut bolts while supporting the hub, once free, lower off the lower balljoint taper. The hub is removed!

Replacement is exactly the reversal of removal with the proviso that once completed you pump back the brake pistons from the brake pedal so there are no disasters on first road test.

This hub swap should only take in the order of an hour and a half to two hours to complete, which considering the perceived scale and enormity of the job is pretty good going and this procedure is very possible for the home mechanic to undertake and acomplish without little problem.

Mercedes-Benz Sprinter

Mercedes-Benz Sprinter

Later Sprinter Crafter Axle Swap – Tips & Notes

Mercedes rear axle replacement 1

For the most the later Sprinter Crafter axle swap procedure is covered in the earlier posting on axle/final drive removal/exchange (older Sprinter) here.

There are however a few ‘extra’ tips that may benefit you should you be contemplating the removal or exchange of your later Sprinter or Crafter (2006 on).

Mercedes rear axle replacement 2

Sourcing an axle can be a taxing time, trying to get one of the correct ratio, from a similar van and of course trying to keep costs as low as possible are the main trouble factors.  After a great deal of searching, we came buy a rather sorry looking axle from a low milage 311 LWB panel van, perfect for our LWB VW Crafter CR35 as they are identical fitment. Because of the state of the back plates that support the handbrake mechanism, or in fact ‘lack of them’ due to severe corrosion gave us great bargaining power with the seller as it needed obvious work before you could fit. The axle came to us in the end for £200 which was somewhat of a bargain!  Generally if the axle appears dry of oil leaks and exhibits virtually no ‘in and out play’ on the input flange (pinion) then it will be a servicable part. You can see here below the large amount of play in the faulty axle that was removed.

The steel backplates that support the hand brake mechanism and offer some protection to inboard side of the brake disc were badly damaged and rotton with corrosion. These had to be replaced. New original OEM brake back plates can be obtained as cheaply as £11.00 each if you scour EBay, and pretty soon they were delivered along with the axle for fitting.

Mercedes rear axle replacement 4

Drain the replacement axle as best you can in preparation for remedial work prior to fitting on the vehicle.

Mercedes rear axle replacement 5

You will probably want if possible to recover your ABS sensors from the original axle as it would be added cost to replace these if not totally nessesary.  I have yet to find a sensor that will just pull out.  Corrosion of the casting where the sensors sit is quite bad as they are located on the top of the carrier where moisture and muck always collects. Undoing the single reverse torx pin is usually not enough to simply pull out the sensor – you will need to be clever!  Spraying the area with penetrant may help but the use of any tool to pry or grip the sensor usually ends in tears, you will have to tap it out from the inside.  Follow the instructions below if you have a stubborn sensor that you want to recover without damage.  Once the drive shaft is removed a soft nylon drift or wooden dowel, tapped with a hammer will make easy work of removal.  Its not such a huge deal to remove the shafts from the diff you are removing as it makes the thing lighter to drop and saves you about £100 in damaged sensors!  Dont forget to file the sensor hole clean on the recieving axle to ease refinement before replacing the drive shaft/carrier.

Mercedes rear axle replacement 6

Stripping off the old hubs and corroded shoes didnt take too long as they fell apart quite easily!  Once access could be found to the four reverse torx bearing cap bolts, located behind the hub carrier on the end of the axle tube, a little blow-torch heat was applied.  This enabled them to be undone quite easily with a breaker bar.  Unscrew them all, exposing about 10mm of thread and tap the heads with a copper hammer.  The bearing cap will start to move forward and a small gap will open up where the backplate is sandwiched.

Mercedes rear axle replacement 7

Undoing the retaining pins fully, carefully tap the flange out of the axle tube and withdraw the bearing, bearing carrier, hub and drive shaft from the axle tube. Be prepared for a little oil, and try and pull the complete assembly out as parallel as possible with reference the axle tube to avoid damaging the seal on the bearing carriers mating face.  Once the shaft is removed, recover the old back plate and note the position/orientation of it. Recover the ABS sensor if required (See note above). Install the new backplates with the ‘cut-out’ next to the brake caliper mounting holes, slide in the driveshaft and locate its splines into the differential internal gear. Guide the hub and carrier back into position, making sure to align the hole in the brass coloured internal end cap with the ABS sensor hole in the carrier (only one hole, make sure it aligns correctly with sensor hole).  Refit the four retaining pins and re-tighten them. The backplates are now now installed.  You can either choose to build up the parking brake now or leave things until it is fitted to the vehicle.  Often if your used axle comes with usable rear handbrake cables, its easier to build everything up first and then just simply reconnect the cables at the compensator – the choice is yours.

Mercedes rear axle replacement 8

If you are interchanging axles between Mercedes and VW you may find the anti-roll bar to axle bushes are different types.  This does not effect the position of the upper eye bushes for connection to the drop links, only the type of bush used.  Mercedes prefer to use a D bush and VW use a round tubular bush for the bar to axle connection, obviously the support bracketry is slightly different to accommodate either, worthy of note if pre-ordering spares.

Mercedes rear axle replacement 9

Fitment of the axle is covered in the earlier post here, apart from the connection of the ABS wheel speed sensors and brake pad wear sensors it is identical.  Be sure to reconnect the handbrake cables before adjusting the parking brake shoes, as if you dont they are likley to be too tight once the cables are connected, make this your last job.

Mercedes rear axle replacement 9

Prize out the rubber fill level bung on the rear of the axle and refill with your chosen hypoid oil, though MB specify a synthetic grade oil for this differential there is a multitude of oils that can be used in this application without detrimental effect.  Consult a manufacturer application chart to help you choose.

These few notes in conjunction with the earlier article will hopefully assist you in carrying out this task, it should also help you to select a replacement used axle that is right for your budget, not being put off by some damage to the backplates and using it to leverage your deal.

Mercedes rear axle replacement 10


VW Crafter CR35 Tappet Clicking Noise – Or is it?


If you have a noise on your VW Crafter CR35 that could be best described as a ‘sticking hydraulic tappet’, a serious (and expensive) sounding, heavy rhythmic clicking from the top end – the chances are that it is nothing more than a faulty vacuum pump!  In some instances it can be successfully diagnosed by ‘pumping’ the brake pedal several times while the noise is present with a running engine, often the noise decreases, indicating its relationship to the vacuum pump – though this is not conclusive in every case.  Here is the noise perfectly recorded by someone on YouTube if you needed to refer to the sound your vehicle is making.

VW Crafter Vacuum Pump Replacement 1

Stiction/wear of the moving diaphragm assembly within the VW vacuum pump on this model range is a common issue and a couple of hours work will restore your van to its former silent glory!

VW Crafter Vacuum Pump Replacement 2

After undoing the induction hose clamp on the left hand side of the air box, uncouple the two sensors on the output side, slide off the battery starting terminal by releasing the clip and lifting it up and off the air box right side.  lift up the front of the air box and release it from the two rubber fixing bungs. Release the oval induction pipe from the right side and remove the complete air box from the vehicle.

VW Crafter Vacuum Pump Replacement 3

You will need to identify the vacuum pump which lies on the right side (looking in) of the cylinder head, if you need to, follow the hard black vac line from the brake servo to the pump.  Although it only has two fixings – 13mm nuts – they are very difficult to access and will take some time and patience to remove and retrieve. You will most probably need to stand on a crate or small step to gain access to the engine bay as the lean in over the slam panel is often out of comfortable reach.

VW Crafter Vacuum Pump Replacement 5

First unclip and remove the rigid vacuum supply hose from the brass spigot on the back of the vac pump, simply pull/twist and work this connection off and it will release. Just be sure to catch and replace the soft rubber inner sleeve at the push fit connection, as it often pulls out of the hose flare on removal. Tuck the pipe out of the work area toward the front of the engine and select a 13mm combination spanner.  Remove the top and bottom fixing nuts on the vac pump base plate to cylinder head flange.  The upper nut is hidden away down the back of the fuel lines and bleed off return, be careful how you work on this nut, as it is easy to damage the bleed off pipework or its unions. With some patience it will ‘free’ to a point where you can get your fingers to it for final removal.  The lower nut is really no better sadly.  The spanner has to be slid into position and worked through a very restricted arc to loosen and remove this nut.  Neither upper or lower nuts will allow the use of a socket due to their location and oblique position under the body of the pump.  As these two nuts are undone, the spring loading of the pump plunger will push the pump casting away from the cylinder head as you go, so take your time.

VW Crafter Vacuum Pump Replacement 6

Lower dipstick tube fixing

With both fixing nuts removed, unclip the upper glow plug harness from the fuel lines and cut the selection of ties (3x) from the dip stick tube that hold a short loom section and the DC power tap that you previously removed from the right of the air box.  Using a Torx bit, undo the single upper and lower dipstick tube fixing bolts, this will now allow enough ‘wiggle’ of the tube to allow the vac pump to be orientated and withdrawn from the side of the engine.  If you rotate the pump about 90 degrees clockwise, once it is pulled off the studs, this is the best position to feed out the pump casting from the nest of wires and dipstick tube.

VW Crafter Vacuum Pump Replacement 8

Upper pump bolt – restricted access

VW Crafter Vacuum Pump Replacement 9

Lower pump bolt – restricted access

Refitting the pump is straight forward and almost a complete reversal of the above.  After cleaning off the mating surface on the cylinder head, secure the new pump gasket with two or three blobs of silicone gasket sealer just to retain it as you feed the new pump back into position. Slightly wetting the rubber of the vac hose coupling will allow it to slip easily back onto the brass spigot.  Once the engine is rebuilt check your work then start it, hopefully the annoying and overpoweringly loud clicking noise will be gone and once you have tested for good vac at the brake servo, by pumping the brake pedal and it feels normal, you can road test the vehicle.

VW Crafter Vacuum Pump Replacement 10

Post Mortem: The vacuum pump operates from a rod/actuator that runs on a cam lobe on the camshaft, on some of the earlier models of VW engine you can replace the short stubby actuation rod too while you have access to the area, but often it is the pump housing/body that is faulty and not the rod. If yours is a removable rod and you wish to replace it then simply pull this from the cylinder head and push in the new item.

VW Crafter Vacuum Pump Replacement 12

There are a couple of failure modes of this type of vac pump to consider, the first is the pump cylinder is quite large in diameter, 4 to 5 inches across and as the piston rod wears in its sleeve, this allows the piston to tilt over slightly causing it to ‘stick’ at its circumference on the cylinder bore during its spring loaded return cycle.  It is this temporary sticking and subsequent release that can cause the clicking noise as the piston ‘jerks’ back to once again contact the rod that rides on the cam lobe.  Obviously this sharp metallic noise travels along the camshaft and gives the impression that the noise is borne of a hydraulic tappet or valve gear component.  The second failure mode is when the bushing on the piston actuator rod begins to oval or wear, this allows engine oil to enter the vacuum cylinder.  There is no where for this oil to go so it remains inside the pump, hydraulically preventing a full return of the piston under spring pressure, this prevents the sprung loaded rod extending to its fullest stroke and causes a physical ‘clearance’ between the pushrod that runs on the cam – hence the clatter.

VW Crafter Vacuum Pump Replacement 14

Here you can see in this example the internal parts of the old pump, dismantled so you can see the scoring to the vac pump bore, where over time the piston as been catching and scrubbing the surface. In the short video clip below you can just hear the noise the sticking piston makes as the pump is compressed, (the gulping noise in normal) imagine this amplified through the rocker assembly.

Aftermarket good quality spare parts are available for this item as it is common to a range of engines.  You can expect to pay anything from £60 to £120 for a pattern part depending on source. EBay was half the price of a leading specialist discount car parts factor for the identical part! Part numbers are: VW 074 145 100 A   VW 076 145 100   Pierburg: 722300690,   VW 072 145 100 C.

Mercedes S500 (W220) and others – ‘Fly-by-wire’ throttle pedal fault


There had been occasion when I would decelerate to an intersection or junction and the engine would not settle to an even idle and remain rather ‘lumpy’. By tapping the pedal only slightly to raise the RPM’s by only the smallest amount resulted in the engine dropping back to its normal smooth idle.  It was also noticed that when pulling away from a junction the accelerator pedal occasion required more travel to get the car moving than it normally would, and when it did begin to pick up speed it moved perhaps more swiftly than intended.  There were no reported engine codes and also nothing illuminated on the dash to indicate a problem.

Asking around, a faulty throttle pedal position sensor was the confirmed as the most likely cause and the consensus of opinion was that they rarely ever caused a fault code to be registered, in fact one of my best contacts in the trade said that this condition directly pointed to the pedal issue, doubly confirmed by the fact that no code was reported.

Mercedes Electronic Throttle Pedal Problem 1

So I purchased a used part from a local breaker for £35 and fitted it in less than quarter of an hour from start to finish.

All that is involved is to remove the floor mats if fitted to gain unhindered access to the accelerator pedal.  In the rear moulding there is a plastic circular bung about half way up the assembly, using a small screwdriver or pick lever this out.  Beneath lies a recessed 10mm nut and washer, undo this with a small socket and extension.  Now grasp the pedal and lift it upward from the bottom, levering it outwards slightly to clear the fixing stud, once clear, pull down to disconnect the pedal assembly from its top locator.  The pedal will now be free, retained only by two wiring/loom connectors.

Disconnect the upper multiway plug to the position sensor model and remove the smaller two pin connector from the ‘kick-down’ switch from behind the pedal.  Note how the kick-down wire is threaded along the side of the pedal assembly and remove it.  The pedal can now be replaced with the new unit, threading the thinner loom back in its correct position and then connecting both wiring connectors back onto their respective plugs.

Feed in the pedal assembly, upper section first. Once located correctly, swing down the pedal to mate with the fixed mounting stud and replace the fixing.  Job done, all you then need to do is replace your mats and test the vehicle.

Mercedes Electronic Throttle Pedal Problem 2

On the S500 (W220) there were two types of pedal assembly used, one with a part number A220 300 01 04 for the post face-lift version circa 2004 onward and  part number A220 300 00 40 for the earlier model ranges to this point. Its a good idea to remove your own pedal, as it is such a simple task, to check the part number of the item fitted before searching for a spare.  A new non Mercedes replacement should cost in the order of £150.00 and a genuine part closer to double that.  A good used item should be in the range £35-£70 – the choice is yours!

Throttle pedal fault Mercedes Benz 1

Interestingly there is a large number of people who still believe there is a potentiometer within the pedal assembly, this is of course not the case and the often read advice to spray switch cleaner on or around the sensor is largely futile.  I have taken (broken) this unit apart so that you can see inside and confirm that in this case and most of the Mercedes models from about year 2000 on, this pedal assembly is all solid state and non serviceable.

Throttle pedal fault Mercedes Benz 2 Throttle pedal fault Mercedes Benz 3

What you can see within the housing is a pair of hall effect semiconductors mounted to a PCB. Each sensor is fixed within a static soft iron slotted core and as the pedal is rotated a small annular magnet rotates about this core.  Minute changes in magnetic field are detected by each of these two ‘Hall Effect’ sensors (compared electrical outputs from both sensors are checked for integrity, before a plausible position signal is accepted by the ECU as a failsafe, much in the same way as there is mechanical failsafe protection built into the pedal assembly by having two individual springs controlling the pedal return, just in case one breaks, allowing the pedal to return to a safe ‘throttle closed’ position rather than simply falling to the floor in a ‘full on’ scenario – Which would be a grand ‘brown trouser’ moment.)

Throttle pedal fault Mercedes Benz 4

Each degree of throttle pedal rotation at the rotating hinge point, relates to a predetermined magnetic field strength and this is interpreted as positional data referenced back to the ECU.

Throttle pedal fault Mercedes Benz 6

So, not a carbon track of a potentiometer to break or wear out, just electronics.  Obviously failures occur but in general this is a far more reliable, if slightly more complex solution to throttle pedal position sensing.  I would imagine the most common problem with failure of these pedal assemblies is the ageing of the semiconductor devices, once one device gives a slightly different output at any stage of its sweep, this is interpreted by the ECU as a mismatched signal and it will be ignored – hence dead pedal!  Once the signals are again in unison the throttle position is relayed and off you go…

Mercedes Sprinter 2007-on and VW Crafter Coolant Level Warning Problem



The later Mercedes Sprinter and Volkswagen Crafter (and probably many others) uses a round plastic header/expansion tank in the coolant system.  This nylon spherical tank houses a rather clever float level switch that not only indicates a ‘low fluid level’ but also will illuminate the warning lamp in the dash binnacle if the ‘specific gravity’ of the coolant is less than specified – indicating to the driver that all is not too well with the coolant circuit.

Mercedes Sprinter Coolant Level Sensor Problem 4

On one of the fleet Crafter vans the coolant level warning lamp had come on and the driver had reported the fact.  When I investigated the issue there was no warning light on the dash, water level was fine but it could be clearly seen that the float inside the header tank had broken up, the plastic becoming somehow brittle and breaking away from its vertical retaining slide/guide. The internal float section is not available as a separate part so a ‘used’ second hand bottle was purchased.  After disconnecting the electrical connector at the base of the sphere, it is possible using a couple of sets of brake hose clamps to remove all the rubber hoses from the bottle in situ.  Once the single torx screw has been removed from the bottle mounting foot, orientating the bottle directly down into the void beside the engine, the connected hose-work can be removed quite easily and the bottle withdrawn upward without losing almost any coolant.  What coolant remains in the expansion tank can then be decanted back into the new bottle once fitted and piped.

Mercedes Sprinter Coolant Level Sensor Problem 3

On closer inspection once the bottle was removed, it could be seen that although the float inside the expansion tank was in this case the obvious problem (the actuating magnet it transpired, had been removed from the loose float by the driver, to turn off the lamp – why do they do that!)  Further dismantling of the float switch and level sensor revealed exactly how it functioned and also highlighted a further weaknesses that could in some cases cause issue with level measurement and warning lamp activation.

Mercedes Sprinter Coolant Level Sensor Problem 5

In the base of the tank is a moulded central vertical column that forms an upright guide that the tubular float moves on. The float rides up and down this central guide tube. Beneath and fitting into this tube is the sensor device. Although moulded in a plastic holder, this sensor is actually houses a small glass tube type reed switch that is triggered by the passing float (and magnet). The contacts of the reed switch close as the float magnet descends past a predetermined point and the warning lamp is activated. As the float rises above the reed switch, the magnet no longer causes the contacts to close and they spring open, resulting in extinguishing the coolant warning lamp.  There is a small resistor across the contact terminals of the sensor (around 800 ohms – the one I measured) This I am certain enables the ECU to detect in addition to reporting the coolant level status, a disconnected plug to the sensor, as it would have four possible measured electrical ‘states’ present between the sensor terminals as measured from the ECU. (1): Reed switch contact open, 800ohms = Correct fluid level. (2): Reed switch contact closed, short = Low fluid level or weak antifreeze water mix, Warning lamp lit. (3): Open circuit = Connecting cable disconnected or cut, warning lamp lit. (4) Cable shorted together = Connecting cable linked or fused together, warning lamp lit.

Mercedes Sprinter Coolant Level Sensor Problem 1

It can be seen from further ‘distructive’ disassembly the level sensor that it is susceptible to corrosion around the resistor and wire junctions, obviously due to the service environment it which it lives.  This discovery is important as if the float inside the water tank looks in good order, it may just be that the level sensor is faulty.  Depending on how keen you are with your fault finding, you could just slot a 1k resistor across the sensor plug and see if the warning lamp extinguished.  If it does, the chances are the sensor is faulty and can simply be rotated through 90 degrees and removed from the bottle base without any draining down or tank removal. Slotting in a working sensor, turning and reconnecting its plug to fit the replacement part.

Hopefully by exploring a little deeper how the float level switch works gives you a better understanding should you ever needed to trouble shoot the circuit.  The coolant level warning lamp is extinguished on the dash as you can see below, however you may notice the engine management lamp illuminated just behind the speedo needle hub – this is due to a faulty glow-plug and is next on the list for repair!

Mercedes Sprinter Coolant Level Sensor Problem 7