Mercedes Sprinter Clutch Replacement (T1N, NCV3, VW Crafter and other MB)

 

Clutch replacement on any vehicle can be an expensive job, especially if you are entrusting the job to a main dealer.  Although large scale and a little mauling, clutch replacement on Mercedes models can be well within the capability of a competent DIY’er with only a limited number of tools.  In this post we shall look at the replacement of the clutch mechanism (including Dual Mass Flywheel DMF) on the Mercedes Sprinter – both older and newer models.

Mercedes Sprinter / Crafter Clutch replacement

There are several important details often overlooked about the Self Adjusting Clutch mechanism or SAC, that the installer has to be aware of so that things go smoothly.  You will no doubt have read many horror stories on the web of people installing SAC clutch units only to find that on re-assembly they have no functioning clutch, then having to take it all apart again to do it properly!  The first thing to understand is how the clutch actually self-adjusts over its life and in this understanding it will allow you to assemble things in the correct manner, so when you put that last bolt in place you are certain things will work as they were designed.  If you are fitting used components, such as a second hand DMF (flywheel) or even a complete used clutch, this knowledge is ever more important.  You would also additionally need to know how check this if you were stripping and replacing the original clutch and flywheel from an engine only to replace it later, say if you were replacing a leaking rear crank shaft seal for instance.

You will remember from days of old that clutches on older vehicles used to have a different bite point as they aged, either right at the bottom or top of stroke depending on design.  This is not the case today with advancements in clutch technology.  Mercedes clutches and other vehicles too, now have circular adjusting mechanisms built into the cover plate and spring that move to compensate as the clutch wears, maintaining the release spring pressure and finger position.  This means that as a SAC clutch ages, it maintains the same spring operating position and ensures a constant actuating force to engage/disengage the clutch over its life.  Indeed it is almost impossible to tell if a modern clutch is ‘new’ or only ‘weeks from failing’ by the pedal position and feel alone – all thanks to the SAC.

When you purchase a new clutch kit you will almost always find that the clutch has been ‘set’, and is ready for installation. However it is always best to check that things are correct before fitting as I have known due to rough handling even new cover plates ‘spring’ into a full adjustment position – clearly fitting this as-is would result most probably in a non functioning clutch.

Mercedes SAC Clutch

From the illustration above you will see the cover plate/spring assembly has an adjustment ring. (2)  Simply put, this circular ring is allowed to rotate if required a few degrees when the diaphragm spring is fully compressed (when the clutch is operated) Its rotational resting position is controlled by the combined action of a sensor diaphragm spring (5) and the main diaphragm spring (4), allowing the plate to slide round slightly, facilitating changing the pivot point of the main clutch springs as the driven plate wears. There are three small springs that pre-load the adjusting ring so that as the clutch wears the adjustment ring is forced to rotate slightly to drive what is in effect a ‘wedge’ into the forming clearances of the cover plate diaphragm spring at its pivot point, thus allowing clearances to be ‘auto adjusted’ within the installed cover plate.  More information about the SAC from LUK if you wish to view here.

The adjustment ring’s spring position can be seen to be fully extended on this worn clutch cover plate below, the photograph below that shows the adjustment ring in ‘set’ position, this is how the clutch needs to look before fitment. Always check this before installing the cover plate, even if just out of the box!  There are many expensive tools used for correctly setting the adjustment of the pressure plate once installed on the vehicle, whilst these are great to own, unless you fit clutches every day it is hard to justify their purchase, this post outlines how it is possible to carry out this work without the special setting tools.

SAC cover plate showing adjustment ring spring positions for a worn clutch

Mercedes clutch SAC adjustment ring spring set position

If you are using a used clutch, or simply refitting your original plate, it is important to check or reset the adjustment ring to the ‘set’ position shown in the photograph directly above. This can be achieved in a press used between the stamped steel cover plate edges and the diaphragm springs.  If you do not have access to a means of compressing the diaphragm springs so that the adjustment ring can be counter rotated and reset, you may wish to read on, but use great care – as there is a fantastic amount of pressure behind those diaphragm spring fingers and a truly huge amount of force is needed to compress them!  The following is an emergency measure, only to be used to get you out of trouble and is definitely not by any means a recommendation.

On a solid driveway, place a hydraulic trolley jack under the rear axle of the vehicle and raise it enough to fit the cover plate, supported on three stout short wooden blocks of the same size, resting on the flange/outer lips of the stamped steel plate only, NOT the pressure plate (form the wooden blocks into a triangular formation).  Using a very large socket that will generously cover the hole in the centre of the diaphragm springs, align this with the axle beam or lower shock absorber mount – use solid wood packing as needed.  When in position bring down the jack ‘very slowly’ to allow the axle weight of the vehicle in controlled contact with the socket via the wooden packing, depressing fully the diaphragm spring, almost to the cover limit stop. (shown in cut away diagram above)  Now carefully rotate the adjustment ring anticlockwise with a stout screwdriver until it rests fully against its stop and the three small springs are fully compressed.  Once achieved, jack the vehicle once more and remove the cover plate that is now set for installation.  Throughout this procedure please consider your own safety at each step of the way!

2005 Sprinter T1N Gearbox Removal

Now you can begin to remove the gearbox and fit your clutch.

Working from ramps with additional additional 4-6 inch raising blocks if you have them, is the best way to achieve enough space to work comfortably around the gearbox, leaving yourself enough room to manoeuvre freely and eventually remove the gearbox from beneath the vehicle.  I always jack the vehicle onto ramps, this allows you to place one ramp forward and the other facing rearward, thus locking the vehicle from rolling either way to supplement the handbrake and rear wheel chocks.

Disconnect the battery before starting any work, as you will no doubt disturb the starter motor during the job. Also on later Sprinters,  W639 Vito and VW Crafter models remove the complete air box from under the bonnet, this prevents any strain on the plastic components, as the engine naturally tilts backwards when the gearbox support is removed.

Sprinter hoses and gear cables held out of the way

Use a trolley jack to support the plate that supports the back of the gearbox near the output flange.  Undo all the bolts that hold the support plate to the chassis rails on either side, allow the jack to be lowered and removed. This will drop  the rear edge of the gearbox down a little so that the rear gearbox mounting pin can be removed and the support plate taken out from beneath the vehicle.

Using a 16mm socket remove the four propshaft flange bolts from the gearbox output shaft.  You will now have to remove the drop protection ‘horse-shoe’ brackets and the two centre bearing bolts to allow you to drop the prop sufficiently to allow you enough flex for it to be moved out of the working area to one side of the vehicle.

Sprinter with DMF removed

Now remove the gear selector cables, make sure you mark the shaft positions in the plastic ball-ends (amount of insertion) before you release them and tie them to one side. Put a latex glove under the cap of the brake/clutch shared master cylinder, before clamping off the flexible clutch hose from the chassis to gearbox. With a small screwdriver or pick, detach the hydraulic connection retainer clip from the gearbox hose coupling, keeping this in a safe place.  Pull out the hose and again tie it out of the way of the working area.  Remove any electrical connector or plug and tuck them out of harms way.

Now using at least a 24 inch extension bar and reverse torx socket remove all the ring bolts from the bell housing. There is no need to fully remove the starter motor, just let it rest in position.  It will be held in place by its thick cable. On T1N models up to 06, you will have to remove the exhaust support (2 x 12mm nuts) as this sits sandwiched directly behind the gearbox and will prevent removal unless fully removed.

Sprinter DMF Flywheel removed

When you get to the last bell housing bolt, support the gearbox centre on the hydraulic jack, remove the final bolt. From the back of the gearbox pull, the casting should now separate from the engine block.  Manoeuvre the gearbox back and lower the jack. Take the gearbox from under the vehicle.  This is a great time to check for leaks or damage/wear to the selector mechanism. Checking the gearbox oil level is easier at this point too!

From inside the bell housing you can check the rotary smoothness of the thrust bearing, this is part of the release slave cylinder mechanism and cannot be replaced on its own. If you can afford it, always replace the slave cylinder when replacing the clutch, often if you purchase a complete kit it comes as a component part.

DMF Mercedes Sprinter Centre Bearing

Always inspect the centre bearing in the DMF, if this is damaged it is not available as separate part from Mercedes only as part of the complete DMF flywheel! The bearing itself is a special construction of a blind roller bearing made by INA that acts directly on the input shaft end of the gearbox, this is concentrically inserted into yet another single row ball bearing race pressed into the DMF.

Remove the clutch cover/pressure plate from the DMF, locking the flywheel with a small crow bar or broad screwdriver on the ring gear. You may have to pry the cover off its locating dowels, be aware it is heavy and it could catch you by surprise and fall on you!  Once this is out, you can inspect the flywheel face for damage. The outer DMF section of the flywheel should only rotate independently about 10-15mm in each direction at its circumference in relation to the other fixed half, any more than this indicates the likelihood of a worn DMF.  If you decide to replace this, you will need a long, large torx bit to undo the eight flywheel mounting bolts from the crankshaft. Once removed pry the flywheel from the crankshaft, it sits on a single dowel peg and can take some working to and fro to remove it.   Always inspect the centre bearing in the DMF, if this is damaged it is sadly not available as separate part from Mercedes, only as part of the complete DMF flywheel!  The bearing itself is a special construction of a blind roller bearing made by INA, that acts directly on the input shaft end of the gearbox, this is concentrically inserted into yet another single row ball bearing race which is directly pressed into the DMF.

Replacement of all the parts is exactly as the removal, although be sure to reference the ‘set’ position of the clutch before refitting.

Sprinter gearbox inspection hole and bleed nipple >2006

Bleeding the clutch system can only be achieved with a Gunsons EzBleed or other pressure bleeding equipment, no amount of pedal pressing, as you would assume similar to brake systems will not work – trust me, you will be very lucky to achieve success otherwise.  Once you have a good pedal feel and the slave cylinder can be seen to be pressing the diaphragm springs back and forth fully through the inspection hole, start the engine. Now press the clutch pedal several times, you should often hear a light clunk, this is the clutch adjustment ring finding its own position.  Select a gear and test the clutch, all should be well.  If for some reason it appears as if the clutch is not fully disengaging and baulking you from selecting a gear, check your work regarding air in the hydraulic system, if re-bleeding it proves to be good, then try starting the engine in gear, handbrake on, with the clutch down, this will often by inertia, force the adjustment ring from its set position to its new working position, a second pedal press should now settle it into its new operating position and you should have a good responsive light clutch.

VW Crafter Gearbox showing concentric slave cylinder and thrust bearing

I hope you have found this information useful.

16 thoughts on “Mercedes Sprinter Clutch Replacement (T1N, NCV3, VW Crafter and other MB)

  1. Hi Steve, this a great article… I would feel confident to do it myself. Actually, I have just had a new clutch fitted to my Sprinter 313CDi as a part of other works being undertaken with the engine out. When it went in, before the work, I asked the garage to look into the the low bite point, aggressive take up and squeaky pedal action of the clutch. Because it was replaced, cover plate, friction plate and cylinder, I assumed it would be cured. Actually it is more or less the same as before the replacement. I was looking for a way to adjust the bite pont when I found your article – it seems there is no way for me to adjust the clutch action. Any thoughts on what the problem / solution might be? Many thanks, Guy

    1. Hi Guy,
      As you have read, the adjustment is automatic with the cover plate being the primary adjusting mechanism. There is a chance if the clutch was fitted without making the correct setting adjustments or there has been a failure of the diaphragm springs this could be the issue. There is the outside chance the clutch actuation system (Hydraulics) has taken onboard air, this would make the pedal go further down in respect to the bite /release point. You can use a Gunsons Ezee-Bleed pressure bleed tool to make sure there is absolutely no air in the master/slave cylinder circuit. The concentric slave cylinders by their design are some times difficult to fully bleed of air and often you have to reverse bleed them – force fluid into the bleed nipple at the gearbox end up through the master cylinder, into the cab then back into the brake/clutch fluid reserve under the bonnet. Only when you are 100 percent sure that there is no air in the system, can you start to make a decision on the condition of the clutch.
      Hope that helps a little.
      All the best
      Steve.

      1. Steve, thanks….. I think I am probably going to be living with what is really quite a minor problem. Maybe at the next service I’ll get the hydraulics checked and see how that goes.

        Best wishes and thanks once again,

        Guy

  2. Good day Steve

    We have had a catastrophic episode with our sprinter, the engine was damaged beyond repair, and the workshop who worked on the vehicle two weeks before claims the driver abuse was the cause.

    the gearbox was serviced and about two weeks later (according to them) the Driver abused the clutch in such a way that it damaged the clutch, which in turn damaged the Flywheel Bearing. this then bent the crank shaft and this obviously damaged the rest of the engine.

    After reading your article I wonder because abusive use of a Clutch would cause the steel to turn blue, I have seen this before. There was no sign of this yet the clutch plate sustained heavy damage, one of the fins between the gripping surfaces was ripped off and the asbestos grips were ripped from the rivets holding it in place.

    Could this have been caused by the “Adjustment rings springs” not being reset correctly.

    If not what could cause this kind of damage to a clutch plate?

    1. Hi Michael,
      Whilst its possible that the clutch was not set correctly and not releasing fully, its going to virtually impossible to prove after the fact. I have known the small flywheel centre bearing get damaged when realigning the gearbox, I presume this is what you refer to in your text, I would have thought it more likely to damage the gearbox input shaft than the crank as it is for the most unsupported in its length with a damaged flywheel centre bearing.

      I have seen clutches that have burned out to the point where there is no drive at all but never seen or heard of the amount of damage you describe – unless you opted for a solid flywheel kit to replace the dual mass standard assembly. I have seen these ‘knock the crank out’ of an older high mile engine, due to the cumulative effect of driveline shock, (crank thrust – front to back wear – ending in eventual catastrophic failure of an engine that would otherwise have been up to many more miles) solid flywheels without doubt do not have the shock absorbing capability of the DM type. First hand experience prevents me even considering these as an option nowadays, the drive, transmission noise and extended engine life is reason enough for choosing not to fit them.
      I don’t really think I have been much help here and I do empathise with your situation – its a tough one!

      All the best
      Steve

  3. Hi i have a 2000 Sprintervan while selecting reverse the gears crunched and on letting the clutch out in neutral i got a heavy clunk i repeated this a few times with same results. Now it seems ok is this a sign of something major
    Tony

    1. Hi Tony,
      It could be that the clutch has self adjusted itself, it could have been stuck. I would monitor the situation for a while. If there is no undue noises or vibrations let it be for a while and see how you go. Any serious fault I can think of would continue to make a noise or vibration – it may be nothing.
      All the best
      Steve

  4. Hello Steve, great article each step well defined, I dont know if I need a new clutch but would like to pull it and check so advice on reset is invaluable , my van has a very very heavy pedal and an almost immediate biting point at floor level with a very violent take up !! could this be the pressure plate itself worn or would resetting the adjustment ring help in any way Ive bled system few times with different methods but I dont think air would cause the very very heavy pedal
    I did see another comment similar to mine although I think the clutch in that case had been renewed, but wonder if theirs was not reset as per your instructions? I really like this van but this is taking the enjoyment away as I have to remember each time I pull away to be very precise in my releasing the clutch. I will get to the bottom one way or the other so this post is a great first step…. Thanks Mitchell

    1. Hi Mitchell,
      I have a customers van exactly the same as that the moment! its in for clutch replacement, pretty much a set of symptoms that show a clutch at the end of its auto adjustment.
      All the best
      Steve

      1. Hi Steve, thanks for reply my clutch pedal feels as if its actually trying to push the pedal up very weird feeling releasing it !! If you dont mind would you post the outcome when you fit the new clutch to your customers van thanks Mitchell

  5. Hi Steve,

    Did clutch and flywheel today on my 313 sprinter. Was a little unsure of how bigger job it was but after reading your article I got cracking.
    In and out in 4 hrs and that included wiping the spanners down!
    Great post, gave me the confidence to tackle it myself rather than paying the main “stealers” their millions!

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