Instrument cluster removal 101

[WGB]

All you experienced guys look the other way (criticism of course always welcome) but it might help someone to get started in meaningfully working on their own 116.

Start with the steering wheel at the central position - hopefully your steering is centalised - If not here is another posting to give you a starting point http://forum.w116.org/mechanicals/steering-centralisation/msg67031/#msg67031 but if at the end of it your wheel is not central you will need a wheel alignment to get it right.

1. Remove the emblem from the centre of the steering wheel with a small hook or screwdriver taking care not to split the pad



2. If you are replacing the wheel in the same position mark the position of the shaft and the wheel and then using a 27mm socket (big spline post 1978 wheel) and medium extension unscrew the nut while holding the wheel securely and not using the steering lock



3. At this stage I protect the woodwork with masking tape



4. Mercedes make a special tool for pulling friction fit clusters but I have never seen a 116 cluster that couldn't be pulled backwards with finger pressure.



5. The cluster is pulled just far enough to get a hand behing the back and unscrew the speedo cable - take care as sometimes loose edges of the dashboard "skin" may come with the instrument and damage your dash.



6. This then gives enough slack for the cluster to be turned at right angles



7. At this point the wiring can be unclipped and the oil pressure gauge connection unscrewed with a 10mm spanner.

Warning - While the cluster is out do not lean on the empty dashboard binnacle or you will crack your dash and do not start your engine unless you want to lubricate your interior,

This is the back of a 6.9 Euro cluster with the connection points labelled - I believe a US 6.9 uses the extra hole for the seatbelt reminder.

Models with less equipment will just have a couple of connections fewer,



Here is my cluster rewired for re-fitment with my usual mistake which is to put the suspension light in the brake wear hole and vice versa - for some reason the speedo cable was more difficult than normal to refit and by the time I had checked it I didn't have the heart to remove the speedo cable and re-take the photo.



On re-fitment make sure you have a good rubber sealing washer and keep all extraneous wiring from getting in the way of the seal but even then it does not sit as well as later designs.

Bill

[KenM]

Thanks for posting Bill, a simple enough job but there are still traps for the unwary. These pics are an excellent reference.

[gf]

Thanks Bill! im actually starting little things on my w116 myself after losing faith in the mechanics- they broke everything!!!!! Ive printed up your instructions as i know they will come in handy real soon!

[Squiggle Dog]

Hmmm... I've never removed the steering wheel as a step toward removing the instrument cluster, but it probably makes it easier to access. It would probably be a good idea to mark where the steering wheel goes onto the shaft so that it doesn't get off a spline or ten when putting it back on.

[WGB]

Thanks for the reminder about the steering wheel position - I have added it to the posting.

It does make it a lot easier to remove the wheel and yes marking the steering wheel position will keep it centralised if it was centralised in the first place.

Simple thing is to start with the wheel at central position and then not to turn steering - worst case scenario is 1 spline out.

As I will be getting a new front end alignment at the end of all this I centralised my box and wheel at the end of the job as per this previous posting - it only takes 5 minutes to unscrew the plug, fit the centralising bolt, fit the steering wheel and then replace the plug.

http://forum.w116.org/mechanicals/steering-centralisation/msg67031/#msg67031

Bill

[TJ 450]

Excellent pictorial...

Removing the cluster is one of my pet hates, along with removing exhausts and suspension springs (OK, hate is a bit harsh... probably a minor annoyance is more appropriate).

I found out the hard way about the various caveats... The masking tape is an absolute must, or at least a towel. I use a credit card or similar to unhook the dash skin if it gets caught.

Tim

[Type17]

Nice writeup, thanks for doing it.


Those MB puller tools - where do they fit on the binnacle, and would they be easy to copy with some stiff wire, suitably fettled?

[navigator]

I suspect that I might have to go through this procedure as bmy instrument binnacle lights as well as the aircon dials/levers area lights are out.

[Casey]

4. Mercedes make a special tool for pulling friction fit clusters but I have never seen a 116 cluster that couldn't be pulled backwards with finger pressure.

I've never been able to just pull them out.  Usually what I've done is remove the under-dash panel and get a hand up behind it to push it out.

But my 450SE has an opposite problem - it won't stay in.  Any ideas how to fix that?  Woodwork is also damaged where somebody apparently tried to pry it out in two places along the bottom of the cluster.

On re-fitment make sure you have a good rubber sealing washer and keep all extraneous wiring from getting in the way of the seal but even then it does not sit as well as later designs.

Sealing washer for what connection?

P.S.  Larger splines were used from '77 on, but you said post-'78.

[WGB]

4. Mercedes make a special tool for pulling friction fit clusters but I have never seen a 116 cluster that couldn't be pulled backwards with finger pressure.

I've never been able to just pull them out.  Usually what I've done is remove the under-dash panel and get a hand up behind it to push it out.

But my 450SE has an opposite problem - it won't stay in.  Any ideas how to fix that?  Woodwork is also damaged where somebody apparently tried to pry it out in two places along the bottom of the cluster.

On re-fitment make sure you have a good rubber sealing washer and keep all extraneous wiring from getting in the way of the seal but even then it does not sit as well as later designs.

Sealing washer for what connection?

P.S.  Larger splines were used from '77 on, but you said post-'78.

Quite happy to quote date of spline size change if you provide me with the reference but as all my cars are 1979 models and have large splines I refer to my cars being post-78's.

There should be a ridged rubber seal that is pressed onto the instrument cluster and locates the cluster in it's binnacle.

Bill

[Kjhall65]

That certainly saved me learning the hard way.  More complex than my 115.  Thanks for the post and especially with the really clear pics.

Ken

[Casey]

Quite happy to quote date of spline size change if you provide me with the reference but as all my cars are 1979 models and have large splines I refer to my cars being post-78's.

Well it doesn't seem that clear from searching online, actually:
http://forum.w116.org/interiors-and-exteriors/116-steering-wheel-spline-sizes-again/

But my '74 has the smaller spline, and all the others ('77, '79, and '80) have the larger one.

[TJ 450]

Indeed,

From what I have gathered, 1977 was the year that the larger spline was introduced, along with the blade style key.

However, all my cars have the smaller spline (the 1977 one is really 1976).

Tim

[koan]

Just for the record

Late model spline measures 21.3 mm, 18 mm thread, 27 mm socket, 80 NM torque.

Does anyone know exact spline size, nut size, socket and torque for smaller spline ?

[Casey]

Just for the record

Late model spline measures 21.3 mm, 18 mm thread, 27 mm socket, 80 NM torque.

Does anyone know exact spline size, nut size, socket and torque for smaller spline ?

14mm thread, 50 Nm torque