108 Heater Issues

[zambo]

One of the heater control levers on my '72 108 is clearly no longer connected to the cable that operates the valve on the passenger side. Fan and demist/floor directional levers still work fine. Also, drivers side heater control has tension and seems to work.

My questions are; are the valves serviceable - I suspect that the cable or whatever links the heat lever to the valve/tap on the core has broken - either due to age or a sticking/stuck valve.

Also, how does one access they a) valves to renew O ring seals and see if they operate freely and b) how does one access the back of the lever controls to see what is connected to what!

Thanks in advance for any advice as always.

Regards

Richard

[1967250s]

Originally posted by zambo
b) how does one access the back of the lever controls to see what is connected to what!

Thanks in advance for any advice as always.

Regards

Richard

I believe trough the dash speeker.

Dan

[jas2wa]

zambo-

Keep me posted on how you make out with this- I need to get back there to re-do the o-rings in the heater valves. I've been told you can access them by removing the radio, ashtray, and glovebox lining. Pretty much opens up the whole area. I am hoping to get to this job soon- and do a new cd player while I have it apart...

Cheers,

JAS

[300SDog]

If the heat lever/wheel on your 108 is completely dead - moving freely from side to side - then its probably got nub broken off from guts of lever mechanism where cables attach.

This happened to my 114..... so i just operated the hot water valves manually under the hood, making permanent heat for wintertime - until finally replacing entire lever mechanism when tearing into the blower motor that died a few years later.

Your heat lever mechanism is attached to dash with 2 nuts (8mm?), one on each end behind the heat control faceplate...... find these nuts and the lever mechanism can drop down and be removed from underneath and through the glovebox. Pulling the radio will provide finger tip access to the nuts securing the heater controls to their faceplate.

You will find the lever mechanism connects with tiny little nubs to cables that should be marked with masking tape for easy reassembly. Also you will see arms, tracks and rails that require little dabs of heavy duty suspension grease.

This is how it works on both the 111 and 114.... am thinking the 108 is very similar if not identical.

[MikeTangas]

The A/C unit prevents coming out the bottom on the 108's, everything comes out the dash speaker hole. Gutting the glove box and removing the instrument cluster provide sufficient access to the assembly. The cluster has to come out to access the net for the left side of the facia. The replacement levers can be had for about $100 through FastLane. This is an 8 hour shop job that you can do at home over a weekend.

Rich,

Have you tried pulling out the stereo like I suggested?

Once the stereo is out, and take the dash speker grille out, you should be able to see the connectors to the ends of the heater cables.

I know on the right hand side, I have managed to foul the right control, if the tunnel cover under the a/c is not put back properly.

I asssume this is similar on the left side. so have a look first at the back of this cover on the left, before you do anything else.

Good luck....summer's coming!

[zambo]

Well, it appears I might have had a win on this issue. I removed the dash grill, the glovebox and ashtray and could ascertain that the left hand side heat control lever still was intact, but the cable end was broken. Now is the issue to reconnect it!

I didn't take out the radio/cassette as I didn't have the necessary special tab-pulling tool to remove the later model unit - so my access under the heater controls wasn't possible. But I am assuming that that is the only way to unscrew the securing device on the left hand heater lever, which is obviously below the fan lever.

As to the valve/taps under the dash, that will need to wait until I get the a/c unit removed so I can then remove the tunnel cover and have a good look around on the heater core, etc. I couldn't see anything from above - not that I would necessarily have known exactly where to look.

The one thing I have noticed is that the Benz comes apart in a very logical manner and goes back together very nicely - everything fits the way it should. On previous classics I have had, things were often difficult to get apart and then didn't appear to possibly go back together without major knuckle skinning!

I think I will get some digi shots as I go thru this process to assist others - for those that have done this before, am I correct to assume that the securing screw/device for the L.H. heater control is accessible only from below?

Are the black tips on the control levers supposed to come off for removal of the mechanism? Mine appear well and truly attached to the levers. The removal of the mechanism as some have suggested thru the glovebox, seems difficult if these tips do not come off as how would one get the levers thru the facia?

Again, any feedback appreciated.

Regards

Richard

[MikeTangas]

Pull the instrument cluster to get at the left side bolt/nut.

EDIT: I just noticed you are down under, so am assuming a RHD model. RHD would put the glove box and ashtray on the left, correct?

Once the ashtray is out, then you have to remove the ashtray track, or what ever you want to call the metal piece the tray rides in, it should be held to the dash by a couple phillips head screws (you'll need a shorty driver). You will also have to remove the lighter assembly from the dash. This should give access to the nut.

By "black tips" do you mean the lever handles? If so the are permanently part of the levers until they break, unless you have Duralever replacements installed. The complete assembly comes out as a unit, through the dash speaker hole.

[psfred]

On Left Hand Drive models, the heater valves are behind the ash tray. I suspect this would put them behind the radio on RHD models, unless Benz mirrored the heater core, too.

Peter

[jas2wa]

Is there an easy way to reconnect the cable ends to the heater valves themselves, without removing the entire set-up? Those little 7mm nuts are a pain!

[300SDog]

Try using deep 7mm long socket on those nuts.... then grab the socket with pliers and turn it. Sure as hell, dont worry about scuffing the socket with pliers.

After breaking them loose, you should be able to turn 7mm socket with fingers.