Ah well, at least it's not the stepper motors! 164 heat...

Well, summer's here, and so is the heat. My Super has decided to vent hot air in my face for no apparent reason.... or so I thought.

Had a look under the plastic cover between false firewall and windscreen base.

It appears the plastic crank attached to the cable from the stepper motor (which regulates the proportion of heat fed through the ventilation) has snapped at the 90 degree bend (i.e. the crank arm has split away from the shaft going into the drum assembly).

Any thoughts as to how difficult this is to get at? Is it easier to remove the entire distribution drum assembly? I am wondering how much rotational drag load is on the drum, I am speculating whether a wodge of epoxy shoved around the broken bit might suffice... if I can get my hand in far enough! Or is it even worth attempting?

I am more than a little irked that an entire weekend's work will be required to replace a 50p plastic part....

Anything?

Originally Posted by Ronald

Well, summer's here, and so is the heat. My Super has decided to vent hot air in my face for no apparent reason.... or so I thought.

Had a look under the plastic cover between false firewall and windscreen base.

It appears the plastic crank attached to the cable from the stepper motor (which regulates the proportion of heat fed through the ventilation) has snapped at the 90 degree bend (i.e. the crank arm has split away from the shaft going into the drum assembly).

Any thoughts as to how difficult this is to get at? Is it easier to remove the entire distribution drum assembly? I am wondering how much rotational drag load is on the drum, I am speculating whether a wodge of epoxy shoved around the broken bit might suffice... if I can get my hand in far enough! Or is it even worth attempting?

I am more than a little irked that an entire weekend's work will be required to replace a 50p plastic part....

Epoxy and some brace on the back should do the trick. Not much to turn it. Easier than pulling it all out to replace the door.
Jason

Originally Posted by AlfissimoInternational

Epoxy and some brace on the back should do the trick. Not much to turn it. Easier than pulling it all out to replace the door.
Jason

That's what I was hoping. Now I only need someone with small hands to get in there.

Thanks, Jason.

I'm slightly confused here. You mention the temperature control flap but then talk about taking the distribution drum out???

As far as I can remember, the temperature is controled by a flap with an arm on it as you describe. It shouldn't have any appreciable resistance to it at all.

The distribution is controlled by a drum and there is a "T" shaped drive to it from the stepper motor which just pushes into a "T" shaped hole in the end of the drum. I've had the plastic split on one of those before and if you can retrieve the broken bit, you can do a good fix by epoxying a bit of copper central heating tube round the broken plastic bits to hold them together.

Originally Posted by Avocet

I'm slightly confused here. You mention the temperature control flap but then talk about taking the distribution drum out???

Sorry, Avocet, only just seen your comment.

To dispel all confusion, see attached image. The broken piece is the bit circled in red. Not sure what the parts are all named, so that probably hasn't helped matters!

Ron

OK, it's not the drum I was thinking of, it IS the arm on the temperature flap. Can't offer any useful advice here although I THINK you'll be able to get to it from under the bonnet after maybe removing the wiper motor assembly. Definitely odd that it should break though. I didn't think there was any appreciable load on that component.

Originally Posted by Avocet

I didn't think there was any appreciable load on that component.

Exactly, that was why I asked re: epoxy as a quick fix.

Unless something jammed inside! Don't know what the internals of the heater box/distribution unit/whatchamacallit actually look like, so it's mere speculation.

I am guessing there's a return spring or something? The cable itself doesn't seem very substantial (although I've seen it described as a "metal rod" it seems very thin and springy ... sufficient to pull on the lever, but to push it? If there's any resistance I am guessing it will just flex and distort...).

Anyway, it seems the easiest way to get at it might actually be to remove the bonnet and rig up a platform spanning the engine compartment, allow me to work over the middle of the firewall area in relative comfort... now I only need the arms of a spider monkey to get into the tight confines....

It can definitely push as well - but not very hard. I have a loose assembly off a scrap car and if I pick it up, the flap inside will flop from one end of its travel to the other under its own weight as I tilt the assembly.

Originally Posted by Avocet

It can definitely push as well - but not very hard. I have a loose assembly off a scrap car and if I pick it up, the flap inside will flop from one end of its travel to the other under its own weight as I tilt the assembly.

Hmmmm...

Unless something was wedged in the way, then, there shouldn't have been any reason for it to break....

Was working fine one day, the next ---

Oh well... Still haven't had the chance to get at it, maybe next weekend....


Cars, who'd have 'em....

Update.....


So I managed to get the broken piece out, and after much cursing and swearing, daubed both broken ends with an epoxy, held them gingerly together for a bit, then left overnight without touching anything. Unfortunately, I could not, no matter how I tried, reach the stub projecting out of the side of the box (wanted to see if it was jammed).

So today after work, I reached in and, voila! The crank/lever/thingummy moves quite easily back and forth (so why did it break in the first instance???)

Now, having reconnected the linkage, I tested the temp. settings, the rod moves the lever from one extreme to another.


So far, so good....



My next question is, does it sound correct in this regard? Or should it move to intermediate positions, dependent upon the temperature selected by the control? Not having had cause to look at it in operation before, I have no idea if it's being driven correctly now...

It's quite a smart-arsed closed-loop feedback system on those - quite clever in the late '80s, I think.

There's a temperature sensor on the inlet side of the heating system just under the wiper and another one on the outlet side of the heater box near the distribution stepper motor. There there is also one for the cabin temperature. If the outside air temperaure is (say) 10 degrees and you've asked for a cabin temperature of 20 degrees, the computer will tell the temperature stepper motor to move the flap to the "fully hot" position. It will stay there until the cabin temperature approaches 20 degrees and then as it gets closer to 20 degrees, it will back off to lower the temperature of the air leaving the heater box. Once the cabin temperature is at 20 degrees, I'd expect the computer to just tell the stepper motor to continuously make slight adjustments to keep the temperature at 20 degrees. I don't know whether the stepper motor stops at the point when the flap is either in it's "fully hot" or "fully cold" position or whether it just stalls. If it's the latter, I guess there COULD be some load on that arm at either extreme of travel, maybe?

Hmmmmmm... or even late '90s...





Yes, that was my thought as well, similar concept to the CC system in the Omega.


I haven't really had too much of a chance to play, but it does seem to be working properly.

Having left it set at "19" last night, there was some warm air this morning going to work.... but as it was parked in the sun all day, the air con was running full on the drive home (it's not a really long journey, so no time to check further...)

One other thing I noticed when putting it all back together - the small motor/gearbox which drives the recirculation flap wasn't moving at all (door was fully open). Having removed it (eventually!!!) from the engine bay and applying 12V to it, nothing happened -- or so it seemed...


Separating it into its component parts, I extricated the small motor itself from the metal gearbox housing. Spins fine with the application of 12V.

Now, partially reassembling the motor/gearbox, and turning the primary gear on the motor with my finger, without the end plate on, the entire gear assembly turns well enough, but with it all buttoned back up, it doesn't want to play. Is it possible there's something physically jamming the gears, or is there some bit of electronics I can't see? All I found is a small circuit board inside the plastic section (final gear assembly and arm to recirc. flap) that as far as I can see, merely takes the current from the connector and sends to the motor contacts. Have I missed something?

I hasten to add that I haven't checked for the presence of voltage at the connector when the "recirculate" button is depressed (my multimeter is out on loan) but the fact that the motor can be driven when connected directly to battery but nothing happens when current is fed to the connector terminals leads me to believe there's nothing wrong with power supply...


Does any of this make sense?

Think I need some sleep...

Nah! Late 80s! Even the earliest 164s in 1988 had climate control! It would have been "on the drawing board" even earlier than that - really quite impressive!

Anyway, back to your recirc. flap motor. I've never played with one but it might be a "stepper" motor rather than a DC one - I honestly don't know! If it is, then it will need a "pulsed" supply to make it turn - 12v DC won't do anything. The fact that you got the motor to turn by itself like that suggests that it is just an ordinary motor but I'm really out of my depth on the electronics! Jason might know, if he's about???

I need to test the pins at the connector as well, ensure I have supply there before I start to panic!


I misunderstood your comment earlier, Avocet, sorry... I thought this morning that you were alluding to the fact that even in the '80s, this car had such a thing....

Another update....

Have played about with the motor for the air recirculation door.


When you apply power to the pins, SOMETIMES it runs, and then the NEXT time it doesn't!

What's up with that, then?

Another update...


Recirculation motor sorted (thanks Philip!)... http://www.alfaowner.com/Forum/alfa-...ion-motor.html (164 recirculation motor)



... but my temporary repair on the temp. flap door seems to have let go. Oh well, the skin on my hand has healed enough for me to have another go...

I think I didn't get the broken end cleaned up, the epoxy didn't "take" very well (the cursory glimpse I had today was not really very good) so it looks like the next stretch of dry weather (will it ever be summer?) I will have to have another go... if I can get the A/C unit off to the left a bit, I might have better luck, get more epoxy around the join...