Heater Air Control Box

[rbgosling]

Almost certainly a stupid question but worth checking....

Would I be right in assuming that there's no way to remove the heater unit (not the box with the fan, which is a separate assembly), without dismantling pretty much the entire dashboard? Later Excel dash, this is.

Trying to adjust the hot air from the demister vents to my knees, the lever went too stiff... then too easy!

Looking in behind the heater controls, I followed the bowden cable to its end, assuming the Lotus position in the driver's footwell. It appears that the end of the cable was looped round a peg on a white plastic lever - the peg has snapped off, so there's nothing to re-attach the cable end to.

Even the white plastic lever is hard to see and even harder to reach - I could just reach it with the end of one of my longer screwdrivers, so at least I could push it the correct way to direct air to the demister vents, allowing safe driving for now.

I can't see any realistic chance of repair without getting the box out; at that stage I could either bodge a fix to the lever, or just get a used replacement from Lotusbits. And it doesn't look likely the box is removeable without dismantling the dash.

If I'm right, then I'll probably just leave as is, until I have another reason to remove the dash. Which will likely be never. Or maybe at the Resto Show this March! But it's not the most exciting project to have on the Grand Tourers stand.

For those with access to the Parts Manual, the cable in question is No. 6 in this layout. I think the broken lever / peg is the one in the centre of the circular panel on the right, in this layout

[rbgosling]

Also those pictures look like the heater matrix sits within this box, so I'm guessing it can't be removed without disconnecting the matrix and dribbling coolant all over the place... for extra PITA in the job!

[bash]

I know yours is a daily but its not that difficult to take the dash out and you could still drive it like that by plugging guage cluster back in !!
Bash

[Alan_M]

As Bash has said. It’s not actually that hard to get the dash out - ask Tony, he spent time masking around to recolour the dash and would have been quicker to get the dash out.
Think it took me about an hour or so to get mine out.

[MetBlue]

My cars sitting on the drive with the dash out currently Richard. If you want to drop by to take a gander without any clutter anytime your welcome. - Drop me a WatsUp
Tony

[Pete Boole]

And if Lotusbits don't have an assembly I might have some bits left over in the shed!

Pete

[MetBlue]

This picture shows what your trying to access

The white peg in the centre rotates the drum (also Off white colour), which directs air either to the face vents or the screen.
Not sure, but you may get enough access to effect a repair to the white lever just by removing the clocks. Certainly by taking the black binnacle out should give reasonable access.

I'd want to investigate what caused it to lock so much that it broke the lever off. Sounds to me from your description that the broken white peg is a consequence of something else temporarily seizing.
I can get some better pictures tomorrow if you need.

Tony

[rbgosling]

That's great Tony, very helpful, thank you for that pic!

I had thought that the problem was just the whole mechanism getting a bit stiff - but when I tried to push the lever so that I'd get screen venting, it moved reasonably easily. Even after the peg had snapped the lever was very stiff to push. But it may just all need a bit of lubrication, and ensuring the bowden cable has an easy route.

Starting to sound very much like a side project for the Resto Show in March. My voltmeter, water temperature gauge and oil pressure gauge all read doubtfully too, so something else to do while I have the dash apart...

[MetBlue]

A couple of further pictures.





Steering column is dropped down when taking these pictures, as the pedal box is out, but the air pipes feeding the face vent by the window and the foot well ( both round connection points visible in these photo's) come out easily when removing the dash which improves access considerably.

That said, I can't see how this could be stripped out further to do a repair whithout fully removing the air box, which doesn't look that easy.

Tony

[rbgosling]

If the peg / lever can be removed on it's own, then it may be possible to replace it, or bodge it (screw a bolt in where the peg snapped off). But from your pic it doesn't look like the peg / lever will come off the rest of the assembly so easily.

Pics are very useful though, thank you very much!

[Pete Boole]

Dug out my old airbox this afternoon and guess what - the same bit is broken off!! I think you're right though Richard - it looks like it should tap OK for a stud to be bonded in. I'll have a mess with it over the weekend. And you're right about it all being one moulding.

Pete

[rbgosling]

OK, so you're saying that the lever / peg is a continuous bit of plastic with the flap or whatever is inside? So that makes it certain the whole thing will need to come out.

If mine isn't the only broken peg, this does seem like a built-in weakness. That said, it's lasted 32 years and 195,000 miles, so I shouldn't be too harsh!

[Pete Boole]

Here are a couple of photos of the white plastic air distribution drum - removed from the heater assembly box:







You can clearly see where the pin has broken off. It is all one moulding. I was hoping that there might be enough "meat" on the end of the pivot arm to tap it and screw in a metal pivot pin, but as you can see it is very sculpted on the rear. The best way to do it would probably be to make up a double-diameter pin and bond it in place after drilling out most of the centre of the end of the pivot arm.

Pete

[Pete Boole]

The other thing I noticed when dismantling the heater assembly was that the metal air flaps had no lubrication at their pivot points - might be worth putting a drop of oil on them if you have the assembly out.

Pete

[rbgosling]

Hi Pete,

I'm thinking that the best plan could be to drill out as far as the outer rim around the peg. Then I could use a little bit of pipe to create a bush that'll fit inside the rim, then a slim bolt up the inside of that, with a penny washer either side to hold it in place. The sticky-out bit of the bolt will then serve as the replacement for the peg - and I could put a further nyloc nut on the end to ensure the cable to the control can't slip off.

So... if you still have that part accessible, could you measure the ID of the rim for me? Then I'll know what size pipe I will need.

Only concern with this plan (for now) is whether the head of the bolt will interfere with the housing, not sure how much clearance there is. But I'm sure I can find a solution to that if needs be.