TR2/3/3A Questions on TR3A steering control head refresh

[TuffTR250]

I'm following the article provided by Randall and authored by Clive Elsdon, called "Sidescreen Control Head". I have not gotten very far, and I've run into a problem where the countersunk screws on the back of the unit that hold the control head to the backing plate won't come loose. One of the screws has loosened, but I cannot get the other two screws to loosen. I'm using a good 9 inch screw driver with a very good tip that fits down into the countersink. The screw driver does slip out of the grove but I'm trying to minimize damaging the grove of those screws. Is it safe to use either Liquid Wrench on those screws, or some directed heat with an electric heat gun? I don't want to damage any thing inside the control head. Thanks!
Bob

 

[bobhustead]

In my experience (one car), buy a new control head. As far as the screws, a motorcycle impact tool should help you.
Bob

 

[karls59tr]

There's a product called "PB Blaster" that I think is better than liquid wrench. Soak the
screws and strike the screw heads reasonably hard with something solid to set up a vibration so the fluid will seep in. Let them soak overnight. Worth a shot.

 

[TR3driver]

+1 on PBB; another product much better than LW in my experience is Kroil http://www.kanolabs.com/penLub.html

A small amount of heat might help, but don't get too carried away. Bakelite will take some heat, but will burn if you get it hot enough; and the insulation on the wires will melt before that.

 

[CJD]

I've found PB will melt some plastics...the new heads look more like plastic than the old bakelite.

 

[DavidApp]

A flat punch sized to match the flat head of the screw is the best thing to hit the screw heads but remember the control head is probable Bakelite so can be brittle. A recoil center punch used against the screw slot may help but could damage the slot.

David

 

[sp53]

I like WD40 but it does dissolve glues. Maybe get a ratchet and screw driver bit to get more leverage. You could use a small drill like a Makita for an impact gun, but that could break it with the impact. There is a clutch on most of those little drills so start slow. My fear is the drills are stronger than they look and will strip it.

 

[TuffTR250]

I borrowed a small Bosch battery powered impact tool and that and the penetrating oil did the job!! I got all 3 screws loose. Thanks for the advice! Does anyone know the size and thread on those screws that hold the control head to the backing plate? I'd like to replace them with some that have a good slot in the top. Thanks!
Bob

 

[DavidApp]

They are more than likely 2BA.

David

 

[TuffTR250]

I have my control head totally disassembled. Very mucky inside. What is the best material to clean it with? Would CRC's Brakleen be ok? Or would acetone be ok? Or is there a better alternative? Thanks!
Bob

 

[CJD]

My favorites are spray cans of brake cleaner, carb cleaner, contact cleaner, and bead blaster...depending on the material being cleaned.

 

[sp53]

I like SOS pads on light rusted chrome, brake clean to remove oil, WD40 to clean and put a light coat of oil back on—depending on if things are glued, and bead blast--- bake light is different than most plastics and it depends on how faded it is when I go to clean it; maybe soap and water.

 

[TuffTR250]

I'm now preparing to reassemble the control head. All the articles I've seen posted only provide step by step procedures for disassembly but no reassembly. Are there any good detailed step by step procedures for reassembly? Preferably with clear pictures for each step.

An item in the TR3 Service Manual is unclear to me, can someone please explain what is the referenced "vertical lever of the stator tube plate"? Here is the wording in the Service Manual >>>
"With the flasher control lever of the head at 12 o'clock ensure that the vertical lever of the stator tube plate is at the 6 o"clock position. Failure to observe this point will mean that the flashing indicators will not cancel correctly."
In this attached picture, is the part sticking out into the ring, what they mean by the "vertical Lever"?
Thanks, Bob

 

[TR3driver]

Yes, that part sticking out has to be turned so it points straight down (ie 6 o'clock) when the steering wheel is in the straight-ahead position.

Sorry, I never did a write-up on how to assemble. But here's the first couple of steps.
1) Assemble the 3 contacts for the turn switch. I find it simpler to leave the wires off at this stage, you can remove the nuts later on to attach the wires.

2) Assemble the springs & flat washers onto the curved guide

3) Assemble the lever (just the bakelite part, without the chrome part) with it's two springs, contact, plunger, and roller

4) Combine those two in your hand, then stuff the lever into the housing so the roller goes into the notch

5) Compress the spring until the trunnion fits into the hole in the housing. Carefully add the two cancelling levers, while holding the lever in place.
(Ignore the two wires, I had to go back and retake this photo using an old head from the parts bin.)

After that, the rest is pretty easy.

Also, here's a copy of a brief article I saved
https://drive.google.com/open?id=0B2H2NJt34OffRVBPNlp1NkVMcFE

 

[TuffTR250]

Thanks a lot Randall!!! Your pictures really help!!! I was trying to follow the instructions from Ian Cornish but I was struggling with understanding how it would go together with his steps. From your pictures it does look quite tricky to get it all together without it flying apart.
Bob

 

[TuffTR250]

I had an idea! I pushed the trunion down into the hole and using a screw driver I pushed the roller into it's central position. That held the turnion in. I then removed one of the springs from the wire loop and stuck the wire through the slot on the trunion and then replaced the spring and pushed the wire loop down into the slots. I then placed the cancelling levers in place. That held everything in place while I put the top bakelite piece on and installed the one screw that held them together. Nothing went flying! Whew!
Bob

 

[TuffTR250]

A question...If I have the flasher control lever positioned at 12 o'clock, and the vertical lever of the stator tube at 6 o'clock, and the slot in the stator tube slide into the indentations on the stator tube bracket tube , is that all I need to ensure that the control works and that the stator tube won't turn causing twisting of the wires inside? Oh yeah, and I'll have the olive and nut on the stator tube at the bottom of the steering box. Thanks!
Bob

 

[TR3driver]

That should do it. I like to leave the nut loose until last, but be sure to tighten it before you move the steering wheel.

 

[sp53]

Don’t those 3 little grub screws on the steering wheel help a little. Perhaps they help center control head, but really they are small and do not look like they would hold much.

 

[TR3driver]

The grub screws are important (also need to be tightened before you move the steering wheel), but they don't "help" keep the control head from turning. In a sense, they try to make it turn, as they force the canceling ring to turn with the wheel.

In fact, the usual failure mode is that the canceling mechanism gets dirty and binds such that the force transmitted from the wheel through those 3 screws and the canceling ring causes the stator tube to flex and break at it's weakest point, right at the bottom of the slot. Once the tube breaks, the head turns with the wheel. The controls still work (tho obviously the turn signals don't cancel automatically), but now the wires are forced to flex when you turn the wheel and they will eventually break from flexing.

IMO it's worthwhile disassembling and cleaning the head from time to time, when the cancel mechanism starts to bind noticeably. Maybe every 5 to 10 years, depending on local conditions and where you store the car. Around here, we get a lot of very abrasive dust in the air (broken sand grains carried in from the desert), which seem to build up inside the control head.