thejaf

Finally got my cylinder lock out. I pulled out the big guns and used the "c" word, and she came right out :smash: :smash: Anyway, ignition switch is fine (tested it by hand with the battery hooked up)

The problem is this: The sector and the lower rack do not align properly when moved to "start" I can set up the sector so that acc, lock, unlock, and run are fine, the 1 large "tooth" of the sector is in the groove, etc. When I start to turn it to "start" the pressure from the ignition switch spring is slowly applied to the sector and rack. What happens next is that the sector moves a little on it's axis and the gears are no longer parallel. The rack then gets pushed down because the pre-load spring gives a little. Once full start position is reached, the sector and rack gears are far enough apart that...BANG!! The sector becomes disengaged from the rack, the rack slams back to the off position fromthe backlash, and now the gears are no longer meshed because they are off by several teeth.

Seems like there need to be some way to take up the slack (endplay) in the sector and/or make the preload spring under the rack stronger so that the rack doesn't sink under pressure.

Any suggestions? :(

thejaf

Here's some pics to show the process in motion:

1. The sector and rack as they are supposed to be mated.


2. When turning to start position, sector moves counter-clockwise. It then disengages from the teeth on the rack when it was mated before.


3. I move it back to the off position, and you can see that it's now several gears from where it was to begin with, and now it will not start because the sector cannot push the rack far enough to start the ignition switch (rack moves to the right in the picture)



ANybody have an idea? My car can't be the only one this has hapended to.
:chevy

gearheadz

Have you tried adjusting the ignition switch? The bracket that attaches the switch to the column has two oblong holes that allow adjustment of the switch in relation to the rod that connects to the rack. It may provide just enough to remedy your problem.

Mark

thejaf

:smash: I'll give it a shot, couldn't hurt. The only problem with lengthening the rod is I don't think I will be able to use the accesory power function.

2ND77

Its a little hard to tell from your pics....but it looks kinda like the teeth on the rack are striped. Or at least, worn down alot. If not....then something is letting the rack move away from the gear. Try the ignition switch screws as posted before. But to me, like I said,....looks like the rack is worn.

Ron

Jim Shea

I think the problem is most likely a worn rack. If you look closely at the pictures of the teeth on the round plastic sector, they appear gray in color from wearing on the die cast rack. Also, the mating teeth on the rack seem to be rounded. (The tips of the teeth on a new rack are almost pointed!)

There is a small flat spring under the rack that preloads it against the plastic sector. You could try and shim the spring so that you increase the engagement between the rack and sector. However, if the rack teeth are truly worn, this may only be a stop gap measure.

Otherwise, I am afraid that you have to continue tearing down the column so that you can replace the rack. You will need to pull the pivot pins in order to remove the rack. Most likely it will be an easier job if you pull the column right out of the car. I have instructions posted at http://www.corvettefaq.com under Suspension and Steering. A first paper entitled Adjust Dimmer and/or Ignition Switch has some helpful hints on dropping (and removing) the column from the car.

A second paper, entitled Tilt & Telescoping Disassembly Instructions and three Pics should also be a help.

There is a Rack Kit available from Zip Products (SC-457) and other suppliers, or from GM dealers (7844651) that should contain the necessary parts.

thejaf

Jim,

Thanks for the info. I was hoping not to hear that, but might as well do the job right once. I know you recommend pullling the column, but is it possible to change out the rack with the column in the car? I also noticed that the grease seems to be the same color as the rack metal, but I didn't see how the plastic sector could wear down the metal rack.

Jim Shea

Jeff,
Actually, the plastic sector teeth are stronger than the zinc die cast rack teeth. So I am pretty sure that what we are seeing in your excellent photos are ground up zinc particles that make the sector teeth gray in color.

You can disassemble the column while it is still in the car. However, after you have repaired the rack you normally would have to tap:smash:the pivot pins back into the support. It is far easier with the column out of the car to support the column head on one side while you tap the pin on the other side.

With the column in the car, you have to get something like a large C-clamp so that you can press the pins into position. Otherwise with the column in place, you risk the chance of shocking your dash and instrument cluster when you tap the pivot pins back into place.

Zip Products as well as other suppliers and GM dealers can order a rack and sector kit to repair the T&T column.

Jim Shea

thejaf

Jim, thanks again for your help. I was able to get the offending rack out this morning. New rack, sector, and spring is on order, should get it next week. Hope everything is as easy to go back toether as it was to get apart. However, that's not usually the case :smash: