Northwest79

My Steering coupler rag joint is worn and kinda crushed.

a) Can I just replace the rag joint ?.. or do I need to replace the entire coupler.

b) If I replace just the rag joint, can i simply loosen the coupler, slide the old
rag joint out, and slide the new one in, and tighten ?.. or do I need to take the
entire coupler out.

Removing the coupler involves either moving the steering column or the box.. both which would be a pain I think..

Anyone done this.?

Thanks :cool:

Jim Shea

The flexible coupling is attached to the steering gear with a pinch bolt. It also connects to a detachable upper flange that is also attached to the steering column with a pinch bolt. The flexible coupling attaches to the detachable upper flange with two special bolts, nuts, and lock washers.

You are correct. You either have to remove the three gear mounting bolts so that the gear can be moved forward and down to provide just enough clearance to remove the flexible coupling from the gear. Or you will need to detach the steering column from the dash so that it can be moved a few inches rearward into the passenger compartment to provide the clearance.

DO NOT pry on the column shaft in an attempt to gain clearance. The prying could collapse the shaft into the column and cause problems with flex coupling installation in the future.

Look closely at the stop pins on your flexible coupling. Do they show signs of wear? If they are worn, this could indicate that your steering column has been out of alignment with the steering gear. This could be the cause of your flexible coupling deterioration. This may direct you to loosen the steering column to remove the flex coupling. Then you will realign the steering column with the new flex coupling as part of your reassembly procedure.

I assume that you own a 1979 Vette. This means you should replace your flexible coupling with the following GM part number 7818568. It is available from GM dealers or from various Corvette parts suppliers. The pinch bolts for the flexible coupling and for the detachable flange are the same. They are GM part number 7807271 and still available from GM dealers.

I would begin by removing the pinch bolt from the flex coupling. The pinch bolt has a special head. You will need a 7/16 inch 12 point socket to remove it. When you have removed the pinch bolt rotate your steering wheel 1/2 turn (90 degrees) clockwise. You will note that there is a slot through the flange boss where the pinch bolt was threaded. Take a large screw driver blade and force it into the slot so that you spread the flange open. This should loosen the flexible coupling flange on the gear input shaft. Now remove the two nuts and lockwashers that attach the upper flange from the flex coupling. However, you will still not have sufficient clearance to remove the coupling.

Now move the steering gear or the steering column to gain your clearance to move the flexible coupling up an off the steering gear input shaft.

You will note that your new replacement 7818568 flex coupling has orange plastic spacers installed on the stop pins. These spacers will assist you in aligning the column to the steering gear. After aligning and reinstalling the gear, column, and flex coupling, you can pull and discard the plastic spacers.

For additional information on flexible couplings and the column alignment procedure you can download the following papers that are posted at http://www.corvettefaq.com in the Steering section.

Flex Coupling and Column Assembly Instructions - AIM Sheet
Flex Coupling Installation Instructions
Flex Coupling Pics

Jim Shea

One other thing! I don't like the "bolt together" replacement kits. If you carefully look at the edge of the rubber disc on your original equipment flexible coupling, you will note that there are 7 layers of cotton and neoprene rubber. Manual steering GM vehicles and ALL C3 Corvettes had 7 ply cotton and rubber discs in their flexible couplings. All the other GM vehicles with power steering had the much softer 4 ply coupling disc (i.e. same thickness of rubber disc but more rubber less cotton fabric).

All of the bolt together "kits" that I have seen, have some kind of soft rubber disc. The softer 4 ply discs will result in more overcenter vagueness or play.
The 7 ply discs are much stiffer.

Also you may notice that you can feel some sharp metal wires sticking out from the edges of your original equipment coupling disc. Around 1970 (and onward) metal screening was molded on the face of one side of the coupling disc. The screening was not for strength. It was for electrical continuity from one quadrant to the next.

This eliminated the need for the metal ground strap. (In other words the screening provided a electrical ground path for the horn down through the steering column shaft; down to the detachable flange; down through the screening; down to the lower flange and into the steering gear and frame; and back to the battery.)

Hope this helps.
Jim Shea

Northwest79

Wow.. with a reply like that .. how can I go wrong !! .. :thumbs:

I am gonna order a coupler from GM and put it in next week..!

Thanks Jim !

Chris

DaddyO

Any chance you know the GM part # for a 71 rag joint?

Jim Shea

The C3 Vette only had two flexible couplings. The first was 7806391. It was used from 1968 through early 1969. The gear input shaft was 3/4 inch in diameter and had 30 serrations all the way around the shaft (we said that it had full round serrations).

The second flexible coupling was 7818568. It started production during the 1969 model year and continued until the end of C3 production in 1982. It was a coordinated change with a change on the gear input shaft. The gear input shaft was still 3/4 inch diameter with 30 serrations based on a full circle but it had a flat machined on it (the flat actually machined off about 5 serrations). The flexible coupling flange was changed to include a flat that matched the flat on the input shaft.

So the 1969 Vette is the only one where you must verify exactly what gear with what type input shaft that is in your car. Otherwise, it is straightforward by model year.

You cannot install a flexible coupling flange with a flat onto a gear with full round serrations.

Both flexible couplings are still available through GM dealers and also through several Corvette suppliers. The detachable steering column upper flange is also still available as part number 7807052.