I am needing a new steering coupler ( rag joint ) for my '68. I have the factory power steering box and a factory tilt column. The worn out coupler I am replacing is a GM part bought at a Chevy dealership in the early or mid 80's. My steering box has the 13/16 inch diameter, 31 spline input shaft with the "flat spot." The GM coupler I'm replacing has the corresponding flat spot.
I want my replacement to be as close in looks as possible to an original GM coupler. I have looked at all or most of the couplers from the usual parts suppliers and things start get pretty confusing.
1) Some say 31 spline and some say 36 spline. I'm gathering the 36 will fit and is the same as the 31 but does not have the flat spot and has five more splines where the flat spot would have been. Can someone verify that?
2) The two bolts in the coupler that I am replacing are different diameters. One is 5/16, one is 3/8. Some of the couplers advertised tell you that they use two 5/16 diamter bolts. I don't know how they can do that since the corresponding holes in the steering column flange are drilled for 5/16 and 3/8. Wouldn't using in 5/16 bolt in the 3/8th hole add slop into the steering?
3) I'm not sure what they are called but I'm referring to the plate that goes under each bolt head that spreads out the load over the rubber disc. My old GM coupler has two of them, one under each bolt. About half of the couplers advertised have the two individual plates like mine and the other half have a one piece unit half circular unit that connects both of them. I don't know why there are two different styles or which one is correct.
4) Some of the advertised couplers say the collar on the coupler that fits over the steering box input shaft is only splined a 1/4 of it's diameter. Mine is splined all the way around except for the flat spot. Wouldn't splining only a 1/4 of it make for a weaker connection?
5) And lastly, not one of the advertised couplers say a single thing about a ground strap being included. I don't see ground straps advertised anywhere. What do you do to complete the horn ground if the coupler you buy doesn't have one?
The attached pictures are of:
1) The GM coupler I'm replacing.
2) My steering column flange with one 5/16 hole and one 3/8 hole.
3,4) The style coupler with the half circle plate that both mounting bolts pass through.
5,6) The style coupler I believe is the closest to what an original GM would look.
I'd appreciate any input as to what looks most correct and also fits my steering box and column flange
Thanks......Dave
