Lower Ball Joint Cotter Pin

[Bill L.]

What size are the cotter pins?

The 70 AIM calls out the same part number 103385 1" x 1/8" for the upper and lower ball joint cotter pin.

However, I have an NOS lower ball joint and the cotter pin is longer at 1"-1/2" x 1/8" diameter.

If I labeled the cotter pins correctly when I took the front suspension apart they both appear to be 1-1/8".

While the ball joints were original I have reason to think at least one of the two front spindles were removed at one point.

The reason I say this is the upper ball joint cotter pin was not installed as shown in the AIM.

Thank you,


Bill

[Joe L.]

Re: Lower Ball Joint Cotter Pin

What size are the cotter pins?

The 70 AIM calls out the same part number 103385 1" x 1/8" for the upper and lower ball joint cotter pin.

However, I have an NOS lower ball joint and the cotter pin is longer at 1"-1/2" x 1/8" diameter.

If I labeled the cotter pins correctly when I took the front suspension apart they both appear to be 1-1/8".

While the ball joints were original I have reason to think at least one of the two front spindles were removed at one point.

The reason I say this is the upper ball joint cotter pin was not installed as shown in the AIM.

Thank you,


Bill

Bill------


GM #103385 was a cotter pin of 1" X 1/8". However, there's no guarantee that is the cotter pin supplied with an NOS ball joint. It's also VERY possible that some cotter pin other than a 103385 was used in PRODUCTION.

One tip here: original cotter pins used in PRODUCTION had a "plain" finish. In other words, they were bare steel. If you find a plated cotter pin on the car, it's most likely one that was field-installed. Most (but not all) SERVICE cotter pins are zinc plated.

[Bill L.]

Re: Lower Ball Joint Cotter Pin

Bill------


GM #103385 was a cotter pin of 1" X 1/8". However, there's no guarantee that is the cotter pin supplied with an NOS ball joint. It's also VERY possible that some cotter pin other than a 103385 was used in PRODUCTION.

One tip here: original cotter pins used in PRODUCTION had a "plain" finish. In other words, they were bare steel. If you find a plated cotter pin on the car, it's most likely one that was field-installed. Most (but not all) SERVICE cotter pins are zinc plated.

Thank you Joe.

I will go with the 1" x 1/8 cotter pins. I take the plating off with vinegar. Since I I abhor rust I then treat the cotter pins with RPM(Rust Prevention Magic) along with the slotted nuts and exposed part of the ball joint.

The cotter pins I found were all bare steel when I disassemble the suspension.

Kind Regards,


Bill

[Joe L.]

Re: Lower Ball Joint Cotter Pin

The cotter pins I found were all bare steel when I disassemble the suspension.

Bill

Bill-------


The cotter pins that GM used at virtually every chassis application on a Corvette were originally "plain" finish (i.e bare steel).

To be honest, I prefer to use stainless steel cotter pins in place of these. They appear pretty much like fresh, bare steel and they'll never rust. Rusted bare steel cotter pins don't appear original, either.