1969 Shifter Bracket Bolts - need some help

[Kevin S.]

Good Morning,

I am needing some help to determine if I have the right bolt for the shifter bracket support where the bolts screw into the back side of the crossmember on our 1969 Coupe. Seems odd to me that they would drill and tap threads directly into the crossmember without also tack welding a nut on the inside of the crossmember to secure the shifter bracket better. There is evidence of a flat washer mark in the LH bolt location on the crossmember.

My AIM shows a bolt PN 9418821 and a plain washer PN 120393. I do not have a parts catelog and I'm not sure how to cross-refernce GM part numbers. I could use your help.

There was no washer on the bolt when I took the shifter bracket off which made sense to me since it was a flange head bolt. The two bolts I have on the car now are 1/2" wrench, indented hex head, washer head (aka flanged head or shoulder head), no head marks legible due to age and wear. They are 5/16" - 18 x 3/4" size bolts. I parkerized them black phosphate.

In my NCRS correctness pursuit, I am wondering if I have the right bolts in this location to secure the shifter bracket on the rear facing side of the crossmember. Also wondering if it was correct that these bolts do in fact just screw directly into the crossmember without a nut on the other side? There is room to get a nut into the opening on the bottom of the center crossmember but there is no nut called out in the AIM.

Kevin

[Ray K.]

Re: 1969 Shifter Bracket Bolts - need some help

Kevin,
Not sure if they were the same, but, my '71 uses part number 3975550, which is a 5/16-18 X 3/4" self-tapping screw and did not have any washers (as shown in the '71 AIM: UPC 7, Sheet B2). Not sure why it would have been different between the model years . . .
Be very careful as both of these screws strip out very, very easily since they are self-tapping into relatively thin steel. Make sure that you torque them carefully.
Ray K (#43777)

[Kevin S.]

Re: 1969 Shifter Bracket Bolts - need some help

Hello Ray,
You are the second person to question the washer. For what it is worth, I spoke with David Sokolowski last night and he thought the '69 used a self-taping 5/16" - 18 x 3/4" flanged head bolt and no washer, which I mentioned to David is different than what it showed in my AIM. David asked me to do some more research and reach out to others so we get the hardware right. Still a mystery. I don't know why there would be a plain washer used with a flanged-head self-taping bolt, especially in this location when the frame steel is not too thick. What purpose would a plain washer serve? I am leaning toward "no washer".

Agree on the torque spec. My threads on the crossmember are perfect. Torque spec in the AIM says 72-96 inch lbs and I will use orange threadlocker and go on the lower end of the torque spec probably in the 65-70 inch lb. range.

Thank you for your reply.

Kevin

[Terry M.]

Re: 1969 Shifter Bracket Bolts - need some help

I may be way off base (it wouldn't be the first time), but my memory is the gear shift, when in reverse position, can contact the trim on the console depending on the body alignment to the frame. The flat washer is used as a shim to move the shift lever toward the rear of the car to clearance the shift lever. Thus not all cars would need it. I think I had to add a washer to one of the early C3s I had. Then again, maybe I just chose a Buba fix.

[Gary B.]

Re: 1969 Shifter Bracket Bolts - need some help

Terry,

So the extra plain washer would need to go between the bracket (support assembly) and the crossmember?

Gary

[Mark E.]

Re: 1969 Shifter Bracket Bolts - need some help

Kevin,

Make sure you're looking at the right AIM page. Your post shows the page for a standard 3-speed. Is that what you have?

[Joe L.]

Re: 1969 Shifter Bracket Bolts - need some help

Kevin,

Make sure you're looking at the right AIM page. Your post shows the page for a standard 3-speed. Is that what you have?

Mark------


The support is the same for either 3 or 4 speed manual.

[Terry M.]

Re: 1969 Shifter Bracket Bolts - need some help

Terry,

So the extra plain washer would need to go between the bracket (support assembly) and the crossmember?

Gary

Gary, sorry, I don't remember where I put the washer. My way back time machine is on the fritz. I am not even sure which car (1969 or 1970) i had to do it to. All I can remember is the gear shift hit the console opening in reverse and I had to force the shifter to get into reverse. I looked at the shifter mounting assembly and determined I had to move it back a bit and the washer did the job.

Looking at the AIM picture I think you are right that it would have to go between the bracket and the crossmember. Under the head of the bolt wouldn't do the job.

[Kevin S.]

Re: 1969 Shifter Bracket Bolts - need some help

Hi Mark,
I have a 4-speed. I did look for a separate AIM page for 4-speed mount bracket but did not find it.

I see Joe's reply below that the shifter support is the same for 3-speed or 4-speed.

[Kevin S.]

Re: 1969 Shifter Bracket Bolts - need some help

Hi Terry,
My shift handle cleared the shifter plate inside the car prior to taking it out of the car. Who knows when I put it back in. Will keep the shim idea in mind if I need to create some clearance.

Kevin

[Floyd B.]

Re: 1969 Shifter Bracket Bolts - need some help

Kevin,

FWIW, 4-spd transmissions are considered an option, so the AIM pages are towards the back of the AIM. In this case, look for UPC's M20 A1 - A6. Page M20 - A2 callout #6 are the shifter AND bracket assembly listed as a single part number - 3960707. I suppose we'll have to assume the bracket is the standard production version as noted by Joe. You might want to take a look at page M20 - A3. This page provides the Transmission Lever & Linkage Adjustment Instructions.

I'm also confused by your original post. You said, "...right bolt for the shifter bracket support where the bolts screw into the back side of the crossmember" and "My AIM shows a bolt PN 9418821 and a plain washer PN 120393." But according to the diagram, these are the bolts that attach the front of the bracket to the top of the transmission support. The bolts used to attach the bracket to the rear of the cross-member are callout #3 - 9419402 - Screw and #4 washer 120393 P. Washer.

Also, FWIW, my car has two flange head bolts with no washers at this location. But my car is not a good reference for originality.

Floyd

[Gary B.]

IMG_2454.jpeg

IMG_2455.jpg

[Floyd B.]

Re: 1969 Shifter Bracket Bolts - need some help

Gary,

Yep. That's what the bolts look like on my '69.

Floyd

[Joe L.]

Re: 1969 Shifter Bracket Bolts - need some help

Back in 2012 Scott Smith posted these photos of what he believed was screw GM 9419402, from his ‘67.

[ATTACH=CONFIG]123936[/ATTACH]

[ATTACH=CONFIG]123937[/ATTACH]

The 1966 and 1967 AIMs both call for the use of that screw in combination with “L. WASHER” GM 3748358 for the shifter bracket to frame mounting. But 3748358 is a plain washer, not a lock washer. At first glance, the use of a lock washer might make more sense at that location. So, one possible conclusion is that the GM part number called out for a L. Washer is incorrect in the ‘66 and ‘67 AIMs. Another possible conclusion is that GM did indeed want a plain washer used in conjunction with the flange head screw, in which case “L. WASHER” should be “P. WASHER” in the ‘66 and ‘67 AIMs.

My recollection is that the holes in the shifter bracket are slotted. And perhaps the flange on the flange head screw is a bit small for use in those slotted holes. And I seem to recall the plain washer GM 3748358 has an unusually large OD, larger than the flange of that screw. I’m just going from memory here, which has its downside.

Gary

Gary------


There are very few, if any, applications in which GM used a flat washer in conjunction with a flanged head bolt/screw.

[Gary B.]

Re: 1969 Shifter Bracket Bolts - need some help

Gary------


There are very few, if any, applications in which GM used a flat washer in conjunction with a flanged head bolt/screw.