69' seat bumpers

[Steve]

I am restoring the seats in my early 69. I bought new seat back bumpers at Danchuks. The threads on the new bumpers are 5/16-16, 5/16-18, 5/16-20 or something like that. However the existing bore in the seat bottom is for a #12 bolt. Which is correct? Also it was mentioned to me that the bumpers on a 69 go into the seatback. This not consistant with my seats which appear to go into the seat "butt". The tags on the seats say "3956021 LS1-UC-331-8-1" and "3958735 LS1-UC-337-8-1". This needs to be resolved before I can put the seats back together.

Thanks In Advance, Steve

[Chuck G.]

Re: 69' seat bumpers

Hi Steve; I believe that 68's and early 69's used a black plastic upper bumper which was secured to the seat back with a sheet metal screw. The adjustment of the seat angle was done via shims placed under the lower bumper on the seat bottom. Sometime by mid 69, this system was replaced with the single 5/16x18 threaded rod that you describe. The seat back angle adjustment is done by adjusting the rod in or out. The later seat back has a nut welded inside which receives the rod. The earlier seat backs do not have this welded nut. This is one of the items to be addressed in the new Judging Manual. My 69 is an August, 69 car and it has the threaded rod. Two friends, one with a July, 69 car, and the other with a December, 69 car also have the threaded rod. Others may elaborate more. Chuck

[Chuck G.]

Re: 69' seat bumpers

Hi Steve; I believe that 68's and early 69's used a black plastic upper bumper which was secured to the seat back with a sheet metal screw. The adjustment of the seat angle was done via shims placed under the lower bumper on the seat bottom. Sometime by mid 69, this system was replaced with the single 5/16x18 threaded rod that you describe. The seat back angle adjustment is done by adjusting the rod in or out. The later seat back has a nut welded inside which receives the rod. The earlier seat backs do not have this welded nut. This is one of the items to be addressed in the new Judging Manual. My 69 is an August, 69 car and it has the threaded rod. Two friends, one with a July, 69 car, and the other with a December, 69 car also have the threaded rod. Others may elaborate more. Chuck

[Reba Whittington]

Re: '69 seat bumpers

Steve, Chuck is correct in his assessment. Early '68 cars had a metal only stop in the seat back, but all 1969's should have a rubber pad. Also the stop on the seat bottom was plastic; most replacements I have seen are rubber, which is correct for 1970 up. Some late 1969 cars might have had the rubber ones. How about that Chuck, since you mentioned a very late car?

[Reba Whittington]

Re: '69 seat bumpers

Steve, Chuck is correct in his assessment. Early '68 cars had a metal only stop in the seat back, but all 1969's should have a rubber pad. Also the stop on the seat bottom was plastic; most replacements I have seen are rubber, which is correct for 1970 up. Some late 1969 cars might have had the rubber ones. How about that Chuck, since you mentioned a very late car?

[Chuck G.]

Re: '69 seat bumpers

Hi Reba; I know that 68's have the metal stop on the seat bottom and the black plastic fixed "bumper" on the seat back. The plastic fixed bumper, I believe, is retained by a sheet metal screw--possibly a small machine screw. By 69, they had begun to use a black plastic stop on the bottom, but continued to use the fixed bumper on the seat back. Sometime later in 69, they switched over to a single 5/16 x 18 threaded rod with a black hard rubber end (like the 70 and up cars). This type of seat back uses the rod to adjust the seat angle, while the earlier design used shims under the stop on the seat bottom. I'm sure that the later style continued to use the shims under the "catch" for the seat back, as this would be the only way to raise it. Regarding serial numbers, I have no idea, but I think that this definitely occurred by July of 69. I hope that other will check their cars. Chuck

[Chuck G.]

Re: '69 seat bumpers

Hi Reba; I know that 68's have the metal stop on the seat bottom and the black plastic fixed "bumper" on the seat back. The plastic fixed bumper, I believe, is retained by a sheet metal screw--possibly a small machine screw. By 69, they had begun to use a black plastic stop on the bottom, but continued to use the fixed bumper on the seat back. Sometime later in 69, they switched over to a single 5/16 x 18 threaded rod with a black hard rubber end (like the 70 and up cars). This type of seat back uses the rod to adjust the seat angle, while the earlier design used shims under the stop on the seat bottom. I'm sure that the later style continued to use the shims under the "catch" for the seat back, as this would be the only way to raise it. Regarding serial numbers, I have no idea, but I think that this definitely occurred by July of 69. I hope that other will check their cars. Chuck

[Joe L.]

Re: 69' seat bumpers

Steve----

As the other responders have mentioned, at least 2 different seat back bumper configurations were used in 1969. Early cars used round, fixed bumpers, upper and lower. These bumpers were attached by phillips head screws. They were adjusted for seat back angle by the installation of ROUND shims which came in a muslin, pull-string bag(with rectangular shims for the lock-side adjustment). Of some interest is the fact that I have a friend who is the original owner of a November, 1968 built coupe. His seat-back upper bumpers, which have never been altered since new, are different from side-to-side. The driver side seat has a "whitish", round bumper of somewhat smaller diameter than the black, round bumper seen on the passenger side seat. His car has the muslin, pull string bag with BOTH the rectangular and round spacers.

My original owner, September 1969 built convertible uses the later design bumper system described by Chuck Gongloff. The upper(seat back) bumper consists of a 5/16" diameter bolt with a large diameter, flat, round head. A rubber bumper is "snapped on" over the round bolt head. Adjustment is provided by rotation of the bolt. The lower(seat cushion) bumper is a round, rubber/plastic bumper attached to the seat cushion frame by a phillips head screw and washer. This lower bumper is GM #3954505, long ago discontinued. I happen to have an NOS set of these bumpers in the original GM packages which I purchased "accidentally" over 25 years ago, so I am certain of the part number and original configuration(which matches the ones on my seats). Incidentally, my car came with the muslin bag with rectangular shims ONLY.

[Joe L.]

Re: 69' seat bumpers

Steve----

As the other responders have mentioned, at least 2 different seat back bumper configurations were used in 1969. Early cars used round, fixed bumpers, upper and lower. These bumpers were attached by phillips head screws. They were adjusted for seat back angle by the installation of ROUND shims which came in a muslin, pull-string bag(with rectangular shims for the lock-side adjustment). Of some interest is the fact that I have a friend who is the original owner of a November, 1968 built coupe. His seat-back upper bumpers, which have never been altered since new, are different from side-to-side. The driver side seat has a "whitish", round bumper of somewhat smaller diameter than the black, round bumper seen on the passenger side seat. His car has the muslin, pull string bag with BOTH the rectangular and round spacers.

My original owner, September 1969 built convertible uses the later design bumper system described by Chuck Gongloff. The upper(seat back) bumper consists of a 5/16" diameter bolt with a large diameter, flat, round head. A rubber bumper is "snapped on" over the round bolt head. Adjustment is provided by rotation of the bolt. The lower(seat cushion) bumper is a round, rubber/plastic bumper attached to the seat cushion frame by a phillips head screw and washer. This lower bumper is GM #3954505, long ago discontinued. I happen to have an NOS set of these bumpers in the original GM packages which I purchased "accidentally" over 25 years ago, so I am certain of the part number and original configuration(which matches the ones on my seats). Incidentally, my car came with the muslin bag with rectangular shims ONLY.

[Steve]

Re: 69' seat bumpers

Thank you all for your responce. I was moments away from retapping the bottom seat frame. "SAVED BY THE BELL"

Steve

[Steve]

Re: 69' seat bumpers

Thank you all for your responce. I was moments away from retapping the bottom seat frame. "SAVED BY THE BELL"

Steve

[Gene M.]

Re: '69 seat bumpers

Chuck, You are correct the plastic bumper is retained by a sheet metal screw on 68/early 69 seats.

[Gene M.]

Re: '69 seat bumpers

Chuck, You are correct the plastic bumper is retained by a sheet metal screw on 68/early 69 seats.