Body mounts

Tom87GNX

Active Member
Joined
Nov 29, 2012
Well fellow TR brothers, today I finally got around to replacing my severely worn body mounts. The procedure went pretty well for the most part..... I had an energy suspension kit sitting around so I figured I would put it to good use. I also got myself a set of replacement bolts from Kirban’s which helped a great deal although most of the bolts actually came out looking good. I did however have to cut the trunk floor to remove #6 on driver side and #7 on passenger side but overall pretty happy. What an improvement!!!! The car just feels so much more solid and for a T Top car (anyone who has one knows) that they are typically full of rattles. Next up when I have some time is front control arm bushings as the well known right front upper rear bushing is trashed. Little by little it’s coming together, someday it will be treated to a frame off but for now I’ve bought BETTY some time. Loving my GN right now!!!!


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Nice I just ordered a set of bushings. I’m not sure why the floor pan had to be cut though. Everything I’ve heard is it should be an easy upgrade


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Depends on how rusty they are. Also sometimes the holes get reamed and you have to weld washers where the mnt goes. Sometimes they strip out, if that happens on the near back ones you have to cut a hole in the trunk floor to grab the spinning part to get the bolt and nut out. Then all that has to be repaired also. Dont forget the one that got put on the gnx's. It just slips in. Can go smooth as silt,can be a royal pain. Def great upgrade though.
 
What Gene said, I had #6 on driver side and #7 on passenger side snap while trying to remove them. I had to cut access holes in the trunk floor to get to the cage nut. I did find 3 frame holes that are just slightly rusted larger then they are supposed to be but plenty of metal for support at this time. I do have plans later of a frame off, so the holes will be addressed at that point. It’s definitely a nice upgrade for a higher mileage car ( mine at 135K) the bushings would spin easily while still bolted together. That type of wear just makes the car ride and feel like crap.


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I installed the energy suspension kit (has the #5 bushing) aka GNX bushing. I recommend to anyone doing this to buy the bolt set from Kirban Performance. Most bolts at this point will be compromised and replacing the bushings and reusing rusted worn bolts kind of defeats the purpose.


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Kirban 2 cents worth

Appreciate the mention of the Kirban bolts for the body mount project. They are the proper grade 8 bolts and as suggested makes good sense to use new bolts. Unfortunately with the cars 30 plus years old depending on the area of the country and miles driven it can be an iffy project when you get to the mounts from the rear axle back.

On the cars we prepped years ago to sell I always installed the missing body bushings and kept my fingers crossed the bolts would come out with no issues.

Another upgrade since the author said he has a T-Top is install the rear seat brace kit if you haven;t already a difference you will feel before you get to the end of your street.

Also dropping in the bearing kit and lower steering shaft we offer with metal joints at both ends is another relatively cheap upgrade.

In other words......the project never ends. our money runs out first....

We just worked with a company to solve another nagging problem with these cars and turns out this new idea will work. Not suspension related but related to those of you that got the power antenna.

Answer in next weeks Inner Circle.

denniskirban@yahoo.com
 
Kirban 2 cents worth

Appreciate the mention of the Kirban bolts for the body mount project. They are the proper grade 8 bolts and as suggested makes good sense to use new bolts. Unfortunately with the cars 30 plus years old depending on the area of the country and miles driven it can be an iffy project when you get to the mounts from the rear axle back.

On the cars we prepped years ago to sell I always installed the missing body bushings and kept my fingers crossed the bolts would come out with no issues.

Another upgrade since the author said he has a T-Top is install the rear seat brace kit if you haven;t already a difference you will feel before you get to the end of your street.

Also dropping in the bearing kit and lower steering shaft we offer with metal joints at both ends is another relatively cheap upgrade.

In other words......the project never ends. our money runs out first....

We just worked with a company to solve another nagging problem with these cars and turns out this new idea will work. Not suspension related but related to those of you that got the power antenna.

Answer in next weeks Inner Circle.

denniskirban@yahoo.com
First let me say I love my poly bushings. Lot of people say they are too stiff but its a personal preference. 2nd, my car was a northern car so the bolt kit from Kirban was a must. Last, I need a power antenna solution. Look forward to hearing about it.

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We just worked with a company to solve another nagging problem with these cars and turns out this new idea will work. Not suspension related but related to those of you that got the power antenna.

Answer in next weeks Inner Circle.

denniskirban@yahoo.com

Currently converting my car from a mast antenna to power and not looking forward to removal of the entire fender to make it happen. Anxious to hear your news....
 
I had the energy suspension bushings. As much as I loved how the car handled with them (T Top car), the combination of those and HR motor mounts transmitted some weird resonance / vibration that over time annoyed the hell out of me. I ended up putting new rubber ones in (GNX bushing and all) and like it a lot better despite the slight lack of tightness. I kept mine and wouldn't hesitate to use them again on a car that was more dedicated for track duty.
 
Just be careful, make sure to have the car supported properly. If they are rusted you will have use some force to get them loose,dont want your fingers in there if it gets loose. Take the time to spray some lube on them for a day or so, makes it a little easier.
 
On what Mr Kirban said about the rear seat gnx brace.,.... *Do it! * I got the " Tin Man " brace and kit from him. Easy install and made a difference even with new body bushings installed. ( I didn't weld mine in. I used the supplied bolts / nuts and added seam sealer. ) NO rattles or squeaks at all. Well worth the money and effort.
 
I had body shop do mine and they had to cut most of them off and even had to weld in metal at some place. N
On what Mr Kirban said about the rear seat gnx brace.,.... *Do it! * I got the " Tin Man " brace and kit from him. Easy install and made a difference even with new body bushings installed. ( I didn't weld mine in. I used the supplied bolts / nuts and added seam sealer. ) NO rattles or squeaks at all. Well worth the money and effort.

For us layman, how does it improve it. I don't get the concept. That and the fender/radiator support brace I just don't get, especially on a hard top car. I can somewhat see how it would prevent side to side flex in the body of a T top car but even then everything is bolted firmly to the frame. I'm not doubting it, I just lack the understanding of what it does because i'm not an engineer.
 
The bolts are 30 years old,the rubber 30years old, the holes are 30 years old. Plus adding the gnx bushing. Hell this will even set the body back down straight and tight on the frame as long as you fix the reamed out frame holes. Im not an engineer either but i can tell you with the poly bushings i installed my car there was a day and night difference. No more bobbing up and down,no more side to side roll, tight is the only way to exsplain it. Its not a mercedes but was by far the best body upgrade i did,like i said night and day.
 
The bolts are 30 years old,the rubber 30years old, the holes are 30 years old. Plus adding the gnx bushing. Hell this will even set the body back down straight and tight on the frame as long as you fix the reamed out frame holes. Im not an engineer either but i can tell you with the poly bushings i installed my car there was a day and night difference. No more bobbing up and down,no more side to side roll, tight is the only way to exsplain it. Its not a mercedes but was by far the best body upgrade i did,like i said night and day.

Oh I have absolutely no doubt about the bushings. One of the best things I ever did to my car. I'm referring to the rear seat brace and the radiator support fender brace. I don't understand the benefit of those. I know there must be a benefit if GM put a rear seat brace in the GNX, I just don't know what it improves or how.
 
I had body shop do mine and they had to cut most of them off and even had to weld in metal at some place. N


For us layman, how does it improve it. I don't get the concept. That and the fender/radiator support brace I just don't get, especially on a hard top car. I can somewhat see how it would prevent side to side flex in the body of a T top car but even then everything is bolted firmly to the frame. I'm not doubting it, I just lack the understanding of what it does because i'm not an engineer.

The support braces do just what you said, they support side to side twist and flex. Hard top cars are obviously a little less prone to flex however the roof doesn’t have heavy bracing either. Adding the Grand Prix brace, Cutlass braces on the front makes the front much tighter by more or less boxing the frame. Keep in mind even though we have full frame cars, the body sits atop 14 bushings, based on the weight of the body, frame flex etc those 14 mounting points can not prevent full flexing of the body or frame. Frame braces help with the addition of the mounts to “tie both frame rails together” which increases overall strength. The GNX brace does the same just in the rear end of the car.


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