Hey Board-
I added the strut tower brace on my 84 vert. Is there any reason to add the lower Beretta brace? I bought it and it looks like I will have to move my exhaust to clear it...
Anyone put an x-brace on their car? Mine seems a little squishy over bumps and train tracks...
No to the ? on the brace.My next ? is how old are your front struts.If they are like 25,000 miles or u push down on the front and it bounces more than one time they are n need of replacement( test check for worn susp).IF there ok or not old u may want to beef up ur struts to something like monroes sensa trac struts which u can buy as a complete part called quick strut which includes the strut,mts,new spring (hardware is sold separate) sold at advance auto parts.They may or may not have it in stock but they do make it for my 85 coupe for about 175.00 a piece.Hope this helps and makes u read alot of my rambling info.I plan on buying the quick struts with all the above when I have the money.
Ron-
The shocks and struts have about 15K mileage on them. The car has movement in the door jambs when going over bumps - the body appears to move around the doors. Seems to be convertible specific.
I've owned 3 convertible J's, but I've been in numerous ragtops over the years. Once the roof is removed, the car always seems to feel as if it's bending at the cowl. I was surprised to feel this in midsize GM cars from the late 60's and 70's, even the full frame models.
I've been considering an X brace as well. If you find pictures of some of the custom frames being built for 1st gen F cars, they do some neat things like making an X with a loop for the driveshaft to pass through.
Also consider that the rocker supports are only riveted on. Today those pieces would likely be attached with adhesive as well as rivets.
Final thought: many of the J car ragtops I've seen have damage around the door latch pins in the body. I believe this is due to wear in the rubbing block found only in convertibles at the top rear of the door and in the matching piece on the door post under the rear glass. When the door is closed this block will add rigidity to the vehicle as long as (1) the hinges and pins are tight, and (2) the blocks make contact. Once the parts become loose it's up to the poor pin to hold everything tight.
Finally, I believe the way to make the X brace effective is to use it to preload the undercarriage of the car. As the weight of the car settles on the wheels the center of the car wants to settle effectively bowing the rockers and creating a reverse arch. By preloading the brace you'll counter this tendency.
Just some thoughts regarding an unfinished project.
-->Slow
Being that is the case did u replace the rear springs too.I know advance auto sells trw springs for our first gens,and even tho ur stuff is not too old a new set of springs front and rear would HELP alot.U have to remember the age of those parts and over time they tend to lose the stiffness regardless of the new struts/shocks around them.Also if the rear springs perch (as I call it) are rusted use some quick steel like I did to repair it( IT worked great).That is the only thing I can recommend being urs is topless.Keep in mind verts have diff springs compared to coupes which is specified on each part with advance.I would enter ur car in there site and click suspen and see what it would cost I think mine for the rear were 75.00 with out looking at the receipts.Hope this helps.
Paul- I ran into the exact same problem with my '86 and the lower suspension brace. I added the strut tower and that helped stiffen things quite a bit. But the lower brace would not fit since my car is a 4cyl and I pulled the brace off a Z24 with the V6. I have had read somewhere that BOTH braces should be used together...but there's no way it will fit since my exhaust won't clear it. I don't think its worth the hassle to try and splice in a section of steel with a curve for the exhaust...nor do I think its worth the hassle & price of having a custom piece made.
I think these cars are just always going to be sloppy going over bumps, railroad tracks, and potholes. Its the nature of the beast. Even my dad's 95 Z28 ragtop with 'extra chassis bracing' and 'subframe connectors' still chattered and wiggled over bumps. (I had to touch-up the paint on the corners of the doors on that car every other year because they would move & rub the door jambs!!)
I wouldn't worry about it too much. You could have a chassis shop give you a quote for adding some braces...but I guarantee the benefits won't outweigh the cost. Just my .02
Paul94Z28 wrote:Ron-
The shocks and struts have about 15K mileage on them. The car has movement in the door jambs when going over bumps - the body appears to move around the doors. Seems to be convertible specific.
My 88 Z24 Vert exhibits this but mostly only on the passenger side door. I haven't addressed it specifically yet, I might put new door pin shims in or a shim around the striker bolt. Mine seems to rattle mostly around the striker bolt and the bolt is tight. Yes it is the nature of the beast but there are some things that you can do. I have KYB shocks and struts all around with KYB mounts. Red urethane sway bar bushings and links. Those things alone seems to tighten up the suspension considerably. I have even though about installing a bar that goes inside the trunk from left to right like a cargo bar with ratcheting. Its a bit crude but cheap and you can see what kind of effect.
GM Powertrain Engineer
Currently in Charlotte, NC
Worked at Lordstown Assembly in Mid 90s
Hamtramck, Lake Orion, Lansing Grand River
Currently work on older cars but support
any GM make or any car for that matter.
Owned 3 J's over the years among other cars.
Currently 88 Z24 Convert. Mostly stock.
Mild exhaust, chip, CAI, stereo, etc.
Feel free to hit me up on anything!
It's certainly possible to beef up the suspension, take a look at my registry here or my website's gallery. I am fairly certain I have by far the most advanced suspension / braking / steering system of any convertible J-body, or even 1st gen at all.
As far as the lower brace, yes you want it. But you could make your own rather easily out of angle iron and it would be pretty good.
As far as rocker braces - they use crappy aluminum rivets to hold them on and on my car nearly all of them broke off, until one day when I jacked the car and the brace came off compleatly. So I welded that one to the body and it's SO much better. i'm going to remove them, clean / prep the metal underneath, and weld them forever to the chassis. IMHO this is how it should have been to start.
As far as an Xbrace, I want to build one, and weld it to the rocker braces. Then Weld my 4 point cage to it (which I dont' have yet). Then weld/bolt braces to the front suspension members. All would be tied together then. The cage alone should help immensly.
Protonus – I am in the middle of a rebuild of an ’87 convertible restore. I have not looked at the bracing that much other than to see that there are umpteen rivets through the floor pan. I too have pondered about welding the brace to the unibody especially after placing the car on jack stands and watching the door shift almost an inch up at the latch; wow!
