Classic STB Mod Brainstorming(SOLVED/COMPLETED)

[sall]

As we know the STS Strut Tower Brace does not fir perfectly on the '95-'96 Classic. You must dremel or die grind the holes where it mounts to the upper strut mount bolts. That part is easy. However, you still run into the brake master cylinder clearance issue. Some say you can bend the bar, etc and get a good fit with minimal hood bow. In my opinion any amount hood bow is unacceptable, period. Even a mm is noticeable to me. It is pretty far off with no modification.

My first attempt at a perfect fit was altering the brake master cylinder by heating it up and pressing the STB into it to form around when mounted. This did work, but made the master cylinder a funky looking shape. Then a a couple weeks later it sprung a small leak. I then removed it. I am not willing to have this happen again especially under a heavy braking situation.


My second thought here is to modify the bar itself without structurally comprising it. Diagram below:

I am planning to remove a small section of the STB piping and cut three pieces and weld back in to keep the rigidity. It would be two semi-circular pieces and one flat piece.

Thoughts on this anyone?

[bobsblue95]

What's the cross-section of the STB look like? I'm guessing it's not solid..?

[sall]

Yeah it is not solid it is hollow.

[sall]

What I mean is and if it's hard to understand I will use my windows PC and draw it in cad. Basically, cut this section out:




and weld in three pieces to keep strength and rigidity:



It's not actually that much the bar is 1" in diameter and I would be cutting about 3/16-1/4" out and then welding those pieces in place.

[XJSman89]

What's the inner diameter? Overall straight length of the bar? Length and height of section that you want taken out once it's all back together? What is the length from the right edge of that section to the end of the bar's straight length? I'll model it real quick tomorrow if you want.

[sall]

I can get the measurements for ya if want them to mock up for future thread visitors. Should not be hard at all to draw up. I assume you want measurements in mm for better accuracy. My windows laptop is just buried and don't have my cad program installed on my virtual client.

Anyways... I went ahead and did it. Fits perfect no hood bow at all. Just have not welded the extra pieces in. All I can say is anyone with '95-'96 that said you can modify without doing this... there is absolutely no way... and I mean that without having hood bow.

In all honesty I put it in my vice that's bolted to my bench and the bar didn't budge a bit after I removed the piece and put weight my weight on it. I will still weld the pieces in though, sometime in the next few days. I'll have to stop by Lowes tomorrow and get a sheet of some like gauge metal.

Very happy. I will post some pictures of exactly how to modify when I am finished. I am a habitual project photographer which is a good thing haha.

[XJSman89]

Ah well since you've got the bar you could model the whole thing more accurately, I would just take a set of calipers to it, my digital ones are accurate to tree decimal places. Mm are fine, but it's not like it's a critical part so whatever is fine.

I can model it if people think it would be helpful but I might just wait until I get one myself or you get something worked up.

Basic measurements would be good tho that way I can do a simple model to use when I tackle it.

[sall]

Piece Cutout:





Cardboard Cutouts to Mimic 16ga Steel:




That should clear things up a bit visually.

I will use my cardboard cutouts to trace pattern on 16ga steel. I think I will actually make it one piece and use a metal break to bend the two semicircular shapes. If not it will be three separate pieces. ;D

[bobsblue95]

Aug 29, 2012 19:19:56 GMT -6 sall said:

I think I will actually make it one piece and use a metal break to bend the two semicircular shapes. If not it will be three separate pieces. ;D

That was the only thing I was gonna suggest, if the metal is thin enough to bend those small ends.

[sall]

Aug 30, 2012 8:10:38 GMT -6 bobsblue95 said:

That was the only thing I was gonna suggest, if the metal is thin enough to bend those small ends.

Yeah! It worked perfectly. I have the piece cut and bent already this morning. I taped it to the STB and did a another test fit. Still A-okay with no hood bow and hood insulation still installed.

Just need to sand down the STB a little to get a good surface to weld. Grind the welds down and then hit it with the same high heat black I used in the engine bay.

Doubt I will finish today though!

[lanceslambos]

so you actually weakened the bar big time instead? oh i didn't read everything sorry. you made a lot of work for yourself then when all you had to do was use a couple of washers to gain that clearance!

[sall]

More washers equal hood bow, sorry. All you are doing is further driving the bar up on the driver side when you do that or both sides if you put washers on both sides.Yes, you gain clearance for the STB over the master cylinder but it causes more hood bow. It then makes the bar hit a section of the hood. I would rather cut and mend the bar than cut the hood. I would not do it if it was not necessary. I will draw a picture to illustrate.

If you read the other stickied STB thread no one got a perfect fit always 'acceptable or I can deal with it and if they said they did quite frankly... they lied. Like I said a mm bow is unacceptable to me, if one can accept that so be it but I am very detail oriented.

Don't take my honesty for condescending attitude, but I tried a multitude of things nothing worked except this.

Remember this is for 95-96. The hoods are slightly different dimensions on other years IIRC from parts list.

[sall]

Welded, welds ground down, primer etched and in process of painting low gloss black. Should be on tomorrow after it bakes in sun all the day.

Knockin' 'em down Truly the last of the suspension upgrades. Feels good.

[RCA1186]

Great work, Who knows if it was even necessary to weld in new pieces, didn't look like you took out much. Where did you get your tower brace if you don't mine me asking?

[sall]

I really wouldn't feel comfortable not welding something else in place to keep the rigidity and strength. I will post some pictures after I eat. I just put it on and torqued the mount nuts down. As for where I got it, I found a little honey hole of new ones. Here is my post from the sticky thread.

Jun 19, 2012 13:35:26 GMT -6 sall said:

I found one used in what appeared to be great shape on eBay, 'bought' but ultimately backed out because I found a NOS stash of them about 30 minutes later. NOS Part# 25653157 STB $50.64 + $7.58 FedEx Ground shipping. New part for less than used one... This company 'Vintage Parts' shows 38 still in stock so I would not even bother hassling GM dealer to find one for you. So quite the price increase over a few years but what do you expect? Still a relatively inexpensive 'mod' which I hope will make a difference.

[XJSman89]

What is the thickness of the bar? I'm surprise you only used 16ga, I wouldn't think that .0598" would be enough to matter, but cool!

[sall]

STB thickness is 0.65"(1.66mm). The steel I used was 0.64"(1.64mm). The portion I cut out was 0.24"(basically 0.25") or 6.31mm by 3.149"(80mm).

So, the steel I used was labelled 16ga but I took my calipers with me when bought it to get the closest I could find. I assume it is galvanized, as it is typically a bit thicker by charts I am reading online.

[sall]

So, here is what I am saying. If you raise the bar up with a 1/4" stack of washers you are going to have some MAJOR hood clearance issues. This clears by about 1/16", with no pressure on the brake master cylinder reservoir. Both ends of the STB mount holes rest flush with top of the strut tower. No hood clearance issues.

I nicked the front a bit with my air die grinder when I was grinding the welds down but it's hard to notice to the naked eye. This is with camera pretty close to the STB haha. I wasn't going to take the time to put filler in it. Just shot it the low gloss black and called it a day. Looks great IMO.

If one can get it installed and be happy with the hood fit clearance without doing this, I applaud your efforts but this took about 45 minutes total minus painting. Plus you get to play with grinder and welder, always fun!

Now to get to that last trans mount... ;D Should be delivered tomorrow.