New shock tower is not perfect

[Casgar 21]

I'm working on replacing the passenger side shock tower since the old one was twisted and had a crack in it. The new shock tower looks good, but have some minor issues. The biggest is that when I have it positioned and flush towards the frame rail and the lower control arm mounting point is in perfect position the part above the frame rail lean out by about 2.5 degrees compared to the driver side tower (0 dergees).

Just pushing the tower inwards at this point means that the gaps towards the frame rail increases and the lower control arm mount gets lower. Not good either. No matter how you turn you still have your ass behind you (swedish proverb).

My current plan is to make a relief cut across the inner structure (red) and try to bend the tower inwards across the top of the frame rail (green), and then just weld it together again.

Just writing this to check with you guys if you think it's a good idea, or if there is some better way to adress this.

    

[RPM 1,190]

I like that idea, and wouldn't have an issue doing it myself. Seems like the easiest way to me. But I've been seeing before. 

[Ridge Runner 1,112]

Measure between the towers ,you shouldnt cut it untill you make sure it will be the right distance between them

[Midlife 814]

Use an export brace to ensure the upper structures of the shock tower are in alignment.

[RPM 1,190]

Two excellent points Jim and Randy. My inner fenders are 40 ¼" apart at the arrow in the pic, which is the front apron surface. 

[Casgar 21]

On 6/30/2022 at 7:06 AM, RPM said:

Two excellent points Jim and Randy. My inner fenders are 40 ¼" apart at the arrow in the pic, which is the front apron surface.

If I push in the tower until it touches the rear fender apron I get pretty close to your number, within 1/8".

On 6/30/2022 at 4:18 AM, Midlife said:

Use an export brace to ensure the upper structures of the shock tower are in alignment.

Originally the car had the 2-piece export brace, which I don't have around at the moment. I don't really think those are a good way to get a reference point though. I bought a 1-piece, but it's not perfect eighter. The mounting surface at the cowl point upward towards the front a fair amount and if I align the tower according to RPM's numbers above the brace still wants me to pull the towers closer together by an adittional 1/2" to 3/4". The center-to-center distance between the inner most holes on the brace is 30.6", if someone wants to compare.

[det0326 179]

On 6/29/2022 at 4:07 PM, Casgar said:

No matter how you turn you still have your ass behind you (swedish proverb

Now thats funny. love it

[RPM 1,190]

2 hours ago, Casgar said:

If I push in the tower until it touches the rear fender apron I get pretty close to your number, within 1/8".

 The center-to-center distance between the inner most holes on the brace is 30.6", if someone wants to compare.

Within an 1/8" on these cars is golden. 

My C to C between the two inner most holes is 30-9/16", which is close enough for government work. 

 

[det0326 179]

I think maybe your frame rail maybe twisted also. You probably need to try to determine if it is or not and if it is you may have to weld the tower to the frame rail with it sitting flush like it is suppose to be and then put a  comealong winch on it some how and pull it back where it belongs.

[det0326 179]

Another question is when u still had the fenders on, how did the fender to hood gaps look?

[RPM 1,190]

Ya, spending some time now checking might save you some trouble later. I'd use a digital level at the rear torque box, Front rails at torque box, and the front of the front rails.

[Brian Conway 264]

On 6/29/2022 at 10:06 PM, RPM said:

Two excellent points Jim and Randy. My inner fenders are 40 ¼" apart at the arrow in the pic, which is the front apron surface. 

Just to verify; 40 .25" is the measurement I have. I have Drake export brace installed.  The engine crossmembers measures 29.5" center to center. Brian

[Casgar 21]

2 hours ago, det0326 said:

I think maybe your frame rail maybe twisted also. You probably need to try to determine if it is or not and if it is you may have to weld the tower to the frame rail with it sitting flush like it is suppose to be and then put a  comealong winch on it some how and pull it back where it belongs.

Hmm... You might be on to something. I quickly went out and measured some angles with my phone and it might looks like both frame rails are twisted out slightly at the top, possibly more on the passenger side, but everything below 1 degree. Another think to keep in mind for sure. The mounting surface for the upper control arm on the old tower were also pulled out approximately 1/2", so that would also explain a twist in the frame rails.

Readjusting the twist should be the last thing to do, right? Cutting, bending and rewelding the shock tower to replicate the relative angles on the driver side tower > welding the shock tower to the frame rail > twisting the frame rails with the tower so that the export brace fit.

2 hours ago, det0326 said:

Another question is when u still had the fenders on, how did the fender to hood gaps look?

Horizontally not that bad, but vertically pretty bad since the driver side frame rail pointed up by about 5/8" in the front. I had the cahssi aligned by a professional 2 years ago, so the cross measurements and datum line measurements should be as good as they can get without risking making them even worse.

58 minutes ago, Brian Conway said:

Just to verify; 40 .25" is the measurement I have. I have Drake export brace installed.  The engine crossmembers measures 29.5" center to center. Brian

My crossmember (or rather the frame rail bolt holes) measures 29.4" C-C, +/- 0.1". So that might also support the theory of twisted frame rails.

This is why many brains together is superior to a single lonely one. :)

[Casgar 21]

Also, trying to backtrack the exact sequence of events in the crash that f***ed up the old shock tower is exiting in its own way!

[RPM 1,190]

I don't know what Ford's tolerance was for measurements was, but I'm thinking it wasn't too tight. My 69 left to right measurements are a quarter inch off on some locations, without any front end damage. They certainly weren't building watches. Ya gotta keep that in mind. 

I've built several engine crossmembers and my car and jig are at 29⅜ center to center for the bolt holes. A lot of our cars have varying measurements from each other. I don't remember what measurement VMF member Zray uses for his engine crossmember, but I've read of several buyers who after buying a Zray crossmember it didn't fit their Mustang. Just something to consider. 

 

[Casgar 21]

Just a little recap. I have just welded the shock tower in place, except from below. It is now identical in measurements and angles to the driver side, <2 mm and within 0.2 degrees. I guess I still need to pull both towers closer together though, since when I bolt on the export brace to the firewall there is still a significant gap. I also bought Zray's crossmember, which arrived 2 weeks ago, and based on that the frame rails is slightly too wide apart. Not so much that you cant get the bold to bite, but you need a tool get the bolt all the way in.

Is it really better to pull the tower and/or frame rails together to fit the brace, rather than make/buy an adjustable brace and accept the offset? I'm not really that impressed with the fitment of the brace anyhow. The distance between the frame rails on the inside just in front of the shock towers is just slightly below 23.75 inches. I guess fitting a hood and some fenders are needed before deciding.

[RPM 1,190]

I can't tell from the pics which export brace you have, the good one, or the crappy one. The good one fits very well, is made from ~.120" material, and the center valley is ~.500" deep. The crappy one is none of those. Make sure you have the good export brace. I bought mine thru NPD.

[Mach1 Driver 560]

It would be good to get the opinion of someone like Ridge Runner, but I don't think there is any need to pull the towers closer together. When you put the weight of the engine and trans in there, the bottom will be held in place by Zray's cross member but the top of the towers will lean in. If they come in too far you can always jack them out to put the export brace on.

 

[det0326 179]

why did u section the lower part of tower down near where the motor support mounts where u welded it ?

[Casgar 21]

4 hours ago, RPM said:

I can't tell from the pics which export brace you have, the good one, or the crappy one. The good one fits very well, is made from ~.120" material, and the center valley is ~.500" deep. The crappy one is none of those. Make sure you have the good export brace. I bought mine thru NPD.

After some googling I can tell you I have a crappy one. It's thick alright, but have nowhere near as deep groves as the NPD one. A problem for later I guess.

56 minutes ago, det0326 said:

why did u section the lower part of tower down near where the motor support mounts where u welded it ?

Not exactly sure what you mean. Do you mean part that goes underneath the framerail and have the LCA holes in it? I did that because the fitment wasn't perfect on them eighter, so I realigned them. If I was going to do it again I would have kept the brackets removed from the shock tower until the tower had been welded in place. That way I could adjust them even better since they didn't, and still doesn't lay flush towards the framerail. Another thing I'll have to correct later when I get the car up on a rotisserie, because it's a PITA to cut and weld while laying on your back.

[Ridge Runner 1,112]

6 hours ago, Casgar said:

Just a little recap. I have just welded the shock tower in place, except from below. It is now identical in measurements and angles to the driver side, <2 mm and within 0.2 degrees. I guess I still need to pull both towers closer together though, since when I bolt on the export brace to the firewall there is still a significant gap. I also bought Zray's crossmember, which arrived 2 weeks ago, and based on that the frame rails is slightly too wide apart. Not so much that you cant get the bold to bite, but you need a tool get the bolt all the way in.

Is it really better to pull the tower and/or frame rails together to fit the brace, rather than make/buy an adjustable brace and accept the offset? I'm not really that impressed with the fitment of the brace anyhow. The distance between the frame rails on the inside just in front of the shock towers is just slightly below 23.75 inches. I guess fitting a hood and some fenders are needed before deciding.

They dont always set flat to the tower ,they will pull down when bolted down . Make sure you are trying to align the brace over the proper end of the bolt hole,it doesnt go over the big hole ,it goes over the notch ,the notch actually holds the bolt ,the large hole is simply to slip the carriage bolt in  

[69Mach1 M code 20]

I know this is an old post but I'm trying to keep as much info in one place for future reference.

It looks like my new export brace is going to require the shock towers to be spread apart by about 1 inch to get the holes to line up. I've seen a number of posts and videos using a portable spreader, bumper jack, etc. to spread the towers. Is the best location to load the towers close to the top or should it be closer to the middle of the height, or does it even matter? The reason I'm asking is I wasn't sure if the towers deform or do they pretty much just pivot around the base where they join to the subframe and tilt outward?

[Ridge Runner 1,112]

If using one of the cheaper braces ,it may be the problem . 

As i said before measure between the towers to see if they are the correct distance apart ,i cant remember off hand what the measurement is but i can get it 

[Casgar 21]

On 6/2/2023 at 12:11 AM, 69Mach1 M code said:

I know this is an old post but I'm trying to keep as much info in one place for future reference.

It looks like my new export brace is going to require the shock towers to be spread apart by about 1 inch to get the holes to line up. I've seen a number of posts and videos using a portable spreader, bumper jack, etc. to spread the towers. Is the best location to load the towers close to the top or should it be closer to the middle of the height, or does it even matter? The reason I'm asking is I wasn't sure if the towers deform or do they pretty much just pivot around the base where they join to the subframe and tilt outward?

I have a hard time believing they would deform, so I would try mount the "spreader" as far up as possible. More leverage and therefore less actual force at the contact points.

[69Mach1 M code 20]

Thanks for the feedback.

I'm using the 40.25 and 30-9/16 inch dimensions mentioned above as references. 

The export brace I have is a Drake unit through NPD.

I was curious how much impact spreading the towers apart has on the mounting points of the upper and lower control arms. Ultimately only time will tell when I have it aligned. Oddly enough, the last time I had it aligned many years ago (but not many miles), the mechanic told me all three settings were able to be obtained with the adjustments in the middle of each range. 

Based on the limited discussion on the net about any alignment problems after fitting the export braces, I'm sure I'm just making a mountain out of mole hill and need to focus on the next task at hand; welding the floor pans in later this week.