RePop Core Support Modification How To
 

For better or worse I'm attempting to correct the issues with the gawd awful repop core support sold for 68-72 GTOs.

I hope it works out since if it doesn't I'm out about $300 including shipping and will have to find a decent OEM piece which would probably cost $500 by the time it gets to my house.

Starting with modification to achieve the proper 9-10 degree forward lean at the top.

I took pictures as I went along and these are the results.
Pictures first .... then caption below picture.

http://forums.maxperformanceinc.com/...7&d=1574288116

Mount core support to a straight and level bench using spacers that fit inside the bottom rail .... this is the way the support would be mounted onto the frame. This bottom rail remains level and horizontal the to the ground when installed in the vehicle.


http://forums.maxperformanceinc.com/...8&d=1574288125
http://forums.maxperformanceinc.com/...9&d=1574288129

There are six spot welds on each side in the lower corners that need to be drilled out ... marked by the silver dots in these two photos.


http://forums.maxperformanceinc.com/...0&d=1574288135

This brace has to be cut along the silver line ... I used a plasma cutter.

The Story continues

http://forums.maxperformanceinc.com/...1&d=1574288592

The horrible chinese part standing straight up, a wavy mess.


http://forums.maxperformanceinc.com/...2&d=1574288602

The brace after being cut.


http://forums.maxperformanceinc.com/...3&d=1574288608

Separating the spot welds.


http://forums.maxperformanceinc.com/...4&d=1574288618

Level on top plate showing 9 degrees ..... it will be hard to keep this perfect as you work ... just keep and eye on it, keep tweaking as you go ... anywhere from 8 - 10 degrees is going to be way better than the way it was made.

And continues so more ...


http://forums.maxperformanceinc.com/...5&d=1574288945

This is what the spot welded flanges look like after bending the support forward 9 degrees. It bends quite easily .... the upper section is now only connected to the bottom rail by the spot welds along the lower front.


http://forums.maxperformanceinc.com/...6&d=1574288957

When you go to bend the support forward, make sure and block under the bottom lower flange, this will make it bend in the right place. Do this on both sides.


http://forums.maxperformanceinc.com/...7&d=1574288978

I started the rewelding with these flanges ... had to crease them, then bend them down to meet the bottom rail, you can see their original position by the bare metal that was underneath them.


http://forums.maxperformanceinc.com/...8&d=1574288984

The first flanges welded back to the bottom rail. Once this is done you can relax a bit as the support will hold itself in position. At this point you could still tweak it a degree or so if you had to.

And even more ...

http://forums.maxperformanceinc.com/...9&d=1574289409

Here is the support at 9 degrees with two of the flanges welded to the bottom rail.


http://forums.maxperformanceinc.com/...0&d=1574289704

I should have posted this at the beginning of the topic ... but this is what the modification is based on, from the 69 Assembly Manual ... these construction drawings obviously show the core support should NOT be straight up and down, but has a pronounced lean towards the front at the top. As verified by owners with assembled original cars.

Will try to finish the project in a timely manner and get the rest of the photos up.


In the next installment of this "how to" I will be fabricated some splice plates for two more spot welded flanges, and the main braces.

So far so good .... assuming I haven't made a gross misconceptual error about how this part was supposed to be manufactured I should be good when it comes time to assemble the front end.

Excellent post! Are there other flaws you'll be addressing, missing holes, etc? Looking forward to the finished piece.

Good job! Based on your previous posts and attention to details I think this will be very helpful to others with the pos repop.

Yep I hope to address the 69 upper lip removal, the 69 "clip" removal ... and AC condenser hole correction, drilling holes for the 68 upper fan guard.

Unfortunately I'll have no proof any of it works for a while as I won't be doing the final installation on the car for quite a while.

More welding ...

http://forums.maxperformanceinc.com/...0&d=1574325345

This is one of the flanges at the lower, driver side corner of the radiator window. Displaced by bending the upper section forward.


http://forums.maxperformanceinc.com/...1&d=1574325370

Flange removed with a hack saw.


http://forums.maxperformanceinc.com/...2&d=1574325380

Make a pattern out of heavy paper and cut out the patch piece. Not sure what the notch is for in the original, but figured I better include it.



http://forums.maxperformanceinc.com/...3&d=1574325391

Test fitting the patch after doing the final trimming. Don't sand off the E-coat ... heat it slightly with a propane torch ... it comes off very easily with a wire brush while still hot, leaves clean bare metal.

And even more stuff ..


http://forums.maxperformanceinc.com/...4&d=1574325749

Patch TIG welded in with Silicon Bronze filler. Weld it at the rear edge also, this prevents it from wanting to flex the patch up from the bottom rail. Dents are from clamping a patch to the other side (as mentioned in last photo)



http://forums.maxperformanceinc.com/...5&d=1574325755

For this area I decided to fit a piece inside the gap. This needs to be something like 16ga steel as the brace is quite a bit thicker than the rest of the core support and that brace ties directly into the core support frame mounting hole.



http://forums.maxperformanceinc.com/...6&d=1574325760

Brace patch welded in ... not my best work there. Plasma cutter leaves a nasty edge and you can't clean the E-coat off the back side of the metal. Seems plenty strong though. This is probably the most difficult area to fix. On the same brace on the other side I used a surface patch instead and MIG welded it a bit at a time, using vise grips to help it conform to the existing metal.

what brand was that core support?

I bought it from Ames about 20 years ago ... I think it is the exact same piece sold by every single vendor that sells them. They all specify the same changes necessary for 68. I have seen some places that list it for only 70-72 .... which is probably what they are actually intended for. I find it very disturbing that places are selling this as a piece suitable for 68 cars.

Lower Corner Tabs ...


http://forums.maxperformanceinc.com/...4&d=1574364119

These are the tabs on the extreme lower left and right ... now misaligned. Cut off the existing upper tab.



http://forums.maxperformanceinc.com/...5&d=1574364125

First drill the proper size hole in the patch to use as a placement guide, clamp it to existing lower tap and mark the outline on the back with a marker.



http://forums.maxperformanceinc.com/...6&d=1574364130

Clamp on aligned with the existing hole and trim as necessary.


http://forums.maxperformanceinc.com/...7&d=1574364140

Align the patch, weld onto existing lower tab and to where you cut off the misaligned upper tab.

A couple of pics of the patches painted ... the whole support will be scuffed and painted in the spring.

Next I will find the places where the drilled out spot welds intersect the patch panels on the other (front) side of support and spot/MIG weld them.

Next project will be removing the fan guard lip not needed on 68 applications.


http://forums.maxperformanceinc.com/...8&d=1574364477


http://forums.maxperformanceinc.com/...9&d=1574364482

Not perfect, but luckily these areas would require disassembling the car to ever see them :)

Impressive detailed posts Dataway, THANK YOU, for shining more light on the serious issues with this non fitting reproduction part.

Agree the "70" coresupport was reproduced by one entity, & then sold by all distributors, & retailers. With nearly every lower quantity reproduction sheet metal piece, there is one reproduction & that reproduction is sold by multiple wholesale entitys. Not sure why folks can't understand this. Partial floor pans, 3 piece trunk pans, quite high volume parts like '67, 68, 69 Camaro fenders & decklids, early Mustang sheet metal, YES, there are different manufactuting entities cranking out slightly different stampings of the same intended part.

On a part like the above coresupport, unless Diedindacorn went to the trouble in later production runs to correct the lower stamping & the jig/welding process, then one gets the same messed up half#ss mess. Could go on and on about reproduction sheet metal, have had quite a bit go through my hands, & the vast majority of it had issues.

On the above reproduction coresupport, it was marketed as a '69-70 GTO piece, which many of us realized could be easily modified to work on a '68. I've never read any early marketing press notating that it could be used on a '71 or '72 GTO or V8 LeMans (actually over a half a dozen different distinctive original coresupports over those applications). Many, however, have cannabilized the repro coresupport for the upright to scab into these later coresupports. Having restored quite a few original '70, 71, & 72 Pontiac A-body V8 coresupports, personally prefer to use a correct upright, & contininue by rebuilding/replacing the lower rail & if need be replace the battery area. On occasion, installing a different core support

Send it to me, and I'll let you know how it worked out! :D

OPH, ... really makes a person wonder about vendors that claim to "care about the hobby" that will sell this stuff. I'm ok with a few alterations ... it is what it is, I'm usually happy to get what I can ... but this piece is just no where close ... I could have literally bent up a new lower rail on my sheet metal break for a rusty OEM piece as easily as modify this one. Jeez ... someone should just reproduce the lower rail and let people weld it on an OEM part.

400 4spd .... actually you'll probably be there a lot sooner than I will. If you end up using a repop support, let me know what you think.

Removing the top lip ...


http://forums.maxperformanceinc.com/...0&d=1574454166

This is why the lip has to be removed, the 68 top plate/shroud is different than the following years and won't fit on with the lip in place.



http://forums.maxperformanceinc.com/...1&d=1574454176

Silver line is where I will cut it with a plasma cutter, can be cut numerous other ways of course.



http://forums.maxperformanceinc.com/...2&d=1574454189

These left over lumps can be ground or hammered down with a hammer and dolly.



http://forums.maxperformanceinc.com/...3&d=1574454222

Picture of the removed lip sitting on top of the core support and showing the edge where it was removed. Cut edge was ground smooth.



http://forums.maxperformanceinc.com/...4&d=1574454230

Now the 68 top plate fits as it should on top of the core support.

Removing the clips ...


http://forums.maxperformanceinc.com/...5&d=1574454655

Picture of one of the clips that has to be removed, same thing on the other side of the support. These are just under the top plate, on the front side of the support. They are pretty thick, like 1/8" and are sandwiched between layers of the support. All that can be done is cut off what you can get to, the spot welds that hold it in place are covered up by other sheet metal during the manufacture.



http://forums.maxperformanceinc.com/...6&d=1574454661

I removed what I could get to with a cutoff wheel and ground down what was left.

Will post soon about the upper and lower insulators I got from Ames. Seriously disappointed, not even freakin close. $20 for the insulators and $10 for shipping that could have been sent in a padded envelope instead of a 5x5 box. What a waste of money. What is it with the 68 stuff? Hey .. if it doesn't fit just say so, don't sell us cr*p that doesn't even come close.

Dataway,
Thanks for the write-up. I have one of these older repop supports too. I've modified the upper portion. Now I can copy your modification to get it to sit right.
Bryan