C3 LS4 Upper control arm removal

[Tom K.]

I removed the radiator from my 73 coupe (454, A-C, PS, PB, automatic) to have it re-cored. This all started innocently enough with a search in the NCRS forums for advice on how to remove the radiator. I saw advice that suggested removing the upper control arm pivot would give the clearance necessary to remove the shroud. That did not work out so well. Perhaps the advice was meant for a car equipped with a 350 rather than a 454. Anyway, while trying to convince my fan shroud to come out, I broke it. So I have a used one on the way - not a big deal.
However, while I was trying to figure out how to remove the upper control arm pivot. I discovered that the studs are too long to allow the pivot to come off. The passenger side pivot hits the cylinder head (fuel pump too) on the rearward end and the fan shroud on the forward end. I tried hammering out the studs and could not get them to budge. I got an inspection mirror down there and discovered the UCA studs on my car are really hex bolts that have been welded in place. I dont know if this is someones idea of a repair or what happened.
While I was planning this whole thing, I figured I would buy a new bushing kit 'while I in there' and take care of them at the same time as the radiator. So here is my question. What should I do regarding the UCA mounting studs - should I try replacing them with shorter ones, and how should I go about re-installing my re-cored radiator? It looks to me like I have to remove the core support to do this without damaging the new radiator, but Im hoping there is another way.
Any advice is greatly appreciated.

[Tom L.]

Re: C3 LS4 Upper control arm removal

I have removed the shroud and radiator successfully (on my brother in law's '69 BB, no a/c). To do it we had to remover the upper arm, the only way was knocking out the arm studs in the mount to swing it out of the way. That went well.

On the other hand, I'm in the middle of swapping the shroud on my '72 BB w/ a/c and it's not going as well as I remembered doing the '69. Not sure why. Not planning on removing the radiator but have been able to get the shroud in and out. BTW, the shroud is a 119, not sure what's in your '73. Good luck!!

[Joe L.]

Re: C3 LS4 Upper control arm removal

I removed the radiator from my 73 coupe (454, A-C, PS, PB, automatic) to have it re-cored. This all started innocently enough with a search in the NCRS forums for advice on how to remove the radiator. I saw advice that suggested removing the upper control arm pivot would give the clearance necessary to remove the shroud. That did not work out so well. Perhaps the advice was meant for a car equipped with a 350 rather than a 454. Anyway, while trying to convince my fan shroud to come out, I broke it. So I have a used one on the way - not a big deal.
However, while I was trying to figure out how to remove the upper control arm pivot. I discovered that the studs are too long to allow the pivot to come off. The passenger side pivot hits the cylinder head (fuel pump too) on the rearward end and the fan shroud on the forward end. I tried hammering out the studs and could not get them to budge. I got an inspection mirror down there and discovered the UCA studs on my car are really hex bolts that have been welded in place. I dont know if this is someones idea of a repair or what happened.
While I was planning this whole thing, I figured I would buy a new bushing kit 'while I in there' and take care of them at the same time as the radiator. So here is my question. What should I do regarding the UCA mounting studs - should I try replacing them with shorter ones, and how should I go about re-installing my re-cored radiator? It looks to me like I have to remove the core support to do this without damaging the new radiator, but Im hoping there is another way.
Any advice is greatly appreciated.

Tom------


The upper control arm bolts were not originally welded in place. The bolts are hex head but they have a splined shank. The splined shank causes the bolts to be a tight fit in the bracket and prevents rotation when the self locking nuts are turned down. I suppose what happened here was the holes in the bracket were worn/enlarged so someone just welded them in place to prevent rotation.

[Joe L.]

Re: C3 LS4 Upper control arm removal

I have removed the shroud and radiator successfully (on my brother in law's '69 BB, no a/c). To do it we had to remover the upper arm, the only way was knocking out the arm studs in the mount to swing it out of the way. That went well.

On the other hand, I'm in the middle of swapping the shroud on my '72 BB w/ a/c and it's not going as well as I remembered doing the '69. Not sure why. Not planning on removing the radiator but have been able to get the shroud in and out. BTW, the shroud is a 119, not sure what's in your '73. Good luck!!

Tom-----


1973 uses a different shroud than 69-72. The 1973 shroud for all Corvette applications was GM #339175.

[Russ S.]

Re: C3 LS4 Upper control arm removal

Radiator support , radiator, and fan shroud should be taken out as one unit.

[Tom K.]

Re: C3 LS4 Upper control arm removal

Thanks Tom - I will keep on working at it!

[Tom K.]

Re: C3 LS4 Upper control arm removal

Thanks Russ I think I may be headed that direction, but it doesnt look like much fub

[Tom K.]

Re: C3 LS4 Upper control arm removal

Thank you Joe - I will check it out - I appreciate the advice

[Dominic B.]

Re: C3 LS4 Upper control arm removal

Tom,

Consider taking the core support bolts out on both sides and slightly moving the support forward enough to allow sufficient clearance to remove the shroud and radiator assembly. It's not as difficult as it sounds, especially if it is a no hit car. Make sure that you mark the bolts before taking them loose to insure proper position of the support on reassembly.

[Tom K.]

Re: C3 LS4 Upper control arm removal



Thanks Dominic,
Here is where I am now. I broke the fan shroud during my attempt at removal, so I just pulled it out and the radiator after that. The radiator will get to the re-core guy in a day or two. Im thinking that I will do just what you suggest and move the core support as far forward as I can to gain some clearance for re-installation. Im looking at a 'GM Reproduction Part' for the fan shroud. I figure that should fit as well as a used one. I am also thinking I should just pull the core support out and repaint it to stop the rust. Maybe Im just asking for more trouble, this car has fought me every step of the way...

[Patrick H.]

Re: C3 LS4 Upper control arm removal

I am also thinking I should just pull the core support out and repaint it to stop the rust. Maybe Im just asking for more trouble, this car has fought me every step of the way...

I would highly suspect that the support is rusted a LOT more than you think. It is uncommon to find one that didn't need repair or replacement, especially once the car is this far apart.

I pulled out a radiator in a 77 last week, and that took some very gentle massage of the fan shroud to get it out. No way it's going back in without a lot of care and careful maneuvering.

[Russ S.]

Re: C3 LS4 Upper control arm removal

Your repo core support will most likely have one metal insert on each side near the top for a bolt to go thru to mount the top brackets to that don't belong there on a 73 LS4. They were used on later cars

[Joe L.]

Re: C3 LS4 Upper control arm removal

I would highly suspect that the support is rusted a LOT more than you think. It is uncommon to find one that didn't need repair or replacement, especially once the car is this far apart.

I pulled out a radiator in a 77 last week, and that took some very gentle massage of the fan shroud to get it out. No way it's going back in without a lot of care and careful maneuvering.

Patrick------

Yup. Core supports can suffer corrosion damage even here in California. For cars that lived in the rust belt, look out!!

[Tom K.]

Re: C3 LS4 Upper control arm removal

Hi Patrick,

I got the thing apart the rest of the way and I was pleasantly surprised that the rust was not real bad. I expected to have to at least weld in a panel and finish the thing for a repair, but it is pretty solid and should clean up just fine. A wire wheel and maybe the sandblaster in some areas and I will just paint it up. Also wondering of there is a smart-guy way to remove those plastic fasteners that hold on the foam seals without breaking the fasteners? Thanks again everyone for the advice!

[Tom K.]

Re: C3 LS4 Upper control arm removal

Hello all,

Here are the latest pix - things are going pretty good - I havent broken anything else!