[off2wildblue]

I need to change my subframe mounts and therefore I can either try to take each one off individually or take the whole subframe off and do it that way.

I haven't done this before so I need a recommendation. I also will need to change the rear springs. I am not sure that matters.

One other thing is that I have access to a lift but when I lift it it sits on the sub frame and I am not sure how to handle it. I thought about lowering the car onto something and work from there.

Any ideas are appreciated. I have been just staring at this thing for a week trying to figure out the easiest and safest way to do it.

Thanks,

SAM

[ericnova72]

Is the car bare from the firewall forward, no sheetmetal, or just no engine, or a complete car??

I have changed them before on a complete car doing one side at a time, raising the body off the subframe doing the rear subframe mount and the cowl area mount at the same time and reassemble, then do the other side the same way, then do the two at the core support. That way you don't lose the subframe to body alignment and have to mess with re-squaring that back uo to the body.

[off2wildblue]

There is no sheet metal, transmission or engine. just the brake and fuel lines that I will be replacing. What do you support the car on when you did your swap? Where did you jack it up or place stands on it?

Thanks for the reply,

SAM

[ericnova72]

It was a complete car, I left the car sitting on all four tires, and used a jack and a 2' section of wood 2x6 up against the floor pan/rocker panel to lift the body enough to slip the old bushings out and the new solid aluminum race bushings in. Did one side at a time, only took an hour or so. I also had solid wood 6x6's placed in a spot out of the way of the work zone so that if the jack slipped or failed things wouldn't go bad an crush me, you could use jack stands if you can find a safe place to set them. Just remember that if you use stands to use some sort of load spreader on top of them so they don't damage the floors.

[alittle1]

When doing the rear springs, check the front pockets for rusting where they mount to the sheet metal. If this are is soft, then you will have to make supports for the spring pockets to sit on.

As discussed above, best to do one side at a time. Raise body up to desired working height, block body of car at that height by using mobile home blocking (log cabin stacking of 2 x 4's) under floor pans. Place floor jacks under suspension and bottle jacks under unibody frame, unbolt body bolts, using gravity, lower jacks and weight of suspension will allow separation from body. Use a pry bar and a stiff putty knife to unstick 40 year old rubber mounts from sheet metal and frame supports. Put new rubbers in and raise jacks as required.

It takes more than an hour to do, so don't rush the job.

[ericnova72]

Originally Posted by alittle1

When doing the rear springs, check the front pockets for rusting where they mount to the sheet metal. If this are is soft, then you will have to make supports for the spring pockets to sit on.

As discussed above, best to do one side at a time. Raise body up to desired working height, block body of car at that height by using mobile home blocking (log cabin stacking of 2 x 4's) under floor pans. Place floor jacks under suspension and bottle jacks under unibody frame, unbolt body bolts, using gravity, lower jacks and weight of suspension will allow separation from body. Use a pry bar and a stiff putty knife to unstick 40 year old rubber mounts from sheet metal and frame supports. Put new rubbers in and raise jacks as required.

It takes more than an hour to do, so don't rush the job.

I had the advantage of having a California car here in Michigan, bolts and bushings came right out with no problems, so yes it only took about an hour to replace the four mounts under the main body with solid aluminum race replacements. If you have rust to deal with it could be an all day job, if bolts break or sieze, or the cage nut in the body spins loose. Then it would be a real pain.

[off2wildblue]

I have my car on a lift right now. I have already checked the bolts and they are all loosened and ready to be backed out. I was just afraid to pull it out with the car in the air for fear the front would drop and I couldn't get the new mount in. I am going to try to lower it onto some jack stands and see how that goes.

As far as the rear springs go. The car was missing 3 or so bolts holding them on. I still need to look at how that will get done. I am not quite sure how to tackle that job either. I just want to get the bottom done so I can move on to the fun stuff.

SAM

[alittle1]

Sam,

Are you lifting the body or the suspension and the body?

Lift the body only, and through the use of jacks and gravity lower the sub frame and suspension down just enough to remove and replace the mounts. Use chains to support the suspension in case of a slip and bolt the chains to your lift. Take your time, this is a two man job if you haven't done it before.

[off2wildblue]

I have one side of my sub frame off and lowered. I have a quick question about the front mount. Does anyone know how large a hole that should be?

I know from looking in a catalog the hole is larger than the rear one but I am not sure how large it should be. I would like to cut a new one out of metal and make a backing plate but I don't know the dimensions.

This should be the same size as a 67-69 Camaro and Firebird.


Thanks,

SAM

[alittle1]

Sam,

If you have the new rubbers to put in there, just measure the O.D. of the bushing part.

[ericnova72]

Yikes, that is pretty rusted away. You'll need to weld a patch in that mount. As Alittle 1 says, it should be about the size of the neck of the bushing, to maybe 1/16" bigger.

[off2wildblue]

Yea, I do but I didn't know if it should be a certain size in order to allow adjustments of the subframe to the chasis.

SAM

[alittle1]

You need to find a frame manual for your car. In it you will find the exact location for the center of the mounting hole that you want to repair. You can try asking at your local frame shop and see if they could give you a couple of key measurements.

To repair that mount and hole, find an used hole saw of roughly the same diameter as your rust-out area, cut down the height of it to fit yours and weld it in place. There is still good metal in using the hole saw plus the thru hole is located in the exact center in relation to the outside. Don't forget to clean the crud before you weld it in.


Check out this link: http://www.artmorrison.com/imagelib/...ont%20Clip.pdf

or this one: http://www.pozziracing.com/Media/F_gen_Firebird_sub.jpg