Here's what the compressor clamp has to attach to. It occurred to me that this is a "critical component". If the clamp fails, then the spring unloads, and the spring compressor becomes a high velocity projectile. Probably terminal!
Front Suspension Leaf Spring Compressor and Removal
A while ago, I rebuilt my GT's front suspension. There are several excellent threads on the topic, but I thought I would build a thread showing what I did to fabricate and use a front suspension leaf spring compressor.
So, to start, you don't HAVE to use a compressor tool to disassemble the front suspension on a GT. If you have the suspension still mounted on the car, you can "compress" the front leaf by placing jacks under each A-arm at the ends of the transverse leaf (the "spring eyes"; this might not work if you don't have the engine still in the car; the weight may not be enough). Then you remove the "spring eye bolts" and lower the ends of the leaf (make sure that the car body is still supported!). Then the rest of the front suspension clip can either be disassembled, piece by piece, while it is still on the car, or you could then remove it as an assembly and disassemble it on a bench. But you have to install it back in the car to reverse the process, and I have heard that it can be tricky to get the spring-eye bolts back into place using this method.
Since I wanted to do a complete rebuild, including sand blasting the components and re-painting them, I decided to build a proper GT Leaf Spring Compressor. The FSM (Factory Service Manual) provides a portion of a photo that shows the proper factory tool. That, and a photo posted by Stanley P. provided the template that I used to build mine.
First, I needed a device to clamp onto the leaf spring. Here's what the FSM show:
So, to start, you don't HAVE to use a compressor tool to disassemble the front suspension on a GT. If you have the suspension still mounted on the car, you can "compress" the front leaf by placing jacks under each A-arm at the ends of the transverse leaf (the "spring eyes"; this might not work if you don't have the engine still in the car; the weight may not be enough). Then you remove the "spring eye bolts" and lower the ends of the leaf (make sure that the car body is still supported!). Then the rest of the front suspension clip can either be disassembled, piece by piece, while it is still on the car, or you could then remove it as an assembly and disassemble it on a bench. But you have to install it back in the car to reverse the process, and I have heard that it can be tricky to get the spring-eye bolts back into place using this method.
Since I wanted to do a complete rebuild, including sand blasting the components and re-painting them, I decided to build a proper GT Leaf Spring Compressor. The FSM (Factory Service Manual) provides a portion of a photo that shows the proper factory tool. That, and a photo posted by Stanley P. provided the template that I used to build mine.
First, I needed a device to clamp onto the leaf spring. Here's what the FSM show:
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I first thought about building a clamp, similar to what was shown in the FSM. But I found the local Princess Auto (a really terrific automotive and farm, new and surplus, store, http://www.princessauto.com ) had a Pitman Arm Puller. I only had to slightly grind the arms to fit under the leaf spring clip
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Here it is installed, waiting on the rest of the Leaf Spring Compressor tool. I removed the centre bolt, to allow the new Redi-Rod threaded rod to be installed, along with the beam. I especially like this design with the cross bolts that hold the puller tightly together. The idea of pulling the front leaf into compression (lets see, that would be, oh, about 1000 lbs of load) and then having the puller slip out from leaf clip scares the crap out of me!
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Next, I fabricated a "beam", that would push against the spring eyes, and used a 5/8 inch threaded rod (Redi-Rod) to apply the required compression. It is just a piece of 2 inch square hollow tubing. The main beam is 43 inches long, dictated by the fact that it had to sit on the spring eyes, but fit within the disc brake backing plates. Since the Pitman Arm puller is somewhat taller than the FSM clamp, I also needed to weld another section of the square tubing to each end of the beam, to create sufficient space for the puller. On my first attempt, I only attached a piece at each end, 4 inches in length. But as I de-compressed the leaf, the width between the spring eyes got MUCH smaller, and the spacers threatened to drop off the spring eyes. So I welded another piece on the inside at each end. The minimum inside dimension is 30 inches, but it could have been less. Here's the beam:
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Here is what the tool looks like installed and just starting to compress the leaf. The Redi-Rod has a nut under the puller, and another on top of the beam. When I used it, I had a large washer under the beam nut, but I forgot to install it for the photo. I just tightened up the beam nut, compressed the leaf a bit, and pulled out the spring eye bolts. OK, I had to fight a bit to get the spring eye bolts out, but I found that turning them released the corrosion. Then I used a brass drift to drive them out
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Here is a photo of the puller and Redi-Rod. Since I had the suspension clip upside down on a bench, I didn't care how long the Redi-Rod was. But if you are using a similar tool under the car, you need to cut the rod down. But don't make it TOO short; the leaf de-compresses about 12 to 14 inches.
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Here's a view of the beam at the spring eye end
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You see the big long thread on the spring compression fixture? Well put the spring into the cross member attaching it with a new or good rubber bit in the center. Then, with the fixture cliched on and the nut on the thread waaaay out at the end (and lube on the thread and the pads the spring eyes go on) wind, wind, wind, till the spring flattens enough to fit into position.
Note that the ends of the spring are fitted through the lower wish-bones
before compression, under the inner pivot bar which is stepped to accomidate them. Then, simply
fit the bolts through the eyes and the outer end of the wish-bone!
Note that the ends of the spring are fitted through the lower wish-bones
before compression, under the inner pivot bar which is stepped to accomidate them. Then, simply
fit the bolts through the eyes and the outer end of the wish-bone!
Short of building your own compressor, where would you find the GM J-21689 Leaf Spring Compressor even if you wanted to purchase one?
Before you "Cobble" something together, and possibly get yourself hurt, may I suggest you do what I did. Check out your local yellow pages for a mobile welder. Go to a metal supply and pick up enough 2 X 2 square tubing to cut the three pieces Keith has pictures of, with the dimensions and have the Mobile welder put it together for you. A hole in the center if easy enough to do with a drill and a rat tail file, get some good hardware and your set, once you get the appropriate puller. The reason for this response is, I got a used lower control arm out of a wrecking yard, the mech there almost cut himself in half when the spring sprung. I yelled at him prior to the spring coming out and probably saved him. He was shocked that the spring came out so far and FAST. This is NOT a coil spring that drops a couple of inches.
Ron
Ron
Ooh. Cross bow. Graphic analogy. It isn't the power of the bow, as much as the travel. Arrow (or tension bolt) through the body...GTJIM said:Yes, once some tension is up on the front spring by the device the whole thing turns into a great big, very powerful, cross bow!
It is imperative that everything is strong enough and the threaded rod anchored immovably to the center of the spring.
If it lets go then then ...........
What surprised me when I disassembled my front suspension wasn't the "force" (as in the load) stored in the front leaf. It was the "displacement". I was worried at first that the 2 inch square tubing wouldn't be strong enough. But I saw NO deflection in at at all (although I did have to put a pretty big washer under the tension nut). But the sheer magnitude of the leaf expansion surprised the hell out of me, and how much it narrowed as it expanded. I was glad I hadn't cut down the tension bolt.
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