Scrap coil over struts

[pkrankow]

I replaced all four struts and springs on my 2001 Cavalier. It has 210,000 miles on it. I suspect these are original, but don't know for sure. It is recommended that struts are replaced ever 60,000 miles, as the gas charge leaks out. As long as the oil is in the strut they still function, but not as well. It is also recommended that the springs are changed at the same time as the strut. There are many shops that WILL NOT remove the spring and install it on another strut because spring sag causes alignment problems.

This means that because the minimum material is used to make suspension parts there are a large number of them available as scrap from auto repair shops. Since the shop will not take them apart, you must safely take them apart. This is one method.


this is the front struts, one before and one after. Notice that the spring is about 4 inches longer once released. There is a lot of energy that is contained in this system.



This is a rear strut locked in my postvise. Note I grabbed the spring and spring plate. This makes all the steps easier since the spring does not flop around.



this is just to show the amount of compression in the rear spring. Again the pre-load is about 4 inches. This means that you need to stay to the side and keep your hands clear of the end of the system at all times, just in case of a tool failure.



The inexpensive compression tool is taken tight using an impact (or other wrench) As much of the spring as practical is captured in this operation since the ends of the spring need to relax and let go of the hardware. you will notice that my marks are not lined up. This was marked for the picture. As soon as you have some freedom of movement you can take the nut off the end.



you take the center nut off using an impact (this way is easy compared to clamping the the shaft and using a wrench) then let the compression tool off evenly, so the spring stays generally straight.

Now you have the coil spring, good high carbon metal suitable for many things, but there is more metal to the strut. The the rod is good high carbon steel, the shell is 2 layers of thin wall tube. The problem is the strut is full of oil (I have collected 2 quarts of oil from 4 struts today) so care must be taken. They are also assembled in a very tight manner, so the process is not necessarily easy.

For the rear struts pushing the rod all the way in, which took no effort since the gas is gone, opens the seal allowing the oil to drain out. The front was not so easy.

I made a small mess of one front strut, so this is probably what not to do.

I drove the rod into the strut, and noted that it bulged the top out, and started leaking. I drained the oil into a container, then drove it till it flowered, then cut the pedals off.


Which left me with this


and this. Notice the mushroomed and broken end. Those chips came off fast, and I haven't found them, I am glad they did not hit me.

With the other three struts, after the oil has drained out and I will cut them about 1/2 inch from the end instead of brute forcing them apart. I have not yet done this, as they are sitting propped up draining, but can post pictures when I do. I will probably use a hand hacksaw since the shell is very soft, probably mild steel.

If the strut still has pressure (you cannot push it in by hand) it needs to have the pressure let off before you can do anything else to it. All four of these struts had already lost their pressure.

While I purchased an import tool for not much money, you may be able to borrow a tool from a parts store with a loaner program. There are much better tools than I am using. I have seen a jig for a hydraulic press used before. (My Dad USED to switch the springs over at the shop he worked at, but they went to not switching the spring, and only installing a complete assembly, a few years before he retired.)

Phil

[Bentiron1946]

That looks like about the right sized rod for making repousse/chasing tools, I guess that I'll need to see if my mechanic will give me a couple of them for the springs. Thanks for the idea! :blink:

[pkrankow]

I spark tested the one rod, compared to the spring, and compared to a piece of 4140.

The color of all 3 was very similar and rather orange. The rod had more exploding ends than the spring, and the spring was similar to the 4140, even though it is supposed to be 5160.

I need to put a library of known samples together, I am not very good at spark testing.

Phil

[John B]

Take care forging the centre rods, as they may be chromium plated.

With all the toxic implications of plating and forging be careful

[pkrankow]

So, how do I identify if the rod is chrome plated? It did have a flange spot welded to the rod inside the assembly.

Phil

[John B]

So, how do I identify if the rod is chrome plated? It did have a flange spot welded to the rod inside the assembly.

Phil

Spot welded by a robot in a factory I would think,

You could try pickling the end and see what is revealed

[pkrankow]

OK, into the vinegar it goes for an hour or so.

Phil

[Francis Trez Cole]

the springs are the best material the rods are medium carbon at best we tested a bunch at the last Faba meeting.

[pkrankow]

The machine threaded area turned black, the seal surface is still rather pretty after a couple hours in vinegar. Hard chrome is a safe bet.

I will stockpile these rods for turning on the lathe or for something...not forged.

Phil