The Brute power of a 85 300D Coil Spring...two thoughts..
 

My first thought on the 85 300D front Coil Springs is that their limit stop when the car is jacked up from the front is the shock absorbers. The shock absorbers are secured to the control arms by two 6 mm light steel bolts on either side with tiny threads. What is scary is that these immensely powerful springs are prevented from exploding by the shear force of these tiny threads on these four 6mm bolts which screw into the control arms which doesnt make me feel great.

Yesterday, I was using a really heavy duty spring compressor to compress these Col Springs, the same set I had used safely some 15 years with no problem. When I was younger I would grab a 27 mm wrench and turn the bolt on each side by hand one rev at a time. I didnt have air tools and this was actually safer, albeit tiring.
This time I was 46, not 31 and I was beat and I donned a face shield, got out an impact Wrench to shoot each side at the time. I held the gun too long on one spring compressor side and D!!!; the other spring compressor shifted out of place and slid 140 degrees around the coils until it was almost hitting the other spring compressor. It was almost slack! The huge spring coiled into a "C", all held by one spring compressor.
Being brave is sometimes stupid. I realized the situation instantly. This spring had the force to kill someone on impact. I literally had two choices: to dispose of it or fix the situation. Part of me thought it wiser to just dispose of it. I had my tires off so I covered the spring with them. then I closed the garage door.
I couldnt even think of a way to get rid of this thing. You couldnt exactly leave it in the trash, that would be incredibly irresponsible.In a way it was like a bomb.
Finally I decided to cover the spring with two tires and I surrounded the outside with garden hose and heavy tool boxes and a bag of sand.I could see through the aluminum rims in places and I shot off the bolt on the remaining spring compressor with my impact gun.
When the spring released, I could really feel the two tires quiver! Those springs are powerful! I stood there looking at it. The spring suddenly seemed very tall, almost 2x taller then when its in the car. Who knows, maybe the shock of its exploding made it even taller! At that moment it seemed as tall as the Empire State building and the coils looked as thick as heavy steel pipe.
The next thing I did was maybe wise or maybe stupider. If I waited until today to do the installation I know I would lose my nerves. The spring was back in the car some 20 minutes later.

Boy am I going to catch H____ from everyone.

Thanks for sharing.

An "incident" without an "accident" and the injuries or property damage is the perfect ending to this. We can all learn, with no real "cost".

This will allow all to learn and possibly come up with additional "solutions".

I hate spring compressors - make me very nervous.

ANOTHER lesson learned,
 

If you are EVER using a lift with worn out, rounded(where should be square ones), rubber lift feet- REPLACE THEM, I'm about to get a pair of doors and rocker panels because of this.

The odd thing???
Between a tank mechanic, helicopter crew chief and a real live engineer, we tried (VERY briefly) to hold up the side of a 300D.

On to another lesson???

Get any military mech. who ever saw a split ring on a "duce and a half" (2 1/2 ton truck) wheel not properly seated when the new/patched tire is reinflated.
GOOD idea - being able to change a tire in the field NO bead breaker - just a big hammer and crowbar - BUT the very second you neglect its power it will be and has been deadly.

yea ... some things hurt when they break... ive had a car dropped on my foot.. an 89 MR2 thank god i had my toes curled at the moment since my foot itched..

Whoo yeah.
 

I have always changed out springs with the car on a lift and a floor jack supporting the A-arms. spring compressors Scare the P#*$ out of me.
Glad you got it back together.
My retired airforce mechanic father, has told me numerous stories about the explosive force of a simple seeming tire. several times he has mentioned that 60 and 80 ton jacks are insufficient to lift some aircraft off the ground for maintenance, so they have a 5psi "air bag" that they lift with... tires have over 30 psi!@!! boom.
John

You should have just put the whole assembly in the trash like you thought originally. Imagine the look on the trash man's face when he says, "Whats that?" and gives it a little poke!

Seriously though, glad you got it taken care of. I'm glad my springs are in good shape...

peace,
sam

WOW.....this should be a lesson to everyone.

#1 use the right tools. That's why Mercedes makes a tool for those springs. Even a clone would be better than the ones that hook on the outside.
Snap-on makes a compressor that grabs from the inside and the hooks can't swing around like that. But even that is a risk.
Also it should be pointed out that if you used the correct tool it would have been so much easier and would not have tired you out so.

You really have no excuse there are compressors for rent here and I have offered mine for free just pay shipping.

#2 NEVER use air tools on a spring compressor!
My God man....what were you thinking?

You were very lucky you didn't kill yourself or someone else. You want to leave your kids fatherless? Your wife a widow?

Get the right tools.

Danny

I know I feel bad
 

I thank the L.. for all the times he's watched over me in life...but in all honesty Coil Springs are a different animal than McPherson strut springs---McPherson springs are much safer to work on and not as powerful and you are protected most times by the top half off the strut assembly when you compress and uncompress them

Well now that I read you the riot act, I'm glad your OK. :)

Yes, you are going to catch H___!
 

We enjoy hearing about the details and thoughts you share! And you have been a help to many of us.

We don't want to read "in memory of" or find out that you have to sell due to a disabling accident and you can no longer work on your Benzes! Enough said?:mad:

Some of the key words you mentioned "I was beat". Even with the proper compressor, I had to stop and focus when I found, while tightening, that the bottom plate had rotated out of the detents and the spring popped free. Fortunately, it was only 1/2".

Ditto: I am glad to hear you are OK. A guardian angel of yours must be awful strong!:D

Thats a tough way to learn a lesson but at least you are okay. There are a couple of points to make here:
1) MB coil springs are no more powerful than any other coil spring. They can be more dangerous because they are placed farther inboard on the lower control arm than most springs and so require more "preload" to achieve their designed ride height. This preload is why there is still plenty of stored energy just waiting to be released even if the suspension is in full extention.

2) If you insist on using outside type spring compressors on this type of spring then the safest way to control the spring is to pass a chain or cable through the spring to keep in from going too far if the compressor slips. I have had close calls with macpherson setups as well. Some of them have to be compressed very far to remove the strut. Its like a bomb once free of the limiting of the strut. A cable or chain makes it a lot safer.

3) Use the correct tool! There is one for rent right near you in NY. No reason to risk injury when rental is cheap.

Glad you are okay. RT

I was rebuilding the front suspension on a '76 Oldsmobile in 1988. The spring compressor was not of the best quality, it let go. Everything happened in a split second.........
The spring hit the frame of the car
The spring bounced off the frame of the car and hit my left hand
The spring hit the concrete floor
The spring lay on the concrete floor and I laid on a X-Ray table hoping my hand was still there.
Thanks to one of the best sports medicine doctors at UVA, I was able to re-gain use of my hand after several months.
Use the right tool. Rent the right tool. And throw the **** from Harbor Freight away.