What, exactly, necessitates the use of an MB spring compressor?
 

Was talking with a friend today and mentioned that I can't use a typical parts-store spring compressor when doing the coils in my 240D. He asked me why, and I realized that I don't actually know. Why do we need the MB compressor? What's wrong with the parts-store variety tool?

the mb compressor comes up through the hole in the control arms in the rear and down through the body in the front, is far more secure, far easier, and far safer in how its designed to work from inside the spring.

though I will add its nice to have a parts store compressor to grab the outside of the front springs to straighten them slightly because of the curve which can make things difficult

Several Members including myself have tried the outside Spring Compressors (mine were from harbor freight) and had the slip and bend the threaded rods n the compressor. Fourtunatly no one on this forum has been injured.

The reason the typical spring compressor cannot be use is that the Front Springs must be something like 4 times as strong as the Springs on even a large US Cae.

Lots of threads where Members have use the copies of the Klann Spring Compressor which runs around $80-$90.

On the Rears you don't need a Spring Compressor depending on what you are doing. But, before I knew that I removed and installed another Rear Control Arm and I used the Harbor Frieight Spring Compressor for that although I had some issues with having enough room to use them.

In My case since I mangled up the Harbor Freight Spring Compressor set I had I made a Spring Compressor that operates in the same manner as the Klann does and anther Member previous to me also made one.

And, someone made one using an extra set of lower Spring seats and ACME threaded Rod.

Later I also made what looks like the typical Strut type outside Spring Compress with on hook on eac end but I made it with 1 inch threade Rod. I tested it twice and it works OK.
I made that because I wanted a tool that could possibly be used on something else besides a Mercedes.

There should be more then several threads on the subject and what people have used. Just search with the word Klann.

Essentially the problem is space. There's not enough of it to safely attach the external spring compressor on the front springs of a W123. Not only are these buggers monster bollock eating death demons but they are rather long too. The "standard" smaller sized external spring compressors are just not up to the job. Far too wimpy.

The MB springs are rather long when uncompressed, and need to be compressed a lot in order to come out (which loads them tremendously), so regular compressors are a) not strong enough, and/or b) don't have enough range.

The first time you compress one of those front springs, you will immediately appreciate (and fear) the amount of energy stored by that compressor.

Those auto parts loaner ones are for Hondas and ΚΙΛ

It can be worth your life to not take every effort to make it as safe as possible when removing the front springs. Offhand I can not think of a more dangerous job on these cars unless done with the proper type spring compressor.

Fyi that compressor you borrowed is a clone and just a hair too big for the bores on the front springs. You will have to enlarge the holes with a dremel

Exterior ones won't fit in the space you have to work with and usually you can't get them high enough on the spring to compress the spring enough to get it out safely.

It's been pulled off a few times with parts store ones. But as stated once you do the job with the proper tool, it will make sense and you'll quickly go buy one for your own garage if you plan on buying more benzes.

Forget what your friend said, or thinks. Maybe he doesn`t.

As mentioned use the proper tool to remove the MB front Springs.
There are probably 100 plus threads on the subject. Here are a few I located.
All from Peachparts.

https://www.google.com/search?q=site+peachparts,+spring+compressor&biw=1093&bih=521&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjJ hcqfj6XMAhWhDpoKHYvlD1oQ_AUIBygC


The Spring Compressors you see on E-bay are a copy of the Klann German compressor.
They work ok for the DIY guy. I think Roy (WHUNTER) said they are good for 50 or so uses.

On the W123 you need to slightly open up the hole to get the rod down through the center of the spring.
On the W126, the hole is large enough w/o making it larger.

As mentioned, on the rear springs you do not need to use a compressor.

The front springs have a lot of OOMPH, and when one comes loose from a cheepie compressor,
it will fly out from the wheel well along with your head through the shop wall. :eek:

Hey Joseppie, where ya been when the Compressor threads were floating around. :confused: :)

Iam in the process now taking the 80 240D front end apart to replace everything. I will be using my MB compressor, if it hangs together pulling the springs
I`ll be back. other wise, :eek: nice knowing you on the Forum.

PP order should be here sometime today. Yeah. :D


Charlie

As an added bit of advice, do NOT use an impact gun to compress the spring. Yeah it works but it is easy to over compress the spring. While this has no effect on the spring itself it is very harmful to the plates and locking lugs on the compressor.

I've seen 4 or 5 sets of spring compressors destroyed or damaged in this manner. Every time I use one I go back and examine them. They'll "scuff" and create a burr where the lugs seat after 3 or 4 uses. IF you stay on top of the wear it's an easy clean-up, usually entailing the use of a Dremel tool and a bit of sand paper.

Hand tools only. A 1/2" ratchet is plenty enough tool to do the job. This serves multiple purposes.

A: You don't over-tighten the compressor
B: You reduce the chance of ruining the plates/screw assembly
C: You develop a healthy respect for the force needed to contain the spring along with quenching the desire to "rush" the job.

There's something to be said about how much the "pucker factor" increases the first time you hear the spring creak as the plates seat solidly.:eek:

MIKE D, thanks for mentioning not to use an impact gun.
I was thinking about it but forgot to type it in.

Loaning out a Spring Compressor if you have one, ya never know it they used an impact gun or not.

Always make double sure that the 3 fingers or nubs are locked into the detents of the lower plate real well
before tightening down on the rod.
Sometimes they can be a bugger to lock in if there is a curve to the spring.

First time I used one was at PNP to remove a set from a 240D. The way the cars are set on the wheel stands,
the suspension hangs down and the springs have a curve. A jack would help but are not allowed in the yards. I got the damed thing stuck
and thought for sure I lost it. Closing time was close :eek:.
Forget now what I did, but did finally get the two springs out.

I think you need to have the plate set to compress at least 8 coils of the spring. Or it is difficult to lift the spring out.
I`ll have my mind refreshed here soon with the 240 project.


Charlie

Charlie don't take any safety chances if you need help let me know, I'm in Carson and have the time. Safety is the most important thing. Plus if you're gone who will post sarcastic replies? (Just kidding there are plenty others).

The older benz springs are still under tension even with hanging suspension, meaning they are about 1/3rd more length of what you see when your car is road ready level.

And comparitivley, if you look at the Mercedes springs and other regular cars they look like to be from a railway car or a Kodiak truck, Don't take this risk. They are immensely powerful units, use the correct tool to handle them.

Thanks Steve. I won`t be working on it tomorrow but be back on it Monday
If you want to come buy let me know so I can get my dusting done. LOL :D

I worked a couple hours today. yesterday I pulled out the Upper Control arm.
Today when I removed the lower BJ nut, the steering knuckle just dropped off w/o having to use the BJ separator.
That was nice. :)
Used the HF Tie Rod Seperator and they popped right off with a BANG.

Used a die grinder and a rasp to grind out the hole to get the Spring Compressor in.
High Carbon Steel Rotary Rasp Set 10 Pc

put in the two plates, then turned the lower on down and the upper one up as far as it would go.
Dropped in the shaft, and made sure the three nubs locked into the three detents on the plate.
Placed a screwdriver under the lower plate to hold the rod in place while turning the rod to snug it till is was securely locked in.
Then from top side turned the nut with a 19mm deep socket and 3/8 Ratchet.
Tightened her up. lowered the Floor Jack, and a little wiggling, she came free.
Laid her on the floor and released the tension.

OH forgot, you need to remove the Shock

One thing I need to mention.
With the Upper Control Arm removed. The Shock will hold the Lower arm from dropping to keep the Spring from flying out.
Though I do not trust the Shock to hold things.

I had a 3 ton Floor Jack under the lower arm to hold it.
Install Compressor, secure it.
Then remove the Shock. and lower the Jack.


Charlie

I think the reason with MB springs is two fold...

One, the springs are small diameter springs, and as such, they need to compress a LOT to hold the car... Also, the coils are very close together, not much room for external teeth to grab.

Two, the springs sit inside a deep pocket up top, so the coils nearly have to touch to clear the pocket.

On most American cars with coil springs, the lower control arm can lower enough to clear the spring without compressing at all, unless it's a McPherson Strut, and they don't have much pressure on them, because the strut has a lot of pressure... So the coil is very weak.

Mb has the spring deal with the entire weight of the vehicle, and the travel rate fully loaded.

It helps to mark the shaft where the nubs are to help with aligning in the bottom plate. I marked mine after realizing that I wasn't locked into the bottom plate. Fortunately there wasn't a great load either.

Also greasing the shaft helps the tightening process very much. It doesn't take a lot of grease but I grease for every job which has been defined as 2 springs each on 2 SDs.

"Toolmarks"....
 

We might not want to overlook the possibility of improper tools causing a mark on the spring.
I once worked at a manufacturer who had to make certain that there were no toolmarks in the structure that could lead to possible future structural damage by being a location where stress in the structure could lead to fatigue cracking. In our case, this could be a spring failure at a later date, and is a possible cause of some reported W123 "random" spring breaks, where a car sitting unused has the spring suddenly break for no apparent reason.
The correct way to work with the spring is only to compress with the proper tool. There are no instructions for heavy prying, hammering, or pounding on the spring. There are no substitutions for the correct tool because of the method that is used to compress the spring, which will cause no "toolmarks".
A "grocery store" variety spring compressor cannot be used as it is not designed to do the W123, as the W123 is above and beyond the safe intended use of the tool.
I will be ordering a Klann-type spring compressor so get what little "peace of mind" I can get in just about a week. It will be stressful enough torquing that spring down. For the extra "expense", I can buy peace of mind for a few dollars, so I can return and post my survival story, without a body cast or bandaids. Priceless.:)

The right tool is worth it!

snapped_bolt

I have to admit that the first four springs (two cars) I did, were done with the outer style spring compressors. I was able to do them successfully, but not without saying many prayers. I have since purchased an inside compressor, and feel much better about it the times I have used it. Even with the proper compressor, removing the loaded spring and compressor feels like I am carrying a live land mine or sweaty dynamite . I take it out with a big pair of pliers, and set it down easy and pointed away from me.....Rich

I had to do this job on my E300. It is straightforward and relatively safe with the proper Klann tool and reasonable caution. I would never try to improvise on this job as there is just too much stored energy.

It's perfectly fine to grasp the compressed spring in the center of the coils so long as you are using the proper tool, the tool has not been abused, and the tabs are properly locked on the disks.

Just be sure to never point the rod towards yourself or others.

Always set the spring down gently (never drop or throw it) with the rod pointing in a safe direction away from the work area.

When initially loading up the tool, stop cranking when the tension starts picking up. Inspect both top and bottom, with a mirror and flashlight if necessary, to ensure the tabs are locked correctly in the disks before proceeding.

If the spring compressor lets go all the energy will go out along the axis. Treat it like a loaded gun.

Great info Jay Bob. :thumbsup:


Charlie

See post #15. On a W123 there is plenty of space to use generic spring compressors but you can see the bending.

In the thumbnail pic is one I made from 1 inch threaded rod that worked OK with the exception that the hook that slides tends to flatten the threads on one side. It is likely ACME threads would be a better choice as the ACME threads do not come to a point but are flat on the outer surface.

I made the big hooked Spring Compressor so I could use it on non-Mercedes vehicles.

ACME, that's what coyote buys to use against roadrunner.

Thank you all for the responses! It's all very helpful and interesting... and gives me more respect for the car and the tool.

Sorry in post 22 I was supposed to have posted a link showing the generic spring compressor bending. Now I don't know where the link is.

And he always looses. :D



Charlie

you may still want a standard exterior spring clamp around when you do the job as it can be helpful to straighten the spring out a bit for removal for the front.
this thread has a pic of what im talking about on the last page

http://www.peachparts.com/shopforum/diesel-discussion/291932-front-coil-spring-snapped-1983-240d.html