McMaster-Carr has Acme rod and nuts in a variety of sizes and materials.

If you search- ACME threaded Rod some also shows up on eBay.

Some also showed up when I searched Amazon.

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84 300D, 82 Volvo 244Gl Diesel

Closer to home, how about the threaded rod inside the factory jack?

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You can't always get what you want, but if you try sometime you just might find you get what you need.

The spring perches are not just flat sheet metal. The curved side profile adds a lot of strength to them versus if they were flat. And yes, these are the parts that are attached to the LCA, and hold the bottom end of the spring in the car.

The washers I'm using are very thick and broad. A larger thicker washer could be used if you're really worried about it, but what I used worked well.

I do wear face protection when using any spring compressor, especially one that's never been tested before!

The tool did not deform or bend in any place, even when fully compressed. I once used a harbor freight macpherson strut spring compressor on a small 120 lb/in coilover spring, and it started to deform when approaching full compression, so I knew to watch out. The tool I made held up well.

To really test it, when I was doing the 2nd spring, I decided to compress it as much as I could. The nut started to become too hard to turn, and the spring was more compressed than in the pic above but still not compressed all the way. I left it like that over night. The tool didn't deform or anything.

I forgot to mention - I clean and oil the threads every time I use it. Oiling the washers helps a lot too.


Diesel911 - that's a cool tool too. So the piece of stock goes at the lower end of the spring, and the larger washer at the other end jams against the body in the engine bay? That's a nice trick - just leave the spring in the car while you do the work. In my case I was cutting a little bit off my springs so I had to take them out. My only suggestion would be to add a little lip at the edges of the bar stock.

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'82 300TD
'77 6.9
'75 280S
'74 280
'87 Porsche 944 turbo

On the Bar Stock I just made it so that it is one inch longer on each side than it is needed; that way there is no way it can slip out. You cannot tell but the Bar Stock has an oval hole in the center so that it can tilt a little.

I think I got the idea from one of our Members who also did the same.
But, evidentaly Mercedes also had a Tool that did the same and it shows up in some of the Manuals.

The big dissadvantage of the Tool is that you cannot close your Hood; or of you forget it is there you could dent your Hood.
You can also only do one side at a time.
At the time I was desparate to make something that would work.

Later I made the Hooked Tool in the right picture so that it could be used on something else besides a Mercedes.

Attached Thumbnails

   

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84 300D, 82 Volvo 244Gl Diesel

The tensile strength of the rod is 60,000 lbs. My springs are the p/n 41 which has a stiffness 310 lb/in. I didn't measure how much I compressed them, but I'd guess around 5 inches from their full length (which is like 17.7"). Even if they were compressed by an absurd 10 inches, that's still only 3100 lb of force on the threaded rod.

Certainly the rod/nuts are not the weak part of the tool. The perches would probably yield first, and they worked perfectly. I mean, they're designed by MB, who (used to) over-engineer things, to hold the springs.

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'82 300TD
'77 6.9
'75 280S
'74 280
'87 Porsche 944 turbo

Hello Admiral,

This is great, thankyou for sharing your creativity. Can I ask, how did you cut the plate?

Regards

Peter<><

Peterac, I cut the plates using an angle grinder with a cut-off wheel.

Diesel911, on that hooked tool, how thick is that rod? Looks like 1 inch. I've seen a similar tool with thinner rods used on a Benz and they bent like wet noodles. Yours looks beefy! I have a heavy duty macpherson strut spring compressor which I use on all my other cars. It is really robust but the hooks are a bit too thick to fit between the coils of the Benz springs.

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'82 300TD
'77 6.9
'75 280S
'74 280
'87 Porsche 944 turbo

Admiral,

Thanks for the reply I will be making one!

What are your thoughts about the welding of the nut and strength of the rod?

Peter<><

The threaded Rod used on both of my Tools is 1 inch, and I don't think the Rod is garde 5 due to the fact it did not cost much.

I made the Hooks on mine and it took some time to fit them to the Mercedes.

I had an issue with My Lower Control Arm Bushings. I actually managed to safely pull off the Springs with the Cheapie Harbor Freight Spring Compressors.

But, the Bores inside of my Lower Control Arms had thick scaley Rust in them and when cleand out they were enlarged. But, I had to get the Car on the Road and I installed the Bushings anyway.

After That I got some used Lower Control Arms and had to do the job over again. That next time I bent up the Harbor Freight cheapie Spring Compressors.
I replaced the threaded Rods on the with Thicker Rods and they still Bent.
After that I made that Tool that pulls the spring up into the Spring Perch.

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84 300D, 82 Volvo 244Gl Diesel

I didn't worry about it at the time, but I guess the heat could reduce the tensile strength at that location. The alternative is to jam 2 nuts together. Maybe if you use a long nut, and just put 2 spot welds on the end, then the part of the rod that will be (slightly) weakened will be the part not doing any work.

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'82 300TD
'77 6.9
'75 280S
'74 280
'87 Porsche 944 turbo

Good point, I was thinking along the same lines.

Very much appreciate you design and sharing!

All the best

Peter<><

Just as a reference point, I bought my 3-foot acme threaded rod from Grainger for $17, and I still have 2 feet left.

Here's an important note!
The 3/4" nuts used with this tool are used with a 1-1/4" wrench. My 1-1/4" socket BARELY fit through the hole in the engine bay. So if you want to use something larger, beware, your socket won't fit!

The idea is to use a socket wrench from above through this hole for the welded nut, and then use an open end wrench through the spring coils on the free nut at the bottom.

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'82 300TD
'77 6.9
'75 280S
'74 280
'87 Porsche 944 turbo

the factory jack has a pretty thin threaded rod. I'd not think it could handle the expansive forces...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Factory jack! Great idea!

Vstech, the acme thread in the jack is designed to lift one corner of the car but not strong enough to compress the spring?

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked