My inexpensive w123 spring compressor

[Admiral Ahani]

I recently did a front end job and I had to r&r the springs. I'm always interested in expanding my tool collection, and I'm really into making things myself.

It's a 3/4" threaded rod with acme threads (the thick flat threads you see on tools), with one nut welded to one end, and one free nut. Two 3/4" washers. The plates are actually spring perches from a w126. I knew these would work because taking the load of a Mercedes spring is what they're made for!

I cut the edge off of the perches so they could be inserted between loops. I made sure that I retained the part of the perch that dips down, so the plate would end up as helical as possible. Then I used a dremel to cut a 3/4" hole in the middle of the perches (it was the only method available at the time and I was pressed for time).

It worked beautifully. The total cost was about $40. I scored the nuts on ebay for about $15 (these nuts are really expensive so that was a deal). I got the rod from grainger for about $17, picked it up at the store. I had the washers already. The spring perches were a few bucks each from Pick n Pull. I wish I bought w123 perches, because apparently w126 springs are wider! Even with the perches being larger than my springs, it still worked. If I had w123 perches, I wouldn't have had to cut off as much material (for clearing the frame rail).

So now you can have a cheap sturdy spring compressor. The only catch is the welded nut - if you don't have a welder (most people don't) just take it to a muffler shop and they'll do it for $5-10. I used to do that, then I just invested in a little welder.

[Stretch]

What's the strength rating on the nuts and the bolts?

[Secondaries]

Originally Posted by Army

What's the strength rating on the nuts and the bolts?

Good question. Either way, i like the ingenuity and knight try to go this route when I'm ready to lower my wagon 8-)

[charmalu]

The spring perch is the plate that is bolted to the lower control arm?

The plate is a full round piece, cutting off one side seems like it would take away some of its strength.

Some of the force of the spring is pushing on the lower control arm, not on the total plate. How much force is excerted on the plates as the spring is being compressed? now 2 pieces of sheet metal are containing the spring.

When in it`s mounting, one end is contained in the upper cup area, and the lower end is sitting on this sheet metal perch. far less force in this state than when it is compressed.

I also wonder about the strength of the threaded rod threads and the nuts.

You were definately thinking out side the box, I commend you on making your own tools. I have the after market Klann clone spring compressor I picked up on CL, brand new, for $75.00. even that one makes me nervous when the spring compressed.

Charlie

[vstech]

... hmm

[ROLLGUY]

I had a former job that we used Acme threaded items in the fabrication of the product we manufactured. Standard threads would not work for high load linear applications. You will find that all screw jacks, bottle jacks (the adjustable portion on top) and other types of machines use Acme threads. I have no doubt that this home made spring compressor is safe for it's intended use. If it were made with home center threaded rod, I would holding my computer at arms length for fear of getting hit by the spring!

[Diesel911]

The use of the Lower Spring plates is clever!

A longer Nut can be had by using a Rod Coupling Nut used with regular threads and size of the Threaded Rod and Nut could easily be increased if someone is worried about that.
The regular Hardwar stores do not sell them in my area but you can get Grade 5 rod coupling Nuts; that is about 8.8 metric grade.

[vstech]

I was with you right up until I read you welded the nut onto the threaded rod... now you have altered the strength of the bolt.
also, the plate to washer fitment is iffy... ANNND the plate itself gets it's strength from the metal around it, so mounting from the center is weak and prone to pull out...putting a steel plate 1/4" thick behind the entire mount would strengthen it, but it would then be too thick to fit between the coils...

[gsxr]

I'd recommend wearing a full-face motorcycle helmet while that system is in use...

[auspumpen]

...and full leathers with armor plating and the like. I love DIY ingenuity, but...this is sketch

[Diesel911]

Homemade Spring Compressor
Homemade Spring Compressor

Below is a pic of mine that pulls the Spring upwards into the Spring Perch. You need to use a Crow Foot and a bunch of extensions to turn the Nut as there is no room under the Hood for a combination Wrench.

You can also decompress the Spring and remove it but it is a lot of cranking.

[funola]

Originally Posted by Diesel911

Homemade Spring Compressor
Homemade Spring Compressor

Below is a pic of mine that pulls the Spring upwards into the Spring Perch. You need to use a Crow Foot and a bunch of extensions to turn the Nut as there is no room under the Hood for a combination Wrench.

You can also decompress the Spring and remove it but it is a lot of cranking.

D911, I don't see any threads in the rod. Is that an optical illusion? Trying to figure out how it works.

[ROLLGUY]

Originally Posted by funola

D911, I don't see any threads in the rod. Is that an optical illusion? Trying to figure out how it works.

I was thinking the same thing. The threads look very fine if they are there.

[Diesel911]

Originally Posted by ROLLGUY

I was thinking the same thing. The threads look very fine if they are there.

Yes, the threads are 1"x14 threads per inch and the threads may still have some grease in them.
I had thar Rod left over from another project.

When I did the hooked Spring Compressor I used the same 1"x14 threads per inch rod.

The end of it turned down and smooth so it will center into the Nut Bottom Nut. The Nut is not attached to the Plate.

[funola]

This just came to mind. A source of Acme threaded rods may come from house jacks (for jacking sagging basement joists).