Front suspension work---will the Lower control arm hang vertically downward if... - PeachParts Mercedes-Benz Forum

bob_98sr5 · #1 06-04-2008, 11:43 AM

Hi all,

I have a 87 300DT. I'm planning to replace my front struts, and eventually, my springs if I can locate a pair of used (and in good shape) front diesel engine-rated springs.

I've read through quite a few threads, but I've only read one related question/thread re my question: If I unbolt everything bolted to the front of the front LCA and also unbolt the front struts, will the LCA drop downward vertically? My concern of course is the front spring flying out.

I know, I know, use a Klann or Klann clone, but my friend is convinced that he can jack my 300DT high enough, place a jack underneath the a-arm, unbolt everything, and then slowly lower the A-arm until the spring drops out. At the very least, I would want to compress the spring with the jack, attach spring compressors from Autozone, and run a steel pipe through the spring

Any insight is greatly appreciated.

Thanks,
Bob

SD Blue · #2 06-04-2008, 11:59 AM

Why risk damage to you or your car? Even with the proper compressor, those springs still need respect. The proper spring compressor is available in the tool rental program.

mkrazy1 · #3 06-04-2008, 12:00 PM

I just replaced my lower control arms on my '87 300D. You ABSOLUTELY need to use a spring compressor if you plan on letting the control arm drop. The spring expands too far and therefore the angle becomes too great to recompress the spring without the compressor. You may be able to put a jack under the control arm to hold it enough, to just replace the strut, but I would think that would be pretty risky and you definitly can't replace the springs without one.

I used a set of spring compressors I had for normal struts that mount on the outside of the spring, and I almost couldn't get it back together because the spring started bowing out. I ended up having to loosen the compressors a bit to get rid of the bow, connected the lower ball joint, then setting the spring on the control arm I had to connect a come-along to the arm and pull it toward the other side to get the bushings to line up, while using a jack underneath the control arm to recompress the spring the rest of the way.

winmutt · #4 06-04-2008, 01:27 PM

Spring compressor is required. Your friend has no clue what he is talking about. Even with the spring compressor its pretty hairy. If that spring gets loose it can take out a brick wall (happened before) so better believe it can take off you head.

rrgrassi · #5 06-04-2008, 01:29 PM

It's the bowing that set set the spring loose and cause all sorts of problems, not only to the car, but also anyone nearby. Death included.

bob_98sr5 · #6 06-04-2008, 01:44 PM

Quote:

Originally Posted by SD Blue

Why risk damage to you or your car? Even with the proper compressor, those springs still need respect. The proper spring compressor is available in the tool rental program.

have you ever successfully tried getting someone to rent you one? i tried for months with no luck.

i guess ill have to bite the proverbial bullet and buy one. anyone have a good source for the klann clone?

patbob · #7 06-04-2008, 03:48 PM

Quote:

Originally Posted by bob_98sr5

If I unbolt everything bolted to the front of the front LCA and also unbolt the front struts, will the LCA drop downward vertically? My concern of course is the front spring flying out.

I know, I know, use a Klann or Klann clone, but my friend is convinced that he can jack my 300DT high enough, place a jack underneath the a-arm, unbolt everything, and then slowly lower the A-arm until the spring drops out. At the very least, I would want to compress the spring with the jack, attach spring compressors from Autozone, and run a steel pipe through the spring

Any insight is greatly appreciated.

Thanks,
Bob

It will swing down far enough to let the spring fly. Don't know about vertical though, but I think I was able to swing them down that far on my car.

Maybe it'll work, but the springs on the w123 are LONG, and I can't see you removing enough compression from them before they are able to go flying -- remember, as you lower the LCA, you change the angle of the spring perch, tipping the bottom of the spring away from the vehicle (and toward you). So, expect flying springs if you let your friend attempt this.

Also, you can't compress the springs with the jack -- they'll compress a little if you jack on the LCA itself enough to lift the tire off the ground, but no more than when the tire is on the ground. If you can manage to put some sort of restraint in there to prevent the spring from extending as you jack the car up, you might (big might) be able to lower the LCA enough to get it out without it going flying. However, you'll find it pretty difficult to get a plate in between the coils at the far ends, and there's still a lot of extension left in the last few turns on them babys.

When I did mine last summer, I compressed 8.5 coils and even then, was just barely able to squeeze it out with the LCA stopped against the shock & lower ball joint (i.e. I didn't remove them first). Fewer coils and I probably couldn't have slipped it out. I struggled getting the plates of my compressor into the springs and 8.5 coils apart -- the coils at the top were limited by the rubber cap and those on the bottom were just too pinched together on once side -- I ended up having to jack on the LCA to get the spring to straighten out, but then there wasn't much clearance left between the coils for the compressor plate.

Your money or your life.. rent a compressor for heaven's sake and do it as safely as this job can get.

ichbineinekrous · #8 06-04-2008, 03:59 PM

Ok I'm ready to be reamed out here but I removed my front springs without the special spring compressor. I used lengths of chain and a normal spring compressor, chained the coil to the A-arm, jacked under the spring perch and removed the shock absorber nuts above in the engine compartment. On the first side I didn't compress the spring at all and just let it decompress, on the other side I compressed it somewhat first and it didn't really do much of anything. Of course I was no where near it at the time of release, these can be very dangerous. The big advantage to the Klann or like is that is makes the job much, much easier and faster. Getting the springs back in with a p.o.s. advance auto spring compressor and lengths of chain took forever, but it was safe.

patbob · #9 06-04-2008, 05:46 PM

Quote:

Originally Posted by ichbineinekrous

Ok I'm ready to be reamed out here but I removed my front springs without the special spring compressor. I used lengths of chain and a normal spring compressor, chained the coil to the A-arm, jacked under the spring perch and removed the shock absorber nuts above in the engine compartment. On the first side I didn't compress the spring at all and just let it decompress, on the other side I compressed it somewhat first and it didn't really do much of anything. Of course I was no where near it at the time of release, these can be very dangerous. The big advantage to the Klann or like is that is makes the job much, much easier and faster. Getting the springs back in with a p.o.s. advance auto spring compressor and lengths of chain took forever, but it was safe.

I (we?) stand corrected -- it can be done. And apparently without killing yourself

After having used a Klann knockoff, I wouldn't have thought it was even possible, much less safe. Thanks for setting me straight.

winmutt · #10 06-04-2008, 05:57 PM

It wasn't safe. Just rent the tool and do it the right way.

mobetta · #11 06-04-2008, 06:01 PM

I have released 2 sets of springs w/ no compressor- one @ the junkyard, one on my car INSIDE my garage.

the JY was first- to see how bad it really is. I happened upon a 126 stripped to the spindles- which I wanted- and so I popped the Lower ball, and the LCA dropped fully- but the spring stayed in. so- I went and got a 6 ft length of exhaust and popped them out- they went flying- it was quite exciting!! scared the crap out of a couple of immigrants walking nearby(no one was in danger).

on my car in the garage- I tied the spring to the control arm w/ 6 different pieces of rebar tie wire- and popped it out- it straightened out all 6 bits, but they held.

that was on one side- I will not tell anyone how I got that back together- partly cause it was stooopid, and I dont really know why/how it worked.

the other side I lifted the car by the LCA and wrapped a tow chain around the spring to hold it in place. worked fine. not a very warm feeling when you are working on your car with that ugly spring etting there like that though...

so to answer your ?- yes, it is really quiet easy to REMOVE the spring that way.

but if you want to put it back in, you should prolly spring for the compressor.

* one old timer suggested to me that I take the springs to a local shop and have them compressed and banded... install, jack up the LCA and cut the banding.* not something I want to encourage anyone to do- doing it any other way than by the book is stupid and dangerous.

babymog · #12 06-04-2008, 07:32 PM

On the 124, and I have done this six times in the past 18months, you can remove the spring w/o a compressor. Installing it again is more difficult.

You will need to remove the sway-bar or do both together.

If you use a jack (or lower the car enough to use a garage floor) to hold the spindles at full-extended strut level, disconnect the struts, then raise the car they will eventually either fall out or come close to falling out, half of mine didn't fall out and were a little difficult to remove because the control-arm bushings are keeping the control arm from going down enough.

The ones I removed at a junkyard were easier, I just removed the top of the strut and let them fly as I didn't want them anyway (gassers), first one doesn't (with swaybar in place), second ones pops out and usually takes the first one out at the same time.

I don't recommend doing it without a compressor, but it can be done. I have the side-spring style compressor which is not nearly as good as the one referenced above, barely does the job and not nearly as safe/idiot-resistant.

SD Blue · #13 06-04-2008, 09:52 PM

Quote:

Originally Posted by bob_98sr5

have you ever successfully tried getting someone to rent you one? i tried for months with no luck........

I don't where and from whom you tried to rent......... and the answer is yes I have rented one.......from the tool rental program

Go to "Advanced Search" and type keywords "coil spring compressor" select "Tool Rental Program" in search in forum(s).

Currently, in the tool rental program there are at least 4 people listed.