87 300D road handling enigma
 

I have replaced virtually the entire suspension system on my 87 300D and it still wags around like a drunk driver. I suspected the subframe bushings but my alignment shop says they look fine and the car does not exhibit play while it's on the alignment rack. Ideas?

It has new Toyo premium tires, fully balanced and aligned, new coil springs, shocks, struts, tie rods, steering damper, front and rear sway bar bushings, rear dog bones (maybe 1 of the 4 has not been replaced), etc etc.

Also, what do I look for on the injectors once I finally find a 27mm socket that fits? It starts rough but is fine after a few minutes once it's warm.

Thanks in advance for the expertise of the forum!
Paul

Can't help you with the W124 suspension.........others who have them will chime in.

With regard to the injectors...........just leave them be.

Use this procedure to start:

Turn key to glow position.

Ignore idiot light.

Wait 20 seconds (use a watch or count).

Start engine.

If the vehicle has been sitting awhile or the temps are below freezing, extend the 20 second time to 30 seconds.

Problem solved.

perhaps another opinion on the alignment.

tom w

As for glow plugs ........ I wish it were that easy. I've tried double 45 second cycles with no improvement. Replaced all glow plugs, one (the last one!) was bad but still no improvement. Haven't checked compression but may do that once the injectors are out.

2nd opinion on suspension is a good idea. This is the best alignment shop in town with life-long employees so it didn't cross my mind.

Paul

Subframe bushings and replace the rest of the links (expecially check the tie rods, they have a large bushing in the eccentric bolt end that shrinks). If the subframe does not stand away from the body by half an inch or so, replace the subframe mounts, they have collapsed and are allowing the subframe to move.

Also, did you replace the bushings in the spring link (bottom one)? If not, do so, as the wheels move in and out at the bottom otherwise, causing them to "steer".

4-wheel alignment? Necessary, and it will not be possible to get it right if there is something loose back there.

Peter

That's certainly abnormal. Once you get a new set of glow plugs in it, these problems usually are eliminated, especially if you are glowing it for 20 seconds or so.

I'm wondering if the bottom of the prechambers are clogged with carbon buildup.........and the heat from the glow plug is not doing an effective job on the incoming fuel charge.

Any history of this vehicle...........driven at low speeds in its past? Problem always exist for you.........or come on suddenly?

The issue does not appear to be injector related........unless the problem is one specific injector that is not firing properly until the engine warms. But, this would be a steady and regular miss when cold........not the typical 603 random kick and bang for 30 seconds or so.

Injectors & starting:
I've had the car for a year and it's always done that. I thought driving it more regularly would cure it. Worse in colder weather. Didn't change once I converted it to vegoil.

If I rev it up to 3000 rpm's after 5 second (and hoping the oil is ready by then) it runs fine, so it seems like one injector not firing fits the description, maybe even 2 based on the amount of smoke if I just let it idle until it warms up. As for steady miss or random kick, it's more steady but not a perfect rhythm....

Suspension:
I'll have them measure the height of the subframe bushings. The thing I can't understand is how the 4-wheel alignment real-time readouts don't change when they reef on the car while it's on the rack. What is different when the wheels are rolling vs. sitting stationary? Wheel bearings don't exhibit play, not sure of the spring link bushings you mention but will flag that for the shop guys. You're referring to coil springs here? Does Phil send new bushings when he sends out coil springs? I just hand them the whole box of goods.

Thanks for all the help.
Paul

Update, Problem Nearly Solved
 

So the bushings were fairly shot (I got to walk under the car at the shop and use the prybar myself!) and after replacing them with the expert advice of Roy from Mercedesshop the rear wag is GONE. There is still some steering wiggle that keeps me correcting the steering wheel, but at least it won't get me pulled over for DUI.

Is there something in the front that gives a loose feeling even though it has new ball joints, tie rods, control arms, steering damper? My goal is to make it drive better than my veggie suburban.

Another update, making progress, Alignment next
 

I had the alignment shop check the front end again, and they said it was within tolerances but toed it out 3/16" and it drives much better, MAYBE even as good as a suburban!

Is there a deviance from shop specs for the alignment settings? They said that they always set Chevy trucks different than recommended b/c they know what works for that vehicle. Maybe the 'book' is wrong? Has anyone had to specify custom alignment settings for their benz's?

Alignments are best-compromise numbers usually.

Some times the best alignment for handing, bump-steer, wind sensitivity and tire wear/mileage are contradictory, so a little tweak from a knowledgable alignment shop can be a fine modification. I usually set front & rear toe to feel after starting at factory spec, I optomize for handling.