Will replacing the rear subframe bushings affect ride quality? 87 300TD - PeachParts Mercedes-Benz Forum

locry · #1 05-17-2010, 05:04 AM

sooooo... will replacing the all rear subframe mounts affect ride quality? i'm aiming for that new car ride... where road bumps and niggles are somewhat dampened... right now every road imperfection is transferred to the interior via harsh rattling and such... no, my accumulators aren't shot.

rear suspension is just fine... just want to fine tune the ride... trying to eliminate any and all vibration from the pavement to the interior.

my goal is to replace all rubber mounts... just want to make sure I replace parts that are worth replacing.

t walgamuth · #2 05-17-2010, 07:06 AM

I am a little skeptical about everything being happy in your rear suspension next to the statement about jiggling and rattling.

IMO replacing subframe mounts should not cause that unless they are massively failed.

Brian Carlton · #3 05-17-2010, 06:15 PM

The subframe bushings are not going to affect the ride quality in any meaningful way unless they are basically non-existent.

I've replaced the upper spring pads in the hope that new rubber will dampen the road somewhat..........but, it hasn't happened.

locry · #4 05-18-2010, 01:49 AM

hmmmm... so maybe i should look into replacing all the links that have rubber bushings in them... basically all of them correct?

and how does one know if the mounts have failed? do they at least serve as vibration dampeners or something? like that of motor mounts?

t walgamuth · #5 05-18-2010, 07:03 AM

If your rubber parts are causing crashing you should be able to see it visually. Have you checked your shock mount bushings?

charmalu · #6 05-18-2010, 02:12 PM

I don`t know how close the 124 and 123 bushings are. but I just replaced the sub and trailing arm bushings on the 85 300D.
I didn`t think they were all that bad looking when I removed them, some cracking in the rubber from age. 25yrs and 361K.

when I set the new sub frame bushing next to the old one, there was a real difference in hight. the old one was compressed down a bit.

I also replaced the diff mount last summer, that helped raise the rear some also. the old one was in bad shape.

I live on a windy mountain county road about 3 miles long from the major metropolis of Down town Soquel, then the freeway.
when I took her for her first run down the hill there is a definate difference in the way the car handled. the suspension feels much tighter in the rear end. there seemed to be less sway in the rear. I ran it down the freeway about 4 miles and back home.
soon as I get the new parking brakes installed and the exhaust but back on, we`ll see how she does.

It all depends on how long you keep the car, and how much time you want to put into it. replacing this stuff will get you back to the new car feel.

Charlie

locry · #7 05-19-2010, 12:27 AM

@Brian... have not considered spring pads because the springs aren't rigid, so i guess vibration from the pavement won't really transfer to the cabin... will consider it though... hmmmmmm

@walgamuth... no i have not checked the strut mounts... can they be seen from under the car? 87 300TD... SLS

@charmalu... i'm pretty sure my mounts have never been changed... i'm trying to find out if they indeed serve as vibration isolators, if they are then it makes sense that after 23 years they may have lost some or most of their dampening properties... if they are strictly mounts, as in spacers, and have no dampening properties then i changing them will be useless... but as you said... your ride did improve.

and we all know how nice that feels.

i'll have to double check all my links as suggested first... then proceed from there...

from pavement to the cabin i see 3 secondary points of vibration dampening... aside from the shocks/struts ...
#1 the tire itself--- excess vibration is transferred to the suspension system---then continues to the subframe
#2 upper (?)strut/shock mount bushing--- excess vibration transferred directly to the body/cabin
#3 subframe mounts--- last stage/gate where vibration gets transferred to the cabin

i don't know... this is how my limited experience sees it...

t walgamuth · #8 05-19-2010, 07:20 AM

If the top of your shock is making the noise you should be able to push the car up and down and hear it clunk easily.

locry · #9 05-19-2010, 07:47 AM

there's no clunking at all... front shocks have been recently replaced with Bilstein comforts, rear accumulators also replaced about a yr or so ago...

the ride is smooth when going over smooth pavement, the rattles and road noise appear when going over rough pavement... its annoying... our newer Fords sound better and more refined... something definitely needs replacing

babymog · #10 05-19-2010, 10:08 AM

Rattles are something wrong, could be as simple as hardened sway-bar parts (common).

Tires are the first link to your suspension, don't expect your car to feel like it's on Michelins if you're running Khumos.

Shock bushings and strut bushings are important for damping high-frequency small bumps.

locry · #11 05-19-2010, 10:31 AM

Quote:

Originally Posted by babymog

Rattles are something wrong, could be as simple as hardened sway-bar parts (common).

Tires are the first link to your suspension, don't expect your car to feel like it's on Michelins if you're running Khumos.

Shock bushings and strut bushings are important for damping high-frequency small bumps.

yup... those high frequency small bumps are what i want to eliminate if possible

tiresmokindad · #12 05-21-2010, 07:36 AM

Quote:

Originally Posted by locry

sooooo... will replacing the all rear subframe mounts affect ride quality? i'm aiming for that new car ride... where road bumps and niggles are somewhat dampened... right now every road imperfection is transferred to the interior via harsh rattling and such... no, my accumulators aren't shot.

rear suspension is just fine... just want to fine tune the ride... trying to eliminate any and all vibration from the pavement to the interior.

my goal is to replace all rubber mounts... just want to make sure I replace parts that are worth replacing.

Yes it will increases the effect of your ride quality if you will replace the rear. I am using the same rear. I hope you can meet your goals. Most of the parts are worth replacing depending on their quality.