non-TD bounce - PeachParts Mercedes-Benz Forum

jsp · #1 07-20-2005, 04:52 AM

There's a stretch of Interstate 10 near my work (Rosemead/San Gabriel/Alhambra, CA) which is a test strip for car suspensions--even the smoothest cars show some bounce bounce bounce.

Recently, I noticed that my 240D bounces here a lot more than normal; the whole car bounces, and I with it, so much so that it's hard at points to keep even pressure on the accelerator pedal. I could take a different route to work, but the problem is, my other cars, including a 300D, don't bounce nearly as bad as this one on this stretch of road.

I tried changing to a new pair of front shocks (KYB), but no difference at all (my old Bilsteins were a little worn).

I think these are the possible explanations:

1. Problem is with KYB brand; should have gotten Bilsteins.
2. The rear shocks are actually causing the bounce; replace them as well.
3. Recently, I had discovered a broken rubber exhaust hanger at the back and fixed it with some 12 gauge electrical wire. Could this have stiffened something which should have remained flexible, thereby causing bounce?
4. Some other suspension component is responsible for the terrible bounce?

So, what do you think? Has anyone else dealt with something like this before?

pawoSD · #2 07-20-2005, 11:34 AM

I doubt it has to do with the brand of the shocks and I know it doesn't have to do with the muffler hanger, but the rear suspension could definatley be a culprit in the car bouncing. We have some roads that make you go "

" when you see them ahead.....michigan.....thats what you get when your state budget for roads is only enough to cover about 30% of them!

My car doesn't usually bounce, but it will bottom out the suspension from time to time on the....road craters and mine fields....its quite a jolt when that happens, and all the change in my tray clanks up and slams down so its loud!

dieseldiehard · #3 07-20-2005, 11:39 AM

Quote:

Originally Posted by jsp

(kut)
I tried changing to a new pair of front shocks (KYB), but no difference at all (my old Bilsteins were a little worn).

I think these are the possible explanations:

1. Problem is with KYB brand; should have gotten Bilsteins.
2. The rear shocks are actually causing the bounce; replace them as well.
3. Recently, I had discovered a broken rubber exhaust hanger at the back and fixed it with some 12 gauge electrical wire. Could this have stiffened something which should have remained flexible, thereby causing bounce?
4. Some other suspension component is responsible for the terrible bounce?

So, what do you think? Has anyone else dealt with something like this before?

KYB's are also known as the shocks that Keep You Bouncing
And always replace front and rear shocks unless you want mixed results.

pawoSD · #4 07-20-2005, 11:42 AM

I will keep that in mind! Bilsteins it is! (I may replace mine in the not too distant future....)

jsp · #5 07-20-2005, 11:58 AM

Quote:

Originally Posted by dieseldiehard

KYB's are also known as the shocks that Keep You Bouncing.

Yes, I can believe it. But the thing is, the bad bouncing happened even before I got the KYB's. Could it be that the new KYB's have just about the same dampening power as my old Bilsteins?

Quote:

Originally Posted by dieseldiehard

And always replace front and rear shocks unless you want mixed results.

It seems this is what I'll have to do. I'm thinking of getting the KYB's for the rear as well ($80 more bucks). My reasoning for another two KYB's for the back is, as I mentioned above, that the bouncing doesn't seem to be related to the front shocks (no difference between old Bils and new KYB's), so new rear shocks, even KYB's, should stop the bouncing. But I suppose some here think I should definitely go for a whole new set of Bilsteins (many more bucks). Please, convince me of one or the other choice.

Also, how about the last possibility, that some other suspension component is causing the bad bounce?

Many thanks for your thoughts.

jsp · #6 07-20-2005, 04:39 PM

Anyone else? Please save me from having to buy 4 new Bilsteins!

diametricalbenz · #7 07-20-2005, 05:18 PM

Quote:

Originally Posted by jsp

Anyone else? Please save me from having to buy 4 new Bilsteins!

Which lanes and exits on the 10 freeway are you speaking of? I can take my 240D and drive over that section this weekend.

Frankenbenz · #8 07-20-2005, 05:33 PM

I thought Bilsteins were guaranteed for the life of the vehicle

jsp · #9 07-20-2005, 08:04 PM

Quote:

Originally Posted by diametricalbenz

Which lanes and exits on the 10 freeway are you speaking of? I can take my 240D and drive over that section this weekend.

Alright, now we're talking! It seems to be limited to the two fastest (leftmost lanes). Westbound: off and on from Rosemead Blvd to the 710, especially bad just round the 710/Cal State L.A./I-5/101 junction. Eastbound: especially bad from the 101 junction near downtown through Cal State L.A./710, up to about Atlantic, and then bad again from about Rosemead Blvd. to Santa Anita.

The bouncing seems to actually build up momentum--like shaking a tall tree back and forth--and gets scary at times. It happens at any speed over 50-60.
If you get a chance to drive this area, pls. let me know!

t walgamuth · #10 07-20-2005, 11:00 PM

the front did nothing, i would put the bilsteins on the rear and see what happens.

i tried the kybs years ago on my saab. when they wore out after about a year, the failure was complete... as if i had no shock on the car at all. it was errie (sp?) i was going down a hill at a brisk speed and hit the little grooves they pot on bridges to evacuate water and the rear end started floating sideways as if on ice. no more kybs for me.

ditto for boges. they are better than kybs but not as good as bilsteins.

the bilsteins can be worn out and pass the traditional bounce test as far as ride quality goes.

diametricalbenz · #11 07-21-2005, 04:57 PM

jsp I drove the eastbound 10 freeway and back from the I-5 to Del Mar at 65-70mph. I noticed some subtle bouncing in the suspension but that seemed pretty normal for LA freeways. I didn't notice it before but there are a few spots where you feel some bumps and bouncing. My rear shocks are going out and even then the the bouncing was minimal. Keep in mind I am driving a W115 so the suspension is a little different. When I get my W123 on the road I will give it a test run.

t walgamuth · #12 07-21-2005, 07:32 PM

is pretty much identical to 123. i think the 115 springs are softer though.

diametricalbenz · #13 07-21-2005, 08:02 PM

Quote:

Originally Posted by t walgamuth

is pretty much identical to 123. i think the 115 springs are softer though.

The w115 does seem softer than the w123. It rides very well and does soak up some pretty big potholes around here but the high speed emergency handling is something to be desired.

t walgamuth · #14 07-21-2005, 08:31 PM

over but stabilize at a somewhat crazed angle and just dig in. they were designed for rougher roads than is common now. also i think that our more rigid modern cars can handle much stiffer springs and absorb the bumps without twisting.

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