A few days ago I observed some 12 year old spring pads of a BMW. Not rotten, broken or something like that. But they where harder than the normal, bound to brittle.
That is why I am raising a generic question:
Is there a consensus on replacement of this parts due to aging ? (eg. time interval)
I think of the heat exposure of the engine mounts, for instance. For 12 years... How are them really even if they LOOK perfect?
About the suspension bushes: what is the net effect of the potential hardenig versus the obvious objective of being flexible and providing a pleasant ride and vibration dampening ?
Comments are mostly welcome.
I would particularly appreciate guidance on the different parts categories. (some get a lot of heat, others weight + heat, others torsion + weight...)
Thanks, Jorge

mm, great question. I hope someone has an answer. My car is 11 years old, and all the seals are still soft. Then again, since year 8 I've conditioned them with 303 UV protectant. As far as bushings, not sure. Most of mine were replaced at 70k/7 years due to squeaking. If you're past a decade, I would say that you need to look at them. That said, my motor mounts are original and show no signs of failing

__________________
former: 83 300D, 97 C230, 93 400E

current: 08 C300 Luxury , 92 500SL

braz,

ill have a really good answer for within about 4 weeks. i am doing a full restoration of all the major bushings and links on my 87 once i get the rust repairs done. im replacing from front to back:

engine mounts
trans mount
LCA bushings and ball joints
subframe bushings
all links
diff bushing
all shocks and struts

im going to keep all of them and take comparison pics. hopefully i wont be too preoccupied to not take pics of the tear down and build up

bob

I have a '69 280SL and have inspected the rubber suspension mounts: They are just fine. Rubber deteriorates because of exposure to UV. Garaging helps. That's why rubber is black: They add lamp black. Tires crack on the sides. But I have this '69 Honda trail bike. The rear tire is cracked but has an innertube. I'm still riding it that way. On my removable hardtop I found the seal at the top of the side window is cracking a little. The conclusion? Black rubber lasts longer, replace unused condoms after 20 years.

Will,
Mine is a C280 1997. I changed every rubber in the front axle, motor mounts, transmission mounts, shocks.
Result: Outstanding ! New car feeling!
I am dealing with this in order to decide if I go for the rear axle. (nothing replaced there)

Bob,
Please post your findings. Yours will be a great case to analyse.

Engineer,
You have a positive situation in an older car. Something to observe. The seals are not a big surprise. Mounts... how about them looking good but being too dry/hard ?

Jorge
PS: Engineer, I think the better statement for condom management is:
- Either buy them on demand or take advantage of volume discounts buying black condoms...

I'm fairly certain that 21 years is enough to make any rubber, almost anywhere in the car go bad.

Either that or 1986 wasn't a good year for rubber production in Germany.

I'm in the middle of a campaign to replace just about everything rubber on my early 300E. Injector seals, vacuum hoses, bushings, everything as I come upon it. My observations is that the iron bits on these cars will last forever. All of the annoyance comes from either rubber or electrical pieces.

I have a 76 450SL and the suspension squeaks, How do I tell if the subframe rubber mounts need to be changed? I would like to try to change them myself. Is there a proceedure to follow to do this?