How long do OE motor mounts usually last? - Page 3 - PeachParts Mercedes-Benz Forum

layback40 · #31 08-30-2010, 10:47 PM

Doesnt it just get to you !! All that work & its still there!! Sub frame bushings in the back need to be inspected I guess.

BodhiBenz1987 · #32 08-30-2010, 11:04 PM

Quote:

Originally Posted by layback40

Doesnt it just get to you !! All that work & its still there!! Sub frame bushings in the back need to be inspected I guess.

Kind of hard to tell how bad the subframe bushing are, but I can definitely tell a lot of the other bushings back there are in poor order. Thrust arm, camber arm, tie rod (boot is torn on one) and the bushings on what I guess would be called the rear lower control arm(?) all very worn. The front suspension was rebuilt entirely in 2002 but in the rear only the swaybar (and linkage) and shocks are newish. The diff bushings are also quite bad, as mentioned. Basically, what I can't decide is whether or not to try this project. I kept putting it off because I couldn't decide (stupid, I know). I'm confident I can do the diff bushings, but it seems silly to do that myself if I'm going to take it to my indy for the rest. Or do that, then take it apart myself again to do the subframe. My concern with the subframe is that it looks like a very physically difficult (dangerous) job. Also has a crack that needs a weld and I can't weld (yet).

layback40 · #33 08-30-2010, 11:30 PM

If you had mentioned all that before the trans mount plan, we may have suggested to start at the back.
With the crack, dont even consider doing it yourself. It needs a properly qualified welder.
I think it needs a trip to a good indi.
Problem is that its not going to be cheap.

vstech · #34 08-30-2010, 11:38 PM

Quote:

Originally Posted by layback40

If you had mentioned all that before the trans mount plan, we may have suggested to start at the back.
With the crack, dont even consider doing it yourself. It needs a properly qualified welder.
I think it needs a trip to a good indi.
Problem is that its not going to be cheap.

this was in her first post...

Quote:

Originally Posted by BodhiBenz1987

As a side question ... the rear linkage on this car is a disaster, and the diff bushings (in the back, that hold it on the subframe) are shot. I plan to have my indy do that job when I get back from London in the fall (technically I can do it, but physically I don't think I can by myself). Can those problems in the rear manifest in vibrations in the front?

BodhiBenz1987 · #35 08-30-2010, 11:39 PM

Quote:

Originally Posted by layback40

If you had mentioned all that before the trans mount plan, we may have suggested to start at the back.
With the crack, dont even consider doing it yourself. It needs a properly qualified welder.
I think it needs a trip to a good indi.
Problem is that its not going to be cheap.

I mentioned it, in passing ... it was in the second graph of my first post.

Yeah it definitely will be a pricey job. Plus I like the pride of doing it myself.

But, I'd rather not hurt myself or my car just over pride and money.
(Re: the crack, I did actually show it to my indy once, it's been there for years ... he wasn't real concerned about it, just said he could weld it whenever the subframe needed to come out next. I think that time has come ...

)

sixto · #36 08-30-2010, 11:42 PM

Going back to the OP, if you've checked wheel roundness and balance and steering linkage, I'd check the prop shaft next and the half shafts after that. Make sure the flex disk, u-joint and center bearing and carrier are in good shape. Rear suspension wear will manifest more as side-to-side wallowing and directional instability than harmonic vibration.

Sixto
87 300D

BodhiBenz1987 · #37 08-30-2010, 11:52 PM

Quote:

Originally Posted by sixto

Going back to the OP, if you've checked wheel roundness and balance and steering linkage, I'd check the prop shaft next and the half shafts after that. Make sure the flex disk, u-joint and center bearing and carrier are in good shape. Rear suspension wear will manifest more as side-to-side wallowing and directional instability than harmonic vibration.

Sixto
87 300D

I replaced the flex discs, center bearing and carrier in March, though I'm not really sure how to assess the U-joint ... it did not feel wobbly or look bad as far as I could tell. It's possible the driveshaft is just out of balance, though it would be odd for it to just suddenly go out of balance on its own (the vibrations were starting before I took the shaft out, so I don't think it was due to putting it back offset).
OK, I feel stupid asking this ... but what is a half shaft?

Billybob · #38 08-30-2010, 11:54 PM

Quote:

Originally Posted by BodhiBenz1987

Kind of hard to tell how bad the subframe bushing are, but I can definitely tell a lot of the other bushings back there are in poor order. Thrust arm, camber arm, tie rod (boot is torn on one) and the bushings on what I guess would be called the rear lower control arm(?) all very worn. The front suspension was rebuilt entirely in 2002 but in the rear only the swaybar (and linkage) and shocks are newish. The diff bushings are also quite bad, as mentioned. Basically, what I can't decide is whether or not to try this project. I kept putting it off because I couldn't decide (stupid, I know). I'm confident I can do the diff bushings, but it seems silly to do that myself if I'm going to take it to my indy for the rest. Or do that, then take it apart myself again to do the subframe. My concern with the subframe is that it looks like a very physically difficult (dangerous) job. Also has a crack that needs a weld and I can't weld (yet).

You should put the word out that your looking for a subframe, maybe someone down south can help you out with a nice clean and rust free one from a car that's headed to the bone yard. Or after some nice guy reconnoiters a decent one in a bone yard get the address, take a weekend and do a road trip down the Carolinas or Georgia hit the bone yard and strip every thing off one and bring it home. grab a couple wheel carriers and you can do the rear wheel bearings also, everything at your leisure!

You've got the place now you can give it the once over, press in all new bushings, bolt on all new control arms, new subframe and diff mounts, then when the time comes drop yours swap the differential onto it and your wheel carriers and then your axles and you'll tight right and out of sight!

The car will ride like it did 23 years ago!

Seriously it is much much easier to do the complete job with the subframe off the car, as long as you have a decent floor jack lifting it back up and into place is really not that big a deal. This job is much more difficult with it still under the car, it’s very hard to get at everything, with it on the ground you can get to almost everything from above it easily.

Billybob · #39 08-30-2010, 11:56 PM

Quote:

Originally Posted by BodhiBenz1987

... but what is a half shaft?

Rear axle!

vstech · #40 08-30-2010, 11:56 PM

half shaft is the rear axles, with CV joints on them.

BodhiBenz1987 · #41 08-31-2010, 12:01 AM

Quote:

Originally Posted by Billybob

You should put the word out that your looking for a subframe, maybe someone down south can help you out with a nice clean and rust free one from a car that's headed to the bone yard. Or after some nice guy reconnoiters a decent one in a bone yard get the address, take a weekend and do a road trip down the Carolinas or Georgia hit the bone yard and strip every thing off one and bring it home. grab a couple wheel carriers and you can do the rear wheel bearings also, everything at your leisure!

You've got the place now you can give it the once over, press in all new bushings, bolt on all new control arms, new subframe and diff mounts, then when the time comes drop yours swap the differential onto it and your wheel carriers and then your axles and you'll tight right and out of sight!

The car will ride like it did 23 years ago!

Seriously it is much much easier to do the complete job with the subframe off the car, as long as you have a decent floor jack lifting it back up and into place is really not that big a deal. This job is much more difficult with it still under the car, it’s very hard to get at everything, with it on the ground you can get to almost everything from above it easily.

I actually have a second subframe in my parents' shed, but it's got a bit of corrosion on it too, so I hesitate to use that one. It's pretty solid other than surface, I could sandblast and repaint but maybe I should look for a perfect one. Can one assume a subframe that hasn't been in an accident, if it doesn't have rust issues, is as good as another?

I still think that's one heavy frame for me to lift (or drop), even with a jack ... unless I take the wheel carriers off first, which I guess is an option.

BodhiBenz1987 · #42 08-31-2010, 12:03 AM

Quote:

Originally Posted by vstech

half shaft is the rear axles, with CV joints on them.

Ah, thanks.

The CV boots looks solid, no cracks or tears, and I can't feel any play (rotation) in them. What else could I check on them?

sixto · #43 08-31-2010, 12:03 AM

Quote:

Originally Posted by BodhiBenz1987

... I'm not really sure how to assess the U-joint ... it did not feel wobbly or look bad as far as I could tell.

The u-joint center section should move easily and smoothly. What you don't want is a u-joint that clicks about either axis.

Did you do a simple wheel bearing check on all four wheels?

Are you sure the vibration is car speed related not engine rpm related? I don't want to alarm you but I hope the damper isn't coming apart.

Sixto
87 300D

vstech · #44 08-31-2010, 12:08 AM

I've not seen the subframe yet, so I don't know much actually about it, but I'd think a brace could be built to attach it to a jack head for lifting it up. also some way to lift and pry is handy. I understand if you, a girl don't feel up to the task...

seriously, it's a pretty big chore to wrestle with a subframe on any vehicle. but with enough jackstands it should not be dangerous or overly difficult. I'd get a set of 12 ton stands to hold up the body of the vehicle, and some 2x4's to protect the "frame" of the car, then get several 1.5 ton stands for supporting the subframe in various positions and I'd wrap the small stand heads in rubber to keep from scratching up your new subframe paint... and it'll hold things from slipping as you lift and pry on the sides to get it mounted into the car.

BodhiBenz1987 · #45 08-31-2010, 12:10 AM

Quote:

Originally Posted by sixto

The u-joint center section should move easily and smoothly. What you don't want is a u-joint that clicks about either axis.

Did you do a simple wheel bearing check on all four wheels?

Are you sure the vibration is car speed related not engine rpm related? I don't want to alarm you but I hope the damper isn't coming apart.

Sixto
87 300D

I have not check rear wheel bearings but replaced all four in the front with factory spec grease and play setting.
Sometimes it does seem rpm-related, although to be very honest, sometimes it can be hard to perceive the "speed" of the vibration ... it does seem to vibrate more when I'm speeding up from 50 to 70 than when I'm cruising steadily at 60 or 70. Do you mean the damper at the front of the engine, the harmonic balancer?

That doesn't sound good ...