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76 450SEL need some advice

Started by GypsyKingg, 20 June 2012, 02:32 PM

GypsyKingg

How do i go about checking these? My apologies for being a Noob.


Another thing to check very carefully would be the flex disc, coupler and center support mount in the driveshaft - especially since the steering disc was obviously shot.

Casey

Quote from: GypsyKingg on 27 June 2012, 12:48 PM
My little bands holding the exhaust do look used and old.

They are not expensive or too difficult to change.  They can be a pain to stretch over the hooks, but you can coerce them into place with a large flathead screwdriver, or just cut the old ones off.

MercedesSource sells upgrade versions that also have a rubber block in the center, which keeps them from coming off if you hit a hard bump, and completely eliminates rattle better.  That's what I've been changing mine to:
http://mercedessource.com/node/9641

GypsyKingg


Casey

Quote from: GypsyKingg on 27 June 2012, 12:53 PM
How do i go about checking these? My apologies for being a Noob.


Another thing to check very carefully would be the flex disc, coupler and center support mount in the driveshaft - especially since the steering disc was obviously shot.
The flex disk is directly in front of the rear differential, which in turn is the enclosure directly between the two rear tires.  I think there's also one towards the front, but am not super familiar with these myself.  If there are any sort of cracks or suspicion about this part at all, replace it.  Because if it gives out while you're driving, it's going to be a real bad day for you.

Here's a new flex disc:



Here's one in dire need of replacement, that hasn't quite failed yet:



Here's the result of failure:




"This is what the driveshaft will do to your car.  It sliced a hole in the transmission tunnel, twisted the transmission side yoke and even torn one of the holes apart.  Also it disintegrated the flex disc. destroyed the transmission mount, broke the aluminum mount that is ON the transmission and twisted the transmission cross member.  Also do you see any transmission linkage??"

Oh, here's the linkage:

GypsyKingg

Woah......... that is insane damage  :'(

Luckily i dont have any vibrations when driving or accelerating or any of the other symptoms that occur with said ailment (not to my knowledge anyway)... but i will be replacing that anyways!!!! now that i saw the damage it can cause.

Like i said mines really just "noise" I really dont think the vehicles performance is being hindered.

Papalangi

I took it to the local Walt's, asked the manager if he knew what I meant by flex disc and said "yup, see 'em all the time on older Benzs" so I let him install the one I bought from peachparts.com (I'm 250 Coupe there).

If I remember, it was less than $100 and done in an afternoon.  It's kinda hard to get to without a lift and I'm lazy when it comes to heavy, rusted or hard to reach parts.

Michael
'83 300SD, I'm back!  It's the son's new car (12/2020)
1976 450SEL, 116.033  Sold it to buy a '97 Crown Vic.  Made sense at the time.
1971 250C, 114.023
1976 280C
1970 250/8

Tony66_au

my destroyed flex disc........








Tony66_au

No warning apart from a slight harmonic that got worse, outward signs were chunks of rubber bouncing out from underneath and I guessed something was wrong and drove the last mile home very very slowly.

The disk had perished and gone hard, then just "Let go"

So for $100 Au each I just replace them now on a new car...........

TJ 450

Yes, keep an eye on those flex discs... The pictures posted earlier are a good example of what can go wrong.

I inspect them every time I'm under the cars.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

GypsyKingg

Thanks guys,

I checked last night and those discs looked perfectly fine and solid. no signs of wear. what did look bad was my rear tranny mount. but would that make this noise? jesus i spent a few hours jacking my car up and trying to pin point the cause but got nothing. the sound occurs when im slightly turning too. i pull up to a stop and tack,tack,tack,tack take off and nothing..... get to speed and feather the accelerator to maintain cruising speed and the humming and tack( not consistent thought)will come back. this is a confusing one. i thought it was my rear end but i just dont see that being the case. tranny??? i dont feel slippage though and it shifts smoothly. Im just lost guys  :-\

do we have limited slip diffs?
I didnt see a catalytic converter ( thats what the mechanic said might be making the noise but i didnt see one)

Tony66_au

Perhaps a cracked flex plate? Is it a tinny noise?

The flex plate BTW is the thing the torque convertor is bolted to which holds it to the back of the engine, and sometimes they crack from the mounting bolts.

If you can do so maybe a video with audio on your mobile phone, take someone to do the filming and point out when it occurs from inside the cabin.

Chuck it on youtube and post the link, you can delete it when we are done.

Tony

Tony66_au

it can also be inspected from under the car via the bottom of the bell housing inspection hole but you will have to have some help doing this

Papalangi

The catalytic converters, if you have them, are part of the exhaust manifolds.  Great big cigar shaped things along side the cylinder heads.

Other places a tack tack noise can come from is a screw or rock in a tire and bad CV joints.

Michael
'83 300SD, I'm back!  It's the son's new car (12/2020)
1976 450SEL, 116.033  Sold it to buy a '97 Crown Vic.  Made sense at the time.
1971 250C, 114.023
1976 280C
1970 250/8

GypsyKingg

I thought about a CV joint but the knocking continues after i fully stop. Sorry for using "tack" haha cause its more of a knock (almost like exhaust bouncing of stuff, but my exhausts barely loose)

Its getting worse, now theres a metalic hum that vibrates my pan (i can feel it through me feet)

Thank you so much guys for all your input.

GypsyKingg

This might make it easier...

whenever i go over bumps or dips in the road. with the floaty feeling of the suspension when it reaches the farthest down point (when it dips) the humming happens heeerrrrvvv. so when im going up and down its like heervvvv.....(up)....heerrrvv...(up)...heeerrvvv