Call on my subframe mount bushings
 

Hey guys-

Can someone have a look at my subframe mount bushing and let me know if it's time to replace? Pic is of the left bushing.

Car seems to drive fine at high speed but it feels like it tracks side/side on grooved pavement.

I had the front end rebuilt about 6 mos ago. Not sure if/when the PO did any repairs to the rear end.

Thanks-
Rob

79 300SD
399K

Hve them changed - you won't believe the difference in ride, ride height and control...
Jake

looking at the amount of rubber shown in the bushing, the rubber is almost fully compressed. a new bushing will show about 2 inches more height than in the photo

:D

bill

Can someone post a diagram showing exactly where on the car the subframe bushing wear can be examined (as in the 1st post picture)

thanks!

Trying it this weekend...
 

...using the Baylor method that I think I saw here in a search. I'll be using the 1/2" threaded rod and using the weight of the vehicle to drive out the old bushings. Can someone confirm that the attached setup is correct?

I don't understand if the car underbody is supposed to bear against the big fender washer at the top, the top of the 1/2" rod, or something else. I also don't get why the method calls for leaving a half-inch of exposed thread above the top washer. Seems like I'd poke a hole in the car if I loaded it onto just the 1/2" rod.

Do I need a block of wood between the top of the pressing tool and the underbody of the car?

Thanks!
Rob

how hard is to actually change these things, mine ar not that bad but are getting there, is it something that i would be able to do or should i take her to the shop?

You can do these yourself with a little effort. I did my front and rear suspension last summer/ fall in my driveway. I used some pry bars to get the subframe bushings out, they weren't as hard as they look. When you reinstall the subframe mount use a bottle jack as a leverage point to get the bolt started. All that will make sense when you get there. Do a search you will find a wealth of info right here.:vbac47679 Good luck.

not real easy
 

You have to unbolt the diff and drop it then you can unbolt one subframe and replace the bushing, then do the other. Not super hard, but not easy either. You need to disconnect your rear brake calipers from the hubs (hang from sway bar with zip ties or wire) and disconnect the parking brake (PITA to get off and reattach) so you won't stress them as you drop the subframe.

You won't need a bottle jack to start the big bolt in the subframe bushing if you just raise the diff back up to level - that gives you the angle you need to easily start the bolt.

Actually removing and replacing the bushing is not the hard part - it's getting to the point where you can drop the subframe enough to get to it that is a bear (a lot of work). As the post earlier said you can use a small pry bar to go around and get it out and use a big c-clamp to press it in)

I never dropped the differential. Didn't unhook e brakes either. Just took calipers off and hung them, placed jack under..wait a minute there is a good pictorial someplace around here with all of this information. A pretty straight forward write up. It might be on diesel giants page if you can't find it under the search function button at the top. There really is no need to drop the differential.

While you're at it...
 

Replace the trailing arm bushings now so you don't have to drop subframe again for a while. Might as well replace the rear Z links and stabilizer mounts too. How old is the differential mount? If you can't get all of that now at least do the trailing arm bushings. The other stuff is fairly easy to get to.

Planning on new diff mount, as well
 

I'm planning on replacing the differential mount, as well.

I'm planning on doing each subframe mount bushing first, then swapping out the differential mount. I checked out the trailing arm mounts and they still seem to be in pretty good shape...was planning on these if I need to do an axle or new strut.

Crash, if you can find that pictoral please let me know. I've searched a lot...the best I could find was the description of the Baylor technique:

http://diymbrepair.com/easley/sframe.htm

There's no mention of having to drop the differential or hang the calipers here...is the write-up pretty accurate?

My car's a W116...not sure if that has any bearing as well, from what I understand they're pretty straightforward to work on back there.

Rob

diff
 

That probably is true (not dropping the diff).

When I did mine I *WAS* doing lower control arm bushings at the same time as the mounts. You have to drop the sub frame pretty far to allow enough clearance to allow the bolts to come out of the trailing arm (trailing arm has to be lower than the frame, otherwise the bolt backs into the frame and you can't get it out! ugh)

Is the w124 chassis procedure similar? Any forum links to pictorials?

Yes, you can do the "Baylor" method without dropping the differential. It's how I did mine. However, from your description of the tracking problem, I would definitely suspect those trailing arm bushings. I had one that was nearly gone that caused strange tracking problems on mine. They can appear OK until you drop the trailing arm.

When you decide to do them, you will need an MB spring compressor. And unless you are young, Epsom salts for the tub soak afterwards......doing that much work on a suspensions is a workout!

workout
 

I second that. Suspension work can be a lot of work. I think my subframe and trailing arms took me all day. I got hung up on figuring out how to get the parking brake free and wasted a lot of time.

The 24mm bushing bolt goes up though the bushing into a tube in the body of the car. The top of the 1/2" threaded rod fits into the tube that the bushing bolt goes in and the nut keeps it from going in too far and munging the threads inside. You might want another washer on top of that upper nut to keep the nut from munging the end of the tube and to help keep that upper nut from tuning and allowing the threaded rod to go too deep into the tube.

Also, I had to put pressure on the bushing bolt to get it to align with the threads. Ended up with some sort of bizarre contraption of a socket, with an extra 24mm nut inside as a spacer and a chunk of 1/2" square rod in the socket's ratchet hole, all pushed up against the bolt with a bottle jack. It was the only way I could figure out how to push (gently) on the bolt with a jack and still be able to turn the bolt. Figuring that out was by far the most time consuming part of the job.

FYI, on the 617 diesels, there isn't a rubber piece between subframe and body -- there's a stop bracket instead. Make sure you get the right kit -- it should come with two new stops that are mirror images of each other (mine wern't, but I was able to reuse the old stop).

Hey Hope this has gone well for you. I've been way too busy. I did a search and found my old posts but I don't see the pictorial that I was referring to. It was here somewhere!! I used a couple of pry bars to remove the rubber mount from the subframe. Yes a cheap ball joint press from harbor freight worked well to remove and install the trailing arm bushings. If I can help any send me a PM.:idea2:

Done
 

Thanks for the help, did the subframe mount bushings and diff mount this weekend and it went well, all in all. The Baylor method worked well.

Right bushing came out just fine, popped out with a bang just like I've read. I lubed the new one with dish soap and it pressed in fine. Very little problem pressing it in. The bolt was straightforward too, just a push with bottle jack and the threads took, cranked it right on in. I was thinking "wow this is easy!"

Karma got me on the left side, of course. The inner part of the bushing was delaminated from the outer, so when I pressed out I only got the "core" of the old bushing out. The outer shell of it was still stuck fast inside the subframe and now there was no bearing surface on the bushing for the threaded rod tool. I tried prying with different breaker bars, driving in a screwdriver, torch, no luck. So I crossdrilled across the bottom metal in the flat sides of the old bushing, shoved an old allen wrench across the span, and used the allen wrench my new bearing surface. Put the threaded rod tool back in, loaded up, and out it came! Installing the new one was straightforward, same as right side, but more difficulty getting the thread on the bushing bolt started. Used a bottle jack, topped with a wood block, topped with an old socket that centered on the bolt and allowed me to get a wrench in and start the thread. No problem.

Differential mount went fine. Some difficulty getting one of the bolts loose but it yielded to some heat and a good breaker bar.

Total for everything was about 4-5hrs including cleanup, not bad for the first time I suppose.

Haven't checked the handling yet, my radiator is out getting rebuilt and I need new tranny and oil cooler lines...but once this is done I'll take her out for a drive and report back.

Rob

way to go!
 

nice job! :)