Did you use a lubricant? If you didn't, I can't imagine how you got them inserted that far. Believe it or not, KY worked great. The FSM recommends a water-soluble lubricant and it will take lots of it to overcome 4" of rubber friction. For a press, I used 7/16" all-thread, nuts, washers and 3/4" dr. sockets (Harbor Freight specials).

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Sam

84 300SD 350K+ miles ( Blue Belle )

Thanks SD. I used plenty of Super Lube an aerosol lube but it seemed like the lube was gone as soon as the rubber is inserted. I have the service manual and will try again. The SM calls for "slide fluid Naphtolen for installation or optionally slide fluid Paladinol". I may try pure silicone spray or Dialectic grease. Will let you know how I do.

Just a couple thoughts/questions on this thread as I am probably going to do this in the near future...

In post #13 step 5, whunter says to remove three bolts that hold the bearing bracket to the body. Believe this should be two.

I have an '84 SD. I need to replace the guide rod mount on at least one side, plan to do both. I know it needs to be replaced since it groans when the suspension moves up and down, and I can feel it when touching the guide rod and pushing the front bumper up and down.

I like to have all the parts I need when I start a job as it is difficult to go pick up parts when the suspension is in pieces. Without disassembly, is there a way to tell if my bearing bracket bushings will also need to be replaced? The car is 25 years old, only has 104Kmiles on it, lived in SoCal all its life. Should I replace the bushings just on principle? I'm looking at about $150 for bushings and guide rod mount, will it be much more for the entire bearing bracket assembly? Will the assembly come with the parts needed to mount it (bolts and captured nuts)?

Mainly looking for info on diagnosing bad bushings. I can call around and get the prices/parts of the bracket assy, but if ya know....

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mjk

'84 300SD 119KMi (Liesl der Diesel)
'84 300D 326KMi when the oil left (former parts car)
'82 300SD 253KMi (new parts car)

Wow! This looks like a complete PITA compared to the 123.

Great write up. This will be helpful when I pick up my SD!

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AJ

1985 300D (SOLD)

I'm right in the middle of the exact same job on the exact same vehicle.

Yes, Roy has it wrong...........there are three cap screws that hold the cross member to the left and right bearing brackets. Two screws hold the bearing bracket to the body.

The bearing bracket bushings "last the life of the car" as stated by many professional mechanics. I took the option to change them in the hope to improve the ride quality. The 25 year old rubber was definitely rock hard..........I don't see how they perform the originally designed damping.

I don't know the cost of the entire bracket assembly...........might be a consideration if it's reasonable. Getting the three components in and out of the bracket isn't going to be any fun without an arbor press. I had the press in the machine shop and it still took a couple of hours to remove the components, prepare the bores, and reinstall. That's for a single bracket.

The SD is getting the full monty...........bearing bracket bushings, guide rod mounts, guide rod bushing in LCA, LCA bushings, upper control arms, calipers, Akebono pads, and rotors. I'll be done with the left side tonight...........seems to have taken forever.

Our environments are quite different, y'know. I'm not expecting the rust and deterioration issues that you might experience. Were the bushing still solidly inserted in the bracket? No movement that you could tell? I expect that even though they might be hard, as long as they were solid and complete that it wouldn't compromise the ride quality too much. Again, still looking for an indication to help decide beforehand if I should buy bushings.

Thanks! I'd like to hear your experience with your new suspension.

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mjk

'84 300SD 119KMi (Liesl der Diesel)
'84 300D 326KMi when the oil left (former parts car)
'82 300SD 253KMi (new parts car)

Surprisingly, this vehicle has no rust. It lived in FL all of it's life until 2002 and has been garaged here ever since.

The bushings were still solidly inserted in the bracket. If cost is an issue, I probably wouldn't change them. As I mentioned, no professional mechanic agrees with me on the need to change them...........I'm just doing it because I can.

The left LCA bushing was in such good condition that I won't be doing the right.

Having done this job on both sides, I would recommend a couple more checks to verify the problem area. On mine, the guide rod mounts would "clunk" when going over uneven ground such as a speed bump and you could feel it in the driver's floorboard. Groaning problems were from dry ball joints. Believe me the ball joints are usually easier. Check for torn boots and if you have a grease gun with one of those needle tips, you might see if you can finagle some grease under the boot to see if it quiets at all. Since the ball joint is at the other end of the guide rod, the source of noise may be deceptive.

IIRC, the entire bearing mount is ~ $400+ per side. With only 104K, I wouldn't suspect worn bushings unless there was something else, such as oil saturation, that contributed. On mine, the left side was saturated with oil from a leaking oil cooler line and there were visible cracks in the surface. I replaced the RH bushings at the same time but don't think it was really necessary, even with over 300K.

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Sam

84 300SD 350K+ miles ( Blue Belle )

Lower ball joints were replaced within the past six months on both sides, upper guide joint was replaced on passenger side. Boot was good on the upper guide joint on driver's side, but I haven't ruled it out as a problem. The groaning is definitely coming from the guide rod mount on the passenger side. If I touch the threaded rod from the mount while the bumper is moved up/down, I can "feel" the groan. Clunking on uneven pavement seems to be coming from driver's side.

I checked the rubber at the bottom of the bushings and it was dry, very pliable, no cracks, no crumbling. So I plan to replace the guide rod mounts only and see if that resolves the problem. All my tie rod boots are also busted, so I'm replacing the tie rods at the same time. My tires are wearing out on the outside edges so I need to get this done ASAP so I can replace them and get an alignment.

Thanks for the advice. Much appreciated.

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mjk

'84 300SD 119KMi (Liesl der Diesel)
'84 300D 326KMi when the oil left (former parts car)
'82 300SD 253KMi (new parts car)

One thing you might add to this procedure is a dry fit between the bushing bolt and the captive nut prior to installation. Had I done this, I would have saved myself an afternoon of extra work. And now, the rest of the story...

Everything was going great. All the old bolts came out easily, and I got the driver's side bracket off about an hour after I started gathering my tools up for the job, jacking up the car, etc. An hour, not bad. So I knocked the mount joint out of the bracket, took some steel wool and cleaned up the hole, greased and inserted the new mount joint, and proceeded to reinstall. After getting the guide rod threaded onto the mount joint (hardest part of the job so far) I was able to get the rear bushing bolt installed using the new captive nut that came with the mount. (Meyle kit.) Once the threads engaged, it was _very_ difficult to turn, a fact I attributed to the deformed nut. Though I hadn't tightened the bushing to the chassis, the metal clip part the captive nut was already deforming so I supported the metal as best I could to keep it straight and continued. Using a ratcheting tie-down strap I pulled the wheel assy forward to align the front bushing and inserted the bushing bolt into the captive nut. This one is not as easy to see and it seemed even tighter than the rear. I hadn't gotten two threads past the top of the nut before it sheared out of the clip. I tried jamming screwdrivers and other objects in the hole trying to get a bite on the nut but no luck. I ended up buying a 1.5 in wide bar of 1/4 in steel and made a tool that would fit into the hole and secure the nut in place.

So the lesson here is to check the fit of these nuts prior to assembly. I've read here that they are prone to self-destruct on removal, but no-one's ever mentioned that they may do the some on installation. Ensure that they assemble to your liking before putting them into service. Careful use of a tap may serve to open the threads up enough to allow proper installation while still allowing enough hold to keep the bolt from turning out. Or tap the nut completely and use threadlock on it. Just don't do what I did and blindly think that because it's new, it's correct out of the box.

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mjk

'84 300SD 119KMi (Liesl der Diesel)
'84 300D 326KMi when the oil left (former parts car)
'82 300SD 253KMi (new parts car)

Whenever I get in that situation, I attribute it to misalignment between bolt and nut...........very common with the fine metric threads. I remove fastener and start again. Never force a metric fastener............disaster always looms.

I had thought the same thing. With as tight as the thread was, I would have expected some scrambling of the threads on the bolt if that were the case. But there was nothing. This is a long bolt with a coarse thread and it goes through two holes (one in the bracket bushing and one in the chassis). So the bolt is pretty much lined up for you once the parts are in place and the bolt goes through the chassis. I started the threads by hand which usually prevents cross-threading. The threads were clean when it was disassembled, none of the usual mess you get after cross-threading. And when I re-assembled there was no issue threading the bolt in the old nut.

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mjk

'84 300SD 119KMi (Liesl der Diesel)
'84 300D 326KMi when the oil left (former parts car)
'82 300SD 253KMi (new parts car)

How does the front of the guide rod remove?

I've unbolted it but am loathe to beat on the stud, even with the nut protecting the threads.

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r2

'85 300SD 193k miles (parts)
'81 300SD 400k miles-sold
'84 300SD 205k miles-sold
'84 300TDT 270k miles-sold
'80 300CD 200k miles-sold

Presumably, the guide rod is already unthreaded from the guide rod bushing.

And, presumably, you're replacing the guide rod mount so go ahead and pound it out by beating on the stud.

You've removed the back cover............??

Yes, I removed the back cover. Just to be clear, I'm talking about the front of the guide rod that bolts to the LCA. I just read that a spring compressor is needed.

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r2

'85 300SD 193k miles (parts)
'81 300SD 400k miles-sold
'84 300SD 205k miles-sold
'84 300TDT 270k miles-sold
'80 300CD 200k miles-sold