Rebuilding entire suspension 87' 560SL. Tips, Pointers and HELP! - PeachParts Mercedes-Benz Forum

red560SL · #1 09-16-2006, 03:51 PM

Years ago I owned a 250C which was stolen at the shop that was doing my body off restoration!!!! Boy did that hurt. Now here I am 15 years later with a 87' 560SL, but this time I want to do the work myself and thanks to the Net, I think it's possible. Here's where I'm at:

I purchased this car at an auction. I was aware I needed to do some work, but I couldn't resist owning my own 560SL. The car sat in storage for years, but was started on a regular basis. The engine is strong and doesn't burn or consume oil. The tranny had all kinds of leaks. I pulled the tranny and replaced all the seals and now I have a tranny that no longer leaks! Over the last few months I saved some money cause I knew I needed to rebuild the entire suspension. Ball joints are shot, lower control arm bushings are shot, brakes, bearing, tie rods, discs and everything else you can think of will be replaced and/or rebuilt. All this stuff is rotted or worn out. After receiving the new parts this week, I started with the front suspension.

Working on driver's side first, I remove the calipers, rotors and tie rods. I supported the lower control arm and removed the ball joint from the spindle. I lowered the lower control arm and removed the spring and have successfully removed the lower control arm. The control arm and ball joint as well as the wheel hub are at the shop having the bearings and ball joints pressed out/in.

Now here's where I'm a little lost. I'm no machanic and all I could find to help was a Mitchell CD manual that doesn't give a lot of detail. I can see the front subframe bushings are rotted so badly that you can barely tell there is rubber left. I have a new set, but not sure how to go about replacing these. I can see they need to be replaced while I have the lower control arm out of the car, but how would I do this and safely? Safety is my #1 concern. Do I need to remove the ENTIRE front frame to remove and replace these? If so, do I have to also remove the right lower control arm first? Or can I do one side at a time? What procedure would you pro's use to replace these? Everything seems so heavy and I don't want to kill myself just because I want to have a perfect riding 560SL.

I would like to keep this thread open as I attempt to completely rebuild the entire suspension as I'm sure I'll have more questions along the way. I also have all the rear stuff to replace, but want to first tackle this front end. The newly pressed ball joint, control arm and wheel hubs will be ready for Monday pickup. If I can continue working on the car this weekend and replace these worn out subframe bolts and bushings, it will keep me busy and out of trouble (maybe).

I'll post any pics you want and will promptly reply to any questions. I just would like a little help along the way and to help my 5 year old daughter keep her daddy in the process.

Thanks for any help,
Tony

psfred · #2 09-16-2006, 04:21 PM

I will probably be doing the subframe mounts on my brother's 75 300D this weekend, same subframe.

Here's what you do:

Raise car on jackstands, placing them under the main frame so that the subframe is free. It will hang down quite a bit from the bad mounts. Make sure the car is stable (it probably already is).

If you have stands under the subframe now, you will have to move them, it must be free to lower down some.

Support the subframe and engine with a good floor jack. Remove the bolts (on the bottom) on one side. Best to have the whole kit for this job (bushings, new captive nuts, clips, and sheilds). You may have trouble with the captive nuts, I had to stick a large screwdriver in a trap one to get it undone.

Lower the subframe enough to get the old mounts out and new ones in. Use silicone oil or undiluted dishwashing detergent on the new mounts. I had to pry one of the old ones out on my 220D, but the others just lifted out. Watch that you DO NOT put you hand between subframe frame in case of slippage!

Raise subframe back up and install bolts, but leave them loose.

Switch sides and remove the bolts on the other mounts. Lower subframe again and remove mounts. Likely you will need a large prybar between the upper spring cup and the main frame to force the subframe down enough to get the mounts in and out -- this is why you dont' want to pull them all the way up on the other side.

Once in, install bolts and tighten up all round, then remove jack.

Quite easy except for the possiblity of frozen nuts on the old bolts and stuck mounts.

Use appropriate care, of course!

Peter

Strife · #3 09-16-2006, 04:38 PM

This is a great time to do the motor mounts. If the rest of the suspension is bad, you can bet that these are also bad.

red560SL · #4 09-16-2006, 04:47 PM

Thanks a million psfred (Peter). I think I understand the procedure and it was kind of what I thought was the process. I do have one question however:

<--you said-->
Support the subframe and engine with a good floor jack.
<--you said-->

Not sure what you mean. I can see the engine oil pan and I can see the cross member subframe in front and behind the pan and I can see how I would support either the subframe or the engine via the oil pan, but what you do mean by support both the engine and subframe? Looking at things it appears the motor (via motor mounts) is attached to the subframe which would answer the question by simply supporting the subframe I would achieve support of the engine at the same time. Just want to make sure I understand things before I stick my head under the car. hahaha

Right now I have four jack stands sitting at the jack points of the body which is super stable. They are 6 ton stands that have a very high lift. I have the car pretty high up with lots of clearance under the car. I do have the entire subframe kit so I'm good to go. I bought EVERYTHING I could think of before I started. So far I haven't missed anything.

I'm headed off to get some silicone oil and take the family out to lunch. When I get back I'll attempt to remove and replace the subframe components. Give me a few hours or maybe until tomorrow. I work slow, but I work cautiously and pay a lot of attention to detail. Once I've completed this I'll let you know the final outcome. Monday I'll get back everything for the left side and then I'll remove the right lower control arm and have the ball joint pressed as well as the new bearings pressed for that side. Then I'll put it all back together which only means it's time to start on the rear of the car. My wife can't understand why I want to do all this myself. I guess they just don't understand the gratification you get when you've done it yourself.

Just before posting I notice "Strife" jumping in. I did not yet order motor mounts. Why is now the best time to do this. Is it easier now than later? When I made my list for repairs I was only thinking about the suspension. I guess I might have screwed up. Maybe I should put in an order for the motor mounts so I have them for early next week.

Thanks a million guys,
Tony

Strife · #5 09-16-2006, 04:54 PM

With the subframe lowered to do the subframe mounts, it was a lot easier for me to get at the motor mounts (which are very difficult). You can use a floor jack on a thick 12" x 12" piece of wood (spreading out the load) to support the engine via the oil pan while doing this. A procedure like this is mentioned in the manual. Hard to believe you can support the engine via the pan, but apparently true.

There are two 7mm? 8mm? bolts on each mount that are tough to get at, I used a cutoff piece of an allen wrench in a socket.

psfred · #6 09-16-2006, 05:00 PM

The engine sits on the subframe. Lower the whole assembly (the engine weight help here). You can run the jack on either the oil pan with a plank between the jack and pan, or on the subframe itself, which ever is easier.

Engine mounts will likely be requried, as the new subframe mounts will effectively lower the engine an inch or more. On the 220D, that caused the AC compressor to knock on the fender until I replaced the engine mounts.

Peter

red560SL · #7 09-16-2006, 08:09 PM

Thanks guys! I'll put an order in for the motor mounts now. I probably won't get them until Tuesday or Wednesday at the latest. At that time I'll replace them and complete the rest of the frontend. And as promised, I'll fill you in on my progress. I'll even take a couple of pics along the way. Then maybe you guys can help me out with the rear???

Later,
-Tony-

Strife · #8 09-16-2006, 09:08 PM

I replaced the two rear subframe mounts, it was pretty "interesting" to dig them out; they are expensive and the ones I pulled out weren't really bad. I probably would not have done this job if I hadn't shotgunned the whole suspension when I bought the car. Replacing them made absolutely no difference in the ride. The bilsteins and front subframe mounts, however...another story.

I have a center (diff) mount but my original one still looks fine, and I haven't replaced it.

red560SL · #9 09-22-2006, 02:00 PM

Finally I have the front end torn apart. However I'm not sure if what I have is correct or what I'm doing is right. I've attached a couple of pics to help explain myself.

I'm just now in the process of installing the front sub-frame mount kit. But there seems to be extra parts in this kit or parts were missing from my 560SL. Here are the parts I have from flybynight.com:

http://www.flybynight.com/search/productx.aspx?partnumber=1153301875

As you can see from the pics I have attached (and at flybynight.com), there are parts in this kit that I don't seem to have on the car. The first pic (if that's how this forum places pics) is the pic from flybynight.com. The following pic is what was delivered (same as flybynight.com). What I don't seem to have are those little half circle retainer clips (4 pieces middle on the right of flybynight.com description pic). Nowhere can I find these. Should they be here and if so, how do they work?

You can see my bushings are shot! All that came out is the rubber bushing, plastic tapered cap, rubber ring, large metal ring, bolt and lock washer on each mount. I don't have these little half circle clips or what ever they are.

Any feedback on this would be appreciated. I can't find a manual anywhere and all I have is a Mitchell CD manual and it does not show this part of the car. I'm at a loss.

Thanks,
Tony

red560SL · #10 09-22-2006, 02:03 PM

I'm adding another picture of those clips so you can have a better look at what I'm talking about.

Thanks again,
Tony

Alkraut · #11 09-22-2006, 05:09 PM

I recently did the same front subframe job on my 560SL. The clips are used on some Mercedes models to prevent the rotation of the winged nuts. Apparently the kit works on other M-Bs. I to did not find the clips in my car, nor did I need them. The only strange thing that I encountered was that a couple of the slotted "windows" in the chassis, that the winged nuts go into was too narrow for the new parts, so I used the old nuts there. I guess I could have ground them down.

When complete, you will not believe the difference in the way your car handles and rides! Good Luck

red560SL · #12 09-22-2006, 06:12 PM

Thanks Alkraut. I was hoping that was the case. I too have those slots and everything fit up nicely. I'm now replacing the motor mounts. WOW! They are broke on both sides! I am sure glad I purchased them before I started. No wonder it would make a clunking sound when I put it in gear or shifted to park. I thought I was up for tranny work, but maybe I'm not. Let's hope...

Thanks!

psfred · #13 09-22-2006, 08:48 PM

The W108/109 chassis is worse, there are only two mounts instead of four!

Having the subframe "steer" under the car is much to much fun.

I'm on my way to do my brother's W115 chassis tonight!

Peter

Richard Wooldridge · #14 09-22-2006, 10:56 PM

Hi Tony,
I did much the same job on my '82 380SL a few months ago, due to the left lower control arm mounts breaking off the sub-frame.
Yes, the left wheel actually folded under the car!
There is a recall for this problem on cast iron engined cars, but apparently when they went to the aluminum engines MB decided the problem would go away.
Guess what, it is still there!
Be SURE to have a REAL GOOD look at the lower control arm mounting tabs.
They aren't very strong, the sub-frame was designed for a lighter car with a smaller engine.
Originally used on the 114 chassis vehicles.
If you find any signs of cracking on the mounts, sub-frame and/or around the mounting tabs (They have the slots in them for adjusting the lower control arms in or out) you should replace the sub-frame!
You almost have the sub-frame out of the car anyway.
I was able to exchange the sub-frame and replace all the mounts in about 4 hours of labor-intensive work.
It was actually easier to replace the engine mounts with the sub-frame out on the bench.
I installed a good used 114 sub-frame, which I welded the MB sub-frame stiffener kit metal pieces onto.
The car is much quieter with the new engine mounts and sub-frame bushings installed.
While you are in there have a look at the steering coupler also, it is a part that will eventually need replaced.
Also, if you have any slack in the steering gear you may be able to adjust it easier with the sub-frame out of the way (provided you do remove the sub-frame).

red560SL · #15 09-23-2006, 11:01 AM

Thanks for the tip Richard. I just inspected the entire subframe with a magnifying glass (just to be sure since I'm getting old). I see no stress cracks or any other sign of weekness. I paid special attention to the welds and couldn't find any problems. I'm the third owner of this car and the last owner had the car for 15 years and they did very little driving as it spent many of those years in storage. Previous owners did not drive the car hard from what I can tell. The biggest problem with this car is the rotting of rubber pieces.

I haven't had a chance to do a good inspection of the steering coupling yet, but I will later today. I found the thing pretty cheap at under $54. I'm wondering if I should just replace it for the fun of it? What do you think?

http://www.flybynight.com/search/productx.aspx?makeid=800016@Mercedes&modelid=1195310@560SL&year=1987&cid=26@Steering%20System&gid=7418@Steering%20Coupling%20Assembly

I'm replacing just about everything else under there. All new tie rods, steering damper, upper/lower control arm kits and ball joints, idler arm bushing replacement, Bilstein shocks, subframe mounts, motor mounts etc.

Would it be a smart thing to replace the steering coupling with everything out or should I wait until after I have it all back together and the wheels aligned? This way when I take off the steering coupling I can center the wheels and steering wheel so that I get everything back together centered. Without any reference I'll probably have things cockeyed and have to remove it again anyway to line it all back up. What are you throughts about this?

Tony