W113 subframe mounts

[Leutgeb]

I'm now getting ready to replace the subframe mounts (for the front crossmember) and the front motor mounts on my 230SL. (I already replaced the rear motor mount). Of course, I should have done this while the motor was out, but since I didn't, the job is now even bigger than it should have been.

I've read Mike Tangas' excellent account of this job at http://www.peachparts.com/Wikka/W108Subframe. I still have a few questions:

Instead of disconnecting the brake lines, wouldn't it be easier to undo the calipers (to avoid having to bleed the brakes on reassembly)?

The BBB says to remove the front springs and undo the tie rods. Mike apparently didn't do this. Is it really unnecessary?

Is wheel alignment needed after the job is complete?

I've been told that the replacement subframe mounts are shorter than the originals, so one needs a spacer to avoid having the engine hit the hood. Is this true? If so, where could I get the spacer? (My parts supplier is unable to find that part listed for the 113 chassis).

I've been warned not to replace just the motor mounts, because with collapsed subframe mounts, that would raise the motor enough to hit the hood. Is that really a danger?

Thanks,

Chris Earnest

[psfred]

Chris:

I didn't remove the brake lines on my 280 SE. However, mine are only a year old, and the brake fluid is new also. If yours is old, you want to exchange it anyway, this is a good time. It's not eaiser to remove the calipers, either, as you must remove the brake line to get them off, it goes around something done there -- metal line from caliper around the shock or something, bolted to the steering knuckle.

The instructions in the manual are for REMOVAL of the subframe, and you don't need to actually remov it, just lower it. Alignment is required, you are changing the relationship between steering, wheels, and subframe. Quite possible to get the caster different, too, with the longitudinal springs.

Replace the sway bar mounts while you are in there. The new ones will have a VERY small hole, and you will need to use a floor jack to force the retainer over the new mounts. Will ride a lot better.

You must remove the two nuts on each side for the longitudinal leaf spring (these nuts hold the sway bar frame mounts on) as you need them free to get the subframe low enough to swap the mount out. It won't go down far enough otherwise, I tried. Suspesion coil springs stay in there, thankfully.

Basic drill is as Mike described. You probably won't have to remove the battery tray, either (I couldn't get mine out anyway) -- it's more difficult to get the screws started, but no impossible.

I would suspect you are running very tight clearance on the W113 on the hood, I would replace the subframe mounts first if you don't want to do them at the same time. New engine mounts will raise it at least an inch! New subframe mounts will LOWER it about an inch in relation to the body.

New subframe mounts are identical to the orignal ones, and will be about an inch taller if you set them side by side. Who started the rumor they were shorter?

Peter

[Leutgeb]

Peter:

Thanks for the reply.

My brake lines are also new (I'm in the process of restoring the car), so I'll try it without taking them off. Even removing the battery tray will be easy, as it is also new.

You've confirmed that alignment will be needed, as I suspected.

As part of the job of replacing the subframe mounts, I do plan to replace the motor mounts -- there's almost no additional labor involved. I was considering doing just the motor mounts first and the subframe mounts later, but as that might well lead to clearance problems (and is more work anyway), I've decided to just do the whole job at once.

It's good to hear that I won't need to take off the coil springs, and that the new subframe mounts are identical to the originals. The guy who told me they weren't is a well-respected mechanic for these cars, but he may have been thinking about another model when I asked him.

Chris

[psfred]

Chris:

I cannot imagine why MB would change the specs on mounts. Did he mean to say the OLD ones are about an inch short, as they will be -- mine were nearly an inch shorter out of the car, in the car they were squashed down the the point that the spring cup actually touched the frame. Terrible ride, lots of noise!

Peter

[MikeTangas]

Watch those brake lines closely as you drop one side of the sub-frame. It might put a bit of a strain on the line. When I did mine mounts I didn't like the strain on the lines and opted to change them out since they were old. Removing the brake hose from the caliper took the strain on the hose out of the equation.

I was ready to remove all the springs and tie rods, but Steve Brotherton (Stevebfl) gave some insight from experience. No need to support the engine, or remove every bit. Remove just what is necessary and let the weight of the engine help lower the sub frame, one side at a time.

A couple of us have been through the drill and should be able to guide you through it. An easy weekend project if you take your time.

[jas2wa]

My subframe mounts arrive in the mail today- going to have these installed within the week, and that diy article by miketangas would be ideal, but I can't get it through that link in the first post- any ideas?

JAS

[MikeTangas]

Just go to the top of this page and hit the tab titled "DIY". Then look for the link to 108/109...subframe mounts.

[Leutgeb]

A couple of other issues on this job:

1. It looks to me like the mounting bolts for the right hand subframe mount are going to be very hard to reach, even with a universal joint socket, unless I remove the intake manifold (remember, this is a 230SL, where the manifold occupies a huge amount of space). Any comments?

2. The BBB says to be sure to reattach the flat springs (which maintain fore/aft position of the subframe) in the same position as originally. But wouldn't the eccentric on the bolt need to be readjusted anyway because the new mounts change the relative heights of the body and subframe?

Chris

[jas2wa]

Got it, thanks.

Did an alignment clear up your remaining wander? (Just looking at the article's conclusion). Anything else you would have attended to under there while it was apart, looking back at the the process?

Many thanks,

JAS

[psfred]

When I did mine the eccentric bolts didn't move. I hope they aren't rusted down, as I plan to (finally) get the alignment done this weekend if the shop can get me in Sat. morning.

You should be able to get a normal wrench on the small bolts, but the large one will require a socket and extension. I don't remember what the intake looks like, sorry, can't help much. Hopefully you can reach in without taking the intake off!

Peter

[MikeTangas]

jas2wa,

Yes, the alignment cleared that last little bit of wander I had. Really amazing what a couple hunks of rubber can do for the overall feel of a car.

I gave everything a good looking over while I was in there, fortunately I didn't find anything else to work on. I would take the opportunity to check the motor mount bolts to ensure they are tight, while you have fairly unrestricted access (compared to when everything is bolted up tight). I was able to access the 19mm bolt heads easily through the gap created when the frame was lowered, glad I did because I found the driver's side mount was a touch loose.

Hope this helps.

[TA250SL]

Good luck with this project. You should also consult with other owners and W113 experts at www.Pagoda113.com and www.sl113.org. You will join hundreds of other owners of this special car, and it's a great source for parts,restoration and maintenance advice.

Tom
1967 250SL

[jas2wa]

Thanks guys, for the info-

I'll keep you posted- hopefully by the end of the month I'll have the subframe mounts done, a proper alignment, and 4 new tires. I think that will do wonders for smoothing out the ride at higher speed-

Cheers,

JAS

[Leutgeb]

Finally got time this weekend to put in the new subframe mounts and front motor mounts on my W113. It turned out to be a fair amount of work, but not as bad as I had feared. The article by Mike Tangas was very helpful.

There are some minor differences between the the job on the 113 and Mike's 280SEL. On the 113, the battery isn't in the way, so doesn't need to come out, nor does the parking brake need to be disconnected The intake manifold does restrict access to the subframe bolts on the right, but by jacking up the engine a bit and using a universal joint on the socket I was able to get at them OK.

To lower the subframe enough, I did remove the tie rods and unhooked the brake lines and the shock absorbers. I didn't have to remove the rod which maintains left/right position of the subframe. I also unbolted the motor from its mounts and supported it on a jack -- I was replacing the mounts anyway, and the subframe is heavy enough to manipulate back into place without also having the weight of the engine on it.

Unlike Mike, I unhooked both sides of the subframe at once, but this was probably a mistake. It gives a lot of room to get the subframe mounts out and in, but it makes it a lot harder to line up the subframe when reinstalling it.

It was a repair well worth doing. The car now rides a lot better, steers tighter, and I can no longer feel the engine vibration it had at certain rpms. In short, the car now drives like a Mercedes should!

Chris

[MikeTangas]

Good job Chris.

Yes the reason for doing one side at a time is to make lining the bolt hole up much easier. Shop manual calls for dropping both sides while supporting the engine from above - an unnecessary step when doing one side at a time.

Enjoy the ride.