Engine mount replacement

[n/a]

G'day everyone

I've just replaced my engine mounts after the right hand side one failed. The rubber centre had come away from the body of the mount and the engine dropped so much that the air conditioner compressor was resting hard on the air cleaner cannister. The additional movement also ripped the side mounting off the radiator and it needed to be re-soldered. Changing the engine mounts wasn't a particularly difficult job especially since I have a mate who is a mechanic and he let me use his workshop. What a difference it makes when you have a hoist, the right tools and some helpful advice! I also replaced the subframe mounts while I was at it. This is not that diffciult but the limited access under the intake manifold makes it frustrating and time consuming. I intend to do as much on the car myself from now on.

Mark

1965 230 SL light blue, auto, RHD

[George Davis]

Mark,

I'd like to know how you did the subframe mounts.  I've done them from the wheel-well side, you seem to have come in the other way.  Did you have to disconnect the brake hoses to get enough clearance?

Thanks!

George Davis
'69 280 SL Euro manual

[n/a]

Mark,

I too need to replace my engine mounts. It looks easy enough but it would be great to have a blow-by-blow description for us novices.

Where in Oz are you? I'm surrently in London but will be heading home probably next year (Melbourne). Too long on these cold and rusted shores.

Cheers,
Andrew

Andrew
London
1967 250SL

[n/a]

Hi George and Andrew

I'm a psychologist, not a mechanic. I consider myself a novice! The engine mounts weren't too bad. This is how I approached it on a right hand drive car.

Right hand side:

I put the car on a hoist and undid the two smaller locating bolts with a 6 mm Allen key attached to a socket. I went from underneath although other people have told me that you can get to the mounts from the wheel arch with the wheel removed. The large centre bolt also has an Allen key head but you can't get a socket wrench in there so I just used a normal 10 mm Allen key. They all came out surprisingly easy. I then took a standing jack and put it on the right hand edge of the gearbox bell housing to lift the motor slightly. It only needed to come up an inch or so. The mount came away (in bits) with a bit of jiggling and I put the new one in. By the way, the mounts are identical for both sides although they have different parts numbers.

After a bit of stuffing around I realised that you have to get both of the smaller locating bolts in and started before you take the jack away from the engine. Otherwise lining them up with the centre bolt in place is a real pain. I tightened up the bolts and that side was done.

Left hand side

While the car was on the hoist I loosened the two locating bolts with an Allen key because the socket wouldn't fit from below. I then lowered the car to the floor and worked from above. It's a bit tight but they are easy enough to get out. I put a piece of wood on a floor jack and put it under the sump to raise it slightly and take the weight off the engine. The mount came out readily. I put the new one in and started the locating bolts before screwing in the centre bolt. Then I lowered the jack from the engine and tightend everything up from above.

Does this make sense? As I said, it wasn't particularly difficult once I was told how to do it.

Subframe mounts

After removing all the bolts I removed the mounts from the wheel wells. I didn't remove any brake hoses.

Working from above with the car on the floor I removed the four outer bolts and the centre bolt from beneath the intake manifold. This is very tight and you need a flexible joint on the end of your socket (13 mm?) to get in there. I then removed the two nuts holding the shock absorber and loosened the mountings on the front sway bar to gain some extra movement. Then I raised the car about three feet on the hoist and the subframe dropped enough to get to the subframe mounts. They were in tight so I had to hit them with a block of wood and a hammer until they popped. You have to come in from below and hit the lower lip of mount upwards. Even with lots of jiggling they would not come out so I put a six foot length of three by two timber between the body and the subframe and had someone lever it down while I jiggled the mount out. I used the same procedure to get the new one in. I tightened up the sway bay mounts and then lowered the car enough to screw the mounting bolts but not so such that I couldn't move the mounts around to line them up. Then I replaced and tightened up the shock absorber nuts.

The left hand side was a breeze to replace. The right hand side took almost three hours! Lining up the four outer bolts and tightening them with the manifold in the way was a challenge to say the least.

I don't have a workshop manual yet so this is probably not the right way to go about it but it worked and the car is as tight as a drum now.

Clear as mud?

Mark

Ps. I live in Sydney, Andrew.


1965 230 SL light blue, auto, RHD

[Benz Dr.]

A bit off topic but I did this exact same job on a 6.3 a fews weeks back. I'm still hurting from that job.
 Sub frame mounts were not too bad but the motor mounts were very hard to remove and even worse going back in. The front air control valves are also held in place by a bracket just below the mounts so all the air lines and the valves have to be removed before the mount will even come out. What would normally take a few hours took more than a day. One of the most difficult jobs I've ever had to do.....

  A 113 is SIMPLE compared to a 6.3

 Dan Caron
  SL Barn

Daniel G Caron

[n/a]

Daniel

Funny that you should mention the 6.3. I was talking to my parts supplier about my recent mechanical work. I though he was exaggerating when he told me that it can take three days to replace the engine/subframe mounts on a 6.3 if things go wrong.

This makes me feel better!

Mark

1965 230 SL light blue, auto, RHD

[n/a]

Mark,

Excellent. I am making my own "manual" and your entry will be included. I find the Haines type manuals miss some critical how to's.

My girlfriend is from Sydney and we are "discussing" moving back to Oz. Could find myself living in your fair city although this will take months of soul searching to come to terms with the Sydney/Melbourne rivalry thing. Anyway, if I can force myself to accept that although Sydney is an inferior place it's OK to live there I'll drop you a line (for our American friends - that is Aussie humour; no Mark will not be offended as he understands these things).

Cheers,
Andrew

Andrew
London
1967 250SL

[n/a]

Andrew

Moving to Sydney is an excellent idea! Make sure you bring a pair of sunglasses as we have sunshine up here. Seriously though, if you do move here let me know if you need any info. Through trial and error I have gained quite a bit of local knowledge about sources for parts, mechanics, panel beaters etc. More importantly, who NOT to go to.

Mark

1965 230 SL light blue, auto, RHD

[n/a]

Mark,

Thanks. It's funny how you develop the info. I know many good (and bad) places here in Europe as well. Have you ever imported any parts into Australia. My basic plan is to export my car to Oz when we leave here and, once home, do a complete nuts and bolts restoration. I can buy all the parts now and ship them to Oz myself but will have to pay the Euro GST. If I buy them from Oz, no Euro GST but have to pay tax in Oz.... and we all know what Nazis the Aussie Tax Office are!!!

Any advice would be appreciated.

Cheers
Andrew

Andrew
London
1967 250SL

[George Davis]

Mark,

thanks for your reply on the subframe mounts.  This won't be of any use to you now, but if anyone else is contemplating this surgery, removing the CSV from the intake manifold gave better access to the right sub-mount center bolt and made the job easier.

George Davis
'69 280 SL Euro manual

[ja17]

Hello,
Here is a motor mount replacement procedure that I posted a couple of years ago on the Yahoo site. I thought I may add it to this string in case someone else needs it.

"Engine removal is not necesary. A good experienced technician can breeze
through the job in about an hour. That's with experience and the right
tools and no unexpected difficulties . Plan to spend three or four hours  if
your a beginner.
There are some important tips and basic tools you'll need. Make sure you
have a 1/2" drive rachet-handle or breaker bar, a 12" or longer extension
(also 1/2" drive), a
19mm  swivle socket (built in universal) or use a swivle extension. You will
need a 6mm allen-socket (a socket with a 6mm allen sticking out the end,
3/8" drive is ok for this with extension and handle). You may want to have a
traditional 6mm allen wrench on hand also. If you do not have a lift or
hoist then a  floor jack and  a nice  10" section of board at least 4"
wide will work for lifting the engine. Your neighborhood Sears store can
supply you any of these tools at an affordable price.
(1) Step number one make sure you have the correct parts. If you are using
the original round style their is a right and a left. Pay attention to the
part number and be sure to install on the correct side. My addition C dealer
parts book gives # 127-223-12-04 as left and 127-223-11-04 as right. These
numbers have probably changed. Kits were also available with some of the
hardware and other minor parts. Kit # 110-586-02-22, I do not know if it is
still supplied or if the number has changed. Maybe one of our other listers
can help us here.
Plan on removing and unhooking one side at a time. If you unfasten both
sides installation and alignment becomes more difficult. First unbolt the
large 19mm bolt in the top of the mount on one side. If you do not have a
hoist use the floor jack with board will  work nicely. Position the wood
board on the bottom of the engine sub pan so that the jack does not damage
the pan. Make sure that the jack and board are positioned to the left or
right so that you lift one side of the engine at a time. Be gentile, take it
slow and raise the engine on the side your working. You should be able to
get about an inch or so above the old mount. Next spend a little time
cleaning out the  grease and grit from the sockets of  two allen bolt heads.
If the heads of these allens strip then the project becomes much more
difficult so spend some time cleaning them out and do not  be tempted to use
anything but a good grade allen tool. Now remove both 6mm allen bolts. If an
allen bolt head begins to strip, take a heavy drift or punch and smack it,
the shock will loosen up the rusted threads. After both 6mm allens are
removed the mount can be lifted out. If your old mount still has the torque
plate attached, remove it and install it on the new mount. Install the new
mount by first installing one of the 6mm bolts ( install the most difficult
to reach first),  Lower the engine and then install the 19mm bolt, lastly
align and install the last 6mm allen bolt.  Move the jack and board to the
other side of the pan and repeat the process on the other side.
One side note; the latter  Mercedes 108 series square style sedan mounts fit
and seem to work fine. They are a latter design, are universal ( both the
same, no left or right), the torque plates do not seem to be necessary.
They bolt up and installation is exactly the same. The V-8 series 108 mounts
are heavier duty and may be more suitable for competition in the 113 series
possibly? They seem to be stronger and last longer also. They may be less
expensive and easier to come by? I've done this change many times and it
seems to work fine. This is just another option to consider. The part number
for the 108 series 6 cyl. sedan was 108-223-01-12 (both sides) or the 108
8cyl sedans (280-SE 4.5) #116-223-01-12 (both sides). Maybe some of  you
have experimented with these also? Comments?
Joe Alexander
Message: 14
   Date: Tue, 22 Jan 2002 10:36:07 -0000
   From: "djg230sl" <david.grainger@ag.gov.au>
Subject: Engine and transmission mounts

Dear List,
Following some advice posted earlier about the incredible difference
new engine and transmission mounts made to the overall general
smoothness of our cars I lashed out and now have two new genuine MB
rubber mounts for each side of the engine and one similarly nice new
MB mount that goes at the back of the transmission (manual, in my
car). My question is this - can the engine mounts be fitted without
complete removal of the engine? Can I put it in a sling and lift it
the 25mm (one inch!) or so that it appears to need, without
disconnecting anything? The transmission mount is, I think, OK to
replace without removing the unit, but, as ever, List advice mightily
appreciated!
David Grainger
Canberra, Australia
1966 230SL, Euro, 5 speed, still rough-ish"







Joe Alexander
Blacklick, Ohio