Rear subframe removal and bushing replacement - Page 3 - PeachParts Mercedes-Benz Forum

Benzoid123 · #31 08-03-2010, 10:33 AM

Wow! Nice work! I'm inspired! And terrified!

dieseldan44 · #32 08-03-2010, 01:02 PM

Army - Did you have bolt snapping issues with the diff from rust? I am looking at my diff-to-subframe bolts and am a little scared of them. (charmalu youre in CA and i envy you)

I had always thought taking off the subframe was too difficult to be attempted by mere mortals without special tools to re-align.

Do i need to get an alignment after doing this? Is there even anything to adjust?

dd

Stretch · #33 08-03-2010, 01:27 PM

Quote:

Originally Posted by dieseldan44

Army - Did you have bolt snapping issues with the diff from rust? I am looking at my diff-to-subframe bolts and am a little scared of them. (charmalu youre in CA and i envy you)

I had always thought taking off the subframe was too difficult to be attempted by mere mortals without special tools to re-align.

Do i need to get an alignment after doing this? Is there even anything to adjust?

dd

I had no problems with the rear diff mount. But if you get into trouble there is a great fix for stripped captive nuts here:-

I cannot get this bolt out

Adjustment - short answer:- not really so long as your ride height is correct.

Adjustment - long answer:-

Well I've read that there is a way of spinning the trailing arm bushings around to get a different camber and castor - but having looked at mine I'm not sure that that is correct as my Febi replacements were as round as round could be - no oval adjustment there. I think this information has gotten confused with the front LCA bushings that do seem to come with some sort of off set and also rubber protrusions / markings on their outer surfaces. I think if you can't get the castor or camber you want on the FRONT then you can fiddle with these...

If you take a look in your FSM you'll see a whole chapter on checking the sub frame integrity on a special surface plate - so if your alignment on the back is out then I guess you'd have to go and find one of those bits of kit:- I bet you couldn't find a dealer near you that could do it!

As for ride height I've worked out a neat way of checking it as per the FSM - I'll post this soon honest! I'm just getting my data confirmed and then I'm ready...

...using the string down the side of the car method it is easy to check toe in / out. (I'll be including this as well - with pictures too)

As for the mortals comment - just remember a little bit of the "well it must be easy because can do it" attitude can go a long way! (It can also send you up **** creek with out a paddle - but how else will you learn?)

Stretch · #34 08-03-2010, 01:28 PM

Quote:

Originally Posted by Benzoid123

Wow! Nice work! I'm inspired! And terrified!

Don't be scared we'll talk you through it - trust me I'm a vegetarian... (Whopper with cheese anyone?)

dieseldan44 · #35 08-04-2010, 12:46 AM

Alright, I think I may take the plunge and just do it. If I do everything at once, it will save a lot of time over doing things one at a time.

I am thinking it will take me 30 hours of work over 6 works days. That includes at least a couple snapped bolts and unexpected hardships.

Question - can I take both subframe mounts out using the cars weight if I am ultimately removing the whole subframe? I know I can get the first one out, but what about the second one?

Stretch · #36 08-04-2010, 01:31 AM

Quote:

Originally Posted by dieseldan44

Alright, I think I may take the plunge and just do it. If I do everything at once, it will save a lot of time over doing things one at a time.

I am thinking it will take me 30 hours of work over 6 works days. That includes at least a couple snapped bolts and unexpected hardships.

Question - can I take both subframe mounts out using the cars weight if I am ultimately removing the whole subframe? I know I can get the first one out, but what about the second one?

I'm not sure as I ended up using bolt cutter etc (see the first posts) but I expect so - if not getting them out otherwise is still possible! Don't worry it actually is an easy job... after all the thought and checking you've put into it I'm sure you'll be surprised.

dieseldan44 · #37 08-05-2010, 12:03 PM

OK, im almost there.

how did you guys disconnect the parking brake cable from the hub?

Im going to post my procedure a little later and make sure it makes sense to you guys.

I really really need this project to go smoothly :-)

charmalu · #38 08-05-2010, 12:46 PM

You do not need to remove the parking brake cable from the hubs.

In post# 28 I described how to remove the cables fron under the center of the car. once you have the vehicle jacked and secure. release the parking brake so there is slack. then disconnect spring, lever adjuster from under the car. one clamp bolted to the floor on the drivers side. there are the 2 clips that hold the cables to a bracket on ea side pull them down and out.

Once you are under there, it will seem clear.

I sort of screwed up at PNP when I removed the trailing arms that I used in my R&R. I cut them off behind the hubs, then had to figure out how to release them from from the hub and install my old cables.
I also replaced the parking brake pads, which was another challenging job. so when I had the old shoes and springs removed, I used the old arms as something to go by along with my Haynes and MB FSM for guidance.

Posr#25 I described how I jacked up the car as per Whunter suggestion.

Yeah, living in Calif has some bennifits to living in Boston, as far as the corrosion goes. It all came apart like it was new, and this after 25 yrs. at least mine is an original Ca car and not imported from Boston. I have seen some at PNP that are totally gone underneith.

Charlie

dieseldan44 · #39 08-05-2010, 01:52 PM

Thank you charmalu.

How did you guys get the trailing arm bushings out? I see the threaded rod thing whiskeydan did for installation, but i don't see how that gets the bushing pieces out.

Pushing out bushings in the northeast is horrible. I want to have a plan going in....

and...

On reinstall, when did you put the springs back in? Align and thread all the bolts then put the springs in with a compressor (which I have)? Or some other method?

Stretch · #40 08-05-2010, 02:05 PM

Here are some more pictures to encourage the brave.

Two are of the trailing arms and the sub frame just before I put them back on - I quite like the one of the sub frame and trailing arms upright against the back of the car - this shows you how light it all is with out the diff fitted. Just in case you didn't believe me...

And in case you're now worried about the parking brake that you may or may not replace here's a solution to those irritating retaining springs:-

Get an old flat blade screw driver and slice a notch in it with an angle grinder and cutting disc. You can then use your new (butchered) tool to twist the little buggers round with ease.

I lost my patience with the old ones (which were going to be replaced anyway) and cut 'em out with bolt cutters. Oh yes I love my bolt cutters and my angle grinder - 2 really honoured bits of kit in my tool box.

Stretch · #41 08-05-2010, 02:10 PM

Sorry I'm having an attachment nightmare - It keeps telling me I've already added the picture I want to show... and guess what the computer doesn't lie: IT IS IN POST #11 doh...

Stretch · #42 08-05-2010, 02:16 PM

Quote:

Originally Posted by dieseldan44

Thank you charmalu.

How did you guys get the trailing arm bushings out? I see the threaded rod thing whiskeydan did for installation, but i don't see how that gets the bushing pieces out.

Pushing out bushings in the northeast is horrible. I want to have a plan going in....

and...

On reinstall, when did you put the springs back in? Align and thread all the bolts then put the springs in with a compressor (which I have)? Or some other method?

I've searched and searched for a photograph of taking the bushings out of the trailing arms but I can't find one yet (I'm sure I took one...).

Anyway here is one of putting in a new bushing. I'll use it to explain what I did to get 'em in and out.

Stretch · #43 08-05-2010, 02:28 PM

Take a look in the photograph in post #42

You can see that there is a bit of threaded bar that is threaded through the trailing arm structure.

To get bushings out you need something that has a diameter slightly larger than the trailing arm bushing but not so large that it will not squarely butt up against the trailing arm structure. The plan is to push the bushing out of the hole into the trailing arm and into this "thing" that you just found.

Whiskey Dan recommended plumbing connectors for this and this is indeed what I used. They are long enough to hold the bushing.

It is best to cut away the rubber part of the bushing that sticks out on one side of the bushing. This makes the next stage easier!

Place your plumbing connector (or what ever you use) on one side of the trailing arm. Thread your threaded bar through the bushing and attach some washers that are small enough to be drawn through the trailing arm's bushing hole. MAKE sure these washers don't scrape the internals of the trailing arm whilst they go through.

Place a really large washer (OR A BIT OF WOOD - WOOD IS GOOD!) over the larger diameter end of the plumbing connector that isn't up against the trailing arm...

And that's it - you just wind up two nuts on either end of the threaded bar until the little chap pops out. EDIT little chap = bushing

dieseldan44 · #44 08-05-2010, 02:35 PM

Thanks Army. You guys are awesome....really lowering the risk of downtime associated with this job for me.

I'll have all my tools made before taking it apart. Hopefully on day #1 I can have everything removed and the bushings out. Thats going to be where all the risk is for me. After that, it'll just be that final line-up.

I am going to go to Harbor Freight and get myself a third floor jack. Ill get the nice racing one this time :-)

Stretch · #45 08-05-2010, 02:40 PM

Again look at the photograph attached to post # 42

To put the new bushing in:-

Make sure the inside of the trailing arm bushing hole is clean / rust free.

Make sure you put the bushing in the correct way round - see photo.

Lubricate the outer surface of your new bushing with a WATER based lubricant such as KY Jelly... I understand in America you guys can get a product call slyglide. This is widely appreciated here on this forum. I can't get it here so I used KY. The point is that you shouldn't use an oil based lubricant because it can knacker your rubber. It is best not to use silicone sprays as they are usually oil based.

Thread your threaded bar through your new bushing, the trailing arm, and something that can react against the trailing arm. Again I recommend wood. Wood is really good especially if you are heavy handed. Wood will generally crack and grown before you are likely to do any serious damage to a metal structure.

Again use two nuts to tighten this configuration until the bushing goes in.

WATCH OUT though that you don't over do it as the metal sleeve in the centre of the bushing will want to go with the tension in the threaded bar (as you're most likely to be winding up against it) and the outer surface of the rubber bushing will tend to oppose this movement. So sort of shear the new bushing into place. This is OK but not if you actually manage to permanently distort it - hence the recommendation of wood again so you don't over do it by accident.