Replacing front sub-frame mounts 114 - PeachParts Mercedes-Benz Forum

#1 10-14-2002, 05:12 PM

Greetings,

I've browsed through the archive and saw several threads in this topic. I was wonder if anyone as a detailed procedure and whether the fron sub-frame mounts can be changed without the the engine hoist that the book calls for. Can one side be done at time or must the entire frame be lower and done together?

Any advice would be helpful and welcome.
Thanks,
Chet

BTW This is my first post to this site. I've had my 250C for more that 10 years and has severed me as a daily driver without fail. A year ago I bought an 89 560 SEC, to give Old Blue a break. I probably did more work on the SEC in 1yr than I did on the C in 10yrs. So now it's Old Blues turn for some TLC...

MikeTangas · #2 10-14-2002, 08:44 PM

In the DIY section, I covered the sub frame mount replacement for a W108. You can do one side at a time without the assistance of an engine hoist. While the article is not specific to your model, it should provide some help.

Oh, and welcome to the board.

psfred · #3 10-14-2002, 09:40 PM

Chet:

Subframe mounts on the W114 are simpler than the W108 except that there are two on each side.

Procedure:

Put car up on jack stands, preferably four, although you can just raise the front. Shake car HARD to make sure it won't fall off with you underneath....

You will probably want to remove the front wheels for access. Once that is done, you need only remove the bolts, one side at a time, to release the subframe. The bolts go through the mounts and into the main frame to a pair of nut plates. The worst you will have to deal with is these nut plates -- if the plate is broken off, you will have to jamb the nuts with a large screwdriver, etc to get the bolt out.

Once the bolts are out, the subframe can be pried down with a large prybar to allow you to remove the mounts -- they fit into recesses in the frame. If they have gotten oily, they will be stuck, so use care prying them out -- if the prybar slips, you can crush your hand. Pry between the main frame and upper spring cup. First side is easy.

Once the old mounts are out, lube the new ones with some silicone spray or dishwashing detergnet (undiluted). Slip them into the recess and re-install the bolts.

Leave bolts loose, you won't be able to pry the other side down otherwise. There are new nut plates with the mounts, and some washers, I think (I did this four years or more ago!).

Repeat for the other side, re-install wheels, and tighten bolts after the cars is on the ground.

You will probably need a helper for the second side. I couldn't hold the prybar down enough to reach in for the mounts by myself.

Peter

#4 10-15-2002, 10:13 AM

Mike & Peter,

Mike, I had gone through your excellent writeup, I just wasn't sure if it would applied to the my 114.

Peter, thanks for confirming confirming it basically would apply and for filling in the blanks..

Hopefully the parts will be in by this weekend and I'll get those mounts replaced along with: Rebuild calipers, replacing rotors, regreasing w/bearing, bleed b/system, install rear subframe mounts and cleaning up the engine compartment.

This car was one of my pet projects until the SEC came along, when it sort of took a back seat..
I'm also in the process of doing body work (rust). I've replaced the entire left-side floor pan, both rocker panels and have cut out & replace most of the metal around the rear wheel wells.
I wish I had my digital camera when I started this job, because I would have throughly documented it. Going forward I plan on documenting as much as possible as I do with my SEC.

Thanks agian,
Chet

psfred · #5 10-15-2002, 07:45 PM

Chet:

Sounds like both W115s my brother and I have -- I need to decide whether or not to fix up the 220D, we are almost done with the 75 300D (floorpans, homemade, fender tip on one side, various other bits, "new" front fenders). Paint is on, looks terrible, will need to get another couple quarts and re-paint to smooth it out.

Peter

#6 10-22-2002, 10:34 AM

Peter,

I replaced the front (and rear) subframe mounts this weekend. The fronts were a breeze. I really agonized over the engine hoist and the special jack craddle the manual refers to, I'm glad they weren't required. It couldn't have take more than 20mins per side (and that's with taking my time). Just followed yours and Mike's instructions, put the floorjack under the lower control arm and removed the 2 bolts. Then I put a support under one of the loose mounts and very slowly lowered the jack. The assembly's weight forced the old mount out easy as pie. Repeated with the other mount.

Installed the new mounts (lube with silicon, one at a time) and jacked up the control arm. This pressed the mount home. The mount kit comes with a spring clip that holds the nut plate in place.

The rear mount were just as easy. I used a procedure by Richard Easly that worked on my SEC. http://business.baylor.edu/Richard_Easley/autofaqs/sframe.htm

Also got all the calipers rebuilt, brake hosed replaced, rotors replaced and w/bearing repacked.

I'm just have a little trouble with getting the brake pedal back up. I bled 3 qts on fluid thorugh the system and still haven't gotten all the air out..

Thank again guys,
Chet

MikeTangas · #7 10-22-2002, 11:44 AM

You really have to keep an eye on the fluid level. The rear chamber will go dry on you and you'll never get them bled. I usually top off the resevoir after every third crack of the bleeder screw.

Watch the rear chamber closely, it will not start to fill until the main chamber is nearly overflowing. Just add the fluid slow.

#8 10-22-2002, 12:36 PM

Hi Mike,

I tried to keep a close eye on it. I'll give it another whack tonight.

Also, would you know if the splash guard between the chambers is available separately or is that a part of the kit? Mine is starting to deteriorate, so I pulled it out until I get a replacement...

Thanks

ctaylor738 · #9 10-25-2002, 06:11 PM

I took the brake fluid level sensors out of the resevoir (they unscrew) - that way you can monitor the levels separately.

MikeTangas · #10 10-26-2002, 01:38 AM

I remove the screen filter and keep a flashlight handy, even in the daytime, to illuminate the resevoir. I don't know about the divider in the resevoir. If it is deteriorated, it could be causing a fluid leak out the underside of the resevoir. The resevoir is only held to the master cylinder by two rubber grommets.

Get a pair of replacement grommets, empty the resevoir and remove it. That will give you a chance to thoroughly inspect it. Should be able to obtain a replacement resevoir for short $$$.

#11 10-26-2002, 09:31 AM

I had the floats out and cleaned everything up before I replaced the fluid and started bleeding the system. The splash guard is a little rubber "Y" piece the fits under the screen inside the reservoir. At this point I still can't seem to get all the air out. I'm not leaking fluid from the reservoir grommets, but could it be possible they are the source of my air leak.

I guess I should have rebuilt the master cylinder too since I was doing the calipers. What do you think? Any suggestions on how to determine if the master cylinder is sucking air?

Thanks again.
Chet

psfred · #12 10-26-2002, 01:56 PM

Two things:

A bad master cylinder can suck in air, especially if you lift your foot too fast while bleeding.

You can also vacuum bleed the brakes with a MitiVac -- this works very nicely, except that you will always get a small stream of tiny air bubbles from the bleeder valve -- once you open it, air leaks down the threads under vac. That stream of tiny bubbles isn't air in the system, and if you try to eliminate it you will be bleeding forever. If you have a high, firm pedal, you don't have air.

A bad brake line will cause a soft pedal just a readily as air in the system, too. Check of a hose that "ballons" under pressure.

Peter

#13 10-27-2002, 09:48 AM

I think I've tried about everything and the pedal seems firm, but not as high as I feel it should be. I started out using my MityVac and I wrapped the bleeder screws with teflon tape. I then tried having my wife pump the brakes (but the up stroke was fast) as I openned the bleeder. Then I tried a speed bleeder. This speed bleeder has a clear plastic hose that has a check valve at one end. The other end is clamped to the bleeder screw. I had someone pump the brake pedal and every 3-4 stoke you could see a little belch of bubbles.

I took the car for a test drive and the car stops in a straight line. No pulling like I had, but I be happier with a little higher pedal.

I did change all the hoses..

I'll order a master cylinder kit. I did everything else, might as well do that too..

Thanks again Peter,
Chet

psfred · #14 10-27-2002, 11:39 AM

Chet:

I have found that new pads will sometimes give a low pedal until you wear the "fur" off the working face. Takes me a couple hunderd miles since I brake gently most of the time. Certainly true so far on the 280, but then I've not replaced the last hose yet (a project for today) and I need to bleed the rear again.

Probably not a bad idea to replace or rebuild the master cylinder. It is possible to get corrosion pits in parts of the bore never used except when bleeding, so you pull air back into the master cylinder around the rear piston seal ONLY when bleeding.....

Peter

Douglas Broome · #15 11-03-2002, 07:30 AM

On all Mercedes the Ezebleed device is a wonderful device for pressure bleeding brakes by one person. Uses pressure from the spare tire. No sucking airt with the Mightyvac. No having a helper mash the brake pedal. I have used one for years on various Mercedes I have owned, the latest two being my 1977 240D and my current 1959 220S. I cannot sing the praises of this gizmo loudly enough!