Coincidental that Steve also should talk about replacing mounts. After the bleeding project, I am going to tackle the left side mount by following Arthur's advice, stated recently in another thread, about undoing the bottom bolt and then removing the bracket from the engine, since the top bolt is a too much of a challenge.

Is that true? That seems high to me. I did mine at 15 psi. Is there a reason/advantage to push it to 30 psi?

There is so much information available on almost everything, that I'm not sure where I got that from. However, I am pretty sure it was from Stu Ritter's 124 Bible. The high pressure had something to do with the ABS system.

I looked in the the Factory Manual and it doesn't specify a pressure.

If 15 psi worked, then you are good to go.

Steve

I use 15 b/c I have seen a plastic res split at 25 psi..

Another change of procedure for me. A ruptured reservoir could really do a number on the paint job.

Steve

Yes .. I blamed the first one I saw as a possible bad/weak res seam, but then a friend with a 113 had the same experience,[ actually cracked the res right off the master seal nipple] .... so, knowing 15 psi does the job fine , why chance it...
The newer plastic res is not built for pressure , mearely back-up fluid containment.. the old units were cast right into the master casing and would take most any pressure, but those days are history.......

Success
 

Well, thanks to everyone, I completed this job. I did it on my 87 300e, which lost its braking ability, eg, the pedal went straight to the floor once the engine was started. I took off the reservoir and found one of the grommets had buckled, which I guess allowed air to enter the system. Hoping this was the cause of my problem, I replaced the reservoir, grommets and master cylinder from my parts car ( in hindsight I probably should have bought new grommets just to be safe), purchased DOT 4 and a power bleeder, and went to work. I also purchased a 9mm deep socket, and used it to loosen all four bleeders to make sure none were stuck, used about 13 psi at the bleeder after putting in two 12 ounce bottles, and started from the right rear. All the old drained fluid was a light, olive green, and not as dirty as the muddy looking fluid I removed from the reservoir with a turkey baster. This made me wonder if MB or another brand of fluid is green, or if the green just was dirt (the castrol I used was clear). BTW, when the fluid flowed through the tube it looked pretty clear, and I probably stopped too early on the rear wheels. But next spring I'll do in again (mb says every 12 months for my '87). Started the car, the pedal was pumped a bit and stayed firm, and I took a test drive, me and my SEG. I was so pleased I threw some more fluid into the bleeder and did the clk, where mb has repositioned the bleeders so that a small 9 mm wrench was all I needed. The old fluid also came out light green, and I doubt it had ever been changed (shame on me). In the clk the reservoir was grimy, so I used a toothbrush to clean the right side area by the cap before I turkey-basted out the dirty fluid, but I couldn't gain access to brush the other side, so when I was done I levelled the fluid in between the minimum/maximum lines, just below the dirt line. Thanks again; without you all I never could have done this.