I replaced my brake fluid today after noting pedal was getting soft - knew it was probably the master cylinder, but thought I would try it anyway (it was time for it, too).

After doing the job, clean fluid ... but, still have pedal slowly moving past where it should be.

What experience has everyone had re: rebuilding or replacing? In case of replacing - should I go for new (if available) or rebuilt?

Quick estimate of time and any tips you have to offer?

Mucho thanks in advance!

George
george.stephenson@trw.com

Most times a new cylinder is better IDEA than to reseal the old one. I wouldn't take the liability, for anyone but myself!!

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Hi stephenson What year is your 350 sdl? I have a 91 and was wondering what your experience has been with this 350 engine. Mine works fine but I have heard so many bad things I am looking for someone who has not had all this trouble.

__________________
91 350 SDL
91 300 E
85 300 D (sold)
79 300 CD (sold)
91 300 CE

i just did this job for my friend with a 84 300sdl.Job is easy ,only takes about 35min.Master was cheap about $145.Don't make the same mistake I did remember to put o-ring on the back side of the new master or you will create a vacume leak.

Chris P,

Mine has been absolutely troublefree. However, it is early!

I have had car for only two years - had about 100K when I got it - now has 120K. Get 25MPG, uses almost no oil between 3K changes on Mobil 1.

The previous owner, a neighbor and friend, cared for it quite well, but drove it very hard - 85 MPH open road - full throttle around town. Lots of oil changes.

Most of the information I have seen re: engine destruction says there will be little or no warning. There were only about 800 1991s and few thousand total 3.5L sixes in US. Not sure there is enough of a database to explain or project ...

How about yours?

george.stephenson@trw.com

500 SEC,

Thanks for comments - did you look at bore after removal?

I love to rebuild stuff like this, but don't want to do it if it is going to fail again in a year or so.

Thanks again.

George

I inspected the booster where it mates looked fine to me,don't really know what i was looking for but nothing out of the ordinary going on in there.I really did not think to look at the master after removal ,just trew it away without a second thought.I never rebuilt a master cylinder or even thought about it ......to much of a liability Ialways prefer the new one if the option is there
Happy Motoring
James

George,

As to expected failure of a rebuilt in a year or two - I rebuilt my master cylinder somewhere between 1981 and 1983; it is still working.

If bore is smooth, I would rebuild, especially if you enjoy that sort of thing. (I do.)

Key to longevity is regular brake fluid changes. Don't have a clue as to why the original failed when it did.

__________________
Ted
1979 240D
165,000 miles

Hi Stephenson

I too have not had the car that long but it runs very well burns no oil. The car has 120,000 miles on it and is very clean. Before purchasing this car I had an immaculate 85 300D. I some times think maybe I should have kept it but the ride and performance of the 350 sdl is so much better that I don't think I would want to go back. The next time I take it to my mechanic I am going to have him check the compression and if there is any sign of trouble on the no. one cylinder I might trade it. But I could not imagine that the engine has anything wrong with it it runs so well.

I would sure like to hear from any other 90/91 350 SDL owners with good or bad experiences because as you state there are so few of these cars in the country. I know that in Minnesota I have not seen another one.

__________________
91 350 SDL
91 300 E
85 300 D (sold)
79 300 CD (sold)
91 300 CE