replacing old hoses
 

I recently had a "breather" hose replaced. My car was still no performing properly and after contacting a fellow forum shop member who was kind enough to take a look at my MB, I decided it would be a good idea to replace more hoses. My 420 sel is a 1989, wouldn't it be a good idea to just replace all of the hoses? Are some hoses more important than others or do some of them never need to be replaced?It has been deceided that my motor was jumpy because of air leaks in hoses. Any thoughts on this subject?Would it be a wise move to just replace them all?

If you have the cash, go for it!! 13 plus years on some of them. They're not getting any younger:D

a famous diy'er saying "while I'm in there"
 

I would replace the belts too if they have not been.

Change all the coolant hoses - they are the ones that can do the most damage if they let go and I'm not just talking about getting the Nike's wet. The coolant should get changed when the hoses are refreashed. The vacuum hoses should come next but you can let them fail. They will cause problems that won't really leave you by the road.

You inquired about the importance of the various hoses, the coolant hoses are the most important. The most important coolant hose on the car is the one that goes bad and leaves you by the road or worse, by the road with a severely overheated engine. It is not something you want to happen.

cost and number of hoses?
 

How many hoses are there and how much do they cost? How long does it take to install them? Thanks!

I'm not sure how many are on your car. Get in touch with Phil at Partsshop/Fastlane and get him to work them up for you.

I've changed almost every hose and vacuum line on my '89 560 SEL in the past 7 months. Lost count of the number, but each new hose improved the idle or performance. The biggest help was the short hoses to and from the idle control valve. O-ring on the oil dipstick cleaned up the engine. When I started, the old hoses were so brittle that I thought most of them were made from molded bakelite. Phil at FastLane was a great help in gathering all the vacuum parts. Good luck.