Did you check the price of a rebuilt one from Fastlane (top of page on this site) If I remember correctly, they're about $60.
Mercedes Shop/Fastlane are the folks who make this forum possible. I'd at least give them a look. I've found their prices and service to be exceptional.
Just my 2 cents -- arguably worth that.
'92 Mercedes 190E/2.3 (247K miles/my daily driver)
'93 Volvo 940 Turbo Wagon (263K miles/a family truckster with spunk)
'99 Kawasaki Concours
'85 Jeep CJ-7 w/ Fisher plow (226K miles)'93 Volvo 940 Turbo Wagon
'53 Willys-Overland Pickup
'85 Honda 750F Interceptor
'93 Nissan Quest
'89 Toyota Camry Wagon
'89 Dodge Raider
'81 Honda CB 750F Super Sport
'88 Toyota Celica
'95 Toyota Tacoma
'74 Honda CB 550F