jimshih

Hi,

I just changed the water pump on a 96 C280. Every thing went ok except I can't get the belt tension/ tensioner to work right??

I compared the old and new belt----same
Doubled checked belt routing

Here is how I think the tensioner thing works after playing with it for hours

As I turned the adjustment nut clockwise, the nut moves up (left hand thread). There is a circular plate thing at the bottom of the nut. As the circular plate starts to contact a metal plate the adjustment rod start to be pushed down. This in turn rotates the rear of the tensioner counterclockwise and rotates the tension pully clockwise tightening the belt.


The problem I am seeing now is when the circular plate at the bottom of the nut starts to touch the metal plate, the nut is almost at the end of the thread travel. There are not much turns until the nut reach the top of the thread travel. Contiue to turn it damages the threads and bends the rod a little. Ask how I know. :p

I was able to get the belt tight on there with the nut almost or to the end of the thread but it lossen up by itself after ~ two hours.

I can provide pictures if someone can give me some ideas on defet parts or install error??

thanks.

redcoupe

Most of the adjustment will come from the allen that holds the tensioner to the block.
There should be a plastic arrow looking thing on the front of the tensioner.
The nut is for fine adjustments only.
So try loosening the allen a bit, screw the nut back down, and try readjusting the allen fisrt and then fine tune it throught the nut.

I hope this helps.