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re.. 1987 300SDL brake and tensioner problems

1087 Views 6 Replies 4 Participants Last post by  whitemikefl
Hello all. I have been a die hard 123 owner for 9 years. I recently made the jump to the 126 body. I am finding it to be a world of difference when it comes to repair. I have a few questions.....

My brakes...More often when the outside temperature is cold than warm my brakes seem to pulsate right before I come to a full stop. The pedal also goes low...not LOW, but lower than norma. I am really at a loss to explain this. The brake reservoir is fine, no leaks, new brakes all the way around (previous owner). Any Ideas?

My belt tensioner is crooked a couple of degrees, the spring, shock & pulley look intact. It seems to be the lower piece to which the pulley is attached to the engine block that is bent? or worn. What is this piece and is this what causes the pulley to ride at an angle to where my belt only rides 3/4 of the pulley?? (dangerously close to the fan blade !!)

Any help is greatly appreciated.

Rochester NY

81 300D
83 300D
84 300D
85 300D
83 240D
75 & 75 240D
76 280C
79 350SE
1 - 7 of 7 Posts
The pulsating is probably the ABS kicking in due to the front sensors needing to be replaced. You can try cleaning them, but it is usually only a short term fix.

Is the brake fluid in the reservoir clean or dirty. If it is dirty, flush the system as it may be contaminated with water causing the spongy pedal.
my 89 420sel was doing the same thing i had to replace my left and right front ABS sensor wery costly $300 for each sensor plus labor
Thank You for your thoughts guys I appreciate it. Is there any specific info on cleaning the speed sensors??????

If you can get them out in one peice, simply wipe off all the debris and refit.
Thanks for the input. I r & r'd the tensioner lever, spring and shock last night in about 2 hours. I didn't even have to take out the fan or radiator! ! I only had to remove the fan shroud for enough clearance. It was rough at first, but once I figured out what tools to use I was golden.

Thanks Guys
1 - 7 of 7 Posts
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