coonpuff

Need help replacing squealing 2028001575.
Left tempering flap actuator making piercing noise. Located and isolated vacuum at 90 degree fitting. My question is how to disconnect and replace upper control arm buried in dash? I was thinking purchase new part and disassemble old actuator, replace diaphragm, reassemble. My concern is not being able to match new part config to older damaged part.
Any input welcome.

City Rat

The sound and location that you describe is almost identical to one that has been bugging me for a couple of months now. I had the sense that a flap in the HVAC system was partially stuck and a high range piercing sound resulted as air rushed past it. I will be closely following this. It would be great if you post pics of the part or the procedure for pulling the dash and getting to it. BTWhow did you diagnose that thia flap actuator was the cause?

coonpuff

Hello,
The diagnostic was simple.
1.Remove the glove box.
2.Remove air ducting to passengers side vent by wiggling the duct tube left to right out glove box opening.
3.Located Y11 vacuum distributor, in newly revealed opening, strapped to blower housing
4.Pinched and released mounting bracket at top fork and bent out of way.
5.Removed black rubber cover to expose Y11 hoses at the connection nipples
6.Powered ventilation system on, selecting the vent with the whistle and
7.GENTLY pinched, partially - the hoses one by one until noise reduced or disappeared.

City Rat

Great write up. My problem is that my high pitched whine comes from the driver's side, left most vent area, the other end of the dash from the glove box.

coonpuff

My/the squeal, whistle is a vacuum leak at the diaphragm of the actuator.
There are multiple actuators and all originate at y11. once y11 is identified - troubleshooting can begin.

See this post for diagram

[URL="http://www.benzworld.org/forums/w140-s-class/1466847-switchover-valve-block-y11.html"]

My leak is in an actuator above drivers right foot.
pics to follow

coonpuff

City Rat - I have the answers
Finally got the courage to tackle my new Possible.
I figured out how to remove the actuator at an angle without damaging the upper control arm.
I'm trying to load pictures and share the progression but cannot get URL pic upload to work.
any suggestions ?

coonpuff

Pinholes in diaphragm causing noise.

Parts just ordered from AutoHauzAZ

2028001575
A/C Vacuum Actuator; For Left Tempering Flap
$33.10

The original part actuator arm can be recycled by disassembling the coupling clip.