Pelican Parts
Mercedes-Benz Parts Catalog Accessories Catalog Mercedes-Benz How To Articles Mercedes-Benz Tech Forums
Call Pelican Parts at 888-280-7799
View Recent Cars  |Shopping Cart Cart | Project List | Order Status | Help
 >  >
Replacing Your Mercedes-Benz A/C Belt
 
Bookmark and Share

Pelican Technical Article:

Replacing Your Mercedes-Benz A/C Belt

Steve Vernon

Time:

1 hour1 hr

Tab:

$8

Talent:

*

Tools:

6mm, 8mm Allen, 13mm, 19mm wrench

Applicable Models:

Mercedes-Benz W126 (1981-91)

Parts Required:

New belt

Hot Tip:

Be careful working around your radiator

Performance Gain:

Cool cabin

Complementary Modification:

Top up refrigerant

The Mercedes-Benz W126 has the proud distinction of having 5 different drive belts. This article will show you how to replace the A/C belt.

The nice thing about the A/C belt is that it there is only one belt (the air pump) that you have to remove to get access to the A/C belt. This article will show you how to remove both belts.

The air pump is located on the lower passenger side of the engine.

To remove the belt you will need to loosen the pump itself. Use a 6mm Allen and loosen the Allen bolt at the top of the pump. The pump has a tensioner/locking bolt on its lower housing. There are two nuts on the same bolt. Loosen the outer 13mm nut and then turn the inner 19mm nut. The 19mm has a spiral toothed ring on it that is used to tension the belt. Turn it counter clock wise to loosen the belt and when reinstalling turn it clock wise to tension the belt and while holding the tension tighten down the 13mm bolt.

Don't forget to retighten the 6mm allen bolt when you are done.

With the air pump belt off you can replace your A/C belt. To remove the belt you will need to loosen the tensioner on the belt using an 8mm Allen. With the tension off you can now replace the belt.

Installation is the reverse of removal

This photo illustrates the five different belts on the W126 (there are two belts on the water pump, power steering pump).
Figure 1

This photo illustrates the five different belts on the W126 (there are two belts on the water pump, power steering pump). The red arrow shows the air pump belt and the green arrow illustrates where the 6mm Allen bolt is located. Note: most of the front of the car has been removed for demonstration purposes.

This is what the air pump looks like from under the car.
Figure 2

This is what the air pump looks like from under the car. Loosen the 6mm Allen (green arrow) and then loosen the 13mm bolt (red arrow). With the bolt loosened you can turn the 19mm bolt (yellow arrow) and either un-tension or re-tension the belt.

Here you can see how the 19mm bolt has teeth in it (red arrow) and the toothed gate (green arrow) that the bolt turns in.
Figure 3

Here you can see how the 19mm bolt has teeth in it (red arrow) and the toothed gate (green arrow) that the bolt turns in.

With the air pump belt (green arrow) removed you can use an 8mm Allen to loosen the tensioner (red arrow) and then replace the A/C belt (yellow arrow).
Figure 4

With the air pump belt (green arrow) removed you can use an 8mm Allen to loosen the tensioner (red arrow) and then replace the A/C belt (yellow arrow).

Bookmark and Share
Comments and Suggestions:
Problem child Comments: Continued: My vehicle also has sel emblems on it and has some things modified I guess to meet some u.s standards i.e. Plugs welded in the door jambs. If anyone has more info about what might have been modified I'd love to talk to you. Date is 6-16-2017. I've never had a benz and want to know as much as I can about this great machine
June 15, 2017
  Followup from the Pelican Staff: I opened a post in our forums. A Pelican community member may be able to answer your question.
- Nick at Pelican Parts
 
Problem child Comments: I have an 85 euro 500se imported to USA and was wondering if I could just tighten my belts as I don't have the money to replace my belts at this moment in time and don't wanna listen to the belt scream at me with every acceleration/engine start. Do I just find my tensioners and turn clockwise?
June 15, 2017
  Followup from the Pelican Staff: You can tighten them if they are not excessively worn. FOllow the instruction sin the article on installing belts. - Nick at Pelican Parts  
91 Benz Comments: The place you show for the thermostat on the w126 420sel. The top of the engine is not where my thermostat is? I think what you show is for the SL model. I could be wrong I just know mine isn't there. Thank you for your services
December 8, 2016
  Followup from the Pelican Staff: What year is your vehicle? Engine code? - Nick at Pelican Parts  
Will Comments: What do you do if a 6mm allen wrench doesn't seem to fit
September 29, 2016
  Followup from the Pelican Staff: Try a 5 or 7. - Nick at Pelican Parts  
JB Comments: I have a 91 420sel Mercedes and it seems that this site has a lot of information that I could obtain I'm excited I'm also hands-on what work I can do myself I will I'm also in what can do myself I will
February 22, 2016
  Followup from the Pelican Staff: Glad we can help get you excited. - Nick at Pelican Parts  
lftdazd Comments: For the ac tensioner, you loosen the 19mm bolt, not the hex on the pulley
November 5, 2014
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it. I will have the article updated.
- Nick at Pelican Parts
 
Fitz Comments: I loosed the tensioner and it just came off there was no tension on it, it was just a idler wheel. Do I loosen the bolt on the arm to adjust the tension ? I like the pictures and edits on your web site THANK YOU
Ray
October 9, 2014
  Followup from the Pelican Staff: What vehicle are you working on? - Nick at Pelican Parts  
jtaon001 Comments: What direction do you turn the AC belt's tensioner to loosen it? Clockwise or Counter Clockwise?
July 7, 2014
  Followup from the Pelican Staff: Loosen the 8mm Allen bolt counterclockwise, then the tensioner releases. - Nick at Pelican Parts  
ray Comments: This is great pictorial instruction from a beginners standpoint. It explains what's involved doing it the correct way.
August 21, 2013
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help. - Nick at Pelican Parts  

QUICK LINKS
About Us
Careers
Pelican Parts, Inc.
1600 240th Street
Harbor City, CA 90710
Order Online or Call:
888-280-7799
CONNECT WITH US
NEWSLETTER
Sign Up for Pelican Pit Stop News & Special Offers
Page last updated: Sat 9/23/2017 02:28:57 AM