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-   -   M44 A/C Compressor Bracket DIY (http://www.318ti.org/forum/showthread.php?t=44481)

lokister 11-30-2018 08:32 PM

M44 A/C Compressor Bracket DIY
 
5 Attachment(s)
Hey everyone,

I chose to write this DIY because I had a hell of a time replacing this bracket with no other clear DIYs nor a Bentley manual that accurately depicts the compressors we have on our M42/M44s.

I broke the mount point on the bottom of the bracket for the A/C belt tensioner during a belt job in October. The mount is made of aluminum and is easy to break if the bolt holding the tensioner pulley is over-tightened.

The diagrams on RealOEM and in the Bentley do NOT accurately depict this repair. Once the initial mystique was removed from the job (thanks in part to members on this lovely forum), it was an easy repair.

Tools needed:
  • 6mm hex bit (a long one -- I used a ball-head long bit from Home Depot)
  • 8mm hex bit
  • 13mm socket
  • Torque wrench
  • Rachet strap

Materials needed:
  • New A/C compressor bracket (64-55-1-739-627)
  • (Optional) 4x hex bolt (07-11-9-904-533)
  • (Optional) 1x hex bolt (07-11-9-912-570)
  • (Optional) 3x allen bolt (I don't know the part number)

Procedure:


#1. Drive your beloved car onto ramps or jack up and place on jack stands. This job does not require that the wheels be removed, so whatever you prefer works. I will note that using ramps makes it slightly easier to "hold" the compressor up during bracket removal.


#2. If applicable, remove the A/C accessory belt. Turn the tensioner to the right to loosen it using an 8mm hex bit. Remove the hex bolt holding the tensioner pulley in place from the bracket. In my case, the entire tensioner was already broken, so I could skip this step.


#3. Remove the top allen bolt holding the compressor to the bracket using the long 6mm hex bit. I would recommend removing this bolt first to allow the weigh of the compressor to be distributed to the bottom bolts first. Trying to remove this top bolt when all the weight of the compressor is being supported by it is definitely not fun.


The bolt is located on the rear of the bracket, above the subframe and steering rack.

Attachment 17426

The bolt is invisible from below, so it helps to (1) use the long hex bit and (2) have a thin smartphone handy (like a newer generation iPhone) to take intermittent photos to "guide" the bit into the bolt head.

Attachment 17427

Attachment 17428

When the bolt is removed from the compressor, it will still not be free from the bracket due to the positioning of the refrigerant lines. It will sit in the threaded hole of the bracket, but the compressor will nonetheless be free.

Attachment 17429

Continued . . .

lokister 11-30-2018 09:13 PM

5 Attachment(s)
#4. Remove the bottom two allen bolts mating the compressor to the bracket. These bolts are far easier to access than the top allen bolt.

Attachment 17436

Attachment 17438

I removed the front bolt first and then the rear bolt last. When removing the last bolt, be sure to support the compressor (I found it easiest to hold it with my hands at first). If the compressor is not properly supported, damage can occur to the refrigerant lines.

Attachment 17437

Use a ratchet strap to support the compressor. I threaded my ratchet strap through the engine bay (hood open, naturally), around the left side (perspective from the rear) of the compressor between the compressor and the bracket, under the right wheel, and around the front right fender. Take care to not strain or pull the compressor too much with the strap, as this can also damage the refrigerant lines.


#5. Remove the five 13mm bolts holding the bracket to the block. I was able to use a 3/8 inch torque wrench to remove all of these, albeit with an extension for the innermost bottom mounting bolt.

Three of these bolts can be accessed from the rear.

Attachment 17433

The top rear bolt is recessed somewhat in the bracket and requires the use of a socket (a crescent wrench will not work here!). I was able to fit my torque wrench with the socket attached into this recessed area, but needed to separate the wrench and socket once I broke the bolt loose (there's not enough clearance otherwise). Be mindful of the two wires coming out of the compressor when fitting the torque wrench into the recessed area.

The innermost bottom bolt requires the use of an extension and socket, but is otherwise straightforward. The outermost bottom bolt is straightforward.

The front two bolts are similarly straightforward, although it should be noted that the bottom front bolt is longer than the other bracket-to-block bolts. I removed the top front bolt last.


#6. Snake the bracket out of the crevice where the compressor is located. On my M44 with an electric fan, I found I did not have to remove any other hardware to remove the bracket, but YMMV.

Here's my old bracket, with the broken pulley mount point in full view:
Attachment 17434


#7. Installation is the reverse of removal with one exception.

When reinstalling the compressor, release the ratchet strap and move it out of the way (i.e. not trapped between the compressor and the bracket). Support the compressor with your hand but DO NOT move it into place yet.

Thread the top allen bolt through the bracket (but not completely) BEFORE positioning the compressor and attaching the bottom two bolts. Otherwise, the rear refrigerant line will block the entrance of the allen bolt.

Once the bolt is in place in the bracket, thread one of the bottom bolts. Then tighten the top allen bolt. Finally, thread and tighten both bottom bolts completely.

I decided to replace my bracket-to-block mounting bolts, but it's not required.

Hopefully, this guide will shed some light on the M42/M44 compressor bracket removal and installation and help an E36 owner get their air conditioning back!!

eurostylez718 04-29-2021 01:46 AM

Thanks
 
Well I didnt break my bracket but it is certainly in the way of removing the crank case cover so I hadda figure that out lol

Gpmann 07-26-2023 11:28 AM

Thank you Lockister,
This post was extremely helpful. I purchased my Z3 with no A/C Tensioner Pulley and the bracket bolt socket snapped off just like yours. Everything looked so tight I would not have attempted it without removing the refrigeration lines from the compressor had your post not shown it to be possible. New bracket in now all ready to go although I did have to machine a very slight chamfer (took about 1.5 mm of material off the head of the top compressor mounting screw at a 45 degree chamfer with a bench grinder) to clear the refrigerant line compressor connector.
Would now like to torg\que the A/C Belt tensioner pulley mounting bolt to a precise Engineering Specification so as not to snap the bolt socket and having to repeat the whole exercise. Anyone know the exact torque spec for that particular bolt?
That aside tanks again for your excellent post.


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