How to Install AC Compressor Brackets

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Part 1 of 2:

As part of my AC R&R over the past few weeks, I had to reinstall the AC Compressor Brackets to the engine. What follows is the steps I took to complete the task. At the end of the thread is a .pdf copy of the thread including pictures.

In order to install the necessary engine brackets to mount the compressor, it’s important to be prepared for what you have to do. It’s not a difficult task, nor truly time-consuming, but could be frustrating if you don’t have all the pieces you need (at least for mounting purposes). I will be referring to LH and RH aspects for simplicity sake, and as always, it refers to the orientation based on the driver. Also, I’m going to use terminology which may not be the correct Porsche terms however, I felt it important in order to make it a little more intuitive for anyone who decides to make the attempt. The part numbers used are from the parts manual, but you could likely get most of the general nuts and bolts at a local store. I have used pictures as best possible without unnecessarily going overboard. I recommend you read the whole document through so you can make sense of it all. The order presented is the way I did it – there could be better / other ways, but this worked for me, without any hassles.

Step 1 – Confirm there is a gap in the engine tin on the immediate left of the engine support bracket / console to insert the main fin-shaped support bracket. If there is no gap, you will need to either find replacement tin, or you could remove it and trim the edge out to allow for the bracket to fit through. The slot is approximately 12 cms long from the right side of the engine support bracket and 2*cms deep when measured from the forward edge of the trim (engine side).



Confirm you have all the parts, including mounting hardware (as a minimum, bolts / washers [P/N: N 010 289 5 – M10x32 (x2) & P/N: 900-025-008-04 – M10,5 (x2)] for the main fin-shaped support bracket [P/N: 930-126-015-00 (x1)], stud [P/N: 999-062-073-02 (x1)] on LH side of said bracket in order to mount the vertical strut [P/N: 911-126-124-02], pan-head screw [P/N: 999-218-009-02 (x1)] and washer [P/N: 900-025-007-03 – M8,4] to mount the rear fastening angle [P/N: 930-126-116-02 (x1)]. If you have this, then as a minimum you can mount the initial support structure. Of note: for the stud requirement, you can simply buy an M8 length of threaded rod, and cut it to size for the two studs required. As part of the process, you’ll be removing the muffler, so an additional gasket [P/N: 911-111-191-01] and three mounting bolts, washers, and locknuts are important [P/N: 900-074-282-02,
900-025-007-03 and 900-910-097-02 respectively].

In order to mount the wave-shaped compressor plate at the end [P/N:*930-126-118-01 (x1) FOR CARRERA or P/N:*930-126-119-01 (x1) – FOR TURBO], you’ll also need, the plate itself, an additional stud [P/N:*900-081-019-02 – M8x25] mounted to the fin-shaped bracket, hex-head bolts and washers [P/N: N 010 335 5 (x3) & P/N: 900-223-001-02 (x3)] to physically mount the compressor plate to the fin-shaped bracket. Once the compressor is ready, you’ll need long bolts and washers to attach the compressor [P/N: N 010 388 3 – M8x90 (x3) and 900-025-007-03 – M8,4].



Step 2 – Dry fit all the main support pieces together prior to install, so you understand what you’re attempting to achieve, and that you confirm you have all the requisite parts.



Step 3 – Drive the rear of the car up onto ramps or place the rear end on jack stands. I found it easier on ramps, which gave me spare jack-stands to use for support requirements during installation. I used two 6-ton jack-stands due to their reach, to support the muffler during removal and reinstallation (or you could use coat hanger wire to hold it in place). Caution: Make sure the car is securely and safely positioned before proceeding.

Step 4 – Remove and set aside the heater plastic elbow and sleeve at its base from the LH side of the engine bay in order to free up the heat exchanger crossover pipe that you’ll have to remove in the next step.



Note: Ensure you have safety goggles of some sort as well. If you look at the muffler, directly forward of it, you will see the heat exchanger crossover pipe. I had to remove both the muffler and this pipe, as removing only the crossover pipe didn’t give me the clearance / access to the upper mounting bolt, this could probably have been achieved by removing the rear piece of engine tin, but I chose this route, and left the engine bay nearly intact.



Step 5 – In order to allow more space to remove the muffler, it’s easier to remove the crossover pipe first. It is attached in two different ways – two metal muffler support straps attach it to the muffler, and a total of four hose clamps attach it to the heat exchangers (two on either side via two red heat resistance rubberish tubes). You may want to spray the 8mm Allen bolts attaching the muffler support straps with something and let it sit for a bit to allow for simpler extraction. Remove the two Allen bolts (8mm) first but leave the straps around the muffler – no need to remove / bend them. Simply slide the LH strap off the brace on the crossover pipe, and leave the RH loose (you’ll be dropping the crossover pipe out next). The next action will release the crossover tube, so be ready – it’s not heavy but you don’t want it falling down. Loosen the four hose clamps and slide them and the red tubes as far back onto the crossover pipe, without stretching / tearing the rubber. While supporting the crossover tube, slowly manoeuvre it and the RH muffler support strap around it to lower the crossover tube.



Step 6 – Removing the muffler is next. Place a high enough extended jack-stand under either side of the muffler in order to support the weight (or you could use coat hanger wire to hold it in place) once the three bolts attaching it to the catalytic converter are removed. You may have to cut the bolts off if they are seized. Once removed, you should be able to carefully lower the muffler out from under the car, with the two muffler support straps still around it. Insert the bolts with washers from the CAT side and slide the new gasket on so you don’t forget it later. Once complete, you will easily see the two bolts at the base of the engine support bracket that will need to be removed. There are four bolts holding the engine support bracket to the engine, and thereby support the full weight of the engine between them. It is important to provide some added support to the engine, while you remove these bolts to secure the fin-shaped bracket. Place a strong enough jack (e.g. 3-ton) in from the left behind the RH rear wheel under the base of the engine to simply provide additional temporary support. Place a piece of wood on the jack (or a lot of cardboard) to avoid damaging the crankcase for the short time it is there. Once in place, remove the two lower bolts from the engine support bracket.

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Part 2 of 2:

Step 7 – It is easier to install the vertical strut at this point vice after the fin-shaped bracket. Ensure that the oil pressure gauge sender is rotated far enough forward to allow the strut to fit and mount to the bolt behind it. Loosely attach the strut to the stud protruding left on the fin-shaped bracket mentioned above is in place with an M8,4 washer and M8 nut.
[P/N: 900-025-007-03 and 900-910-097-02]



Step 8 – Remove the air filter cover for easier access. Loosely fit the fastening angle to the engine cowl bolts below the RH fuel rail – there are two bolts you’ll have to remove and reuse.

Step 9 – Remove the two bolts which hold the muffler support bracket to the engine support bracket / console and put them aside. Slide in the fin-shaped bracket from the engine bay downward through the open slot shown in Step 1 and align the bolt holes. Loosely fit the bolts to the face plate as shown below.



Step 10 – Align the vertical strut you just installed in the engine bay to the stud on the fin-shaped bracket and attach it loosely with washer and nut. Then use the pan-head screw and washer to fasten the fin-shaped bracket to the fastening angle. You’ll have to likely fiddle a little to align it through a rearward slotted hole on the fin-shaped bracket (you can use an Allen socket with an extension first before attaching the ratchet head for tightening). Once all is loosely fitted, return to the underside of the car and tighten up the mounting bolts. Then you can tighten up the two engine cowl bolts, the pan-head bolt and the two nuts on the vertical strut.

Step 11 – Reattach the muffler support bracket to the engine support bracket using the bolts you set aside in Step 6 and tighten to 40 Nm / 30 ft-lb. With these bolts firmly in place, you can remove the jack or jack-stands supporting the crankcase.

Step 12 – Place the muffler carefully onto two jack-stands to support the weight, and adjust their height equally, to be as close to the CAT mounting point as possible, ensuring you don’t knock the bolts and gasket you’ve pre-positioned.



Align the bolt holes (the lowest one is easiest to start with, then top, then RH side). Once all bolts are loosely fit, slowly tighten them up to 25 NM / 18 ft-lb. Roughly align the two metal straps on the muffler to be ready to attach them in the next step. Insert the Allen bolt into the LH strap loosely, so you can slide it immediately back over the brace on the heat exchanger crossover pipe in the next step. At this point you can remove the LH jack-stand. Leave the RH in place for now.

Step 13 – Lift the crossover pipe into place, aligning the upper LH open-ended pipe through the hole in the engine bay tin and carefully move the RH muffler strap which doesn’t have a bolt in it yet, around the crossover pipe without bending it out of shape. Slide the red tubes back over the end of the two heat exchangers and slide the LH metal muffler strap over the brace to hold it in place. The crossover pipe should be solid enough not to fall. Align the two respective hose clamps over either end of the red tubes leaving some of the tube visible on the outer edges, and tighten, but not over tighten, the hose clamps. Tighten the LH muffler support strap to 40*Nm / 30 ft-lb so that the Allen bolt is vertical and directly forward of the bumper. Carefully align the RH strap in a similar fashion, insert the bolt and tighten to 40*Nm / 30 ft-lb. Remove the second jack-stand.

Step 14 – Reattach the rubber sleeve in the LH side of the engine bay to the crossover pipe using the hose clamp, doing your best to seal the base of the sleeve to the tin. Then reattach the heater elbow and secure at the rubber sleeve with the second hose clamp, as well as to the heater blower with the screws you removed earlier on the upper LH side of the engine bay.

Step 15 – Do a walk around to ensure you have all the bolts snug, and haven’t left any tools in the engine bay. You may now wish to install the compressor plate if you’re moving on immediately to mount the compressor. Lower the car to the ground.

[1987911Coupe]

Skip, a big thank you for taking the time to document the process, as a newer 911 owner it is very helpful. I am going to tackle my AC at some point this year after a few smaller projects.....thank you again!

[Skip1]

Happy to be able to provide some experience for a change. The forum has been extremely helpful since my purchase nearly five years ago. If you want a .pdf copy of the thread entries, PM me - happy to send it along. Can't seem to figure out how to upload it, as it's not a picture.

[lawrencejuliano]

Hello Skip,

Sorry to revive an old thread, but I'm desperately trying to figure out a vibration issue in my AC installation and have a couple of questions regarding your install.

# 1 - What are these bolts & washers used for? They don't seem to support anything



# 2 - I don't see either of these parts in my car, what are they? I don't see them referenced in any AC install diagrams either.




Thank you!

[Michael7810]

The 2 circled pieces look like the adapters that are used to mount the hoses onto the compressor

[lawrencejuliano]

Originally Posted by Michael7810

The 2 circled pieces look like the adapters that are used to mount the hoses onto the compressor

That makes sense, thank you. Must be for a difference compressor than what I have.

The two bolts that mount onto the bracket still confuse me though, they must be for some other application.

[porschyard]

Originally Posted by lawrencejuliano

That makes sense, thank you. Must be for a difference compressor than what I have.

The two bolts that mount onto the bracket still confuse me though, they must be for some other application.

You are correct, The two bolts you are referring are for the muffler bracket on 84 and later 930’s

Richard

[lawrencejuliano]

Originally Posted by porschyard

You are correct, The two bolts you are referring are for the muffler bracket on 84 and later 930’s

Richard

That answers it, thank you!