How to mount an A/C compressor on a 402

[71CHEVYSHORTBED402]

I pulled the A/C nearly 30 years ago. That always bothered me. Luck would have it I bought another 402 truck with A/C. Overall I'd say it was mostly stock. Turns out I had all the brackets for the truck I'm working on, and some of the hardware.............Still, somehow this was a real (*^(^ noting how this is slammed together. I referenced the assembly manual quite a bit. This was a "dry run" only on the truck I'm restoring. Next run is easy peasy.

Anyway, here are my notes. Perhaps others may find them useful. Sure helped me, but what a pain in the shorts. Where you see RH (TS), that just means the RH truck side. Also, flathead bolt only means the bolt head isn't recessed/flanged.......Keeps me organized. I welcome any corrections, please. First image IDs the parts. Then notes, then a few pics of the brackets assembled on the truck. Man, this stuff fits nicely.




NOTE: Be sure the stud is installed first. Do not tighten the brackets until after the compressor has been installed.

Bottom bracket (A portion of the bracket is a triangle. The LH (TS) portion of the triangle mounts onto the face of the head):
• The bottom front of the bracket mounts to the lower front corner of the head using a 5/8" flathead bolt and washer. The bolt thread is 7/16-14 x 1. NOTE: This mounts the negative battery cable as well.

• The bottom of the bracket mounts to the RH (TS) front post in the engine block using a 9/16" flathead bolt, washer and lock washer. The bolt thread is 3/8-16 x 1.

• The bottom rear of the bracket mounts using a stud on the front hole of the exhaust manifold. The stud is 3/8-16 on both ends. The longest end (1.1/4") inserts into the exhaust manifold. The short end (1") mounts the bracket. A washer fits between the exhaust manifold and stud nut. The bracket is secured using a nut and lock washer.

Front bracket & hose retainer (A portion of the front bracket has a half moon for the front of the compressor. The hose retainer looks like a cabinet handle):
• The top of the hose retainer mounts to the front bracket using a 1/2" flathead bolt. The bolt thread is 5/16-24 x 7/8. The bolt inserts from the front.

• The slot portion of the front bracket is placed on front of the bottom bracket. These secure to the top front outside corner of the head using a 5/8" flathead bolt and washer. The bolt thread is 7/16-14 x 1.1/4. The bolt will be positioned near the bottom of the slot in the bracket.

Other: The bottom of the hose retainer, and the front and bottom brackets are secured using a 9/16" flathead bolt, lock washer and nut. The bolt thread is 3/8-16 x 1.1/2. The bolt inserts from the front.

Front arm bracket (Longest of the two arm brackets. The slot portion is to the compressor. A triangle is engraved onto the front of the bracket): This bracket secures to the top hole on the face of the RH (TS) head using a 5/8" flathead bolt and lock washer. The bolt thread is 7/16-14 x 1. The arm is positioned behind the front bracket for mounting the front of the compressor. NOTE: The front arm bracket extends approx. 9/10" beyond the top edge of the front bracket.

Brace support (small three hole bracket, looks like Mickey Mouse): The brace support mounts using the RH (TS) exhaust manifold bolts & lock washers. These are the 2nd & 3rd bolts & washers from the front.

Brace (shaped like a snake. The slot end is the top): The brace secures to the front of brace support using a 9/16" flathead bolt and nut. The bolt thread is 3/8-16 x 1. The bolt inserts from the front.

Rear arm support (shaped somewhat like a horse shoe, with a ridge on top for mounting the rear arm bracket): The rear arm support mounts using the RH (TS) intake manifold bolts & lock washers. They are the 2nd & 4th bolts & lock washers from the front. NOTE: The standard intake manifold bolts are 3/8-16 x 1.1/4. They're too short for this bracket. If using a lock washers, then the bracket requires 3/8-16 x 1.3/4 bolts.

Rear arm bracket (shortest of the two arm brackets. The ridge at the center faces up): The slot end of this bracket is secured on back of the rear arm support using a 9/16" flathead bolt, washer and lock washer. The bolt thread is 3/8-16 x 1. The bolt inserts from the rear. The rear arm bracket is positioned in front of the brace for mounting the rear of the compressor.

Compressor plate (looks like a frog): The plate mounts to the back of the compressor using two 9/16" flathead bolts and lock washers. The bolt threads are 3/8-16 x 1.1/8. Three thin shims were used between the compressor and plate. NOTE: The triangle engraved on the plate faces out.

Mounting the compressor:

• Position the compressor's flange in front of the front bracket.

• The compressor plate mounts to the rear bottom bracket using one 9/16" flathead bolt and nut. The bolt thread is 3/8-16 x 1.1/4. The bolt inserts from the front.

• The top front engine side of the compressor mounts using one 1/2" flathead bolt, washer and lock washer. The bolt thread is 5/16-18 x 1. The bolt inserts from the rear. Assembly order: Bolt > washers > front arm > front bracket > compressor. NOTE: Some debate whether or not this takes a 5/16-24 bolt instead. I can only speak for two compressors, and an 18 seemed to thread much better. That and the "sample" truck used an 18.

• The top rear of the compressor mounts using one 9/16" flathead bolt, washer and locker washer. The bolt thread is 3/8-16 x 1. The bolt inserts from the rear. Assembly order: Bolt > washers > brace > rear arm > compressor. NOTE: The bolt seems a bit short. 1.1/8 would be better.

• The bottom front of the compressor mounts using one 1/2" flathead bolt and lock washer. The bolt thread is 5/16-24 x 1. The bolt inserts from the rear. Assembly order: Bolt > lock washer > front bracket > compressor.

• A 1/2" flathead bolt and lock washer mounts the compressor to the front bracket. The bolt thread is 5/16-24 x 5/8. The hole is located above the hose retainer. The bolt inserts from the rear. NOTES: This MIGHT be used to mount the compressor ground. I need this bolt.

See assembly manual pages 525-527.

[woody82]

I am having a similar problem.I recently put my 402 back in and don't remember exactly the routing for the starter solenoid wires.Do they run down the front of the engine or behind it? If anybody has any pictures that would be a big help.Seems they are awful close to the exhaust.

[71CHEVYSHORTBED402]

Originally Posted by woody82

I am having a similar problem.I recently put my 402 back in and don't remember exactly the routing for the starter solenoid wires.Do they run down the front of the engine or behind it? If anybody has any pictures that would be a big help.Seems they are awful close to the exhaust.

Pretty sure the wire or wires run through the cowl gutter, down the RH valve cover, over the front of the block to the frame then starter. Using clips and such. For specifics, the assembly manual might be your best option.

Edit: Page 398-399 in the manual shows through gutter, down the firewall to starter.