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I'm trying to determine the correct bolt length for the lower bracket bolt connecting the A.I.R. bracket, through the AC bracket, through the water pump, and into the main block. My bolt is 3.5" and it appears too long as I get tension with about 1/2" left on the bolt... I can't find any info on the bolt in assembly manual or parts book. See attached images for reference. Thanks in advance.
Thanks Stan. I do have an A/C bracket in there as well…not sure if your spacer is in lieu of the A/C bracket.
I missed your initial comment that you have air conditioning. Yes, your bracket takes the place of the spacer. Here’s a photo of a 1972 with C-60 and A.I.R.
Considering this, you may be correct and your bolt length is at issue. You did tap the block threaded holes, correct?
Do you know how long your bolt is?
Off hand, I don’t, but I do have a spare 1969 L-46 in the shop (same A.I.R. bracket). I can pull the bolt and physically measure it tomorrow if you can wait a day.
Thanks Stan, yes I can wait till tomorrow. I didn’t tap the block but did use a die on the bolt threads. Installing the bolt didn’t feel right and don’t want to force it in…
OK… Made it out to the shop this afternoon and here’s what I found.
Pulled the upper right (passenger) water pump bolt (that passes through the A.I.R. pump bracket). Bolt is a 3/8” - 16 (9/16” head - grade 5), that measures 2 11/16” from under the head to the end of the bolt. The threaded portion of the bolt is 1”.
One other thing that I noticed is that your a/c compressor bracket seems to have been ground a bit on the end that takes the place of the spacer. I’d also make sure that bracket is in spec as well.
Hope that this helps.
Regards,
Stan Falenski
Last edited by Rowdy Rat; Sep 9, 2025 at 04:19 PM.
bolt length connection A.I.R. bracket
