Air Hydraulic Cylinder Assembly Rebuild Kit Questions

[rmesgt]

Hello all...

For brevity, I have renamed the Air Hydraulic Cylinder Assembly to "Airpac", which is, I believe, what most folks call it. I have the long style airpac on my truck. I ordered a rebuild kit for it from Erik's (PN 8345007) and received it right away. It took me a while to get to it, but I finally disassembled my airpac, following the instructions I printed from TM 9-2320-209-34-2-1 Section III.

It took me a while to clean it up as it was full of water, oil, and sludge. I really didn't run into any problems until I tried to remove the "Control Valve Piston" identified on page 12-15 (item 5). I can get this part to move up or down, but I cannot remove it. I tried a hammer and punch, guessing that it might just me stuck or rusted into the housing, but no luck. I removed the plug on the back side of the housing, expecting it come out that way, but again, no such luck.

I decided to compare the components in the rebuild kit to the original parts I had laying all over the table. I thought if the kit contained a replacement "Control Valve Piston" (item 5), I would be able to see how it is installed, but (yep, you guessed it) the rebuild kit does not have this part. There are however, several parts in the rebuild kit that are not part of my airpac. I put a pic below that shows MOST of the parts in the rebuild kit. I have identified two parts specifically (circled in red).

Now for the questions: Did I order the correct rebuild kit for the long style airpac? Does this rebuild kit support other models of the airpac? Do I need these identified parts, circled in red? If I do need these parts (circled in red), where do they go? Have any of you run into these problems (extra parts in the rebuild kit or the inability to remove the "Control Valve Piston (item 5)? Please let me know what you think. TIA...



Peace in Christ...
Leo

 

[M37M35]

Might be helpful...

MY Airpack Rebuild with Photos!

So here is my airpack rebuild. There have been other posts out there but I took allot of pics and thought I would post all the info I have learned in one place. I wanted to show it visually so you can actually see the parts in it. I have learned so much on this site it’s time for me to give...

www.steelsoldiers.com

Airpack Rebuild Warning.

The following attachment is from TM 9-2320-209-34-2-1. This is the commonly available TM in PDF format that has rebuilding instructions for the air pack. The attachment is a page right from that TM. The "Note" at the top explains the difference between the piston cup and pushrod seal. The TM...

www.steelsoldiers.com

 

[rmesgt]

Might be helpful...

MY Airpack Rebuild with Photos!

So here is my airpack rebuild. There have been other posts out there but I took allot of pics and thought I would post all the info I have learned in one place. I wanted to show it visually so you can actually see the parts in it. I have learned so much on this site it’s time for me to give...

www.steelsoldiers.com

Airpack Rebuild Warning.

The following attachment is from TM 9-2320-209-34-2-1. This is the commonly available TM in PDF format that has rebuilding instructions for the air pack. The attachment is a page right from that TM. The "Note" at the top explains the difference between the piston cup and pushrod seal. The TM...

www.steelsoldiers.com

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Thank you for your link! I read every word and looked at every picture. I also checked the tool part numbers you sent. Unfortunately, NAPA has increased their priced by 100%. What was $26.00 is now $51.99 (Ouch) but I couldn't find other hones much cheaper. Here is what I found on Amazon for $49.50.

Kolvoii Cylinder Hone Tool Set with Tool Box, Adjustable Engine Cylinder Honing Tool for Sizes 3/4" to 7" Cylinders, 1-1/8", 3" and 4" Diameters with Extra 11 Piece Replacement Honing Stones 220 Grit

I saw in your pictures how your "Control Valve Piston" seemed to easily lift out of the housing. Mine seems to be stuck. Did you notice if there was anything in the housing that would slide into the Control Valve Piston (such as a ball bearing or pin) that would prevent it from just lifting out? So far, this is my "Stuck Point". Also, what part number was the kit you purchased from Eriks? My kit is part number 8345007. I am wondering if perhaps I bought the wrong kit. Finally, did your kit have any unused components?

Thank you for responding to my post...

Peace in Christ...
Leo

 

[M37M35]

I'm not the original poster of the thread and it's been a few years since I rebuilt my airpacks, so I really can't tell you any more info then what is in the above thread.

There's two different styles of airpack, long and short, so there's only two possible kits to order.

Here's a thread on the short airpack for reference: https://www.steelsoldiers.com/threads/new-style-short-airpack-teardown-repair-with-photos.111972/

Mine seems to be stuck. Did you notice if there was anything in the housing that would slide into the Control Valve Piston (such as a ball bearing or pin) that would prevent it from just lifting out?

I don't recall anything, but it's been a few years. I'd soak it good with the penetrating oil of your choice and see if it frees up.

The part number you posted is for the long airpack, if that's what yours is.

 

[rmesgt]

Thank you for your reply! I kept working with it and I was finally able to remove the Control Valve Piston (Yeah!). Once out, I used my tiny wire brush and some WD-40 to scratch at the bore. I tried my fingers and some crocus cloth, but no such luck. I kept moving forward with the disassembly and found, to my surprise, where my "extra" parts go! I learned a great lesson: Be Patient, follow the directions, and it will all work out. I suppose I was just terrified of making a mistake. As for the cylinder hones, O'Reilly auto has a cylinder hone in their "loan-a-tool" program that did an AWESOME job. Fortunately, I have a much smaller hone that worked out well inside several other places with this airpack. I should be about to begin reassembly tomorrow. Super excited! I suppose I have either done this correctly, or my truck just won't stop. We shall see....

 

[rmesgt]

About ready to start reassembly of my airpack. Is it wise to put it back together dry or should I lubricate the rubber parts with a thin coat of DOT 5 brake oil? Thoughts anyone???

 

[rmesgt]

Again.... I am chagrined! If I could just learn to RTB (read the book) I wouldn't have to ask so many foolish questions. Apparently, the TM will tell you which lubrication you should use and which parts to lubricate prior to reassembly. Apparently, I need to learn to read about the entire task, beginning to end, BEFORE I begin the task...

 

[swiss]

Again.... I am chagrined! If I could just learn to RTB (read the book) I wouldn't have to ask so many foolish questions. Apparently, the TM will tell you which lubrication you should use and which parts to lubricate prior to reassembly. Apparently, I need to learn to read about the entire task, beginning to end, BEFORE I begin the task...

That is wise words from a wise man.

 

[G744]

Aren't there 3 types of 2.5 ton 'airpaks'?

Don't forget that in the G749 series GMC trucks.

All things considered the form & function is very similar to those in the G742 Reo trucks.

 

[rmesgt]

I have no idea how many different style/model/types/ or aripacks there might be. I am only familiar with two of them (Long and Short). My spare parts truck has the short style. My functional truck has the long style, which is what I just rebuilt. I hope I did it right and that it works properly.