long VS short airpack pics

[gimpyrobb]

I bumped it so a member could identify weather he had an old or new style. He needed to find a rebuild kit. I would love to see pics of the new style opened up! I'm sure it would help more people than you know.

 

[welldigger]

And just how many right arms, first born children and gold bits did TNJ want for this elusive rebuild kit?

Well I won't bash tnj Murray too hard for a few reasons. Number one they were the only people who had one I could find. And believe me I looked. Also they have a very large selection of parts.

That being said they are not my go to parts people. Shipping is slow and CS well there is none. I lime Erik's much more.

The kit was about 170 plus shipping. But compared to 400-500 for a new airpack.....well you do the math.

 

[welldigger]

Here are the pictures I currently have on my phone. I will post pictures of the rebuild kit later tonight or tomorrow when I get a chance. I will also post the part number.

 

[gimpyrobb]

Wow, that was pretty bad.

 

[welldigger]

Wow, that was pretty bad.

Ya it was pretty rough. Everywhere that air traveled was full of rusty water. All the spring clips that hold the piston rod into the hydraulic end had to be beat out with a punch. Everything was rusted. The inside of the hydraulic end was squeaky clean remarkably.

Also I still have the old air pack broke down into parts. If there are any pieces that someone needs more detailed pictures of just let me know and I will post them up.

 

[welldigger]

Ladies and gentlemen I present the fabled "short" air pack rebuild kit. Many have claimed sightings even fewer have caught a glimpse. However here is proof that it indeed does exist. My research indicates this is a haldex part. However I cannot prove its ancestry other than I purchased this from tnj Murray. The part number is RN25T. I do not have a nsn #.

 

[clinto]

Ladies and gentlemen I present the fabled "short" air pack rebuild kit. Many have claimed sightings even fewer have caught a glimpse. However here is proof that it indeed does exist. My research indicates this is a haldex part. However I cannot prove its ancestry other than I purchased this from tnj Murray. The part number is RN25T. I do not have a nsn #.

HA! I feel validated!

Check posts 6 & 8: http://www.steelsoldiers.com/showthread.php?64068-New-Style-Airpack-Rebuild&highlight=RN25T

 

[Ferroequinologist]

$165 for the kit from TNJ

 

[DeucesWild11]

If anyone switched from a Long Airpack to a Short one, did you notice any difference in performance? By that I mean a properly functioning long one vs. a properly functioning short one? Are there any benefits to be had by making the switch? I rebuilt my long one last year and it's terrific now, just curious.

 

[gimpyrobb]

If anyone switched from a Long Airpack to a Short one, did you notice any difference in performance? By that I mean a properly functioning long one vs. a properly functioning short one? Are there any benefits to be had by making the switch? I rebuilt my long one last year and it's terrific now, just curious.

I swapped from a long one to a short one. The difference was amazing, but the long one was bad. Thats why I did the swap. You shouldn't be able to tell the difference between the two when driving a truck, thats why the fit in the same place. I will tell you, the short one has less parts in the rebuild kit than the long ones.

I looked up that part from Haldex, seems I should be able to get them for $140. Anyone able to find them cheaper?

 

[welldigger]

Clinto you were correct. In fact I remember reading that post and when I finally found that kit it had the same part #. That got me thinking maybe I could find a haldex distributor and get it. But I was on a time crunch and never did that. Hey gimp where did you find it? Pm me if its classified information. The a3 I'm working on has 2 of these bad boys on board. Saving 30 bucks a kit would be great.

 

[peashooter]

Do the airpacks (specifically the shorties) have a hydraulic residual check valve?

Does anyone know if either airpack has the residual pressure valves? I'm pretty sure the short ones must because the Master Cylinder in an A3 doesnt have them, but I am curious on the long airpacks.

If anyone switched from a Long Airpack to a Short one, did you notice any difference in performance? By that I mean a properly functioning long one vs. a properly functioning short one? Are there any benefits to be had by making the switch? I rebuilt my long one last year and it's terrific now, just curious.

Also I posted this elsewhere but I think its important..... I'd personally wouldnt use the "short" style air packs on a single circuit truck. They are short because each one activates one half of the split circuit brakes on the newer trucks. The Long ones were longer because they needed the extra stroke to reliably activate all 6 wheel cylinders on the single circuit trucks. The "Long" style air pack can be used on both the single and dual circuit trucks because it has enough travel to move enough fluid to activate all the wheel cylinders. If you use a short style air pack on a single circuit deuce, it will be possible to run out of Airpack stroke before your brakes are engaged enough..... especially if your shoes arent adjusted close.

 

[welldigger]

I don't know if I agree with that. My truck came from the military with a short style and single circuit brakes. With 9.00x20 tires I could lock up all 6 and with 395's it won't quite lock them up but its close.

 

[peashooter]

Maybe a better way to say it is that your safety factor is much lower with the short style air pack on a single circuit truck. If shoes are adjusted tight then its probably okay, if they are fairly loose or you have a leak somewhere then you may run out of "stroke" on the short air pack where as the Long air pack would have additional stroke left.

 

[hndrsonj]

I have had a short one on my truck for almost 10 years-no problems. I have never read anything in the TM's warning of a short airpack used in a single circuit deuce. Also, isn't the hydraulic side virtually the same size between both types?

 

[peashooter]

I have had a short one on my truck for almost 10 years-no problems. I have never read anything in the TM's warning of a short airpack used in a single circuit deuce. Also, isn't the hydraulic side virtually the same size between both types?

It may not be a problem, I'm just putting it out there that its something to be aware of. Both single and dual circuit trucks have the same 6 wheel cylinders that require the same volume of fluid (Dot 5) to operate.
If the hydraulic side of the airpacks are the same size, then more pneumatic stroke will produce more brake fluid volume.
-1 Long air pack moves enough volume (Dot 5) for 6 wheel cylinders
-2 short air packs move enough volume (Dot 5) for 6 wheel cylinders
-1 short air pack probably can't move the same volume (Dot 5) as 1 long air pack.... So if I needed to replace one on my truck and had a choice of a new LONG style or new SHORT style air pack, I would personally think the Long style is safer way to go.

 

[welldigger]

I still don't agree. Regardless of whether one gives a little more stroke than the other my shoes were not adjusted at all when I got my truck. I had no problems with stopping once I replaced my air pak and rebuilt my mc. I replaced a short with a short. If anything the short one has a larger air piston meaning it can build more boost pressure. Though I don't believe you could really tell the difference between the 2 while driving.

Regardless if giving a hair more stroke thats still no excuse for lack maintenance. I think your mc would drain before your air pak ran out of stroke.

 

[hndrsonj]

I also just checked the TM's again, you would think if this was an issue there would be a warning. (there isn't)

 

[peashooter]

Just pointing something out that I recently learned from a rebuilder of air packs and it makes sense to me... I'll leave it at that.

However back to my actual air pack question (and Clinto's) in post 32, Does anyone know if either airpack has the residual pressure valves?

 

[gimpyrobb]

My swap from a long airpack to a short made all the difference in the world! Granted the long one was shot, but..