Airpack Rebuild Complications

[LowTech]

So I started having some brake issues and decided to rebuild the airpack, then I ran into a couple issues.
First off it looked really good inside the cylinder and the piston's components were all in great shape . . . then in the clean up I used brake cleaner. At that point the felt came unglued and fell out. So then I rigged up a way to clamp the piston in my vice (which does NOT have solf teeth) and removed the locking nut. Attempting to remove the follower was unsuccessful and the whole piston eventually came off the rod but still won't come apart.

Having already created difficulties for myself I figured I should just stop and ask advice. I have been going off the TM, Rusty Stud's posted article in the TM section, Jeep Sinker's YouTube channel, and various threads.
So . . . how do I get the piston apart w/o damage to replace the o-ring or should I just leave it together? And what are we using to glue new felt together w/?

 

[LowTech]

After carrying on w/ other parts of the rebuild I noticed that the compensator piston felt was also not glued together at the ends. Is that common and exceptable?

 

[Jeepsinker]

You couldn't zip the nut off with a good impact like I did? You need a good fast hitting 3/8" gun. A 1/2" gun hits too slow.
I'd use rubber cement, or maybe some 3M trim and weatherstrip adhesive for the felt. Don't use silicone. And I would glue the ends.
That felt is there to hold and spread oil, so the glue should resist air tool oil. Don't use anything other than air tool oil in there either.

You might try clamping the rod in your vice with some wood between the rod and jaws.

 

[LowTech]

You couldn't zip the nut off with a good impact like I did? You need a good fast hitting 3/8" gun. A 1/2" gun hits too slow.
I'd use rubber cement, or maybe some 3M trim and weatherstrip adhesive for the felt. Don't use silicone. And I would glue the ends.
That felt is there to hold and spread oil, so the glue should resist air tool oil. Don't use anything other than air tool oil in there either.

You might try clamping the rod in your vice with some wood between the rod and jaws.

Thanks! I was starting to think the days of getting responses on the deuce section of the forum was in the past.

I did use wood in the vice and got the nut off w/o much of a problem. The issue is w/ the piston head, which is made up of two parts - the "follower " which holds the felt and the cup expander - and the "pressure plate". Those two parts are not coming apart and they came off the rod together.
I didn't want to start prying on them and end up causing myself more problems, so thats where I stopped and started asking for input from others.

I know that there's an o-ring in between them that I'm supposed to change out as well.

Also thank you for the glue suggestions, I'll pick up some of that today. I do have air tool oil ready to be used.

Oh, and an impact is not something that I have available so I'm glad I didn't need it. All my working on the truck is done in the field since I live in it.

 

[Jeepsinker]

Thanks! I was starting to think the days of getting responses on the deuce section of the forum was in the past.

I did use wood in the vice and got the nut off w/o much of a problem. The issue is w/ the piston head, which is made up of two parts - the "follower " which holds the felt and the cup expander - and the "pressure plate". Those two parts are not coming apart and they came off the rod together.
I didn't want to start prying on them and end up causing myself more problems, so thats where I stopped and started asking for input from others.

I know that there's an o-ring in between them that I'm supposed to change out as well.

Also thank you for the glue suggestions, I'll pick up some of that today. I do have air tool oil ready to be used.

Oh, and an impact is not something that I have available so I'm glad I didn't need it. All my working on the truck is done in the field since I live in it.

I honestly can't recall if I took that apart or not either. It's been too long. I want to say I just replaced what I could peel off of the piston and follower but not sure anymore.

 

[LowTech]

I honestly can't recall if I took that apart or not either. It's been too long. I want to say I just replaced what I could peel off of the piston and follower but not sure anymore.

The answer is yes, you have to separate the two parts of the piston. I went back and looked at the rubber cup in the parts kit and it definitely only comes off and a new one goes on if the two pieces are separated. I did manage to separate them by running a thin blade in between the two parts.
The little o-ring that goes in between is NOT provided in the kit I got from Eriks. Mine was still in great shape, as was most of the parts I changed out so I'm reusing it.
Once I finish some of the other projects I started while waiting for replies I'll get on putting it all back together.

 

[LowTech]

Ok, some things to note,
I was not gentle enough w/ the new felt and ripped it. At that point I took a two pronged approach and glued the ripped pieces back together, but I also cleaned up the one that was in previously to evaluate that one. When it came time to install I decided that the previously used one was the better of the two and used that one.
Another thing,
I'm not sure how Jeepsinker managed to make the air cylinder piston stay in during install. For me it required three hands and a couple uncomfortablely squeezed fingers to hold it down and get the end cap back on. I think if I did it again I might try pushing the piston down w/ the end cap instead of making it separate monuvers.

A couple things that made the install back into truck easier was that I don't have the stock tool box (took that out way back as soon as I realized that it didn't keep the contents from getting wet at times other than just deep water fording). And I remounted it w/o the skid plate just to hold it in place for tightening the lines. That was after leaving it loose enough to get the lines lined up correctly and started.

Now off to build a pressure bleeder.
Does anyone know offhand what ID a bleeding hose should be? Sounds like I was speaking British english there.

 

[NY Tom]

You do not need much for the air supply to pressure bleed. I just made mine up with a quick disconnect fitting to my normal shop airline. 1/4" I believe.

 

[LowTech]

Since I use a remote resavoure I was planning on using the same type/size quick release on that line and the pressure bleeder tank that I have.
I was asking about the tube that goes onto the bleeder screw fittings when bleeding into a container.

No shop air out here in the field.

 

[NY Tom]

I never thought of it before but if the truck runs you have air anywhere. I did buy a gladhand adapter...

Can you bleed the system with air in the tanks?

I think I used 1/4" flexible plastic line to attach to the bleeders. They might measure 1/4"

 

[Jeepsinker]

Just use a pump sprayer and a 1/4" air hose with a 1/8" NPT nipple. Screw it into the master cylinder cap and bleed it, then attach your external reservoir line and fill that reservoir. I would strongly advise against using a compressed air source other than the hand pumped sprayer to bleed it. Far too easy to overpressure the master cylinder and blow the front seals out.

 

[SCSG-G4]

Jeepsinker is right! You only need 5 or 6 pounds of pressure in the pump sprayer to properly bleed the brakes - just enough to get the fluid coming out of the bleeders w/o any bubbles.