923A2 Brake problem with pistons on the wedges or the wedges themselves

[FIREFIGHTER]

So I am PMing the forestry tanker for our dept. Jacked up front left drive axle (left intermediate axle/ the one in the middle) to check wheel bearing play. With the parking brakes on, the wheel moved back and forth (the play on the pinion travel). No parking brake engagement from the spring brake. Parking brake spring is good. Ridge on the outside of the shoe material threw me when I had done the feeler gauge check. So I've pulled the can, checked travel on the rod from the can to apply pressure to the wedge-all good. Caged the spring back and checked the travel / throw on the rod with the service brake. All good there. Freed up the adjusters with PB blaster so now I can move those without a 3' bar. The pistons on the park/service brake can are only moving ..MAYBE.. an 1/8". The pistons on the other side (just the service brake can) move about 1/2" when the brakes are applied. How much travel are these pistons supposed to have when the parking or service brake are applied??
What kind of suprises am I going to run into trying to pull the wedge out from the pistons??

I DIDN'T WANT TO GET INTO THIS TODAY. JUST WANTED TO CHANGE OIL AND FUEL FILTERS AND ON TO MY NEXT JOB. Now it looks like I should/need to pull all of the tires and drums and check this thing out. Volunteer dept, they hope out of their Honda's and into THE BIG RED TRUCK, drive it like you stole it, and none the wiser.

Figured I'd reach out to those who have been there done that. We're all born into the world knowing the same thing....nothing. And its only easy if you know how to do it. Give me an S cam truck and I can wrench on that like nobodies business. Wedges?? Not so much.

I've done searches on the brake adjusters, but I can't find anything. Was hoping maybe someone could steer to me to correct forum or give me advice. Maybe its not even worth trying to take apart and mess with?? Unknown.

 

[Floridianson]

If this helps.

 

[NDT]

Can you reread what you wrote and edit it please. Does not make sense to me. Pinion? Wheel wobbles with spring brake applied?

 

[FIREFIGHTER]

NDT...writing on the fly. Sorry it doesn't make sense to you, but it did to me at the time. The wedges were 'stroked out'. I took some pics and will post them tonight. Writing from the laptop mounted in my truck. So the rollers went beyond the wedges and got stuck, they weren't retracting to allow stroke. I'll fill in the blanks tonight with pics and descriptions. Thank you to those who replied. Floridianson, haven't had a chance to check out your PDF. Thank you for posting that.
Its only easy if you know how to do it.

 

[Floridianson]

They are easer than skinning a cat. Bet if you are care full removing the seal- adjuster plunger it could be reused. Everything else will seem simple to check, clean / lube.

 

[NDT]

Oh now I understand, when you say “wheel” you are talking about the wheel that the wedge engages, not the tire/wheel. You used “wheel” right after “jacked up to check wheel bearing play” and that confused me.

 

[FIREFIGHTER]

Hey NDT,
I had jacked the tire up off the ground to check wheel bearing play. It was when I leaned on the tire with the pry bar that the tire rotated an inch or 2.......with the parking brakes on!! No beuno. I tried adjusting them with the tire on (that's frustrating). I had ordered the adjuster a few years ago and hadn't needed to use it until now. It really doesn't get driven much. Bent the adjuster to hell trying to dial it in. My intent was to tighten the adjuster until the shoe dragged on the drum, then back off a touch. Then do the same to the other shoe (upper or lower...whichever one I hadn't done). Ended up tearing the tire off, found out the hard way about the 'boot seal', then had to take the parking brake/service chamber can off to figure out why I wasn't get 'stroke' on that plunger.

 

[FIREFIGHTER]

If this helps.

Thank you very much for that parts list!! That went into the folder for that truck as reference.
Looking at that parts diagram makes alot more sense now that I've taken it apart and understand the in's and out's of those brakes. I was kind of suprised to find that there wasn't a return spring behind the plunger on the service brake side. (Took that apart to make sure the plunger going into the wedge wasn't bound up).

 

[FIREFIGHTER]

I emailed the pictures on my phone to myself hours ago so I could post them. Figured it might save someone else some trouble. They still haven't arrived in my 'InBox' yet........go figure.