Air brake question for the heavy mechanics

[greywuuf]

I am trying to move an "H" series (7500) that does not run. I believe them to be "modern" "s" cam brakes.....there is a unlocking bolt installed on one side of the rear axle but when I went to install one one the other can .....I.can not get it to "hook" ....it feels to me like the diaphragm (or spring perch or whatever is inside there ) is so far in that I can not get the bolt through it.
I do not know if this makes any sense to anht of you or not....but never having seen the inside of a can (but knowing enough NOT to take it apart) I am at a loss as to what to do? Any tips hints or suggestions?

[greywuuf]

Ok , a little bit of research has revealed some better terminology . I am trying to cage the brakes....the caging bolt will not rotate and lock..is it just the wrong bolt? Some crap in the hole? Or could it be something else?

[63 & 64 Bowties]

Odd for sure. Have you tried backing off the slack adjuster as far as it will go?

[72 5500]

DO NOT remove any clamps that hold the brake can together until you have the caging bolt in place and tight. There is a very large spring in the back section that is holing the brakes on (parking brake). There is dirt caked in the hole where the caging bolt or T bolt engages into the plate inside or the spring inside is broke and is not lined up to the hole for the release bolt. Clean out the hole and or re alien the holes and install the caging bolt. Make sure the nut is on the caging bolt and you might have to tap it in place with a hammer.
Turn it a quarter turn clockwise until it locks in. Keep tightening the bolt until the push rod stops going in the other end of the can. The diaphragm's are replaceable but the springs are not. If you take the can apart, do not remove the caging bolt to get the spring out. The bolt is not long enough to release all the spring pressure.

[greywuuf]

Thank you for that. Yes I know about the spring. It is weird, it feels like the caging bolt is just wrong...I can feel I am in the right place (drops into the notch and won't spin...ya know....you feel it is in there...and it bottoms out solid...guess I will assume packed dirt or something (there were no caps on it of course) and go from there...or maybe it will be easier to just go with fresh fuel and bleed it....see if I can make her run.....

[72 5500]

Um......... no bleeding required as long as the air compressor works and it goes above 60 psi to release the parking brake. if you are trying to move it with out getting the motor running, just fill the air tanks from the shop compressor if available.

[greywuuf]

I was referring to the fuel system, by "bleeding" just talking about getting her to run, this is a "it ran when it was parked" truck and it is kinda out in the back 40 ... I could bring an air tank, but I need to getting it running sometime anyway.....

[greywuuf]

Thank you guys. It was dirt. Took some digging with a long skinny screwdriver and a gentle tap......it's all good now.

[72 5500]

Great. Good luck on getting her runin......

[greywuuf]

It runs and builds air (notb sure how much all the gauges are pretty sticky and sluggish) got it moved from the swamp to a gravel pad. Monday I deal with the seized water pump and check all the air lines and valves......kind of take stock of where I am at....also maybe the PB will have done it's magic on the brake pedal and throttle pedal by then.