jbrunson Report post Posted September 27, 2015 Guys, I'm learning fast but need a little council here. Spent an afternoon under the belly of my new to me Beaver looking, locating, etc.. One objective was to adjust the parking brake on the tail shaft of the transmission. The thing is there is some sort of hydraulic device that actually engages the brake (I was expecting a simple purely mechanical system- yea). As best I can tell, the teleflex cable is routed to some valve that in turn operates a hydraulic dashpot that pulls the lever that engages the brake shoes that stops the hub that is integral to the driveline. Keep in mind this is not an air powered chassis and I am assuming that I am dealing with hydraulic over hydraulic braking. ( Magnum Blue Streak chassis) Please take a moment and answer some basic questions for a beginner: 1. Does the engine have to be running to engage the park brake? If so, does placing the transmission in gear release the brake? 2. At this time, I can see about 80 thousands of an inch clearance between the shoes and hub; also there is over 5/16" of lining on the shoes. Should I continue to take up slack in the cable between the dashpot and park brake? 3. Does anyone have a Bendix, etc. part number for the shoes and hub. We had a nice leisurely Sunday afternoon drive.... It would be nice not to have to have the dear wife chock wheels before I get up from driving. Share this post Link to post Share on other sites
wolfe10 Report post Posted September 27, 2015 The parking/emergency brake is spring applied, hydraulic pressure released. So, engine off, it absolutely should hold the coach. The engine has to be running (to provide hydraulic pressure) to release the parking brake. ONLY if the parking/emergency brake will not hold the coach against the engine at idle/transmission in gear do you need to look at adjustment/parts. Share this post Link to post Share on other sites
jbrunson Report post Posted September 28, 2015 Parking brake definitely will not hold coach against engine at idle with transmission in reverse. Parking brake will not hold coach on slight incline. Parking brake is ineffective. Going to re-check, but it appears that parking brake can be released with engine off and brake pedal depressed. This seems much different than air brakes. I am going to tighten the cable Clevis another tenth of an inch or so. There is plenty of lining material on the shoes. Also, much easier to deal with this if you slide out the battery tray and crawl under from that side... You can actually sit there and adjust as opposed to laying there... Share this post Link to post Share on other sites
wolfe10 Report post Posted September 28, 2015 Yes, very different than air brakes. Sure, it may be possible for engine off/stepping on service brakes to release the parking brake-- never tried that one. But, your hydraulic over hydraulic service brakes will engage the electric boost motor if the engine is off and you step on the brake (you should hear it). Again, never tried it, but it is possible that that electric boost pump could also pressure up the emergency/parking brake. Let us know if this is what is happening. Share this post Link to post Share on other sites
jbrunson Report post Posted October 5, 2015 Ok so brake now holds coach when transmission shifts into drive or reverse. I do not think that the electric boost pump will disengage the park brake. Next time I will need shoes I think... No more slack to take up. Share this post Link to post Share on other sites
