Hi, I have an old P&H 440TC which I run for years. I am in peace with always adjusting the drum brakes , but the swing brakes have been a problem since day one. The manual says they are auto adjusting but this neither works nor do I understand how it works. I put again new actuators in (I don't understand why the interior of those is not made of stainless steel they ALWAYS rust and the get stuck) and the brake liners are to far away from the drum so it hardly touches when pushing the lever. Those do not have adjustable length of their connectors like the drum actuators, so how can I get this to work ?
A few pics of your swing brake set-up would help. There were several types of adjusters on friction cranes of all models.
When I was 8 or10, single digits or so, I was playing around on a friction crane left for the weekend on a construction site behind my house in Michigan, in the late '50's. I was sitting in the op seat pushing levers and pedals and released something that caused the boom to descend, scared the heck out of me! That help?
Attached the pic of the swing brake. One can see that the upper liner is far away from the drum, so it hardly touches it when the lever is pulled
@Tugger2 and @ryanmueller are the two guys that visit this board, that run friction cranes. Maybe one of them will see this and offer some help. Looks to me like its set up that you could get the shoe adjusted better. Here's a link to a shop manual on ebay. I'm going to guess that it goes through the brake setting procedure. Harnischfeger P&H 440TC Truck Mounted Crane Shop Service Repair Manual | eBay This is in good used condition. www.ebay.com
I've no experience with cranes so this is just a general observation. The spring nearest the slave cylinder looks broken to me and is quite different to the one one the other side. Comparing the 2 shoes the lower one to me is sitting OK and the top one is out of wack, the difference could be that spring. Also I can see 4 places to adjust the shoes, at 2 o'clock, 4 o'clock and the 2 rods through the springs.
I think tones is on the right track. Here's my wild guess. The two springs marked in blue, hold the shoes from dragging on the drum. The upper one looks like a much lighter spring than the lower one, and wouldn't provide as much resistance. I think the stop bolts and adjusters marked with red arrows, are where you adjust it out to stay close to the drum. I think the cam over by the green arrows is the "automatic adjuster portion" and I think it may have to have a spring in it somewhere where the arrows are, to hold it closer to the drum. It acts like a equalizer between the two shoes. The parts book is going to be your friend in this instance.
I wish I could put nice coloured arrows on photos. It would save my decrepit fingers heaps.
I'm a visual kinda guy. If I can stand and stare at something long enough, I can usually figure out how its supposed to work. If I was trying to make it work, I'd have someone sit in the cab and pump the brake so I could see how everything moves, and that would help me figure it out. I think there's a adjuster/ stop also where the upper green arrow is. On that thumb sticking up. To get the arrows on the picture, I save the image to my computer, open it in photo editor, and that has a "magic marker" function to draw my crayon marks. Then I resave the new picture, and post.
Thanks for that CO I'll give it a try.
Are the frictions grabbing suddenly and taking you for a ride or just not giving enough power to swing? Ill look and see what ive got for books on them,its been 20 years since ive owned the 325TC .I think its pretty similar to the 440 in how they are set up.