Slipping boom brake on P&H TC440

vendredi 24 juillet 2015

I bought an old P&H TC 440. I fixed up everything and it basically run incl operating the boom up and down.

A few days ago when lowering the boom it started to run down and before I could do anything the emergency pawl system abruptly stopped it.

There was no load on the boom and just one extension attached (i.e. 20 foot base, 30 foot extension and 20 foot tip).

I was reading in another post (http://ift.tt/1CZj8Vw) that on some cranes this might happen in wet conditions. That is exactly what mine was, it was after heavy rain and I saw that on the brake drum it was wet and greasy. Also I check the spring AFTER the incident, and stupid me, yes it as at 13.2 cm not the factory length of 11.8 which I adjusted now.

Boom and cables look fine and I can put the boom up BUT The wormshaft got damaged and is slightly wobbling now. After adjusting the spring to factory settings I VERY CAREFULLY tried to lower the boom which worked for a short time but than stopped. Reason is that with the wobbling the teeth hang on the emergency break pawl.

So well I have to replace the wormshaft. Now how to best do this ? I assume I would at first remove the emergency brake pawl and carefully lower the boom. Can the wormshaft be removed without taking apart the whole upper crane part ?

Did anybody do this yet and does anybody have an idea where to get a new (or used) wormshaft ?

Anything else I should obey/do after such an incident ?


Slipping boom brake on P&H TC440

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