Hitachi ZX850 lift ram

[Hammer man]

As stated in Excavators,Volvo,the nearside lift ram cracked on Wednesday on the EC460 i`m using,& started leaking.A small horizontal(?)crack about 2" long at the base of the ram.Our fitter managed to weld it,& so far it seems to be holding.
But he did tell me the same happened on our old Hitachi ZX850 a couple of yrs ago,also at the base but verticly(?).1 week after welding it,it blew big time.So i`m not holding out much hope for the Volvo.As long as it dose`nt blow & come through the side window at me!!

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[Joes1989]

Surely its fairly dangerous to weld rams? I mean the pressure involved the them is immense....not something id have done on my machine i have to say!

[Green Dragon]

Looks like thats broken with a capital "F"

[Martyn Henley]

Blimey Neil, thats some hole .. that must of gone with one hell of a crack .. so do you think there is a pattern emerging here, what with the Volvo going the same way in the same place? is your little Hitachi going the same way or showing signs of going the same way ?

Martyn

[Hammer man]

Surely its fairly dangerous to weld rams? I mean the pressure involved the them is immense....not something id have done on my machine i have to say!

Not what i would have done either,hence i`m keeping a close eye on it.The fitter told me that as i`m hammering & putting some downward pressure on the hammer,the moment the hammer breaks the rock & drops down,that puts immense pressure on the lift rams,that slight drop of the boom.

[john345me]

i would park the machine up till it was replaced

[Hammer man]

No such problems on my Hitachi.It was a 1 driver muckshifting machine untill i got it 2 yrs ago,so was well looked after.In 2 yrs of pretty constant hammering its stood up very well.I`ve had some welding on the boom,as it split on the welded joints,the boom base pin housing was line bored last yr as it went sloppy,& a few rams have been re-sealed.But i find it the best machine i`ve driven for breaking,very strong & well built.Most of the problems on it are just wear & tear & age related.Its now 5 1/2 yrs old with 9500 hrs,but looks very tidy.Its been off the road for 9 weeks now with its hydraulic probs,but thats nearly sorted with re-built pumps & sensors etc,& its had new track chains etc so should feel like a Rolls Royce now .Cant wait till i get it back

[DaveS]

That could have been baaaaad!

Small weld repairs like that often just serve as stress raisers and with the cyclical nature of the pressure in the ram simply serve to cause bigger problems - as illustrated! That big crack probably propagated from the repair.

It's difficult to get a flaw free, good penetration weld on a section like that, hence the problems.

Dave. S.

[IBH]

If that excavator were owned by me or my company i'd have no hesitation in replacing the whole ram straight away, no fannying around with welding to make sure that a) the operator and machine are safe and b)reduce the likelyhood of further downtime to keep the ££'s rolling in.

[Jeremy Rowland]

Welding up broken rams thats nearly as bad as trying to weld up a crack in a truck chassis, which happened at a company that I used to work for and was not successful in the end the chassis actually cracked in two so I must say I would not be very happy at having to put up with a welded repair specially to a component that is put under immense pressure.
A classic case of penny wise pound foolish

Jeremy