Mark from OZ

Not a Bucyrus probably a NCK rapier 305b

Could be a few things There is a spring that holds the difflock out with no air (should not stay in) My Mack starts to clunk going down hill in low Usualy it tells me that one set of tyres is getting a bit low. The Mack rear end likes to have all the same size tyres.....Mark

The value liners here in OZ only had 1 aircleaner on the RHS I have seen the econodyne's here fitted with 2 aircleaners I bought the kit to do mine even had the air tube to connect into the existing system but i sold it before........ The inside plate is easy to miss. You have to look to see it. They are hard to get out of a wrecked cab as you have to bend it to get it out and realy hard to put back in. It is a strange shape thing that fits inside the door pillar in a U shape that's where it gets it's srength as it is bolted inside . I could never find one in the parts book.......Mark

When putting an extra air cleaner make sure you put the stiffner plate on the inside they tuck inside the door pillar or it will crack the panel . Seen it happen a few times. The air cleaner and bracket are heavy.......... Mark

Ducky that would most likley be just an air tank. I think all the CH macks, at least all the ones i have seen were electric start All the start tanks were up near the fuel tanks on the out side........... the air tanks go either side behind the gearbox or where ever they will fit....Mark

mackmech The engine was an out of chassis re build Piston to liner height checked under spec New liners pistons fitted ring gap checked over boost? "standard fuel" runs 21.75 boost. spec is 21.6 Now pistons 2 & 4 cracked in 4100.00 Ks it took up to 139.00 Ks to crack No5 How come pistons 1 3 6 are still good....... If pistons were hitting the head i would not be asking questions it would have dropped a valve by now. Keep guessing........Mark

Mike i will let you know how it goes. Should be good That particular brand uses MAHLE brand, Google them up very good brand. Certanly better than the other brand........Mark

Thanks HK. I have been pulling my hair out or what's left over this. They jus talk round in circles down a Mack now as they are non current item now I have learned how to decipher the markings and serial No's on the piston tops and the different suppliers. All made over seas now. I put it down to a bad batch / quality controll on the day. The set i have now is fron a different builder and looks a better finish itm I'll put them in and see what happens. Thanks Mark

Picked up the Re build kit. It seems that all the 2 valve pistons are of the later design. I am sure that it was just a faulty batch. They seem to be a little better finish. After a lot of reserch i now know the company's that manufactured them. Never had a piston failuer in 30 years of Macks. The PAI Kit was $2772.25 AUD so not too bad. Time will tell.........Mark

picture sez it all it think

All the pistons that failed were at the steel ring land

Thanks Bollweevil Gleemans have a kit in stock Skip don't know why your's pollished the liners I use rx super and never had an oil related problem My engine has 98% hone marks still in the liner Its just crap parts. Saying that it most probably was a faulty batch pistons 1 3 & 6 are still good piston 5 was still good til this week 2 & 4 cracked at 41833 2 & 4 replaced at that K's still good Mark

Have been thinking of PAI rebuild kit this time have used PAI in the past with no worries at all if Mack can only supply the after market stuff they have lost me. Is PAI still made in the US? may bee they have better quality controll. going at this rate i will have to put zippers on the heads........Mark

bolweevill thanks Now the engine was fully Rebuilt pistons rings liners whe whole deal Jan 07 ring gaps spot on done 41833 ks cracked 2 /4 nov 08. put it down to bad luck Now No 5 cracked in the steel insert, done 139455 ks sept 09 piccy later. the thing is pistons 1 3 6 are still good standard fuel pyro never goes over 4/12 to max 5 degrees C. owner driven by me. Sitll 99% cross hatch marks in the bores. Me thinks crap parts. Remember the original pistons were in there for 11 years and were still serviceable.......Mark