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Thread: Bit of brake trouble.

  1. #1
    Senior Member Footsfitter's Avatar
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    Bit of brake trouble.

    Been having a palava with the old Cat950B shovel from the lime quarry. It has old fashioned dry disc brakes and over the years we have had the odd leaking caliper piston or three, seized pistons to name a few, recently the rear axle hub seals started to leak oil- they are Cat's Duo-Cone metal face seals mounted on a pair of jumbo "o" rings that push them together until like ours the rings get old and hard, then leak.

    While it was in for new seals, we had both calipers leaking too, one was a slight weep from the side plate & plugs that blank off the piston bores but the other was out of the piston gaiters having got by the lip seals. We have had issues in the past and these had been resealed a few years ago using Cat Classic pistons and seals- they are "value for money" genuine cat parts for older machines, but our problem lay in the actual caliper being old and its tolerances from wear and corrosion simply mean the seals don't fit properly any more plus the bore the pistons go in are wearing which allows the pistons to wiggle slightly as the pads move with the disc under hard braking. The classic parts and new anchor pins had held the leaks off for a bit but now it was time to bite the bullet and replace a caliper.

    Our usual supplier of Non-genuine parts had one in stock that was supposed to be a good quality Italian brand, once it was fitted, just removing the pipe clamp and allowing brake fluid to flow under gravity produced a leak from a grub screw that was supposed to block off a gallery for a bleed nipple!





    When fitting it it seemed "odd" to have daylight visible between the caliper and side plate- never seen that before, so having spoken to the supplier they agreed to let me see if the screw would tighten up or be seal-able at their risk. The grub screw seemed tight so it had to come out for sealing, it then became obvious that this was probably a real Chinese lump of rubbish............ The hole and thread had been drilled off centre to the gallery so there was no way the grub screw could blank off the gallery! As the screw came out a little layer of cast lifted off revealing real cheap granular cast which proved correct when it went back in and the threads just collapsed. Off it came and 650 worth of caliper went back.



    Meanwhile Our cat dealer had found a "genuine, new-old-stock" caliper in the states after I had turned down their option of a 1600 genuine caliper knocked down to 1200 after special discount. At not much more than the non genuine one I had hedged my bet and said we'd have it as a spare ready for when the next one sprung a leak, luckily this meant that it was already on its way on economy shipping. The caliper arrived, was a bit dusty but looked new although it had white marker part number and made in canada on it........ All was well until it was offered to the axle where it was obvious that this was for either an earlier model or something else with a smaller axle? the flange was smaller and the bolt holes were 5/8" instead of 3/4". After checking the part number I had supplied was correct averting the imminent coronary I was expecting, luckily it looked to be someones fault out in the USA where they had marked it up incorrectly!





    It really was bite the bullet time now with a dry spell and the shovel stuck in the workshop, so it was plan C - order the 1200 caliper, that was friday afternoon and somehow the 48hr delivery from Grimbergen in Belgium became really rapid as TNT dropped it off first thing on Monday morning!! Soon had it on and bled up which was a relief at last. I suspect its made by Carlisle, a US make but most stuff seems to be made in China but to much higher standards as can bee seen by the machining of the primed Cat unit







    Sometimes trying to save money too much comes back to bite, although it is fair to argue that regardless of price it should work without leaking!
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  2. #2
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    Re: Bit of brake trouble.

    Having similar trouble with parts for a massey 398 having had all the non genuine alternatives wrong then main dealer suppling allegedly the correct one to find its wrong aswell. The dealer then saying it's right but it's 80mm too short. So back to the main dealer and finally got the right one on order. Can't fault the stores man really helpful in tracking down the correct one so like yourself what was going to be a straight forward job had turned into a lot of searching

  3. #3
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    Re: Bit of brake trouble.

    Quote Originally Posted by ct28 View Post
    Having similar trouble with parts for a massey 398 having had all the non genuine alternatives wrong then main dealer suppling allegedly the correct one to find its wrong aswell. The dealer then saying it's right but it's 80mm too short. So back to the main dealer and finally got the right one on order. Can't fault the stores man really helpful in tracking down the correct one so like yourself what was going to be a straight forward job had turned into a lot of searching
    It would of been nice to of pressure tested the first one but it didn't even hold back the dot4 fluid gravity feeding from behind the cab- about 5ft head I expect!!
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