hey there, got a hyd pump on a 753 that is leaking round the UNO'ring port on the rear .......sorted a temp fix , but it has to be sorted after a job it has to do shortly....don't think the housing is cracked, i think vibration and side loading on the port by a steel pipe has done it a injustice....routed a hose in a different spot to stop this happening in the future whats the easiest way to pull it out, is there enough width to slide it side ways, or do we un bolt the hydrostatic from the mount, pull the belt off slide it the other way to give room customer is worried about the time and labour, thought we would ask on a forum first once i get it off my offsider in the hyd shop will strip down and sort it, just need to install a bit of confidence in the removal thats all any ideas will be well recieved pudding :drinkup
I have changed several of these pumps out and there is enough room to slide it away from the drive pumps without moving the engine/pump assembly. I worked at a dealership so we didn't troubleshoot the cause of the leak once it was narrowed down to the pump and not the fitting/o-ring we installed a new pump rather than trying to repair the old one.
cheers for that mrfixitpaul i have never seen a housing slog enough to cause leaking round a UNO'ring fitting either, but it seems to be what its doing, and we can both see it happening, have put more then one new fitting in to stop it, replace more then one 912N90 o ring, to no avail, replaced the positionable 90 adapter with a new one, it leaked, replaced it with a straight port adapter and a male/female 90 on top of it (because sometimes oil travels out under the steel washer on the positionable fittings)...it still leaked. ended up putting the male/male straight uno/JIC adapter in the lathe, cutting the top of the thread to create a larger shank that the o-ring sits on, put a dowty washer over the top then run the 912 o ring under neith it, and that has stopped the leak for now ) I was amazed, the customer was happy, so now when this job is finished hopefully it will majically appear in our workshop.....we have a bucket cylinder to rebuild for him too, its bypassing across the seals, down time wouldn't be such a issue, but its one of 2 genuine bobcat loaders in this town.....and the customer doesn't want other contractors to know about this job thanks mr fix it paul pudding New Zealand
MrFixitPaul, is it possible to remove and replace / repair the hydrostatic pump on a 753 without removing the engine? Fairly certain my hydraulic and hydrostatic pumps need service and hoping I can do this without the engine removal. Thank in advance MrFixitPaul
The biggest problem you would have with that method is removing the pulley that's connected to the pump input shaft, it's a keyed/tapered shaft, I don't know that there would be enough room in there to fit a puller to remove the pulley. One thing all you guys need to check is the support bolt at the bottom rear of the hydrostat pump unit, that bolt is bad about shearing off and leaving the 2 bolts at the pump input shaft flange to support the load of the hydrostat pumps and work pump.
if the leak is coming from the pressure side port, and you have the aluminum body pump, i can pretty much guarantee there is a crack in the threads. probably cant see it until you remove the pump.
I agree, I've seen a number of them cracked, and sometimes it's damn hard to find the crack, especially if it's in the bolt threads like crewchief mentioned. The crack pretty much closes up until the pump is under pressure which expands the aluminum housing and opens the crack.
Its WAY easier to pull the engine and pumpset out as an assembly than to try to pull the pumpest by itself.....