743B hydraulic leak

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pokey55

New member
Joined
Jul 6, 2022
Messages
1
have a 743B with a leak between motor and pump. it's not a bad leak just enough to make things miserable. though it was a seal on pump till someone told me it's probably the lines that run between motor and pump and lay in the muck. anyone ever experience this before? Can't see where those lines go.
 

brdgbldr

Well-known member
Joined
Jun 1, 2012
Messages
1,165
have a 743B with a leak between motor and pump. it's not a bad leak just enough to make things miserable. though it was a seal on pump till someone told me it's probably the lines that run between motor and pump and lay in the muck. anyone ever experience this before? Can't see where those lines go.
Not sure by what you mean by "run between motor and pump and lay in the muck".
There are lines that run to the back of the machine for the filter and all of the lines that run to the lift arms including tilt, lift and aux.
You can look up your machine by serial number at: bobcatpartsonline.com
and you can find the exploded view of your hydraulic/hydrostatic system and you should be able to see all of the hoses, tubes and seals involved.
You should really clean out the machine and then you might be able to see exactly where the leak is coming from. You will also lesson the chances of having a fire.
 

hobbyfarm743B

Member
Joined
Nov 9, 2022
Messages
6
have a 743B with a leak between motor and pump. it's not a bad leak just enough to make things miserable. though it was a seal on pump till someone told me it's probably the lines that run between motor and pump and lay in the muck. anyone ever experience this before? Can't see where those lines go.
One of my hard lines under engine was replaced with rubber prior to me purchasing my 743B. When my engine gets pulled will prob replace with hard line.
Apparently they develop pinholes.
I saw that reply about fire, good to be reminded of leaks and fire are possible.
 

Markle

Well-known member
Joined
Sep 8, 2020
Messages
75
Here is my 743 after hours of work pulling blown engine, scraping, vacuuming crud over and over again, and degreasing. debris mixes with oil residue and gets jammed between eng and the yellow plate, which I think is the rear of the chain case. My lines were all buried in the grunge. That debris traps moisture, and yes, I had the pinhole leaks as mentioned, in 2 hard lines. Since I was in this far, changed all the horizontal hard lines (a local diesel shop made new ones on a pipe bending machine $300). if you get this deep, perfect time to change spool valve seals. A local hydr fitting shop had the "T" fittings which were NLA at bobcat (no longer available). Engine slides right out after the 4 motor vibration mounts were removed , and the other stuff (exhaust, fuel line, wiring, fuel shut off cable). I made a wooden platform the exact height of the engine bay floor, and slid the engine out onto it. And yes, I learned most of this from this forum and thanks to forum-veterans like Tazza, bridgebldr, and others. Hope this helps .
 

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