Hello, this is my first post and I just bought a 753. I am not new to Bobcats as I grew up running them for my dad but they are all older simpler machines. I also owned a model 310 for a while and this spring bought a 443B to fix. I haven't gotten a chance to get into it yet, but will have questions about it when I do. I bought a 753 this week and noticed it leaks a little fuel from the top of the injector pump. It appears to be coming from the fittings for the lines on top the injection pump. Is there o rings there, and worst case senerio if it it the top plate gasket leaking is that something an average joe that's mechanically inclined be able to fix? Also the machine has aux. hydraulics. My dad has a Bobcat backhoe that mounts to the quick attach. The 753 has a pistol type trigger on the right handle to operate the aux hydraulics. How will this work with the backhoe that will need them to run all the time? Surely you don't have to use a rubber band around the handle to hold the trigger down? Thanks in advance for all the help. I'll probably have more questions once I get this thing home and get to try it out good on the farm!
753 few questions for a new owner
- Thread starter BBaker
- Start date
Welcome to the site!
Ok, the aux hydraulics first. With the machine running and the ho attached press the aux hydraulic button twice, both lights could come on. Press the trigger, this will engage continuous flow to the attachment. To stop simply press the trigger again. One light means intermittent flow with the thumb switch, 2 lights is for continuous flow.
Now the injector pump! This can be done by anyone with slight mechanical ability. Remove the lines to the delivery nozzles, remove the delivery nozzles (the part that the tube lines go to). There are O rings at the bottom that seal against the pump housing. Just ensure that when you remove them you don't go any lower! JUST remove the threaded part and install a new O ring then screw it back in. Ensure you install the one way valves the correct way around.
Ok, the aux hydraulics first. With the machine running and the ho attached press the aux hydraulic button twice, both lights could come on. Press the trigger, this will engage continuous flow to the attachment. To stop simply press the trigger again. One light means intermittent flow with the thumb switch, 2 lights is for continuous flow.
Now the injector pump! This can be done by anyone with slight mechanical ability. Remove the lines to the delivery nozzles, remove the delivery nozzles (the part that the tube lines go to). There are O rings at the bottom that seal against the pump housing. Just ensure that when you remove them you don't go any lower! JUST remove the threaded part and install a new O ring then screw it back in. Ensure you install the one way valves the correct way around.
Thanks for the quick response. I need to get an owners and service manual for the machine as I am sure those 2 questions were covered in there. Do you know if the seals in the cylinders are o rings or are they some other kind of seal? They aren't leaking, but my dad was asking me, and I am not sure.
skidsteer.ca
Well-known member
- Joined
- Jan 20, 2006
- Messages
- 3,853
The only cylinders I pulled apart were on my hoe but they were a combination of poly packs, and o rings
Not certain on the loaders but likely the same
Ken
As far as i was aware, all the cylinders use either rubber for the old style or some sort of nylon for the newer style. Once you have the ram apart, most hydraulic seal shops can match them for you or even your dealer.
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You guys have been very helpful and I have a few more questions. It does not appear this machine is getting power to the glow plugs. I check at the plus witha meter and never did ge any voltage to them. There is a spring loaded rocker switch the glow symbol on it that appears to be how you glow the engine. Could it just be a bad fuse somewhere or where do I start to figure this out? Also if the machine sits for a few days you have to pump the primer bulb for it to get fuel. Somehow it appears to lose pressure? I plan to replace the seals on the injector lines, and around the fuel pump on the injector pump but should I consider anything else? It will not start if you don't pump the bulb. Once it has been running it will strt right up without hesitation?
sterlclan
Well-known member
- Joined
- May 1, 2004
- Messages
- 528
there is a relay for the glow plugs its probably that or a bad connection as far as loosing prime check the lines most likely cracked or the primer bulb is cracked ...Jeff
Thats where i'd start too, check the relay in the engine bay that the glow plugs get power from to ensure you are getting power to the relay, if not you know the problem is between the dash and the relay.
I'd also check your bleed screw, if its loose you could be drawing in air loosing prime. I agree it could be a cracked line or loose clamp too. I wouldn't go attacking the injector pump unless its leaking, if the delivery valves are not wet i'd leave them alone.
The delivery lines are wet, so I know I need to put new o rings in them at the top of the pump. I didn't realize their was a relay for the glow plugs so I will have to look into that. Thanks for the suggestions. The loader is at my dad's farm, 2hrs away so next time I am there I will have a look see.
