Bobcat 743 In Frame Spool Valve Repair Part 2
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- Опубликовано: 25 окт 2024
- This Bobcat 743 has been a real helping hand around the Century Homestead. It is over 30yrs old and we've had it 20. It is in town for some work and repairs. The spool valve has been randomly leaking for a few years. To repair it, I decided to remove the engine for better access to the valve and do a nice cleaning. The engine removal is simple. The repair was reasonably easy. It would probably be OK to do it with the engine in. It would take some patience. I did remove all the hard line clamps in the rear area so as to clean and wiggle as needed.
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Thank you for taking the time to make this video. It was a great help.
We used to take the bolts off the caps on the engine side, push the spools from the front end (ease the boot over the spool or it would jam) then take the boots and washers off the front top to bottom, replace the seals ,refit the boots and washers on the front end, bottom to top as more room for your hands.then reseal the cap end of the spools, put grease on the seals and make sure you slide them down the spool gently as the edges are sharp (unless you have issues with detents etc no need to remove the caps) then refit spools bottom to top refit linkages as you go again more room for your hands.
I find these things very interesting but frustrating. I have a 753G 2001. only way for me to remove the spool valves is to disconnect all the hoses from the hydraulic valve body, then one of the mounting bolts and rotate it down 45 degrees so I could remove the spool valves. OR like you remove the engine to access them... the wires to the BICS valve and pressure relief valves are identical in every way so I reversed them on re-install. took me 2 years to figure this out but I got it and the cat lives again!!!
Thanks, I learned a lot. Have a 743 that I don't really know how to use, and found that the front aux hydraulic linkage had fallen off the lower spool when I tried to use it. Reinstalled linkage, but front hydraulics now seems to have intermittent or momentary pressure and no return flow (909 backhoe attachment cylinders extend but no retract). I'm not sure if I have a return coupler problem or if the spool valve detents aren't working and also, I don't have any documentation for the 743. Not sure what to do next but I'm considering replacing both ends of both quick-disconnects first. I will try Alans (next comment below this one) first if I end up needing to repair the bottom spool valve.
I just did my T250 spools. I think my lift spool may have a bit of a misalignment issue that I never clued into because when I installed the spool assembly getting the second bolt installed was a bit of an issue. I had to rotate the spool and get it aligned. The issue I have is it clicks into float but the boom wants to occasionally drift up. I have to push and hold the peddle to get it function without the drift. Looks like another weekend shot to address this thing.
Enjoyed these 2 repair videos :) I subscribed.
Thanks for posting, these videos were a big help on my 743. My intent was to just fix a leak & ended up fixing my float mode too. On mine, it was really rusty under the cap for the lift valve.
You can test the float detent before installation by pushing down hard on your bench & see if it stays in position. Just be careful pulling it back out so balls and spring don’t go flying.
I have to push my toes down hard on the lift pedal to ‘click’ into float detent. Maybe you need to push harder or linkage needs adjustment to get it to extend a little further?
Hmm. I'll try that. The assembly seemed fine when it was all apart, but I didn't know about the test you suggest.
Thanks, I'll try pushing harder.
Did that amazing fix you performed for us give you the float position on the boom cylinder? And also the video in part one stops at the area around 20.10 and it is the important part for my repair. Can you replace that part of the video??
I was never able to figure out the float. Parts of the repair manual lead me to believe I don't have it, but not for sure. Anyway the video is complete on RUclips. I just checked.
What happened you left off with the plastic plug and bypassed it all togther
There is the Part 1B. RUclips butchered up my video and won't fix it.
Right on I was needing to know which way that plastic plug and oring goes
@@jmidds3245 Go watch Howididit
Your awesome:))))
Did this repair fix the float problem?
Not so much. Maybe I don't know exactly how to activate it.
Great vid. I have a bobcat 641 that I got a few weeks ago for $1000. The gentleman I bought it from needed it out of his front yard because the city fined him.
I recently replaced the seals in the lift cylinders, though the interior seals in the kit seemed to be a little too big. Now the lift cylinders are performing poorly.
Waiting on a new lift cylinder seal kit. If the new kit doesn't do the trick, I'll probably have to do the same job you did
Any thoughts?
All the best
I would have to guess that since the last thing you messed with was the lift cyls, that's most of the problem. When I did the spool valve, my major problem was an oil leak. Minor was the drifting down of the arms and bucket over time.
Before the spool repair, I did blow a lift cyl. So I replaced both as I knew they were at least 20 yrs old. All fit fine. All from Bobcat dealer and parts tied to the machine serial number.
Some of the o rings have a shim so the hydraulic fluid doesn't push past the o ring
turned out it was the hydraulic pump!Bought a new one for $375 and installed. Immediately after installing the new pump , it was apparent that the lift and tilt were working very well. Now onto the relief valve.. The only issue is I blew 3 lines in the past 2 weeks! I think I set the relief valve pressure too high when I was initially testing the hydraulic system.Had to pull engine to access the last line that blew ( its a long 6' line for lift that's behind the engine). I thought I'd look at the relief valve when I have the engine out (might as well?). Is there any way to determine if the relief valve is good, just by a visual examination?The O-rings look fine..