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Cat d4c hystat stopped dead in it's tracks

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Landbutchr

Member
Joined
Dec 2, 2014
Messages
22
Location
So. california
Our d4c hystat just stopped yesterday . It still runs but wont move. The park light stays on no matter what position that the lever is in. It starts fine We put a new solenoid at the brake release and also installed a new battery as the old one was about toast any way . All to no avail. The serial # is 8cs o1614 . I don't know what else to check . Any thoughts would be appreciated .
 
L

Landbutchr

Member
Joined
Dec 2, 2014
Messages
22
Location
So. california
Well folks ,We had the experts out today and after 3 hours of trying to keep this an electrical problem . A pressure check has indicated that it is a probable coupling failure. Checked three or four points all essentially "0". Woe is me. I haven't looked in the manual yet but I am assuming at this point that pulling the engine is the most efficient way to access the coupling . Any thoughts on that would be appreciated.














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Vetech63

Vetech63

Senior Member
Joined
Aug 10, 2016
Messages
6,402
Location
Oklahoma
Landbutchr said:
Well folks ,We had the experts out today and after 3 hours of trying to keep this an electrical problem . A pressure check has indicated that it is a probable coupling failure. Checked three or four points all essentially "0". Woe is me. I haven't looked in the manual yet but I am assuming at this point that pulling the engine is the most efficient way to access the coupling . Any thoughts on that would be appreciated.


I was afraid of that.











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ih100

Senior Member
Joined
Feb 27, 2009
Messages
731
Location
Peterborough UK
Don't be too pessimistic, you may find that once the cab is off you will be able to pull the engine and leave the pumps in place. I've done it three times on D6K's, don't see why a 4 should be any different. You just need about 5 inches at the front of the engine to draw it off the coupling. Crib the pumps up well, or strap them from the top. SIS doesn't always give the best solution, this way you avoid breaking and blanking an awful lot of hydraulic lines. I think I had to slacken the cooling group and slide it forward a bit to get room, but that was the only complication. Put a bit of ply against the rads in case the engine departs the pumps in more of a hurry than you expect. And good luck.
 
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ih100

Senior Member
Joined
Feb 27, 2009
Messages
731
Location
Peterborough UK
Just looked at Nige's PDF, i thought it was an excavator type coupling like on the bigger hystats and Tracked loaders. It's that poxy up-sized skid-steer coupling. I've seen them fail when they've been a part-spline out and some genius has still managed to yank the housing bolts up tight. Just trying to say that it isn't necessarily a seized pump.

Don't know whether this will transfer over as I haven't done one of this type on a dozer, but on SSL' and CTL's I find it easier to line things up by assembling the pump onto the mounting plate, fitting the nylon drive onto the pump, and then putting three or four studs in the flywheel housing so that everything has to go together square and in line. Never damaged a skid-steer coupling doing it this way, but seen a couple damaged following SIS. Just my experience, your mileage may vary.
 
L

Landbutchr

Member
Joined
Dec 2, 2014
Messages
22
Location
So. california
ih100 said:
Just looked at Nige's PDF, i thought it was an excavator type coupling like on the bigger hystats and Tracked loaders. It's that poxy up-sized skid-steer coupling. I've seen them fail when they've been a part-spline out and some genius has still managed to yank the housing bolts up tight. Just trying to say that it isn't necessarily a seized pump.

Don't know whether this will transfer over as I haven't done one of this type on a dozer, but on SSL' and CTL's I find it easier to line things up by assembling the pump onto the mounting plate, fitting the nylon drive onto the pump, and then putting three or four studs in the flywheel housing so that everything has to go together square and in line. Never damaged a skid-steer coupling doing it this way, but seen a couple damaged following SIS. Just my experience, your mileage may vary.
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So Gents here I go again I need to release the brakes in order to load this dozer for a ride home. There is a procedure spelled out in my book for a pump to hydraulically release the brake but I don't have a pump. It also says that I can removes the axles but lists no procedure . any body who could enlighten me would be appreciated . Thanks
 
Nige

Nige

Senior Member
Joined
Jun 22, 2011
Messages
29,224
Location
G..G..G..Granville.........!! Fetch your cloth.
There is no procedure for removing the shafts, but it is fairly simple. The illustration below is from the Parts Manual.
NOTE: Be careful because once both axle shafts are removed the machine will have NO brakes at all.

Drain the oil from the final drives and remove bolts #45 to get the cover #44 off.
You will need a bolt or a length of threaded rod that screws into the end of the axle shaft #43. Use that to pull the shaft out.
You may need to move the machine slightly forwards or backwards to get the weight off the splines on the parking brake (inner) end of the shaft in order for the shaft to slide freely out.

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ih100

Senior Member
Joined
Feb 27, 2009
Messages
731
Location
Peterborough UK
X3. 1st shaft will pull easily, then you'll only need to rock the machine to get the second one out. Set a railway tie across either end of the machine, giving room for it to roll a little to ease the shaft. I normally do this with an eye bolt, then put a bar through it. Threaded bar is best for replacement as you can lever the far end up for alignment. Removing, not a problem.
 
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Landbutchr

Member
Joined
Dec 2, 2014
Messages
22
Location
So. california
Well Folks believe it or not we finally got around to pulling the engine out of our d4c this week . the failure was indeed in the plastic drive coupling . one thing that seemed odd was the opposing steel gear that engages the plastic coupling was also in pretty rough shape .( Teeth mangled ) We replaced both parts and re installed the engine today , fired it up and voila it seems to be ok. we haven't re installed the axels yet but the brakes seem to be releasing alright .So to all of you that offered advice and reassurannce thank you all .
 
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