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Cat D7D 17A Non-Running Project - Can I Rescue It?

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8 months 3 weeks ago #253286 by trainzkid88
there is a "notch" for throttle closed and a notch for flat out. so when you think you have full noise you may not.

open it to half throttle that way the throttle has less influence and try moving the rack. gentle tapping can help free it. it may well just be stuck from sitting. also check the oil level in the injection pump too there is a bung on the side for that.
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8 months 3 weeks ago #253288 by bulletpruf

there is a "notch" for throttle closed and a notch for flat out. so when you think you have full noise you may not.

open it to half throttle that way the throttle has less influence and try moving the rack. gentle tapping can help free it. it may well just be stuck from sitting. also check the oil level in the injection pump too there is a bung on the side for that.


The notch you're talking about - where is that?  On the throttle lever assembly near where I grab it?

Thanks for the info on freeing up the rack.
 

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8 months 3 weeks ago #253297 by bulletpruf
For more details on the issues that I'm having, here's the video that I put together:


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8 months 3 weeks ago #253312 by D8Dude
Hi Bulletpruf,
I love seeing projects like this reviving something that some might give up for scrap.

I may be on the wrong track here, but I would use caution in trying to force the fuel rack. The cause of the rack to not be moving if it's been sitting for some time is more likely a stuck fuel pump plunger than the rack itself being stuck. Forcing the rack can rotate the gear section on the pump plunger as it's only a press fit on the shaft, and alter the fuel pump setting. The pump plungers need to be checked to see that they will rise and fall freely and turn freely, one or more is likely stuck in the raised position after being pushed upwards by the fuel pump cam. They can prevent the rack from moving as it should.
To repeat myself, excess force must not be applied to the fuel rack in order to free up fuel pump plungers.

Hopefully someone will correct me if I am wrong.
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8 months 3 weeks ago - 8 months 3 weeks ago #253313 by PhilC
D8Dude is correct about the rack. Forcing it will only end is more issues. Having said that though I have freed racks up by gently levering them back and forth with a screwdriver but you must be careful not to force it too much.
In regards to the serial number location on the engine it should be higher up than where you pointed to in the video and it may or may not be stamped where the tag was. There should be four small holes where the tag was. Serial number on the rear of the machine would most likely be covered by the winch. If the engine block was replaced at some time then it may not have a serial number. I have a D8 15A with no serial number on the engine block.
In regards to the winch controls, the two levers that you were looking at are the brake and clutch with the outer one the brake and the inner one with the broken cable the clutch. If you follow the cable to the winch you may be able to move the other end of the cable to disengage the clutch
The way the throttle works is it increases or decreases tension on a spring in the governor that in turn moves the rack. The only exception to this is when you shut down the machine, then the throttle lever forces the rack to the shut down position overriding the governor as the governor would be doing its best to keep the engine going. The link between the throttle lever and the rack has to be flexible so that the governor can control revs. I had a D6 with a seized counterweight system on the governor and it was surprising how much the revs fluctuated with a non functioning governor.
You could probably get away with the broken track tension spring as it is near the end. if it was in the middle then it would be a bigger issue.
Re chroming the rods in the rams is more expensive and less effective than replacing the chrome shafts. The nose of that machine seems to be way lower than it should be even with the blade raised.
That hole in from of the gear stick should definitely not be open. There should be a plug with a breather on it.

944A - Machine SN 43A2589 Engine SN 90A284
955K- Machine SN 71J3772 Engine SN 83Z0704
D6 SN's 4R732sp, 5R2724, 5R4832
D8 SN's 15A1254, 15A2287, 15A2723
Last edit: 8 months 3 weeks ago by PhilC.
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8 months 3 weeks ago #253315 by trainzkid88
thats why i said lots of penertrant time and gentle taps.
by notch i meant you feel a detent you feel it "click" its on the governor ratchet pall mechanism itself there is notching to see its all internal to the governor.
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8 months 3 weeks ago #253316 by trainzkid88
as phil mentioned rechoming rams is cost prohibitive and can ruin the shaft anyway then you have the expense of a get shafts re-manufactured we had new shafts welded to the original rod ends done for around 900 bucks.
it was quoted at 700 bucks each for the rechroming job plus parts and labour. if your interested in how its done have a look at cutting edge engineering on youtube. it his bread and butter he does rams for 300 tonne capacity mining shovels.
its a good idea to park the blade on a block of timber etc if the machine will sit for a while in the weather so the rams arent exposed.

the cousin worked in the mines doing maintenance and he said he saw some companies had made covers out of canvas to help keep the ram shafts clean and protect from weather somewhat.
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8 months 3 weeks ago - 8 months 3 weeks ago #253318 by seiscat
Wait!!! The D7D Used the same basic engine as the D7E. The fuel rack doesn't move despite movement of the throttle control lever until oil pressure is high enough to allow it to move!!
Be Careful,
Craig
Last edit: 8 months 3 weeks ago by seiscat.
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8 months 3 weeks ago #253319 by seiscat
Here's the transmission fill plug below. The broken recoil spring is not as serious as you think. I ran a D6D with a similar break for 15 years. The hydraulic ram chrome missing that far down isn't that important.
Craig
 
 
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8 months 3 weeks ago - 8 months 3 weeks ago #253321 by seiscat
That D7D is factory equipped with a D339 engine (same basic engine as D7E) rated at 140 HP(if I remember correctly.) All D339 engines had the safety feature of the fuel rack that only advanced when sufficient oil pressure was achieved. The early D7E was 160 HP and later models 180HP. The D7D was originally equipped with a 2 cyl. starting engine.
I'm pressed for time this morning, I will be available for more later.
Craig
Last edit: 8 months 3 weeks ago by seiscat.
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