Cat 955K service questions

[Iron Dinosaur]

I bought a Cat 955K S/N 85J3811 last year, also have PDF service manual. My questions:

1. there is an electrical problem and 2 people are needed to start the machine - 1 to adjust the throttle, and 1 to jump the starter solenoid to the battery cable terminal with a screwdriver. start switch on the dash does nothing. how do I diagnose what is wrong? Is it a safety cut-out somewhere? Do I need to remove the dashboard?

2. the right side final drive does not work. it is not locked up; the right track freewheels. the final drive oil reservoir was full of dirt, so I figure either the duo-cone seals are bad or some other seal is gone and water/dust was able to get in.

3. does anyone know the year? I think it's 1974 or 1975, but that is a guess.

Thanks to all.

 

[fest777]

there should be a breaker fuse on the dash a red button, possible starter switch bad need a vom and check wiring.i have had my 955 do that 2 times the fuse blew and would not start , had the dash apart and never could find what the problem was , are you getting power to glow plugs ? if so the fuse is good .on the case all i can say is flush and new filters then try again, possible someone put that in the filler tube i.e. little kids or i think you get the picture grown kids. check screens real good, check linkage and adjust . i have a 85j07794 and its around 1973 or close to that year

 

[Dave Neubert]

There is a plug between the dash and engine compartment it gets messed up. sounds like you will be rebuilding a final drive too hope you have access to a cat press to pop sprocket off

 

[Iron Dinosaur]

thank you fest and Dave, new to the site and I'm not a mechanic by trade, so constructive feedback is MUCH appreciated. that is a good question on the glow plugs, I don't know if they work or not, but I'm thinking no. yes, unfortunately with the inboard final drive configuration the sprocket will likely have to come off. I do not have a Cat press, probably make a rig for it and get a hand hydraulic pump. there are many things I can't find or understand yet with the service manual; I just ordered an old original Cat parts manual last night off eBay.

 

[Dave Neubert]

You will need 50 to 100 tons of force to pop it off so I don't think something rigged up will do it plus it could be dangerous best get someone with the proper press to do it for you it also has to be pressed on with 30 -40 tons of force

 

[Iron Dinosaur]

you are correct, service manual states press on is 35-40 tons; I think I read somewhere on the web pull off is ~60 tons; it is not in the service manual. I am aware it is dangerous to do many things on these machines; the weight alone of many components is unbelievable. I will do more research on the issues with the press before actually doing anything.

do you have any idea on cost to have a mechanic pull that sprocket off? or put it back on? I'm trying to avoid going directly to Cat because I know field service is $$$. thanks again Dave.

 

[Dave Neubert]

About 3 hours labor is what I get the hourly rate varies I get 70.00 a hour but it is probably more up your way

 

[leadfarmer]

I replaced my starter switch because it was internally bad and not sending power to the glow plugs, but it would send power to the starter, so you don't know what's wrong until you start checking wires with a meter to see where power is going and where it isn't. Sit a 5 gal bucket in front of the seat, unbolt the dash, and lay it on the bucket, then you can start probing wires. Make sure you use a meter and not a common 12V auto test light since this is a 24V machine. There is no safety switch in the wiring to keep it from starting. These machines have a pretty simple wiring lay out. Get a manual that shows it. The only thing close to a safety switch is the oil pressure switch located on the front right of the engine. This is just to keep the hour meter from ticking when the key is on but the engine isn't running.