Cat 277 problem

[drystack]

Has anybody had to do any work on the undercarriage of their Cat track loader yet? I have what appears to be a collapsed bearing/failed seal on the front idler that is leaking fluid quite badly. While this system is similar to the design on my ASV 4810, it does differ in a few aspects I see. Hopefully its easier to work on than the ASV, but I'm looking for some reassurance before we take it apart :wink2

[trailrunner]

I work at a cat dealer as the a CCE field mechanic. The undercarriages are fairly easy to work on. The best way to remove the track is to detension it remove the track drive (squirrel cage) and usually you can kick the track off the rear idler first then the front idler. Installation is reverse of removale. You didnt say if your machine was a A or B model but there was an update done to the idlers that requires you to drill out your current wheels to 1/2". they are plastic so its really easy to drill them out. If you have any more questions feel free to ask.

[Tigerotor77W]

Hey trailrunner! Glad to have you on board... should ease up the CCE questions quite a bit. Out of curiosity, and if you don't mind my asking, which dealer are you with?

[trailrunner]

Thompson Machinery in La Vergne TN. Feel free to ask any questions and i will try my best to answer them.

[cachatz]

I have a 277b and the parking brake will not release. Light just flashes. Problem started a couple of weeks ago but if you let it sit and warm up for about 10 minutes it works fine. Yesterday during a jod it just stopped and light started flashing and now it is stuck at the job site. Replaced the solenoid today and it did not fix the problem. Anyone know where I can get a wiring diagram so I can trouble shoot this problem. Any help is greatly appreciated

[Cmark]

OK. Tricky one. First the bad news.

The interlock system is controlled by a (OH NO!) computer (ECM)

However, here's a couple of questions from your friendly ex-cat field serviceman

1. Work out what's flashing. Armrest indicator, Park brake indicator or both?

2. Does the light(s) flash before you hit the park brake switch or after, or both?

Sorry, there isn't really any good news. It could be any one of several solonoids, harness fault, park brake switch, seat switch, armrest switch, detent coils or even the ECM (unlikely).

If you're in a hurry, I would get your local dealer to take a look.

If time isn't such an issue for you then feel free to get back to me with the above info and I'll run through the next stage of troubleshooting based on your findings.

Good luck.....

[cachatz]

Ok. I found 5 wires that were chaffed and one was rubbed through in the main harness behind the cab. Fixed that and no change. Checked voltage at wire going into ECM from switch and I have 12 volts when switched is depressed. Checked yellow wire which is the output to solenoid and it jumps up to 8 volts when depressed and then to 0 volts. I'm no Cat Tech but I do believe that the soleniod shold hold 12volts to release it out of park. The light for the seat does come on when your out of the seat so I do believe that it is working and the lap bar safety is also working. What I do not know is if there is another safety or switch mounted on the brake that tells the ECM if the park is released? The bucket controls work and it starts up but when you hit the switch it just blinks and you do not have drive controls. My thought is an ECM????

[Cmark]

If I understand you correctly, only the park brake lamp is blinking, and only blinks after you have hit the park brake switch?

If this is right then the problem should be in the transmission pilot solenoid or wiring.

This is part of the LH pilot valve/joystick. It will have two wires running to it; a 416 green and a 975 white. The wires go to the ECM. 416 green to pin 29. 975 white is a common return which goes to pin 68. Check the resistance of the coil. It should be 10 ohms plus or minus 0.5.

The good news is that if you decide the pilot solenoid is faulty, it should be the same part as the park brake solenoid you already replaced and which is probably not faulty. Part number 195-9700.

Let me know how you go.....

[Cmark]

Apologies, not finished yet....

If this all checks out, move on to the RH joystick.

You will find the same 195-9700 solenoid and also the bucket detent coil. These two components are wired in parallel. 988 orange goes to pin 24 on the ECM. 975 white is the same common return as the LH solenoid. Pin 68 on the ECM.

Once again check the wiring for continuity and shorts. Check the resistance of the coils. Pilot solenoid as per the LH. The detent coil should be 9.4 ohms.

Good luck....

[GREGGV]

thanks for the help Cmark with the above question as it turned out it was the ECM problem is fixed now........

[ATCOEQUIP]

Greggv, what's up with your responses on this forum? We can only assume you've changed your name from cachatz to greggv, at least that's the way it appears. But then there's your last post "...fixed now". We are all at this site, novice operators to experienced operators/mechanics to either learn something from each other or help someone. I am an experienced mechanic, but the problems you described was something new to me and I was reading the post's wanting to learn something. Cmark was giving you some detailed advice, and you leave us with "as it turned out it was the ECM problem fixed now...." What does that mean? Did you just up and replace the ECM? You just left us with "fixed now......"! What the heck just happened here?

[GREGGV]

well cachatz is a good friend of mine and found this site first then told me about it..........so no name change.....but sorry I was not more clear i did replace the ecm #154-4233....

[GREGGV]

we did find some corrosion inside the ecm also....we are going to dig a little further into it to find out what went bad the machine only has 1280 hrs on it .......

[cgustafs]

Sorry to hijack this thread, but I am a new member and still can't seem to post a new thread after following all of the instructions for a new member. Anyway, I have 2 questions:

1) Where can I get a diagram of the hydaulic lines for the joysticks? I have a burned cat I am rebuilding and have to re-route them.

2) Are the OEM hydaulic fittings reuseable? They look crimped to me, but all of the cat ads state they can be reused? All previous reuseable fittings I have seen are screw-on. Do they somehow expand and reuse the ferrule?

Thanks

[ATCOEQUIP]

Sorry to hijack this thread, but I am a new member and still can't seem to post a new thread after following all of the instructions for a new member. Anyway, I have 2 questions:

1) Where can I get a diagram of the hydaulic lines for the joysticks? I have a burned cat I am rebuilding and have to re-route them.

2) Are the OEM hydaulic fittings reuseable? They look crimped to me, but all of the cat ads state they can be reused? All previous reuseable fittings I have seen are screw-on. Do they somehow expand and reuse the ferrule?

Thanks

You would have to get diagrams from your Cat dealer. If your going to keep the machine for a number of years, I would get the manuals for it from Cat. You didn't state what type of Cat you are rebuilding. Most of the hyd lines do not have re-usable fittings, they're crimp type. The re-usable you referred to as screw-on are Areoquip fittings. Cat may have used these on some models. Some Cat assemblies also have a re-usable fitting that's different from the Areoquip, the sleeve unlocks and can be removed and the fitting can be removed, then the assembly can be used in a new hose. Most of these fittings, though, are used on the larger hoses with big expensive fittings. The smaller hoses are usually crimp type fittings. You'll be able to start a new thread after enough posts to the forum.

[cgustafs]

Thank you. I have already posted more than the minimum 3 so hopefully it comes soon.

My machine is a 287b. The dealer quoted over $800 for a manual.. was hoping it was $1-200.

I thought the fittings were crimp so thanks for confirming.

[Shifty]

Hi all Trying to get my three posts in to start some 277 topics. Had good luck with the tracks and electrics. My problems have been hydraulic leaks.Blowing low pressure return lines,steel hard lines, and the oil cooler. I know I've put at leased 25 gallions in the tank and out the belly pan.:mad:

[special tool]

Thank you. I have already posted more than the minimum 3 so hopefully it comes soon.

My machine is a 287b. The dealer quoted over $800 for a manual.. was hoping it was $1-200.

I thought the fittings were crimp so thanks for confirming.

$800???
That is insane.
Someone is trying to retire on you.

[cgustafs]

A dealer in another corner of the state was kind enough to print of the one page schematic so I am back in business. Also bought a second parts machine which is going to save real $$$$

[brabe]

we just replaced tracks on 277 with aftermarket tracks
i was a little weary when we got it back because every cat rep told us that you should not do it. the only problem i see is not getting the tracks tight enough. the adjustment is all the way out and they could be tighter
they told us that are idlers are worn down but the old tracks were completly shot and we had plenty of adjustment and they were tight
anyone else used aftermarket tracks??

[cgustafs]

The spare machine I bought was a 277 needing tracks so I would be very interested in this too. Were your rollers worn to a smaller diameter? Hard to believe this would affect the adjustment that much

[brabe]

i didn't have anything to do with the repair work \
i thought i was getting cat tracks not aftermarket
i guess my next step is going to be making sure the size of the aftermarket track is correct(right number of lugs etc) i'm not sure
any advice from anybody would be greatly appreciated
i just can't get past the fact that the old track were tight and they were completely shot ( nylon showing everywhere. we were using it on a job were there was alot of shot rock)