Our Cat D4GXL dozer will not come out of park. put the rocker style park brake switch to "on" like normal to start the machine. Engine starts just fine but even after moving the park switch to "off" the park light stays on and the machine wont move in forward or reverse.. any ideas.?? yes i shut it off and turned battery main switch off and tried a couple of times and same result. Thank you for any help!
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CAt D4GXL park brake
- Thread starter OCD
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Nige
Senior Member
Do you have any other of the warning lights lit up on the panel when you try to switch off the parking brake..?
Have you tried starting the engine with the parking brake switch in the "Off" position and if so what was the result..?
Have you tried starting the engine with the parking brake switch in the "Off" position and if so what was the result..?
Nige
Senior Member
Well the fact that the engine will not start with the Park Brake switch in the "Off" position indicates that the switch is working and is sending the correct signal to the Electronic Control to inhibit engine starting, so to a certain extent that's good.
Now you need to get to the Park Brake release solenoid valve. See the illustration below. The valve is mounted just to the left of the hydrostatic pump. The Parking Brake solenoid is Ref. #4. Is that solenoid energizing when you release the Parking Brake..? BTW don't be tempted to try switching the coil on valve #4 with the one on valve #2, they are different Part Numbers. If you have a digital multimeter try measuring the resistance of the coil to check if it has failed. It should be 10.16 +/- 0.2 ohms.
Now you need to get to the Park Brake release solenoid valve. See the illustration below. The valve is mounted just to the left of the hydrostatic pump. The Parking Brake solenoid is Ref. #4. Is that solenoid energizing when you release the Parking Brake..? BTW don't be tempted to try switching the coil on valve #4 with the one on valve #2, they are different Part Numbers. If you have a digital multimeter try measuring the resistance of the coil to check if it has failed. It should be 10.16 +/- 0.2 ohms.
Peter Brewer
Member
I have the same problem. Did anyone come up with an answer.
Nige
Senior Member
If your symptoms are the same as the OP then see posts #2 & 4 above. Try what’s suggested there and see where it gets you. Unfortunately it’s not unusual for people to ask for help then not post back saying what the fix was.
Nige
Senior Member
Also post a Serial Number or at least a prefix to confirm the information given above is accurate.
Peter Brewer
Member
Sorry Arkrite, I got sidetracked. It's night time here at the moment but I'll give what you say a go when I get back to the machine. Unfortunately and typically It stopped in a **** of a spot to get to so it might be a day or so before I get back to you but your help is much appreciated. I did try starting with the brake switch off but no go. I also tried disconnecting the battery to see if might reset the computer but I don't even know if that's a thing but it didn't work anyway. Thanks mate.
Nige
Senior Member
If you want to get deeper into it a Serial Number at this point would be an advantage to make sure the info supplied is correct.
Peter Brewer
Member
Must have written serial no. a hundred times, don't know where. Had to go out to machine to get it. D4GAHYDO2263 I tried what you said but the diagram on your post looks different to what's in the bowels of my machine. I've got two pumps with two solenoids on each one as far as i can guess. I couldn't see anything else that came close. ( my parts book's on loan to my brother in law which I'll get back and suss it out.) The front solenoid only came up to 5.4 ohms but I can't say i trust the result, I tried every position in the Karma Sutra but I could only get one hand in to attach the probes and all unsighted (they had male plugs just to add to the challenge ) so I made up a plug with a couple of leads to get some sort of reading but they were pretty rough. Then it started to **** down rain so I got out while i still could. I'll try again when it stops raining but I'll make up a propper plug with longer leads to make things easier this time. This shouldn't effect the reading should it. If it is the solenoid f#×k knows how I'm going to replace it/them! I'd appreciate any comments you have and once again many thanks for your time. I'll keep you posted. (when the rain stops)
Nige
Senior Member
That's the problem when you're working on a different model (or different Serial Number prefix) to the one the thread originally related to. The diagram below is the one from your machine Parts Manual and may be a bit clearer than the one above. Still basically the same arrangement and in the same location on the machine though. Park Brake solenoid (#4) coil resistance still the same, 10.16 ± 0.2 Ohms. If you can get on to the nut (#1) that holds the coil on to the valve body maybe removing the coil and then measure the resistance off the machine could be an option.?
I've attached the parts breakdown that shows the location on the machine. The block with the two solenoid valves is #3.
Peter Brewer
Member
A nice local young bloke who's a Cat mechanic did me a favour and ran a free diagnostic for me. Nothing there, no error codes, nothing. The brake switch was working O.K. and the brake solenoid was being energised but that didn't mean it was working, it was just energised. Thanks for the diagrams, I wasn't testing the right solenoid, looks like to get to the brake solenoid I might have to drop the belly plate and go in from underneath. The Cat doctor was surprised at the lack of diagnostic info but seemed to think it may be the solenoid. Didn't think I should push it and ask him seeing as he was already there to test it. It's still raining and cold enough to freeze the walls off a bark humpy at the moment so it could be a day or two before I have an update unless your interested in how good the fire in the bar at local pub is, but I'll keep you posted. Until then thanks again.
Nige
Senior Member
You know what they say. If you can't take a joke then you shouldn't have joined............
Welder Dave
Senior Member
It's no joke when a machine is down and you can't figure out what the problem is. 
Even worse is when it's supposed to show a code and doesn't. A think the new 150 grader thread takes the cake and the Cat techs/Cat can't figure it out.
Even worse is when it's supposed to show a code and doesn't. A think the new 150 grader thread takes the cake and the Cat techs/Cat can't figure it out.
Nige
Senior Member
I was referring to the weather at his end ............!!! It's a standard response where I come from if anyone complains about the weather.
It's only going to throw a Code if the electronics are acting up. The spool in the solenoid valve could be seized solid and it wouldn't throw a Code because electrically the solenoid coil would be energizing. The only way to test that would be to hook a pressure gauge up to the system and watch it as the park brake was applied and released.
Welder Dave
Senior Member
I was kicking myself for not putting up a shop a lot sooner. Just having somewhere under shelter to take things apart is a blessing. Walls stop all the wind, rain and snow from coming in and a roof stops the blazing hot sun as well. If the weather turns bad you can either work on the machine or wait till the weather clears up. Would have liked a concrete floor but concrete is stupid expensive here. Put up 40x60 pole shed for around 40K cad. and a concrete floor would have been a little over 20K. Just not in the budget. Actually most repairs aren't in the budget but you have to fix the machine so you can use it. This may be where the term "money pit" originates.
On a side note, I'm very happy today. Had chemo yesterday at greatly reduced doses and so far no bad side effects. Was off chemo for 2 weeks because the last time I ended up in the ER and was wishing for death! It was that bad, no control over anything and in too much pain to get up. Some nurses in the hospital could care less how you feel. Great to be home and feeling pretty good!
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Peter Brewer
Member
We have a say that goes "you've got the bull by the tail". I wasn't complaining about the weather but explaining why you wouldn't get an update for a few days. On the contrary, on the days that I can't work because of the weather,which isn't often, I can take the day off without the protestant work ethic I was raised with making me feel guilty. I joined the club over forty five years ago and I've had my fair share of adversity, but I've learnt alot in the process. I enjoy dozing more now than I ever have and I'm happy that I still learn more in a week than I forget but I'm no spring chicken any more an the dust and smoke from pushing up fires and cigarettes has taken its toll. What I used to do all day now takes me all day to do. Apart from a couple of fuel pumps with built in obsolescence the last major malfunction the machine had was seven and a half thousand hours ago and that was only major because the diagnostics said "undetected track movement" (one track was turning twice the speed of the other)which convinced the $135 an hour Cat mechanic that it was a mechanical problem because if it was electrical "the computer would have said so". After three and a half weeks, a thousand dollars worth of parts from America that "should have fixed the problem"and three and a half thousand dollars in labour later I swapped over a couple of speed sensors with each other and found the opposite track was moving quicker. When If told him what I'd found he assured me the problem wasn't electrical and that I'd got the tracks mixed up. To cut a long story short it cost me four and a half grand for me to find out that paying $135 an hour for a"Cat" mechanic because i didn't understand hydrostat technology, was no guarantee he knew what he was doing or that I would get value for money. If I get paid four and a half grand to build a dam it comes with the guarantee it will hold water, even in the worst material I still give a guarantee if the client is happy to pay for it. If I can't give a guarantee then all I'm doing is running around making a nuisance of myself digging holes and ripping people off. When I explained this to the management at Westrac (the Cat franchise) with said mechanic present when I went to pay the bill, I was told that that might be how I worked but it wasn't how they did business. After getting some signed statements off people in the trade I'd met over many years who only did business with that branch if they had too, I sent them off with a long letter of my own to Westrac head office. After waiting a month without a reply i sent the letters along with note to say i was still waiting for a reply from Westrac head office to Cat head office in America it didnt takeIf I had backed myself I would have checked the obvious things first and all it would have cost me was $300 and a couple of days down time. I'm not in a rush and I'm enjoying the time off while I chase up the possible problem and how fix it and as soon as I do I'll let you know. Thanks for the backup Dave . I can only guess what the chemo is about and I wish you nothing but the best.
Peter Brewer
Member
Tested the solenoids, I thought I might as well check them both while I was at it, the right ones this time. The both went 10.5 ohms. There's two sensors on each pump and I think two more on the drive motors which I'll run the meter over. I'm thinking that may be the brake may come on as a fail safe measure when something has failed to prevent more damage but you'd think that would show up in the diagnostics. Lately I've been thinking that I could hear a noise coming from the right motor when steering to the left in reverse but I wasn't sure if I was just being paranoid. I've also had my suspicions that it's started getting a bit sluggish lately when you take off forwards.
Nige
Senior Member
I would suggest removing the park brake valve complete and applying battery voltage to it to ensure that the spool makes a distinct "click" noise in both apply & release directions.