D5G parking brake won’t disengage

Brycewayne12 said: I’ve got nothing in any of the test ports Click to expand... But I checked the the alternator after I checked the test ports and at first it read 13.04v and then it jumped to 14.21v the battery was at 12.02v then jumped to 13.10v so my question is should I have pressure to the parking brake test port no matter what or if the light on the dash isant going off will there not be pressure?

Alternator output sounds OK. I have no idea why it should jump like that. The pressure tests at all those test ports are made with the parking brake released. If the electronics are not giving the signal to release the brakes then it is quite possible that the rest of the hystat system will not function.

Nige said: Alternator output sounds OK. I have no idea why it should jump like that. The pressure tests at all those test ports are made with the parking brake released. If the electronics are not giving the signal to release the brakes then it is quite possible that the rest of the hystat system will not function. Click to expand... Can you send me a diagram of where the parking brake Selniod is at

Brycewayne12 said: Can you send me a diagram of where the parking brake Selniod is at Click to expand... I'll send you a complete electrical schematic. That shows the wiring as well as component locations. Check your messages.

Welcome, Clear the codes,turn the key on but don’t start it see if it sets 255 again

Thank you guys for all your help! It’s most likely the drive coupler I’m going to pull the pump in the morning. So the dozer belongs to my mothers husband who has taught me everything I know about operating, but he did not trust my mechanicing ability at all (granted I will rig some **** up on my own things to get by, so I have some strikes against me) but we got a cat tech who’s a family friend come out and hook his computer up to it, basically cuz he didn’t trust me and needed a second opinion…. The tech said sounds like you have good help and you might oughta listen to him! So thank you guys, I got some much needed respect outta this whole catastrophe! This was my first time using this forum and I am very impressed at the response times and knowledge people are willing to share! Again thank you!

When we did ours we pulled the engine and left the pump in the machine so you dont have to remove all the lines. I talked to a few cat guys and thats how they do it.

Brycewayne12 said: Thank you guys for all your help! It’s most likely the drive coupler I’m going to pull the pump in the morning. So the dozer belongs to my mothers husband who has taught me everything I know about operating, but he did not trust my mechanicing ability at all (granted I will rig some **** up on my own things to get by, so I have some strikes against me) but we got a cat tech who’s a family friend come out and hook his computer up to it, basically cuz he didn’t trust me and needed a second opinion…. The tech said sounds like you have good help and you might oughta listen to him! So thank you guys, I got some much needed respect outta this whole catastrophe! This was my first time using this forum and I am very impressed at the response times and knowledge people are willing to share! Again thank you! Click to expand... According to the dealer they pulled motor to replace drive coupler. It was a expensive job, 13k $ I probably should've tried to do it myself but didn't really have time

The procedure shown in the service manual is to remove the engine and pump as a unit and split the pump off it once it is out of the machine. There is no procedure just to remove the engine alone. If an experienced technician decided to only remove the engine and leave the pump in situ he's probably the type of guy who has done it before and doesn't need to refer much to a procedure anyway. However for anyone who has not done this before the service manual procedure is probably all they have to go on. My suggestion would be to do it way the book shows because at least you'd have a procedure to work to. This is based on the fact that nobody involved in the job has ever done it before. The difference in weight between just the engine and the engine/pump is not going to be much. Whatever is used for lifting will likely have the capacity to lift either just the engine or the engine/pump.

Nige said: The procedure shown in the service manual is to remove the engine and pump as a unit and split the pump off it once it is out of the machine. There is no procedure just to remove the engine alone. If an experienced technician decided to only remove the engine and leave the pump in situ he's probably the type of guy who has done it before and doesn't need to refer much to a procedure anyway. However for anyone who has not done this before the service manual procedure is probably all they have to go on. My suggestion would be to do it way the book shows because at least you'd have a procedure to work to. This is based on the fact that nobody involved in the job has ever done it before. The difference in weight between just the engine and the engine/pump is not going to be much. Whatever is used for lifting will likely have the capacity to lift either just the engine or the engine/pump. Click to expand... Im having same issues but drive coupler was fine is there anything else that could cause no pressure at any ports

Alanol said: Im having same issues but drive coupler was fine is there anything else that could cause no pressure at any ports Click to expand... It's happened before where the hub to which the drive coupling connects has slid away from its position and results in no drive even though everything looks undamaged. Did you investigate that possibility.? Also did you attempt to rotate the pump input shaft.? If you did how hard was it to turn.? What model machine are you working on.? Serial Number.?

Nige said: It's happened before where the hub to which the drive coupling connects has slid away from its position and results in no drive even though everything looks undamaged. Did you investigate that possibility.? Also did you attempt to rotate the pump input shaft.? If you did how hard was it to turn.? What model machine are you working on.? Serial Number.? Click to expand... Yes everything looked good , and yes I could rotate the hub by hand but it takes a little pressure to make it turn. It’s a cat d3g 2008

Alanol said: It’s a cat d3g 2008 Click to expand... That's like saying it's a '08 white Ford F150. Machine Serial Number please. What is the current state of the machine.? Still disassembled.? Alanol said: yes I could rotate the hub by hand but it takes a little pressure to make it turn. Click to expand... You literally should need a pipe wrench on the hub to turn it. Where were you testing pressures.? Also did you obtain the list of Diagnostic Codes from the machine electronic control system.?

Nige said: That's like saying it's a '08 white Ford F150. Machine Serial Number please. What is the current state of the machine.? Still disassembled.? You literally should need a pipe wrench on the hub to turn it. Where were you testing pressures.? Also did you obtain the list of Diagnostic Codes from the machine electronic control system.? Click to expand... CATOOD 3GL JMHO 1951 It’s currently put back together to get it home. And yes there is zero pressure at either port other than the auxiliary pump for the blade

Let's get into looking at the electronics, even if only to rule it out. See the attached. Start from Page 4. All you need are a couple of bent paperclips to extract the Codes.

Is there a charge relief valve on the hystat? Could that potentially cause no pressure?

Did you look for Codes yet.? You should really eliminate any possibility of a fault in the electronic side before diving into the hystat system. Attached the hydraulic schematic.

Nige said: Did you look for Codes yet.? You should really eliminate any possibility of a fault in the electronic side before diving into the hystat system. Attached the hydraulic schematic. Click to expand... I got code 261

Alanol said: I got code 261 Click to expand... That is for the throttle switch. It needs fixing before proceeding further. The troubleshooting procedure for the code is on Page 172 of the document that I uploaded above. See where that gets you.

Nige said: That is for the throttle switch. It needs fixing before proceeding further. The troubleshooting procedure for the code is on Page 172 of the document that I uploaded above. See where that gets you. Click to expand... Im now getting just 222