CAT D6R's

Im currently working on 2 D6R's and another D6 which i havent seen yet but will be checking out in the morning. The 2 ive looked at have A/C problems. One i believe has a bad clutch cuz it has power all the way to the clutch but engages and disengages when it wants to so i got a new clutch assy. coming for it. The other seemed low on freon it was like below 20psi on the low side and around 200psi on the high side so i added a can and a half. Now it showes around 30psi and below on low side and high side is 350 so i cleaned out the condenser which had alot of dirt in it but it still is just below 350. Shouldnt it be around 250 or 300?
Now the other one doesnt move forward or backwards im not real familiar with this machine. I think it has electric switches to control the FNR right? Where should i start on troubleshooting this one? If anyone has some schematics they can send me that would be awsome!

I had the A/C gauges on a 6R this afternoon in the 104* heat, and it was at 30 lo side and 300 high side and blowing 50 degree air. I would say yours is in the ballpark. as far as the FNR goes, yes it is controlled electronically. The park brake switch must be functioning properly for it to move also. Check for fault codes as they usually log faults when the sensors go bad or get out of calibration.

I had a 6R that was kicking the clutch in and out like that and it was a pressure switch acting up. Might check that if the clutch doesn't fix it, or make sure that the clutch isn't losing power causing the it to kick in and out.

About 3 weeks ago, I had the park brake set on a 6R for no reason at all, while pushing up a 3:1. Wouldn't steer, or shift forward or back. Had the park brake light come on, the gear with a "!" inside of it light and the brake presure light, along with the buzzer. Called Cat out to look because our mechanic couldn"t get his computer to link up to it. Neither could the Cat man. Turns out the park brake fuse was blown. Put in new one, released brake, shifted into reverse and it blew again. We stuck a heavy piece of wire in the fuse hole to get it off the slope. Cat man held wire while I eased it off the hill. When the wire would get hot he'd pull it out and we'd stop. Turns out there was a wire in the harness that was rubbing through. Spliced it up, added some extra protection and haven't had any trouble since.

Plan B said:

Im currently working on 2 D6R's and another D6 which i havent seen yet but will be checking out in the morning. The 2 ive looked at have A/C problems. One i believe has a bad clutch cuz it has power all the way to the clutch but engages and disengages when it wants to so i got a new clutch assy. coming for it. The other seemed low on freon it was like below 20psi on the low side and around 200psi on the high side so i added a can and a half. Now it showes around 30psi and below on low side and high side is 350 so i cleaned out the condenser which had alot of dirt in it but it still is just below 350. Shouldnt it be around 250 or 300?
Now the other one doesnt move forward or backwards im not real familiar with this machine. I think it has electric switches to control the FNR right? Where should i start on troubleshooting this one? If anyone has some schematics they can send me that would be awsome!

Click to expand...

Need some serial numbers to determine if this is a FTC or diff steer machine, as well as series (i.e., II, III.) I've seen this problem before and it has ranged from a broken/corroded wire in the foot brake box, to an adjustment issue with the linkage, etc., etc.

I just sent you an email about the a/c, let me know if it helps.

Best,

JCS

Thanks for all the feedback but heres the deal....the dozer i had to check the forward reverse on isnt even a cat its a komatsu D61 sorry about that, but i checked it out and it goes forward and back and side to side only problem is i cant get it to go into 1st gear and the brake pedal is seized up totally. They asked for an estimate on fixing the problem if its external, like linkage sticking or hand control messed up or cable only going so far cuz of rust or debris. So im waiting to hear from them on it but id appreciate some ideas on what yall might think on it. Also the A/C with the high pressure on the high side, they said it stopped cooling about an hour after i left. I was wondering if there is a relay or circuit breaker between the switch in the cab and the compressor. Im thinking there might be some trash in the system clogging up the orifice tube and causing it to build pressure and shutting off compressor or maybe a weak relay but i have to get it to shut off while im there to find out where im loosing power. If it is loosing power between the compressor and the control unit and not at the pressure switch what might be the problem?

dblaneyfan said:

Need some serial numbers to determine if this is a FTC or diff steer machine, as well as series (i.e., II, III.) I've seen this problem before and it has ranged from a broken/corroded wire in the foot brake box, to an adjustment issue with the linkage, etc., etc.

I just sent you an email about the a/c, let me know if it helps.

Best,

JCS

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It helps out alot!! The machine i swapped the compressor clutch on is right on the money according to the chart and its not cutting off anymore so its fixed. The other one is way too high on the high side and i might have put alittle too much 134 in it. Thanks!!

dblaneyfan said:

Need some serial numbers to determine if this is a FTC or diff steer machine, as well as series (i.e., II, III.) I've seen this problem before and it has ranged from a broken/corroded wire in the foot brake box, to an adjustment issue with the linkage, etc., etc.

I just sent you an email about the a/c, let me know if it helps.

Best,

JCS

Click to expand...

I might be wrong, but I'm fairly certain all D6r's are differential steer machines.

JimBruce42 said:

I might be wrong, but I'm fairly certain all D6r's are differential steer machines.

Click to expand...

No, they make them in fingertip steer also, we had one on lease for a year.

JimBruce42 said:

I might be wrong, but I'm fairly certain all D6r's are differential steer machines.

Click to expand...

No, we have three 4MN's with FTC. I prefer the diff steer when operating, but the FTC's have been relatively trouble free on the maintenance side.

JCS

Straightened out the fins on the condenser and cleaned it again and the high side was still too high. So i decided there was a restriction in the system. Replaced the dryer/orifice tube assy. and its right on point now, so its fixed. Im going out monday morning to try and figure out whats wrong with the gear selection on the komatsu!

Let us know how it goes. Also, what model is it? A -12?

Kamatsu D31EX i think. It ended up being the switch that i think controls the lights on the dash that tell you what gear you are in, being stuck and not allowing the linkage to turn to put it in first gear. I just freed it up with a screw driver and some cable lube. Then i cleaned all the rust and dirt from around the brake pedal and lubed it also and freed it up with a hammer. Its functioning properly now!! Of course i checked everything else before i found that switch sticking but they were real happy they didnt have to pay for a new transmission..lol!

I had to go check out the D6R i replaced the dryer on for water in the oil. Driver said he has to add water frequently and oil too and he found some water in the oil today. I checked it out found slow coolant leak on upper hose and tightened hose clamp and the tank where cap screws on was bent up so i tapped it back in shape with hammer. Also found a hose split almost in half coming from a canister bolted to the side of the motor that the blow by hose connects to coming off the valve cover. I took a pic of it but dont know how to post it up. I believe since it was pressure washed a day or two ago that water went into that split hose and got into the motor there, since it wasnt a whole lot of water. Does anyone know for sure that that blow by canister allows oil to flow back into the motor where its bolted to the side of the block? If so then ill know for sure thats where the water came from. Thanks.