950f series 2 no brakes.

[MDIWayne]

New to this forum so I will introduce myself. My name is Wayne and I am the mechanic for a gravel company. I am currently pulling my hair out trying to figure out the brakes on this loader. ser# is 5sk00814. They will barely stop the machine. Brake discs are barely within specs. I've been through the troubleshooting in the manual and I'm finding that I have lost the pressure at the foot valve and at the accumulator charging valve. When I originally started this project I had 1000psi at the foot valve and around 2100 at the accumulator charging valve. I removed the accumulator charging valve to disassemble, inspect and reseal.Since then I have around 300 at both ports. Is there something in the valve that I could have installed wrong?

 

[Mark250]

Hi check the relief valve in the accumulator valve
As the steering and implement pilot also use the same pump cap off the line going to the reducing valve as it could have some influence on the low readings
Mark

 

[MDIWayne]

 

[MDIWayne]

That is where I'm running into a problem. Both the picture in the book and the picture on the cat sis website show a pressure release valve on the accumulator charging valve. My machine does not have a pressure release valve mounted externally in the port that it shows it should be in. Caterpillar has been absolutely no help as far as telling me if I order a new accumulator charging valve if it would have a pressure release valve or if a pressure release valve would be included in the rebuild . kit. Almost at my wit's end here. And my wife is tired of watching me pull my hair out of my already balding head

 

[kshansen]

Wayne, Any chance of attacking this from a different direction? Can you get the part number off that tag I circled in red in your picture below?



Or any chance there is a tag with a number on the valve itself? My hair is very grey but guess I can afford to loose a little trying to help.

 

[MDIWayne]

Tag# is 04 8631. I believe the original number on that accumulator charging valve is 8R - 5603

 

[kshansen]

Well I think the tag number should have a "1" at the start 1048631 shows as the steel line going to the bottom of the accumulator charging valve.

Going through SIS I'm seeing the valve starting as a 8R5603 then 1386875 then 2899972.

My only guess is your machine has had one of the "updated" valves installed. I'm thinking Cat never changed their drawings to show the newer style valve. And in the NPR it appears to list 1393285 as a repair kit for the 2899972 valve. There does appear to be a service magazine that might reference this valve but my version of SIS does not give me that access it should be SEPD0783

 

[Mark250]

this is what the service letter says

Mark

 

[Liviu Popescu]

Hi. Did you ever manage to sort your problems? I have a similar issue on mine.

 

[Nige]

Hi. Did you ever manage to sort your problems? I have a similar issue on mine.

This was for G-Series.
Accumulator charging valve updates as detailed above by Mark250 do not apply to your F-Series machine.