Hi, I have a 953C that seems to lose more power than it should when attempting to turn slightly and resumes full push power when going straight. What should I be looking for? I have a new full undercarriage on it. But it seemed like the lose of power while turning gradually started. Any suggestions would be appreciated. I’ve had two mechanics adjust the pedal’s sensitivity and it didn’t seem to help.
You need to monitor charge pressure, if when you attempt to turn slightly your charge pressure drops - then the problem is in your hydrostatic pump(s) displacement controls.
Is it one direction or both?
It happens in both directions
Does your low charge pressure light come on under load? check high idle switch electronic function (engine off calibration sub mode 10) check high idle, could possible be speed sensor bad
The low charge pressure light does not light up under pressure.
Does it make any difference warm of cold? I would check hi idle and switch
Does the SERV CODE icon on the dash stay on after the panel has gone through the self-test after the key is first turned on.?
It is consistent while running just getting started or after a couple hours of work
No the dash light all shut off after a minute or two after initial start
It only happens going forward. Reverse is as it should be.
Does it do it when turning both ways?
Yes it happens both ways left and right and more specifically going forward. Reverse seems to work as it should.
I'm thinking there are shuttle valves in solenoid manifold that cause drive problems but I can't remember what the symtoms are I'm almost positive there is a service mag on it the valve is 1832808 Nige might be able to find it
Who are you calling “shuttle valves”?!?! Ya gatta call it CAT names - “resolver”!!! That thing always cracked me up!
I did
Dang!!! They not being true to themselves!
sneaky aren't they
Resolver is scuch a “old school British thing”, I don’t think anyone besides CAT called those things that. Or I might not be old enough.
I think first of all we need to know the Serial Number of the machine in question to figure out iwhether or not SEPD0746 actually applies. The change came part way through 953C production. The use of shuttle valve or resolver seems to depend which product group is talking. The BHL guys always used resolver, it appears the track loader guys used shuttle valve. As for the others, your guess is as good as mine.
I'm sure all the c s use the same valve
2ZN03618
They do, but the shuttle valve was "improved" and the Part Number was changed during the production run of 953C. Everything after BBX00157 were built with the new P/N of shuttle valve already installed. But we have a 2ZN-prefix machine which predates BBX, so the shuttle valve Part Number update would apply to all machines...........
I can remember changing them I can remember you have to remove air filter to get at them But I can't remember what problem they caused But I'm old it may take a while for me to remember
Ordered two new shuttle valves to see if that causing the issue.
Had a chance to replace the shuttle cakes the weekend and they seemed to help a little but still had the same issue. After a while he was able to s determine with use of a scanner the high ideal was not hitting the required 2250 and it would keep it in limp mode which allows the engine under pressure to build up RPM to increase power. The throttle cable seems to have stretched and after some significant adjustments the power lose issue seemed to resolve. Thanks to all assisting with the trouble shooting.
Thanks Nige & Pittsburg Cat Man