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336 CAT Hydraulic Accumulator Issue

Justin98

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Sep 9, 2020
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33
336 ELH CAT Excavator. Serial #CAT0336ECRZA00244 the warning light came on and when you cut the machine off you hear fluid running back to the tank any ideas how to proceed?
 

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uffex

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Good day
Suggest you check out the non-return valve that retains the pressure.
Kind re
 

Per Eriksson

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Oct 24, 2007
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Your machine is an XE machine that has a different hydraulic system than other F series machines.
There are 2 large high pressure accumulators and 1 small low pressure accumulator for the swing circuit.
The warning you see can be for any of them so you need to go into the diagnostics and look for the specific code there to know which one it is that has the problem, look for E1435, 1436, 1437, 1438 or 1565 codes

Usually the problem is for the high pressure accumulators and I don't recommend anyone that doesnt have the correct schematics and T&A procedure to work on them because they store alot of energy and if the valves don't work properly that energy won't be released when the machine is shut down.

But with that said, the sound you hear when the machine is turned off is most likely the high pressure circuit dumping to tank which is normal and can take up to 2 minutes to drop all the way to zero.
 

Justin98

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Sep 9, 2020
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The codes 1438 and 1565. What should the charge pressure be on the accumulator? Thanks.
 

heymccall

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Feb 19, 2007
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Western Pennsylvania
I think I may have misled you. Is that machine a hybrid. If so, there are two more LARGE accumulators for swing regeneration.

In other words, ignore everything above except Per Eriksson's post.

1438...Low swing accumulator #2 gas pressure.
1565...isn't in my book.

And, as stated above the swing accumulators are under VERY high pressure and must be serviced following all the steps, to a tee (and they are not the steps above).
 

Nige

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Jun 22, 2011
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G..G..G..Granville.........!! Fetch your cloth.
E1565(1) Event - Swing Accumulator Gas Pressure Mismatch

Event occurs when the pressure difference between Accumulator Gas Pressure Sensor 1 and 2 is greater than 3200 kPa (464.128 psi). No impact on machine efficiency. Operator will continue to see pop-up message "Accumulator Pressure Warning" on the monitor until serviced.

Determine the accuracy of the accumulator gas pressure sensors, refer to Troubleshooting, "Pressure Sensor (Swing) - Functional Test". If sensors are good, obtain an accurate temperature / gas precharge measurement, then adjust per specifications. Refer to Troubleshooting, "Accumulator (Swing) - Functional Test". Also Testing and Adjusting, "Accumulator (Swing) - Test and Charge"and, "Accumulator (Swing) - Test and Charge - Nitrogen Booster Group". Follow the correct testing and charging procedure.
 

Nige

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G..G..G..Granville.........!! Fetch your cloth.
E1438(2) Event - Low Swing Accumulator #2 Gas Pressure

Event will only be detected after 6 hours have passed from the previous key off. Event is active when the gas pressure is below 13000 kPa (1885.5 psi) @ 20° C (68° F). - Accumulator System is Disabled -

Event deactivates when pressure is in normal range, 16200 kPa (2349.6 psi) @ 20° C (68° F) to 22000 kPa (3190.8 psi) @ 20° C (68° F). This reset requires a 6-hour interval from the previous key off.

Check indicated swing accumulator for damage. Check the precharge pressure with a gage and then charge back to specification. Refer to Testing and Adjusting, "Accumulator (Swing) - Test and Charge"and, "Accumulator (Swing) - Test and Charge - Nitrogen Booster Group".
 

LACHAU

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Joined
Aug 11, 2009
Messages
992
Location
Saigon, Vietnam
E1438(2) Event - Low Swing Accumulator #2 Gas Pressure

Event will only be detected after 6 hours have passed from the previous key off. Event is active when the gas pressure is below 13000 kPa (1885.5 psi) @ 20° C (68° F). - Accumulator System is Disabled -

Event deactivates when pressure is in normal range, 16200 kPa (2349.6 psi) @ 20° C (68° F) to 22000 kPa (3190.8 psi) @ 20° C (68° F). This reset requires a 6-hour interval from the previous key off.

Check indicated swing accumulator for damage. Check the precharge pressure with a gage and then charge back to specification. Refer to Testing and Adjusting, "Accumulator (Swing) - Test and Charge"and, "Accumulator (Swing) - Test and Charge - Nitrogen Booster Group".
Hi Mr.Nige,
Could I ask Caterpillar 336E is a "HYBRID" excavator???


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LACHAU

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Aug 11, 2009
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992
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Saigon, Vietnam
Not an excavator expert by any means. Per Eriksson is probably the best guy to answer your question.
I think it depends on the Serial Number prefix whether or not it is hybrid - and there are about 20 different prefixes of 336E.
Thanks for your information.
I think it's a "HYBRID" excavator because a normal hydraulic excavator doesn't have "SWING ACCUMULATOR", is it right??


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Per Eriksson

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Oct 24, 2007
Messages
652
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Sweden
There's both an 336E XE which is the hybrid version with it's own hydraulic system but also as a regular 336E with the same hydraulic system as all other E series machines so you have to look at the serialnumber prefixes to know for sure.
These are XE or hybrid
RZA
HDW
JEA
SSL
GNY

While these are normal machines
YCE
YEP
BMH
DPX
BZY

The big accumulators have a precharge of 2785psi @ 68F with a gas volume of 8.45 gallons so a normal nitrogen gas bottle won't be of much use when filling these so you can use either a booster pump or as we can do around here, order special nitrogen bottles with a higher pressure and special regulators fitted on them, expensive but not as crazy expensive as the booster pump setup.
 

LACHAU

Senior Member
Joined
Aug 11, 2009
Messages
992
Location
Saigon, Vietnam
There's both an 336E XE which is the hybrid version with it's own hydraulic system but also as a regular 336E with the same hydraulic system as all other E series machines so you have to look at the serialnumber prefixes to know for sure.
These are XE or hybrid
RZA
HDW
JEA
SSL
GNY

While these are normal machines
YCE
YEP
BMH
DPX
BZY

The big accumulators have a precharge of 2785psi @ 68F with a gas volume of 8.45 gallons so a normal nitrogen gas bottle won't be of much use when filling these so you can use either a booster pump or as we can do around here, order special nitrogen bottles with a higher pressure and special regulators fitted on them, expensive but not as crazy expensive as the booster pump setup.
Thanks for your informations, especially about accumulator specifications and how to recharge it.
In the other way, we can rent a portable gas (nitrogen) booster, it is cheap also.

I think we can tell the difference by looking at the model name, where H means hybrid, is it right?

336 E L H meaning:
E = series E;
L = long crawler;
H = hybrid.


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