Author Topic: prentice 210d cylinder creep (Read 1356 times)

loader man · « **on:** October 06, 2011, 09:05:15 pm »

Everything (grapple, jib, main boom, outriggers) is leaking off on this machine. We swapped the grapples hoses and it held the logs, so im sure the packing is good. We just packed the jib boom. I've messed with the main and port relief valves but nothing helped. Any suggestions?

loader man · « **Reply #1 on:** October 06, 2011, 09:11:01 pm »

it is lever operated to

oldseabee · « **Reply #2 on:** October 07, 2011, 08:59:30 am »

Possibly crack in main valve housing.

snowstorm · « **Reply #3 on:** October 07, 2011, 04:55:47 pm »

or dirt under the cirtuit releaf valve

loader man · « **Reply #4 on:** October 07, 2011, 06:24:01 pm »

is the circuit relief the same as main relief, it has 2 main reliefs that i know of

snowstorm · « **Reply #5 on:** October 07, 2011, 09:20:36 pm »

no. there will be 2 main releif if it has a tandem pump 3 if a triple pump.load check is another name for it. the pressure will be set a bit higher than the main.

oldseabee · « **Reply #6 on:** October 07, 2011, 10:52:44 pm »

There is usually a circuit relief for each direction of each circuit usually set higher then main relief but not always. They are mainly to act as shock relief for the circuit when it not being used. Example would be if a somehow a large tree fell on the boom, the circuit relief would pop open and allow the boom to drop from the shock instead of blowing hoses or breaking something.

loader man · « **Reply #7 on:** October 09, 2011, 03:18:46 pm »

how would be the best way to clean it?

loader man · « **Reply #8 on:** October 11, 2011, 10:08:33 pm »

anybody know how to clean dirt out from under circuit relief?

snowstorm · « **Reply #9 on:** October 12, 2011, 05:39:29 pm »

everything leaks down? how quick? any chance someone put something in the oil tank? the problem happen all at once? i have seen a little peice of dirt ect keep the ball in a circit releif open just enought that it would leak down. with 2 boom cyl if the packing in one is bad bolth will leak down cause they are plumbed together

loader man · « **Reply #10 on:** October 12, 2011, 06:07:03 pm »

jib boom is the fastest if extended all the way probably a minute main boom about half stabilizers i have to push down about every time i load a tree or the machine will be rocky grapple will leak open with a big tree fast (its almost scary) the grapple rotate is continous and if you bump against something it will just spin everything leaks off both ways

snowstorm · « **Reply #11 on:** October 12, 2011, 08:49:27 pm »

the stabilzers should have lock valves to prevent drift. how old is this thing?? did you play with pressure settings?

main reliefs??? buy a pressure guadge check the pressure. dont know the spec but start with 2100psi thats safe enought. if the main releifs are at lets say 700psi the weight of the boom would let it come down. lets hear it what have you done to it?

loader man · « **Reply #12 on:** October 12, 2011, 09:18:45 pm »

the stabilizers do have lock valves on each one. It is a 93 model. I have'nt adjusted any pressure settings. It started with jib boom and everything started after that individually. I replaced one of the port reliefs on the grapple close side. I bought one main relief valve and swapped it with the 2 that are on it and it didn't change anything so put them back and took it back and got my money back. replaced some of the orings on some of the port reliefs.

kiko · « **Reply #13 on:** October 13, 2011, 05:17:32 pm »

As far as the grapple goes you are on the right track. Three things will make the grapple open with a log in it. 1. Grapple cyl. packings, it could be one or both cly as they are more or less just teed together, the same goes for the main boom with the dual cyls one cyl could be bypassing on the piston seal but the boom will still leak down. 2. Relief valve, I may be mistaken but I believe that the grapple open and close works off the main for that section as there is no port reliefs on open and close valve. 3. If it has a continuos rotate grapple the seals in the rotate manifold are likely the cause. There is a simple way to check the cyls for piston seal by-pass I will be glad to try to explain if you do not already know how . Pressures should be 2500 on mains and 2800 on ports

loader man · « **Reply #14 on:** October 13, 2011, 07:36:32 pm »

how do you check port reliefs pressure versus main relief? How can you check piston seal by-pass

kiko · « **Reply #15 on:** October 14, 2011, 10:22:36 am »

To check a cly for piston by-pass, extend cyl all the was out, cut engine off. Remove hose that is close to the rod( near gland) and plug that hose. Crank machine and activate same function that you extended cyl with. So you are pressurizing piston with out cly moving. If oil comes out of the open port near gland then the piston seal is by-passing and cly needs repair. Yesterday I was off on pressures but have looked up since . Mains 2200 psi ports 2800 psi. Presurre checks should be done after cyl condition is verified. Main reliefs are located on the sections that do not have a spool. ports reliefs are for saftey and load check, but your main pressure works off the main rerliefs. To set ports correctlyt you must raise the main above the port setting and then set port. After ports are set you then back main out to specified setting. All pressure checks have to be done with the function you are checking stalled out. IE in order to check main boom pressure up , the boom must be lifted all the way up to a stop and then continue to engage function. Do not remove relief valves without parking the boom as they may have pressure on them and the boom will be on the groung shortly and you will covered in oil. Brand and style of grapple would be ness to give instructions on packing grapple swivel

loader man · « **Reply #16 on:** October 15, 2011, 09:52:03 pm »

do the stabilzers work off the main relief? I don't see any port relief for them.

kiko · « **Reply #17 on:** October 16, 2011, 10:21:08 am »

Yes the stabilizers work off the main. Your control valve should have 2 spool sections for the stabilizers and a selector valve in order to work four stabilizers. Going back to the lock valves that Snowman mentioned, If lock valves are operating correctly and there is enough pressure to pick the loader up and... then stabilizers will not leak down unless the packings are gone on all of the stabilizer cyls. Your loader has one pump with three sections. Each section of the pump works independently. The section of the pump closest to the engine works main boom, grapple and saw if equipped, second section works jib boom, grapple rotate and stabilizers, third section works the swing. Each pump section has a main relief. The swing has a completly different control valve. The control valve for the rest will appear as one unit but is actually taking flow from two pump sections (the two pump sections share a common return). This can be seen by tracing the pressure lines form the first two sections of the pump. Pressure hose from the first pump section will enter the control valve on the end section of the valve and pressure hose from second pump will enter same valve on a mid-inlet. There will be a main on the sections that each of these hoses enter the control valve. In a long winded way, sounds like you have multiple issues rather than one malfunction causing all your problems.

loader man · « **Reply #18 on:** October 16, 2011, 03:45:37 pm »

how do the lock valves work? When you pick up the stabilzer how does the oil come back through the lock valve?

kiko · « **Reply #19 on:** October 17, 2011, 09:50:23 am »

Lock valve is a two way check valve. When pressure is applied to lock valve it opens up inlet and outlet port.

loader man · « **Reply #20 on:** February 11, 2012, 07:38:30 pm »

just packed both main boom cylinders and they still leak down the glands were dirty like rust but would wipe off thats probably in the valvebody and everywhere else

kiko · « **Reply #21 on:** February 12, 2012, 10:38:16 am »

Did you get boom pressure checked? If port pressure is set below weight of boom and grapple it will leak down. If piston packing were blown a piece of the seal could be stuck in relief(s).

loader man · « **Reply #22 on:** February 12, 2012, 06:49:49 pm »

i will check boom pressure and see

loader man · « **Reply #23 on:** March 23, 2012, 11:49:05 pm »

how do you pack grapple rotate on older 742 its leaking ?

loader man · « **Reply #24 on:** March 27, 2012, 11:00:41 pm »

i dont think it is the rotate the hoses coming off go to grapple cylinders. does anyone know what it is called and if it can be packed?

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Author Topic: prentice 210d cylinder creep (Read 1356 times)