View Full Version : Help with hydraulics?

06-30-2006, 08:17 PM
Trying to figure out a way to put a hydraulic thumb on my 97 Komatsu PC-35R-8. The machine has auxiliary hydraulics but they are set to only flow one way for a hammer. There is no switch or lever to change them over, I have tore the machine apart looking. Cannot switch any hoses under the machine either, or that is what I am told. Talked to some people in my area with no real results. I hope someone out in the Lawnsite world can help me. Thanks

06-30-2006, 08:28 PM
Now I got it...Thumb..I confuzzeled myself....have a good look at the foot pedal that would normally operate the hammer...is there a pedal thing you can flip over so the dual direction control can be used??...Otherwise track down a manual.

07-01-2006, 03:17 PM
Thanks Squizzy for the reply. With all the people on this site I hope I can get some more help. No lever on the foot pedal, working on the manual. Your help will be appreciated!

07-01-2006, 08:40 PM
Found this if it helps:


07-01-2006, 09:56 PM
Some only flow one way. You may need to get a two way spool through Komatsu, if the machine was two you would know. At least you have piping that will save you some.

07-01-2006, 10:43 PM
ksss , what do you mean by a spool? Thanks for the info.

Dirty Water
07-01-2006, 11:21 PM
ksss , what do you mean by a spool? Thanks for the info.

He is talking about a spool valve, common name for the hydraulic valve you are acutating when you push the pedal.

They make them that will go in both directions, swapping outputs when you do, this allows you to plumb up the thumb.

This link shows how a 2-way spool valve works:


07-02-2006, 10:57 AM
Thanks Dirty Water for the info. It is good to know the lingo when you call for parts. Know my way around my machines pretty well but when it comes to adding on to them, as with a thumb it is always good to ask for parts by the right names. It makes the process a whole lot easier!!!

07-02-2006, 01:18 PM
If it has a two way valve there would be a threaded rod coming out of a valve block to switch it from one way to two way operation. Monday I will take a picture on my pc45 to show you what i mean.

07-03-2006, 10:26 PM
Thanks nac, looking forward to the picture. Sometimes up here in Vermont it is hard to get help with some of this stuff. And if you get the newbie parts guy on the phone it is even worse:confused: :dizzy: !!!

07-04-2006, 08:49 PM
Hey nac, looking for that picture when you get a chance. Happy 4th of July!!!:usflag: