Hello all, I am trying to figure out a pulling problem with a Case 450 dozer. I believe it to be a straight 450. S/N plate is missing. The unit will not move unless I push in on the LH brake/clutch pedal. Then it will pull on the RH side and the LH side free wheels. I have checked pressures on High and Low clutch packs thinking that both packs were getting pressure at the same time somehow but pressures are good, and both clutch packs are not getting pressure at the same time.
Item 21 is your declutch piston the seals on these are probably bad and not letting pressure go to clutches as it should. What was your pressure reading when you checked it?
I have those pressures written down at the shop. I will post them when I get back. I am out of town all next week. I am thinking around 250 psi?
Okay good deal be safe on your journey.
After a week of R and R with my family, I am ready to get back to this. My pressures are 240 psi in gear with clutch pedal up. The pressure drops to 200 when i push on the LH clutch pedal.
What does pressure do when you push the right brake pedal?
Following, I am a new 1965 450 ( no letter) dozer owner with non operating brakes and when I traced the lines, I see they go to the hydraulic block and now I know there is a "declutch piston". So am I correct that pressing on the brake cuts out the feed to the drive? I am also missing one slave cyl and must assume I need to rebuild the other one as well as the brake pedal cyl. Where do I go looking for these? thanks
You can go to www.mycnhistore.com to look up your part numbers, be sure and have your serial number, then do search on internet for parts. I like to use borkentractor.com and ebay.com
Welcome to HEF, Sailorman ! If you need the service manual the good people at Minnparr Parts is hosting it for downloading. Click on this LINK for it. The CNH online parts manual may be missing part numbers for some of the parts they no longer have available in their inventory.
Coy, thanks so much for the lead. I will check tomorrow as the pics look a little different than what I have. Thanks Tinkerer, I did manage to download the complete manual and then got the CD. Just finished putting on a new sprocket and chain so brakes are next on my list.
So the above information is incorrect. Here is the correct pressure readings. The pressure when in FWD is 240 psi on the RH side. The pressure is 0 when clutch pedal is pressed. The pressure when in FWD is 200 psi on the LH side. The pressure is 0 when the clutch pedal is pressed. Not sure how I got that wrong but anyway...
kawfarmer, where are you tapping in to get the pressures? Pic? Ed
Hey Ed, I am tee'd in right at the valve. See pic. Thanks
So you're doing one clutch at a time then.
Yes, that is correct. Do you have a better test method?
Disconnect brake lines at trans control valve and redo test. It sounds like one of the declutch pistons are sticking. Also check the clutch shaft ring seals on the front end of clutch shafts. They're inside the caps behind the brake housings.
Ok, so we unhooked the brake lines and retested. The pressures are all still the same. As far as the clutch shaft ring seals, We have not taken the caps off, but wouldn't I have some pressure on the FWD side when in REV and vice versa, if those seals were bad? Just a question, trying to learn. Thanks. Also, where is the declutch piston. At some point I thought you had posed a picture of the valve.....
The oil would go back to the sump if the seal was bad through the return side of shaft. If my old brain is thinking right.
Found the Clutch shaft ring seals are bad, actually one was missing. Also the housing is worn and will be replacing it also. A shout out to Coy Lancaster for your knowlege and helpfull input. You sir are top notch. Thank you.