Does anyone have access to a parts manual for a Cat 420D? I need the part number part the large hydraulic line that returns from the hydraulic oil cooler and connects to the hydraulic oil filter. There's a smaller hose directly off the cooler then a fitting that connects to a larger hose that runs back to the filter. I need the number for the larger one. unfortunately there's not number on the hose, at least not the I can see. I was backing up today and saw a red puddle:Banghead . At first it looked like I split the transmission, but luckily it's just a hose. I had been working for most of the day and nothing could have cut the hose, because it's tucked up high on the machine and doesn't even rub anything. There's about a one inch split with just a small hole leaking fluid. I guess it was just its time to go, we were about ready to change the hydraulic fluid anyway, but I would much rather do it on my own time frame. I would prefer to be able to call the dealer with the number rather than go there and try and find it in the book, but it's not a big deal if I can't. Thanks in advance if anyone can help. It's on the left side of the machine. Here's a diagram of how it looks on the machine.
Update Part # no longer needed. Would you believe the new hose is only $38 at the dealer? That's at least one bright spot. New question though. How much trouble is it to change a hose out up under the machine? Also whats involved with adding the new fluid and getting everything bled and properly set up? I have zero experience repairing hydraulics and my dad only has a little.
If that hose is generally above the oil level in the hydraulic reservoir, it's no a big deal. But get a large bucket and loosen the lower end first. Let it drain for a bit to see if the flow slows down or stops. If it does, disconnect that end and let the residual oil drain out. Then remove the other end and pull the old hose out. Make sure you use new o-rings if required on the new hose and reverse the order to install it. If the flow of oil doesn't slow down or stop, whimper, run in circles and yell help at the top of your lungs! Just kidding. You will likely have to get a bigger container or drain a bucket full at a time till the flow stops as the ends must be below the oil level. If you was real lucky, a passing Cat field mechanic would loan you his vacuum cap tool. This screws or snaps into place over the hydraulic reservoir filler opening and with an air hose hooked up, it draws a vacuum in the reservoir and keeps any oil from leaking out thru an opening. Handy. If the hose is in a bad place to reach, keep the protective caps on till you have it nearly in place so as to keep the dirt out. Keep the ends as clean as possible. Once in place, carefully remove the caps and make the connection. Replace the oil and check for leaks. Good Luck!
Does the system bleed the air out on its own or is there something manual to do that? I really don't feel like killing the pump by messing something up. Unfortunately the hose is both tough to reach and still well below the reservoir, so it puked pretty much everything out. As it stands now, the dealer is set to come out Monday to fix it up. My dad is getting back tomorrow, so we'll take a closer look this weekend to see if it's something we feel like messing with. I figure we can always cancel the service truck, but they were pretty busy, so it was best to get a spot. Thanks for the help.
Yeah, typical Cat house, always busy. You don't have to bleed the system. Once you get the hose on and refill the reservoir, it will bleed itself once you start it up. Just let it idle a moment or two, then gently exercise each function, check for leaks whilst doing this too. You may feel the machine shake a bit or hear the hydraulics groan or squeek a little. Just keep working each function till everything settles down, then recheck your reservoir oil level and top off if needed. If this were a hose leading to the pump directly, then maybe a bit of effort could be directed to bleeding, but generally, these things bleed themselves well and most will do it while you refill the reservoir initially.
It does run right into the hydraulic oil filter, but I didn't see how far away the pump was. Thanks again.
Old thread but good info. Yesterday I was lovin' on my 420D in the shop - painting some rust spots on the steps and cab. When I backed the machine out, there was a puddle of hyd fluid on the floor underneath where the radiator area was. I hope mine is just a hose too. Will be breaking it down today and seeing what it is.
Luckily it was just the bottom line.:notworthy After disassembling the entire front end of the machine - removing the front cowl, counter weight and A/C cooler I was able to get to the bottom line on the hyd oil cooler. Changed both the bottom and top lines to the oil cooler out. While I had the coolers apart it was a good time to clean a few years of dust and debris out. Top picture - the culprit Bottom picture- everything you had to take off