Any of that old Cletrac era stuff is going to be low pressure high volume hydraulics like 650 - 1000 psi max. The 98J (special application) with built in hydraulics and designated pump is going to be higher pressure, probably in the 2250 psi range. I don't have the service manual for the 98J, just the parts manual for 98J1591-up.

"mrsmackpaul" wrote:

Ian being a special application crawler it might only have a low volume pump Old Magnet will no doubt be able to check that off your serial number for you
and yes Old Magnet is 100% correct in does the ram or rams hold the scoop or do they drift

some more thoughts maybe being a SA crawler I assume came from the Downs it may have had a flow diverter valve put on for a air seeder and and you need to open that up to increase the oil flow

Paul

Guys
Following on from what OM and Paul said about do the rams hold the scoop. When i first answered this i was thinking about the blade rams which do hold when the dozer is running and turned off. The blade will lower overnight. However the other 2 circuits will not hold the scoop rams. So i guess that points the finger at the valve stack which i hope is a fairly simple replace o rings type of job. I will research the spare parts manual before asking any questions. When i bought the dozer the blade was in fact connected to the number 2 circuit rather than number 1. When i blew the hose to the blade from the stack i swapped the blade over to number 1. What i will do now is swap it back and use number 1 for the scoop to see if i get a better result. The blade worked well enough on 2 as you are always working the control anyhow when pushing dirt or scrub.
Ian

Swapping valves/circuits is a good way to check. I'd be more suspect of cylinder leakage. The spools don't use o-rings/seals other than on the ends. Spool leakage depends on how worn the spool and bore is.

You have two hydraulic systems, a high volume low pressure for the scraper and high pressure low volume for the tractor/blade, small leaks which allow the blade or scraper to drop overnight won't make much difference to operation. If the scraper rams are double the volume of the blade rams, their operating speed will be half the blade rams. If a ram is the same length and 1.5 times the diameter of another, its volume is getting close to double. We need more detail of ram dimensions for this question. Meanwhile, do a blocked cylinder test, hold the scraper up with a crane, disconnect the hydraulic lines, if they aren't quick couplers, the lines will need to be blanked off, then let the crane off. If the scraper still creeps down, you can forget any seal or spool leaks in the control valve, the fault is in the ram seals.

"catsilver" wrote:

You have two hydraulic systems, a high volume low pressure for the scraper and high pressure low volume for the tractor/blade, small leaks which allow the blade or scraper to drop overnight won't make much difference to operation. If the scraper rams are double the volume of the blade rams, their operating speed will be half the blade rams. If a ram is the same length and 1.5 times the diameter of another, its volume is getting close to double. We need more detail of ram dimensions for this question. Meanwhile, do a blocked cylinder test, hold the scraper up with a crane, disconnect the hydraulic lines, if they aren't quick couplers, the lines will need to be blanked off, then let the crane off. If the scraper still creeps down, you can forget any seal or spool leaks in the control valve, the fault is in the ram seals.

Guys

Attached some pictures that relate to a number of my posts on this topic plus a few others.

But first in response to a number of your suggestions I have determined that:
1. the scoop rams are not leaking as they hold when the tractor is running and turned off (I did as Catsilver suggested)
2. the blade rams are not leaking much as they hold when the tractor is running and turned off for several hours
3. swapping the blade and implement circuits made a small difference in the slow lift of the scoop such that it is now just usable particularly if I don't fully load it. The blade also lifts nearly as fast (acceptable) as it did before the swap. To get the scoop to lift I have to run the tractor at full revs while I can lift the blade at much lower revs.

So based on what you have told me it looks like I don't have a problem with blade or scoop rams nor the valve spools. That leaves pressure relief valve and pump performance does it not? I cant measure pump flow or pressure as I don't have the diagnostic equipment.

The photos

1. the scoop which shows the log stroke but fairly small bore rams and the half inch hoses which implies it should run on a modern high pressure system does it not?

2. 2 photos showing the broken cast iron ram retainer (gland packing ring) and my home made solution. I have a lathe so instead of paying $700 quoted for repair I turned up 2 pieces of mild steel, bored 4 holes for the bolts (not shown) and now have a working ram that doesn't leak a drop. I still need to turn a recess for a wiper seal when I get one.

3. my new stick rake still to be fitted by the manufacturer. Cost me $13000 which included delivery and fitting from a firm in Bundaberg which is about 7 hours driving from here.

4. my scrub canopy work in progress - using 75x50 RHS, a lot of welding rods and eventually to be sheeted with galvanised walkway expanded mesh that I got for free. Also to do a guard above the fuel tank to protect my back and a side guard on the right side down to the footplate. Note that this is not a true ROPS structure but is intended to protect me and the dozer from the smaller regrowth scrub I will be clearing. I wont put a tree pusher on so I won't be tempted to try pushing big trees down.

Ian

"Old wrote:

Any of that old Cletrac era stuff is going to be low pressure high volume hydraulics like 650 - 1000 psi max. The 98J (special application) with built in hydraulics and designated pump is going to be higher pressure, probably in the 2250 psi range. I don't have the service manual for the 98J, just the parts manual for 98J1591-up.

Sir
Despite having spent hundreds of $ buying operation, maintenance and spare parts manuals I still don't have any document that applies directly to my dozer. In particular all manuals refer to a hydraulic tank located under the bonnet at the rear of the engine. My dozer does not have this - the blade and implement hydraulic circuits are part of the transmission, steering clutches system apparently run of a pump driven by the flywheel. There is also a hydraulic pump at the front left of the engine and a very large diameter pipe runs from it to the rear. The manual REG00685 D5 (SA) Tractor Hydraulics is not the right manual even though it says serial number 98J01591 up. The Manual REG00864 D5 (SA) Tractor Power Train does have a diagram of the lubrication system for the transmission, steering controls and flywheel clutch but it does not show the blade or implement circuits.

All i know is that I fill the transmission with oil through the breather cap under the seat and I do this every time I blow a ram or implement hose and lose hydraulic oil. As I write this I am wondering if the front engine pump is in fact the pump for the blade and implements but it shares the transmission oil in lieu of a separate hydraulic tank.

Can you explain this for me?

Ian

Lots of questions.....
The hydraulic control does not use a tank. Suction is drawn from the transmission used as a sump. Only one suction line to the dedicated pump and one discharge to the controls then back to the sump (transmission). It is not part of the transmission, steering clutch hydraulic circuit other than shared sump. It uses a common piston motor pump, group #8J6332, pump # 8J448. I looked but I can't find specs on the pump. I suspect it is in the 2000-2500 psi range. You need to check with a pressure gauge even if someone can come up with the specs.

Your not going to find the hydraulics on your blade in the Cat literature as it is not a Cat product. The hydraulic control arrangement on the tractor is a 3P8586 for use with tool bar and one rear implement. It is covered under Form #GMG02185

As oldmagnet says that is not a cat blade it looks like a cat tool bar is not designed for heavy work if it is a cat tool bar even if it isnt a Cat tool bar it is not very strong compared to a normal blade so be careful other wise you may end up with bent bits were they should be straight also this may get a lot worse when you put the stick rake on as the load will be increased and so will the shock load just some thing to think about

I think the pump is working fine as all it was designed to do was list an implement out if the ground so maybe only one or two 8x3 rams at a time and the rams on your scoop are a lot bigger than that

The tool bar looks like a cat designed swing around tool bar to me Rome ones are much bigger than Cat ones or maybe a locally built one

Its only a D4 tool bar but gives you a good idea




A Rome tool bar



this the minimum type of blade strength I would think about using in your situation with a stick rake there is lot of added load out the front



dunno if this helps or not

Paul

Yes, I would agree, hanging that big brush blade on the tool bar dozer is asking a lot. I show the D5/6 tool bar dozer as using two 5x16" cylinders and is really only meant for light dozing.

Paul
It is starting to look like i was suckered in my ignorance and impestousness. I will have to be careful to push only the light regrowth originally intended. I will also hold my breath while i find out what a real cat blade will cost me secondhand. As it is i already miss being able to angle the blade like i could on my old Cletrac. I had already been considering modifying one of my Cletrac blades to fit the D5. They are certainly heavy duty blades of exactly the same width. I have now got my fingers crossed that i will be able to lift the stickrake although it doesnt seem to be that heavy. I did unload it of the top of a trailer which was on top of a truck using my wheel tractor front end loader as you can see in the photo. Hopefully i will be able to console myself with the view that for $32000 i got a very good engine and undercarriage.
Thanyou to all who have helped me so far. I might pull my head in now and just post news and photos of the dozer working within its limitations.
Ian