Hello, First post here. Great site. I just purchased a late 80's 743 that had the main hydraulic manifold/valve out of it. I have since had a new lift spool installed, cleaned and checked out by my local dealer. It is installed and everything seems to be working. The machine has not been run in more than a year. There was no fuel or hydraulic fluid in the tanks. The engine will puff white smoke then fire immediately with a half second shot of ether while it is being cranked. Fuel supply and glow plugs will be checked. I have learned here that the key turned to the left is the glow plug selection and not accessories like I had thought (aftermarket switch) I will try glowing the plugs for 10-20 seconds and see if that makes a difference (it has been around 50 degrees F when I have tried to start it) The hydraulics chatter while being raised but, silent on way down. The hydraulic fluid is foamy. I will try operating the lit/tilt while driving at midrange rpm's being careful to not bottom out the rams and see if that clears it up(per a rocommendation in another thread). I put in all new nipples on the valve body and had many new lines made; so air intrusion should not be an issue. I used standard hydraulic fluid (what I use in a Case 580 backhoe) to fill tank. I asked at the dealer yesterday what they recommend and they said the Bobcat brand Hydraulic/hydraustatic fluid is different. Will the "incorrect" fluid be harmful to the machine and/or cause foaming? Thanks for the help....any thoughts, advice or opinions are welcome.
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Sounds like you have air in the system. It should clear up with use. Unfortunately I don't think hydraulic fluid is the correct application for the hydrostatic drive and may cause damage. There are many threads on here that discuss the use of hydraulic vs oil. I use 10W-30 motor oil in my machines hydraulics.
With the glow its normal to turn the key to the left to glow then right to start. I'd avoid the ether though, get the glow plugs working and see if it will start without the ether.
Now oil, thats correct, you need thicker oil like 15W40, 20W50 etc. I believe there is a hydraulic oil that is suitable, but i don't know what grade off hand, standard hydraulic oil is too thin and can cause pump failure. I personally run 15W40 or 20W50 and have never had any issues.
The foam is simply air in the system, as you had the system pretty well empty it will take some time to get it all out. When i re-built a machine and i had everything drained it took weeks to get it running just rite. Run it for a bit then let it sit, the bubbles will go to the top of the tank so non foamy oil will be drawn in. Give it time, it will get there!
Ok...figured out the glow plugs. 15 seconds at 50 degrees f equals easy start. I will go to auto store and buy 15w40 to put in hydraulic reservoir. I have one minor leak at a nipple on the main hydraulic valve. Will that allow air in enough to contribute to foamy fluid or is it still from the initial fill of the reservoir? I will tighten fitting in the a.m. . Now I need to find a good deal on a used standard bucket. Can I find one for $400 ? Where is best place to look and also a set of over tire rubber tracks? Still need to change oil (Delo 400) and oil filter and fuel filter. Keep advice coming if you have more for a newbie. Thanks again, Jon
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Jon
Just a note from my perspective
15/40 is good if your climate temps don't dip below freezing. It terrible thick stuff in my Canadian however. When buying a used bucket look how straight the cutting edge is (not bent or bowed down) and how far its is wore back from the lower front sides of the cutting edge. The rest of the bucket does not wear too much unless its been abused and bent up. $400 is pretty cheap for a good 60" imo but you may find one.
Ken
