My 1984 953 Loader has a problem, when tram forward is engaged only the Left side track pull and when the tram reverse is engaged only the right side track pull the machine just truns clockwise in a circle. any help with this would be appreciated.
The first thing our resident track loader expert Mr. Cmark is going to ask for is a Serial Number. The second is going to be a bit of info about how the problem started, how it developed, etc, etc.
The Ser# 76Y01281 it is the first machine that in 1984 they added a dual setting relief valve. the problem has developed slowly pulling to the right going forward and to the left in reverse then the other day the slow side just stopped tramming.
Thanks for All the help, I can always cut it up for scrap.
There is a track loader guy on HEF. It appears as though he hasn't seen this thread. FYI he's in Australia and does not call in at the same times as most. When I posted above I was expecting him to comment. I've dropped him a message. Hopefully he's around.
Please don't get too bent out of shape if you don't get an immediate reply. As with everything in life, you get what you pay for. At first glance this seems like a strange problem. So if you go from forward to reverse the machine goes in a clockwise circle, but if the left track drives in FWD and the right track drives in REV that would make a kind of "S"shape, right? I can't immediately see it being anything other than a problem with the linkages between the cab and the HPCU. Have a look at the bell cranks underneath the cab. Check for seized joints. For a quick and dirty test, remove the clevis pins connecting the rods to the HPCU on the right hand side of the machine and see if it will drive straight. If it doesn't then it's time to lift the cab, remove the tranny cover and see what's going on inside.
Had the cab up looking for issues with the linkage, took the HPCU cap off hard to tell everything has a lot of slack, changed filter did not help , going to block loader tracks off the ground and check deeper, the hoses to the servo's are worn with outer jackets flaking off some where in the filter, can't tell if hoses are bypassing, can you run machine with HPCU cap removed or will it sling oil out? P.S. thanks for the help can't afford a big problem.
Yes you can run it with the lid off. It will throw a bit of oil out but if it's too much, drain the level a little. Can you confirm, RH track absolutely no drive in FWD and LH track absolutely no drive in REV? Does using the steering pedals have any effect (except for slowing the good side)? The hoses going to the servo cylinders are a good candidate for failure but it would be odd for two to fail at once. If you want to study the HPCU working: On the left side of the machine, disconnect the hose going to the brakes. Put a cap on the elbow coming from the HPCU (1/2" JIC, from memory) This will prevent the brakes from releasing. In the middle of the transmission, disconnect the rod from the brake pedal to the lever. Move the lever about halfway and you will see two holes line up. Put a 5/16" bolt through to lock the lever in the brakes-off position. You can now safely stroke up the two pumps by moving the FNR lever. Try it gently at first until you are sure that the brakes are going to hold.
yes that is how they are working, and the steering pedals only slow the good side, My brother & I are going to block and troubleshoot (weather permitting) today, will use the information you gave on the brakes. I will post back on what we can figure out.
I know you say that you can't afford a big problem but do you have a Parts Manual..? They are available for $90 or so on the internet, it might prove really helpful. If you would like to get hold of one go to - https://catpublications.com/ When the popup appear click on "Continue as Guest". Type SEBP1432 in the box and click Search. The illustration below should appear. (If you don't have an Operator/Maintenance Manual follow the same instructions but type SEBU5758 in the search box. This manual costs $46 to download)
Thanks Nige this old loader was worn badly when I got it from a friend that worked for a construction Co. they where going to auction it off but the owner let me have it if I paid transportation (about 200miles) My brother & I are using it for personal landscaping. I have downloaded several articles off internet and a friend sent me part of Maintenance manual.
The Parts Manual would be invaluable to you IMO. Because if you have to go looking for used parts (in your position I’d probably be doing the same) it’s nice to know what Part Number you’re looking for. There are often leads for used parts on Machinery Trader but you need to know the P/N or you’d never find them.
Here ya go. $40 from eBay ………… can't get a better deal than that. And it is bang on for your Serial Number. https://www.ebay.com/itm/CAT-CATERP...-BOOK-MANUAL-76Y1144-99999-TS78-/162597451716
The problem has now changed to where neither side will tram, going by the troubleshooting we had 375psi charge pressure, about 180psi on plug 1 and 0psi on plug 2 on top of the main control valve. the book said this indicates a plugged orifice in the main control valve, we went by the instructions and tryed to backflush the orifice but still only had 0psi at #2 plug. (while backflushing the main valve the main pumps tried to stroke. any other way to clear up the orifice? The Venturi pressure differential is about 70psi The book says both Plug #1 Plug #2 should be close to charge pressure what is causing plug #1 to onle be at 180psi?
Which test port are you checking charge pressure at, 7 or 8? What are the venturi upstream and throat pressures? Have you checked case drain pressures on the motors yet?
Going by this drawing I took the Charge pressure at pressure tap #36 the Venturi upstream pressure was 375psi took this pressure at tap #41 the Venturi Throat pressure was 300psi took this pressure at tap #43 No we have not checked the case drain yet.
First off, you need to realise that we're dealing with two seperate charge pressures here. Charge Pump Pressure and Charge Pressure . It's not very clear in the manual and an easy mistake to make, compounded by the fact that you seem to have an older version of the service manual without a callout for the charge pressure tap. The Charge pump pressure tap is #36 in your service manual, the charge pressure tap is the one on the left of the valve in this picture. I take it you have the service manual and are working through the troubleshooting procedures in SENR3193 and you're now up to step 2. You have charge pump pressure at 375psi and also venturi upstream pressure at 375psi, correct? That leaves you with 5 possibilities. For now, discount numbers 2 & 3. Concentrate on 1, 4 and 5. If I've misunderstood you so far, let me know. Did you catch my thread on rebuilding one of these things? I try to give a brief rundown on what's going on inside. It may help. HeavyEquipmentForums
Well I am done with this if we have to pull the transmission to fix the problem, found left servo jack pin or the jack bad the swash plate is banging in and out hard sounds like a striped gear on the drive but it is the plate.