B 26 backhoe running slower and slower

[murphy1244]

There is just a small problem with that in that with the hoe attached, you cant get to the couplings, you have to unhook the back hoe, drive forward a foot or more to get to the hoses so I couldn't just stick one inline and see what was happening. The tractor has no other hydraulic outlets on it. I suppose I could unhook the hoe, then put the gauge in between the lines (you unhook from the hoe and loop the supply to the backhoe back into the return. I don't think I would get much pressure showing in the loop as it would just be circulating to an open end so I wouldn't think it would show me any pressure above the resistance. I watched a video of someone checking the flow by doing the same thing, except they had a needle valve to gradually shut down the flow till it dead headed to check the max pressure before the relief valve opened. Flow seems to be based on no load conditions, as the pressure builds flow decreased till 0 at max pressure and dead head. That is what I was concerned with was that the relief valve was set too low. NOW it would be nice to have a flow meter and verify the flow.
Anyone know where to get one of those?

Attach the tee inline with the FEL.

 

[Coyote machine]

If you take a look at the link I posted it shows exactly what Murphy mentioned as to where to tap into the FEL lines. I don't think you even need a tee to read the PRV max setting. This will establish what the setting is even without the hoe in the circuit. Read through a couple of pages it also tells you what NOT to do.

 

[Gary Fowler]

If you take a look at the link I posted it shows exactly what Murphy mentioned as to where to tap into the FEL lines. I don't think you even need a tee to read the PRV max setting. This will establish what the setting is even without the hoe in the circuit. Read through a couple of pages it also tells you what NOT to do.

What you don't realize about the B26 is that the FEL is not removable like the add on to tractor type so it doesn't have QA links on the FEL to disconnect. I looked at the loader that has some 1/4" tubing fitting and some 3/8" fittings but they split to each side so each cylinder raises simultaneously. Rather than have it pump the oil out when the cylinder moved, I just tapped into the BH stabilizer connection that was the same thread as the pressure gauge and using the stabilizer control valve pressured up the gauge. It gave me the same pressure as main hydraulic without all the mess and was easy to get to, didn't need any QA couplings or tees or any other fitting to make it work. Now if I want to check the flow rate, I will have to unhook the back hoe and make up a test tree with male QA, flowmeter, tee with pressure gauge on top and then throttling valve to increase the pressure and finally female QA to tie it back to the tractor. I looked at Surplus Center and they didn't have any flowmeters so hopefully someone on TBN that has one will chime in with a place to get one and a price.

 

[murphy1244]

What you don't realize about the B26 is that the FEL is not removable like the add on to tractor type so it doesn't have QA links on the FEL to disconnect. I looked at the loader that has some 1/4" tubing fitting and some 3/8" fittings but they split to each side so each cylinder raises simultaneously. Rather than have it pump the oil out when the cylinder moved, I just tapped into the BH stabilizer connection that was the same thread as the pressure gauge and using the stabilizer control valve pressured up the gauge. It gave me the same pressure as main hydraulic without all the mess and was easy to get to, didn't need any QA couplings or tees or any other fitting to make it work. Now if I want to check the flow rate, I will have to unhook the back hoe and make up a test tree with male QA, flowmeter, tee with pressure gauge on top and then throttling valve to increase the pressure and finally female QA to tie it back to the tractor. I looked at Surplus Center and they didn't have any flowmeters so hopefully someone on TBN that has one will chime in with a place to get one and a price.

You need JJ, this is getting beyond me sorry. Only flow test I could say is to time a 5 gal bucket.

 

[Gary Fowler]

You need JJ, this is getting beyond me sorry. Only flow test I could say is to time a 5 gal bucket.

After watching a couple of videos on testing the flow, the true test is flow at pressure. One video said that if flow at pressure is not 90% of free circulating flow, then pump is bad. They were testing a big truck fertilizer distributor on that one. I did note on a TBN video about testing a Kubota that the PRV setting was 2200 just like mine.
Those flowmeters look like they might be a high dollar item, so this might be an issue to haul to the shop OR NOT.

 

[Tractor Seabee]

From what others have stated and reading into your posts it appears you may be ignoring the PB connection. That hose at the top of the BH connection points that you loop and reconnect with the BH off is the pressure from the pump into the PB line. On my 25 that is accessible with the BH on. With every thing hooked up proper the pressure on the PB is the same as the pressure line from the pump. What you are going through is why I bought the shop manual. You can trace out the whole hyd circuit. Your problem may be that two hoses are swapped. On my 25 you can't do that as the M/F QCs and hose lengths are set up so that you cannot make that mistake. If you find and can afford a flow meter you have deeper pockets than I have. You still have to get it in-line of the circuit to measure the flow, so back to connecting at a set of QCs. If you have pressure you probably have flow unless a connector interior ball check is screwed up and partially blocking flow. These are mechanical devices and are prone to failure.

Ron

 

[Tractor Seabee]

I was drafting my last when you did your last post; follow up.

If you can get that pressure gauge in line then by working the valves you can see what happens. If a load is applied and the pressure drops way off then you probably have some blockage to flow or a worn pump. I have serviced and rebuilt a lot of gear pumps for other applications and when they wear they will not produce design pressure or flow so pressure swings can tell a lot of stories. That relief valve is there because the pump can produce more pressure than the system was engineered for. Engineers select pumps based on optimums which is far less then max capability.

Ron

 

[woody]

Gary, connect your gauge in line with any cylinder you can get to easy. Then work that cylinder read the pressure when the relief opens up. It does not matter if you connect to the back hoe or the fel, the relief valve works the whole tractor on the B-26. If your are careful you can run and use the tractor till the oil gets hot watching and recording the readings the whole time, it might be interesting to know.

 

[Tractor Seabee]

Woody has another good idea. That fitting on the cylinders is a flare fitting. The hyd store will have a flare tee and get a double nut swivel for the cylinder side. You gauge will screw into the branch if you get a 1/4" IPT branch tee. Actually you can put the flare adapter any place where there is a hose flare connection and you wont bend and work harden the steel tubing. Kubota has that item as a special tool but the gauge comes with it. Probably mucho bucks.

Ron

 

[Gary Fowler]

Actually WDCHYD has offered to send me his flowmeter to check the flow. It is a $400 item available at Northern Tool. It wouldn't break the bank for me to buy one, but that is a lot of money to have it for a one time use. I am going to try to get the oil hot today and check the hot temp pressure and see how much it drops from cold pressure or 2200. If it drops a hundred or two I am going to see if I can shim up the PRV to give me max pressure of 2450 when hot that is 48 psi above max FEL rating but should be ok. I just have to wait a while to see if that 50F temp is reached today. It was 25F when I got up today so it would take a while to warm the oil at that temp.