L48 no forward or reverse after split

[hopcitymaple]

So we had a small leak that started to get worse in between the hst and the valve plate. Split it apart only enough to be able to remove the gasket that disintegrated and replace with RTV. Slid it all back together. tested for leaks... as there were none reassembled entirely. Went to move it out of the garage, and no forward or reverse. PTO works, front loader works. everything else works. Husband pulled the filter and found a perfectly round piece of RTV that was the size of the port hole between the pump and the filter... So i definitely clogged the port holes. we found the second port hole rtv chunk in between the valve plate relief valves. split it apart cleaned all ports out reassembled only the tractor portion. Jump started it, no forward or reverse. split for a 3rd time. cleaned piston and servo assembly (no noticeable RTV) put back together. still no go. changed filter split again made for sure there was no rtv anywhere checked all relief valves ports and the oil cooler.... then we started to check pressure ports and inspection ports. cracked the one on top of the valve plate. very little pressure. cracked the one in between the charge pump and the filter before the relief valves, there's little pressure. so we are thinking its the Charge pump. What do you think?

Should I call a tech to come and confirm? Should i get the charge pump ($1187) or do we think i should try to source a used HST (Maybe $1600) and call it a day... i'm just going to go cry in the corner about it for now.

 

[fried1765]

So we had a small leak that started to get worse in between the hst and the valve plate. Split it apart only enough to be able to remove the gasket that disintegrated and replace with RTV. Slid it all back together. tested for leaks... as there were none reassembled entirely. Went to move it out of the garage, and no forward or reverse. PTO works, front loader works. everything else works. Husband pulled the filter and found a perfectly round piece of RTV that was the size of the port hole between the pump and the filter... So i definitely clogged the port holes. we found the second port hole rtv chunk in between the valve plate relief valves. split it apart cleaned all ports out reassembled only the tractor portion. Jump started it, no forward or reverse. split for a 3rd time. cleaned piston and servo assembly (no noticeable RTV) put back together. still no go. changed filter split again made for sure there was no rtv anywhere checked all relief valves ports and the oil cooler.... then we started to check pressure ports and inspection ports. cracked the one on top of the valve plate. very little pressure. cracked the one in between the charge pump and the filter before the relief valves, there's little pressure. so we are thinking its the Charge pump. What do you think?

Should I call a tech to come and confirm? Should i get the charge pump ($1187) or do we think i should try to source a used HST (Maybe $1600) and call it a day... i'm just going to go cry in the corner about it for now.

My L48 TLB is running just fine, but your story makes ME want to cry TOO!
I had to split my little Ford 1920 FEL twice in two weeks, so I absolutely do understand your pain.

 

[hopcitymaple]

My L48 TLB is running just fine, but your story makes ME want to cry TOO!
I had to split my little Ford 1920 FEL twice in two weeks, so I absolutely do understand your pain.

It's been a long road of defeat I'm afraid. I called messicks tech line and they confirmed our suspicion of the pump being bad. Will try and find another one I suppose and slap it in there.

Also crying about the 5 gallons of oil on the floor. And in the middle of the L48 being down the draft pin on the Ferguson TO30 snapped so we had to take the axel tube off and do that. Thank god that was easy enough. And my clothes dryer belt broke. Damn it

 

[fried1765]

It's been a long road of defeat I'm afraid. I called messicks tech line and they confirmed our suspicion of the pump being bad. Will try and find another one I suppose and slap it in there.

Also crying about the 5 gallons of oil on the floor. And in the middle of the L48 being down the draft pin on the Ferguson TO30 snapped so we had to take the axel tube off and do that. Thank god that was easy enough. And my clothes dryer belt broke. Damn it

You are likely now headed for only good things.
Bad things usually come in threes!

 

[rbargeron]

Maybe a long shot, but is there a chance the HST output shaft coupling came off while splitting the tractor? There are three couplings that can simply slip off - for the pto, front driveshaft and the HST's main output. Requires separating again to have a look - but would be a simple fix if the output coupling isn't in place.

In these pics the two upper couplings are not shown, but the bottom one is still in place. Its the bottom one that gives people trouble lining everything back up. I used the red wire
to hold the shaft up so it would go into the coupling back in the rear case.

There's more about my hst saga at this link and related threads.

 

[hopcitymaple]

Maybe a long shot, but is there a chance the HST output shaft coupling came off while splitting the tractor? There are three couplings that can simply slip off - for the pto, front driveshaft and the HST's main output. Requires separating again to have a look - but would be a simple fix if the output coupling isn't in place.

In these pics the two upper couplings are not shown, but the bottom one is still in place.

View attachment 105483 View attachment 105485

So we are pretty sure they were lined up. I could slip my fingers in-between and slide the couplers over both shafts to make sure they were engaged. I think I ran into your post about lifting the longer 4 wheel drive shaft up with a wire to get that one lined up. Also with the return tube in the bottom I could see if that one was lined up or not.

 

[rbargeron]

Another thing to check is the dry clutch -

Does this L48 have a lot of hours on it? Their HST's don't usually fail abruptly.

 

[hopcitymaple]

Another thing to check is the dry clutch -

The pto engages and disengages with the clutch, and whatever other diagnosis thing my husband does, he doesn't think it's the clutch. Last time apart we free spun the pump shaft with the pto and engaged and disengaged the clutch.

 

[PoTreeBoy]

If it was working when you took it apart, except for the leak, it's hard for me to believe that the pump just went out.

 

[#40Fan]

If it was working when you took it apart, except for the leak, it's hard for me to believe that the pump just went out.

Unless the RTV got into the pump and snapped a shaft.

 

[hopcitymaple]

Unless the RTV got into the pump and snapped a shaft.

We've split now 5x. the shaft is still intact. Also when you spin the pto shaft by hand the pump shaft spins. They are meshed together with gears. So I'm sure it's not snapped.

 

[Henro]

So at this point, perhaps the conclusion is that RTV got into the hydraulic flow path and caused the HST to fail?

I know that using Teflon tape on hydraulic connections is considered dangerous on HST tractors. So I suppose RTV could be just as bad or worse.

I’ll bet it is safe to assume that as things progress you will forgo using RTV and install the proper gasket.

live and learn experience perhaps...I feel your pain…

 

[rbargeron]

If any RTV got into the regulator through the small passages the charge pump pressure might not be high enough to clear it out. The pressures at the big valve plate passages can get to 5ksi but the charge pump is only 300+ psi at the regulator. It would take some patience but it might be possible to get it all out. Doubt any internal parts are actually damaged - just clogged maybe.

If the unit is still assembled it's possible to take the regulator off to work on it. I made some little tools to get access - see pic

Best luck in getting it to percolate again! Dick B

 

[hopcitymaple]

We tired everything and cleaned everything. Our conclusion was that something got into the pump and chewed through that and perhaps the cradle bearings. Thankfully for @rbargeron only being 2 hours away and an extra hst laying around. We swapped it out, and wala. Forward and reverse... Worked it for a couple hours, works as it should...

Unfortunately everytime we were testing it without the subframe we had the front shaft from the engine to the front pump attached and it was off kilter so it weeble woobled itself until the bolts snapped and ate the bearings about a couple hours of work after we got it back together. So new seal, bearings and bolts in the front pump and we are back.

What a trip.