I have had my 90xt for about 10 years and for much of it have had an intermittent problem with the park brake not releasing. Usually it will not release after being applied, after running for some time. A few days ago park brake came on while I was running and it took til yesterday to get it going. The problem is I don't know what I did to get it going, I suspect poking and pulling on the wiring harness around my legs in the cab may have done it, not sure. As of yesterday it was running again. Anyway, my main question has to do with the Neutral over-ride solenoid. In my trouble shooting I saw the body of the solenoid has a number of serious cracks, and a couple pieces of plastic faked off. It tested 5.8ohms. I can't help but think given it's appearance I will end up changing it at some point. The way it is installed on the top of the tandem pumps, it appears I have to remove 2 covers on top of pumps? The one that has the solenoid installed in it, and the other cover has what appears to be a steel pipe connecting it to the cover with the solenoid. The solenoid is sitting between these covers and it does not appear that it can be removed without taking covers off? So, what would I be getting into to change the NOR solenoid? 2nd question: In regards to the 3 green indicator lights, my seat presence light is always on. Could the seat switch fail, yet show a green light? Yesterday I jumped that switch at the plug above the pump, that and looking over the bundle of wires in cab around from left side is all I really did and the park brake started releasing again. Luckily I'm not out working with this machine, just doing my own stuff. Thanks guys.
Local shop had what appears to be the right coil for the NOR solenoid. Will try to swap it out in next couple days. So no one has had those control covers off on the top of tandem pump? Just want to know if little springs and ball bearings will be flying all over when I pull it off. I will update later.
Top cover with solenoid on tandem pump came off uneventfully. Old solenoid coil completely rusted on to stem that it sits on. Had to be surgically removed. It looks like I will have to go to OEM for replacement.
If you have the part number or even just google 90XT solenoid something may come up. I found new OEM/Parker solenoids for a Champion grader at a surplus parts company for $9.20us. Getting through Volvo would have cost $575.00cad! With exchange and import duties 2 solenoids were just under $100cad. Still a huge savings. Only difference was the new solenoids had ring terminals and the original are spade terminals. Simple to change and I thing ring terminals are better anyway.
I've done lots of looking around on-line, there are lots of options for just the coil part, however it turns out I need the whole thing which includes the stem the coil goes on, and the little shuttle inside, that hooks on to the spool, inside the pump cover. I ordered one yesterday from local dealer, it's shameful how much they charge for it. Works out to about the same if I ordered from USA. But machine is a lawn ornament without it. I have not found any reference online about someone having to change one of these NOR solenoids, so I'm just sharing my experience. The parts involved can be seen up and down from page 626 in the 90xt service manual. Case part# 372552A1
So I picked up the new "Neutral over ride" solenoid from local Case dealer a couple days ago. Installed it yesterday, was quite straight-forward. The only thing that "got me" for a minute was that the direction control pin under the cover that the NOR solenoid is in is spring loaded so goes out of position when cover is removed. In the manual it details removing a plug for a spool, to take off spring pressure. However I just used a piece of light copper wire with a hook in the end. Wire was used to pull pin to proper position so it engages the slot in the control housing. * (there is a plug that can be removed to see that pin is correctly in the control slot). Once in position I just pulled the wire enough to straighten hook, and pulled it out. Used the machine for at least a couple hours yesterday and had no issues. Was just splitting wood however, so brakes were not released for extended periods of time, which is when my issue usually presented itself. It is an expensive little part, but quite vital. Hopefully that is the end of the only real issue I've had with this machine in 10 years. Maybe someone will find this helpful at some point. I couldn't find any info about it online.