Bobcat 773 spool valve seals, Green or Black??

[jambalini]

I'm just in the process of changing the 4 spool valve seals (lift and tilt) on my Bobcat 773. It's all gone very well using trip and instructions from both this forum and YouTube. I've found that 2 of the old seals were the black ones, part No. 7931367, and 2 of then are the green ones part No. 6683274. Every instruction I have seen has shown the green ones either being installed or instructions saying to only use the green ones. I went to order them from our UK Bobcat agent and they tell me that Bobcat are always changing what to use between the above part No.s, and currently they say to use the black ones, and that's all they stock now. Is this correct? I've got to say, they don't look as good but what else can I do as that's all I can get and what the dealer tells me to do. What do all you think please.
Thanks, Andy

 

[SkidRoe]

My guess - the black ones are nitrile, the green ones are likely viton. As long as you are using a non-exotic hydraulic oil (Bobcat's fluid, engine oil, regular hydraulic oil), either material is compatible. Viton has a wider range of compatibility with exotic hydraulic fluids (aircraft fluids, fire retardant hydraulic fluids, etc.)

 

[jambalini]

So, bit of an update since I changed the seals in both the spool valves, black seals. I am now having both of the spools not returning to their neutral position correctly. Before if you let your feet off the pedals they both dropped into neutral no problems, now both of them keep creeping in whichever direction you last used until I purposely knock the pedal into neutral position. The detents still work ok, it just appears that they are both binding slightly. I'm suspecting these black seals supplied by Bobcat. I've got green ones on order from the states so will change them out when they arrive here in the UK in a few weeks. So annoying, especially when you buy the genuine parts.

 

[jambalini]

So I've now changed the black spool valve seals for the green ones and everything is now ok. I'll be contacting my local UK bobcat dealing to advise them on my findings and see what they say.