Valve Stem Seal Replacement

[Dave344]

Valve Stem Seal Replacement D-950

Need to replace valve stem seals on the M-25xp(D-950 Kubota) used in the marine envirorment. I want to do the job with the cyl. head on the engine. What is the best way to keep the valves from dropping into the cyl.? Compressed air in the cyl. to hold the valves up is one way. What fittings are used?

Thanks

 

[Kubota Newbie]

Well.... Using air is risky 'cause if you break the seal without somehow holding the piston at tdc the air escapes and the next thing you know the valve is sitting on top of the piston at the bottom of the stroke. At which point you're basically screwed. If you pull the manifolds you can "sometimes" grasp the valve with long nose vise grips.
Keep the piston at tdc on the cyl you're doing so if you loose your grip it won't fall clear out of the guide. A little tape on the jaws will protect the stems.
Plug all your oil return holes so you don't drop a valve lock down in the block.
A sharp rap with a hammer and a socket roughly the same diameter as the spring/retainer usually pops the locks right out.
Had a single cyl OHV pulling motor once that required the springs to be put on after the head was bolted on, been there and done that a hunderd times. 'Bout have to have the manifolds off though.
Good luck, be patient.

 

[lsmurphy]

http://www.summitracing.com/parts/MOR-62385/

 

[Wbk]

Re: Valve Stem Seal Replacement D-950

Need to replace valve stem seals on the M-25xp(D-950 Kubota) used in the marine envirorment. I want to do the job with the cyl. head on the engine. What is the best way to keep the valves from dropping into the cyl.? Compressed air in the cyl. to hold the valves up is one way. What fittings are used?

Thanks

Hi I have a little valve spring compressor made by KD tools, it makes it a little easier and gentler as you don't want to drop the valve. As previous quotes stated make sure the piston is at TDC and take your time. Barry