Parking Brake Valve trouble potential

[Learjetter]

This is applicable to 337 G & H models with the lever-type parking brake handle.

The service manual and the parts manual have no procedures to rebuild the parking brake valve. So my buddy dared me to open it up and see if it's rebuild-able. It is, with standard o-rings suitable for 5606 fluid.

Use Service manual procedures to remove the valve from the aircraft.

Remove two lower hydraulic fittings, exposing valves, rods and springs. Remove circlip from cam lever and pull cam out. Replace 7 o-rings and re-assemble in reverse order, then reinstall in aircraft per service manual.
Good wrenching!

[SkyMac]

Hi

Same as learjetter, found it difficult to find info, ended up using a diagram from McFarlane for what i considered was an identical valve they were selling which described parts (O rings), with the clear images, I decided to remove and rebuild.

Why, fluid bypassing valve and overfilling lower reservoir, every few months I was refilling the top reservoir. Found the insulation to be soaked in oil when I removed the carpet.

It’s actually quite a straight forward rebuild, took about 30 min, made sure dual inspections were done before final assembly. Longest time was removal and reinstalling the valve.

I also purchased another valve and rebuild that unit for a spare. O-rings are only a few dollars.