Hey folks, This '74 Case 850 is almost impossible to steer using the brake pedals. It does somewhat ok on an upgrade, it be comes much harder to brake on level ground, but on a downgrade it takes all my might to disengage the tracks (thus no turning or braking) ability. The following photo is its Transmission Control Valve (TCV) View attachment 135556 We have all new seals that goes in the TCV, fairly new master cylinders & slave cylinders. We have bled out all the air in the brake lines. The slave cylinders & brake levers does operate with the brake pedal. I removed the back plate (#2) on the TCV & the brake spools (#10) do function with the brake pedals. All the mechanical(s) check-out. My 5,000 page service manual states "Check to see if the spools fit their respective bores with a slight hand pressure & w/o excessive side clearance". That is not a very scientific description! They should have included wear limits in this manual - especially when it comes to brakes. Does any1 know how much is too much? The min spool diameter? The max bore diameter? Can just enough fluid pass through worn spools to make the drive train clutches only partially disengage? such as clutch slippage. What else can cause the tracks to keep driving when the brakes are depressed?
Seems to be a problem with your picture, can't see it. The issue you have with the brakes is likely with the neutralizing valves located at the front of control valve. The plungers (#21) may be seized & need resealing & freeing up. Don't worry about the spool tolerances as these are unrelated to your issue. Does your machine have the brake neutralizing selector valve? (lever behind operator legs under seat) this may also be an issue. Case 850 transmissions were designed to be steered using the transmission range selection only, not by using the brakes. Use the brakes only when tight maneuvering is required. Because they are dry & not a pleasant job to repair - you want to keep there usage to a minimum. :drinkup
Thanks for replying alrman, I had problems getting the photo to show too & not sure what went wrong there. That photo is the photo I tried to upload, with (#10) circled in red. Part (#10) is referred to as a "brake valve piston" & we put new quad-seals (#22) on them. We inspected it for freedom of movement 1st thing & it checked out too. The brake piston does push the brake spool, which furthers this quandary. :beatsme The "neutralizing valves" you are referring to, sounds like the same thing this manual is calling the "Clutch Cutout Control Valve" and would be located in the same place. This loader is not equipped with that feature. If it were, it would cause the symptoms you're describing. I do use the high-low speed control as often as I can, but my dad doesn't. I failed to mention that the passengers-side track braking tends to operate with little brake pedal force. the drivers-side track is what gives us grief