JD 400 TLB on rubber

[Dave Seager]

My brother has a JD 400 TLB, the steering doesn't work right (steers very hard) also the hydraulic system "loads up" when trying to start the engine cold! (practically stalls the starter!) If he works a control lever while trying to start it that relieves the pressure build up and it will turn over fast enough to start. Once the engine is warmed up it will catch quick enough to avoid the problem. Any thoughts on this would be appreciated! We aren't even sure whether both problems are related, or we have 2 separate problems! (It would probably work better if it was on tracks!)
Thanks, Dave

[RANDY Fay]

These pumps have destroke valve in top of front cover some are electric
some are manual--have a small roll pin to turn it down in to destroke pump start eng. then turn it back up until it's snug--I think your problem is in the steering-- blown o-ring--bad valve bodies--or piston sealing ring (rubber about 3/4" wide)--and could be brake problem--as the steering an brakes are on the same priority oil system first to get oil--last to loose it This hyd. system is closed center-- pump has stroke control valve that should destroke it after first revolution with starter--if any presure oil is leaking interal it won't destroke have fun Randy

[Dave Seager]

Well, more input from my brother! It steers hard because he removed and plugged the supply line to the steering box! He tells me that the steering shaft will move up and down about an inch. He wonders if the answer is a replacement steering box or if a rebuild is practical.
Next issue with the steering, the steering arm that the inside end of the tie rods attach to is worn to the point that the tractor wanders because of play! Is it practical to install a bushing or is a replacement part the way to go?
There's more! the torque convertor slips when the oil warms up! Is there a simple adjustment or do we need to do the whole nine yards with pressure gauges, etc?
Oh yeah, He says that it still doesn't destroke even with no oil going to the steering!
Dave

[RANDY Fay]

The steering shaft has to move up and down some this is how it works the valve bodies for power assists (it is more noticable without oil pressure) This valve is an easy rebuild as there are no replacement parts in the two valve bodies just a lot of hard to reach o-rings--Bellcrank bushings are replacable--T21538 up to sn.46445--T23118 sn.#46446 up-- new bellcrank sub to AT52868 Transmission slip would have to know more about it presure and so on--but I would check eng, clutch for free play first of all I find this is the problem a lot of the time--pump don't destroke could be pump valve seats are worn out and pump can't make 2100 psi or internal high presure leak any where in hyd system feel for hot spots after tractor has run and done some work high pres.oil leaks cause a lot of heat----These hyd pumps can be rebuilt also o-deere have fun Randy