OK, I'm a newbie at this type of brake system. I just bought this 98 F700 and the PO had no Idea why the buzzer was going off ,stating that the brakes seem to work fine, even though the electric brake was kicking in.

So he has no clue and I have 200 miles to drive this thing home.

I stop at Gas station to fill up and decide to look the master cylinder over. It's a little low and I add some fluid.

Now I see the pump for the PS on the drivers side. It's OK.

I go around the truck and I see a 2nd pump and resivoir. Pull dip stick and nothing in it. Stick has residual red fluid that feels and smells like ATF. SO naturally I pour in a Quart. Buzzer Stops, Electric stops kicking in. SO I'm happy Right ?

DID I SCREW UP ?????

I have a 2000 Mustang GT with Hydroboost. But it also runs the PS. So naturally I ASSumed the same for this.

I gotta be truthful here.. I asked the PO what the 2nd Pump and can were for and he did not know. He owned the Truck for 9 years ! Never on the road, always off road, and he just put gas in it and drove. GEESH.
I looked at the plumbing and frankly being a newbie I thought this was the pump for the dump bed. Silly me.

Ok, jump in here. I can take it.

 

My 95 with Lucas Gurling has a separate round metal tank on the passenger side of the engine for the parking brake. If this gets low a buzzer in the cab stays on till you put more in it. On mine I am supposed to run plain power steering fluid in it. ATF will eat the seals out of the booster motor. This is $249 from Truck Pro. Ask me how I know.

 

We used atf in our 90 f700 with girling brakes.

 

I use ATF in my 1985 F700, with no issues. I have owned it since 2000.

 

Thanks for the info folks. The PO had this truck for 7 years and no telling how long ATF has been in the system. Probably will just roll the dice and leave the ATF in there for now.

What is the failure mode if the seals do fail ?

 

On mine the buzzer started going off and fluid started pouring out of the booster motor. I put the ATF in it that morning and by the time I had hauled one load of rock 28 miles each way it was pouring. If it is already in the system you might be ok.