Our 1989 F700 (23,000 pound rated I think) has the 429 Lima engine and the Lucas Girling hydraulic over hydraulic parking brake system. Bought the old truck 300 miles from home and had to cross Mount Eagle getting back to KY from TN. The seller did not know how to keep the parking brake from setting was one reason he was selling it so I asked around and found a guy that knew the LG system and all we had to do was pour in ATF to the pump opposite of the power steering pump with the engine running and it started rolling off but one parking brake can (spring loaded part).
A truck shop in Cleveland TN blocked off the left parking brake for me and it is still that way buy I have two new (rebuilt) ones from Reilly's but since the one holds well and does not leak I have not got around to changing them. Now that the son is 16 and 6' 2" it is about time "I" get that job behind me before he moves off.
The 429 in the F700 has no where the power of the GM 454 (1992) in the MH but it only has 108K on it. The F700 is showing 144K but I have not history on it. I do know years ago it got a Modine labelled radiator and the Munice dump pump for the 16' flat dump needs new seals. It came out of GA and is rust free and the third member still has good black paint on it and the two speed axle shifts up or down on demand.
Still do not know why they used the 429 engine when at the same time a lot of trucks got the 460 and all of the F53 motor home chassis got the 460. With the 5 speed and split rear axle it has all of the power the clutch can stand I expect. As long as we can insure it as a farm truck I want it around. This year we have hauled two loads of hay and brought the 10x20 horse barn 100 miles to get it home. The barn is still setting on the bed and the kids washed it up well (used for two horses by the seller for over a year) and they are currently painting the tack room and the lower part while it is hanging off the edge of the bed on each side and in the rear. A portable building mover wanted $500 (a fair price for sure after making the trip) but it was licensed and insured and ready to go. Some for $100 for gas the family has a long day outing going, loading and get it back to the house at 35 MPH.
We need to tune it up because it may have been 15 years since the last one. Did move the UTF from the backhoe and ATF from the two SUV's from bucket flushes to the 25 gallon hydraulic tank that was full of thick looking mud so it is looking better but may some day flush it all with diesel and replace with new hydraulic fluid or at least that currently in the BH and MF after I install a pump seal kit.
These old F600-700 series make good trucks to have around the place especially if they dump. That is how we were able to load the building and will get it off next week. The wood bed has its pluses but I sure miss the 12' steel bed on the old 1955 F600 that I grew up with because it was better for dumping dirt and protected the lift system.