I have a 1989 F-800 with the Lucas Girling brake system. The line that comes out of the hydromax into the Hydraulic relay is building up too much pressure I believe. I put a new line on it that was rated at 315 PSI and it started to bubble out of the side like it was about to blow. I then went back to the park store and got a higher rated psi hydraulic hose. After running for 15 minutes with the parking brake on it, blew the line off. Since it's a stronger line a normal hose clamp would not hold it. I went and got a better hose clamp put on it and it appears to be holding now but still believe it is building up too much pressure. I've took off all the lines and made sure none were stopped up or collapsing. Then made sure the electric pump wasn't running while the engine was running. I'm stumped. The brakes will pump off back Brakes when the emergency brake is off but it is making a constant straining or whistling nose when the E brake is off. If you press the brake hard the sound will stop until you let your foot off the brake. If you put the parking brake back on the whistling sound will stop. I might add that this truck has been sitting for 7 years. I've had to change the 2 back parking cylinders due to leaking but they are fixed now. Everything is working properly except the brake issue. Any ideas?
How much have you searched on this system? I've read this at least once here, and it sounded like a unique system, maybe more prone to trouble than other brakes and DEFINITELY harder to diagnose and fix. Something like a control valve that regulates the pressure for braking and parking brakes. Where did you figure 315 psi was enough? I'd guess one or two thousand PSI, at least for the hose pressure rating. I'll also guess it was too much trouble to fix the brakes 7 years ago and that's why it sat.
I've searched a lot. I just assume that there wasn't that much pressure with it just being held by a hose clamp. Here are pictures of the schematics. The hydraulic relay is the only thing possible i can think of now but the fluid is flowing through it because it pumps off the brakes and also returns to the brake pump. The truck was working 7 years ago when it was parked. My Dad was the owner. He just parked it because he was getting out of business. The tags and insurance were to high to keep it up. He planned to sale it but never did. You are right, a terrible pain to diagnose.
I think I have the whole manual for those somewhere. PM me your email and I'll send it to you.
I would be interested in this manual as well if that's alright.
I have a 1989 F-700 with this PITA system. I could certainly use a manual also.
Way back, when I had a Durapark equipped F800, the folks at BEPCO proved to be the most knowledgeable.
There are 2 rigs with this setup were i work they have been truble one we replaced the truck but they would like me to replace the brakes and put a park brake on the trans But i am haveing truble finding were this rear end was used with regular brakes.I have a manuel that i found in a junk shop. The truck is in very good shape but i think it would take around 1600.00 to change it over.
Will NOT buy a used Ford with this crap on it, consider them salvage yard bait as all they do is leak and fail. Have been nasty since day one first released.
The 2 at work had 2 problems from day one the brakes and they run off propane. Propane isnt so bad but they had problems and the dealer ship didnt have anyone that could fix them.5 years ago there were alot of these trucks for sale cheap.
Good evening I'm a new member If this is still available I could most definitely use it! Having a problem with mine but think I've narrowed it down to the pump
Did you figure it out?
Sorry for the delay. Pm me an email address and i will try and find that manual & send it out to you
Not sure if anyone still has the manual to these brakes. Looking to redo ours on our 1990 F600, I specifically am looking for the torque specs and diagrams for them. I had them a few years ago when I did the one side but can't seem to find them now. any help is appreciated.
I am pretty sure i have a set of manuals . They are at another place i will be there tomorrow i will look. I wouldnt try to fix them i would convert it over somehow. Were i work has a truck with that setup they told me i could have it. Its in very good shape but i dont want it .
If I owned it and had the time/inclination, would drag axles OUT, go to Salvage buy Air Brake axles/tanks and convert the machine to Air Brake, not hard to Add compressor or Swing Mount E-7 foot valve. Get to Ten Lug wheels and heavier axle sets, eliminate the Hydraulic garbage.
Till you did that you may as weld get a different truck. Well thats what we did
Like Doug said, convert it to a driveline parking brake, there are decades of driveline parking brakes with a hand lever and cable out there working just fine. The problem is the automatic parking brake and the hydraulics that go with that. The power steering pump, hydroboost is common and reliable. I believe I have a similar hydraulic set up and automatic parking brake, but it's mounted to one chamber on a driveline brake instead of the wheel end brakes.
Thank for the input I will keep that in mind but for the moment looking for a manual to take a peak at the brakes and the specs for them.
If you do have them can you send me pictures of the brakes section. I one point I had diagrams with torque specs but can't seem to locate them. I appreciate any help
I went by my house in town i couldnt find the book i was thinking about but i found 3 others that have sections on the the brakes . I will look them over today i also have to go back to town early for an appointment i will stop and look agin. I have alot of books and manuals they fill a small bedroom . I haven't lived there for i think 3 years its a mess.
"A2LS" is what I recall the book being marked.
And more
I have this book and it has a lot about the brake set up in it.
Thank you! that takes some of the mystery out of them, still dread having to deal with it. I didn't see any torque specs, but I'll assume standard torque chart based on fastener grade and size should work.
Freaking Hydraulic Roto Chambers, TWO Evils.
Thank you. I appreciate all the info
50 years later and Lucas Girling juicebrake systems are still haunting the transportation industry.
The problem is in the relay valve I just had this happen
I dont understand why a company could take something so simple as the park brake on the back of a trans and turn it into something so bad. Whoever did this should get a trophy at the least and should be recorded so others dont make the same mistake .
Air Systems TOO Simple in comparison. Could ONLY wish had them on light trucks.
C'mon...you didn't notice the "prince of darkness" name preceeding all the info? Lucas - Prince of Darkness - Lucas Electrical Humor Jokes www.mez.co.uk
Near as I can tell it is just to get around air brake restrictions on licenses, so they came up with something more complicated and worse.
LUCAS, Bottled Magic Smoke as their products released so much, then moved to Hydraulics!!!