Lucas Girling Parking Brake chamber
 

I'm looking for some help on removing a lucas girling parking brake chamber on a mid 80's L8000. I'm trying to remove the wheel cylinder/expander that it's attached to in order to remove a broken brake line and have gotten stumped with this brake chamber. I was hoping to back off the large (2" or so) retaining nut and then it would come off. However that doesn't seem to happen. I can back this nut off about 5 turns or so, then it doesn't go any more. It appears that there are still threads there holding it to the wheel cylinder but it's like the nut bottoms out and doesn't want to turn any more. Anyone out there have any suggestions on this as this is my first time messing with this system?

Thanks

Subscribing - just looked all over the place for any info on this, but can't find anything specific to getting it apart.

If I remember correctly you have to cage the chamber in order for it to be removed.

Isn't there bolts on the inside of the backing plate holding it on as well? I just did mine not to long ago and can't remember if there were bolts. But before breaking the hose connection be sure to cage them like mentioned.

You must be working on Wedge Air Brakes. I wasn't going to post since I haven't worked on wedge brakes since the 70's but it sounds like you are going to get hurt. Don't remember a chamber called lucas girling but if this is a rear wheel with a spring brake you need to secure the spring before you get hurt. That spring is like a suspension coil spring and it could kill you!!
The chamber should screw out of the backing plate but it has extreme spring pressure pushing on the wedge brake push-rod. Spring must be caged (as mentioned).
Dennis....

At the end of the chamber there is a nut pinned to a caging bolt. Turn the nut counter clockwise until it stops. Next disconnect the line from the chamber. Have a pan ready to catch the oil. Spin the chamber bleeder screw out then unscrew the chamber. Reverse the steps to reinstall.

I don't remember the oil. I remember the wedge assemblies packed with grease. Wedge brakes weren't common in salt country. They claimed the wedges have more braking power than s-cam. I guess they were popular on the west coast.
Best, Dennis.........

:) Dennis, we're talking about 2 different systems. Lucas-Girling systems are hydraulic brakes that use a wedge style parking brake chamber. A heavy spring applies the park brake like air brakes use but it is released by a seperate hydraulic system. A lot of Ford medium dutys used this set up. A quick way to tell if a truck ( or bus ) has the Lucas-Girling system is to look at the front of the engine. If it has 2 power steering pumps it has Lucas-Girling brakes. 1 pump is used for the steering the 2nd pump supplies pressure to release the parking brake. Other O.E.M's also used this system and variations of it.

I've also worked on air wedge systems. Often called Stop Master brakes I've called them lots of things the mods would frown upon.

Lucas Girling are hydraulic brakes that are a pain to work on and very expensive. They can cost $1000 per wheel to repair.

Wow!! Never heard or saw that brake system. Sounds like he's in good hands now.
Thanks, Dennis.....

Yup, Good old Lucas - the only company who can screw up a wet dream. (he said, after having worked on Triumphs for a better part of his younger life).

Off-topic: It was interested to me, how wheel cylinder seals in a Triumph TR7 could not stand regular DOT3 brake fluid, and yet, Castrol DOT 4 brake fluid, never had a problem with.

I think anything with Lucas in it is a pain. Like the electrical system on my MG.

I firmly believe these brakes were the main reason Ford lost their dominance in the school bus business.

That very well may be... interesting thought.

I tend to agree however I also suspect International's DT466 was a contributing factor.

Where do you find parts for the Lucas Girling brake system?