I purchased a Lucas Resevoir kit from British Atlantic. It is identical to the original item. When the kit arrived I read the instructions and everything seemed pretty straight forward. Following the instructions I:
Disconnected the negative terminal on the battery
Removed the old brake fluid from the resevoir
Unbolted the lines coming off the master cylinder
Unbolted the master cylinder from the vacuum servo
Clamped the master cylinder using a shim into a vise
THIS IS WHERE THE FUN STARTED
There is a yellow plastic (nylon?) housing that provides a channel for brake fluid into the master cylinder as well as encloses a portion of the piston that is connected to the servo. The instructions said (and had a nice explanatory drawing) to grasp the yellow housing with an adjustable pliers and rocking it back and forth apply pressure to slide it free past the piston.
After 30 minutes or so of coping with frustration as the housing refused to move any direction other than roll back and forth,I examined the replacement grasping for a clue.
Upon examination there was an inverted T shaped area hollowed out of the body of the housing. This area served to allow brake fluid to flow from the resevoir to the master cylinder. It also provided an opening where a slotted ring (sparger?) seated in a groove on the body of the cylinder could pop up a few of the tabs and hold the plastic unit in place.
The instructions did not refer to this. Nor did they offer any suggestions on how to compress the tabs to release the housing.
I use alldatadiy.com as a great on-line shop reference manual but to no avail in this case. With no help from the instructions or the website I went to work opening up the chamber by whittling away the housing over the chamber with a utility knife. Eventually I succeeded in opening up the cross channel and sure enough, there was the ring exactly as feared, with its tabs protruding onto the housing, preventing its removal.
I took a short piece of aluminum angle stock and filed an arc similar to the curve of the ring and then grabbed this and the housing with a vice grips. This had the desired effect of compressing the tabs so they slid under the housing and I was able to finally proceed acording to the directions.
From here I cleaned everything and following the steps precisely I installed all the new seals and o-rings and put the unit back together. I really am not comfortable with the pressure mounting of the resevoir into the master cylinder. After all the above plus bleeding the brakes to flush the system I think I may still have tiny bit of fluid escaping around the seals where the resevoir is inserted into the cylinder. But at least the brakes are working great and I will wait and see if I have any noticeable fluid loss.
If there are any more problems I will look for a compatible master cylinder unit the has the resevoir attached via threads to retro fit into my Disco.
Anyway now I know why Land Rover sells only the entire master cylinder assembly instead of rebuild kits!