hey folks, i DID look before i posted it, but couldn't find anything directly related to my issue, if there is i apologize in advance, just point me in the right direction and ill gladly read up.

My master cylinder has an internal leak, which looks like its actually heading into the vacuum booster. Now granted i haven't dismantled it, do to the daily driver drag im having to put it through atm. But i have fluid loss from the reservoir and a bit of fluid around the mounting bolts heading to the vacuum booster. Ive looked at rebuild kits, and there just as much as buying a new one. My question is this... Has anyone rebuilt one of these ? If so, can i buy generic o rings and seals, if so what size would i need, and what would it entail. Normally i would tear it apart and drive something else, but don't have that option atm. Looking forward to any information provided !!

 

LRAdventure

Save yourself some time and a heck of a lot of headache and buy a replacement master cylinder and buy original equipment if possible. I just went through this headache with loosing fluid at the mounting bolts. Chance are highly likely that you will need to change the brake booster as well. As it turns out over time if the rear seal is leaking it does not tend to just leak at the seam where it bolts up, but runs into the booster. The way the booster works it will draw the fluid that leaks into it in every orifice and valve and every time you push the break pedal it will continue to distribute the brake fluid within the booster. Once any substantial amount of fluid gets in with will eat the diaphragm and seals. Hopefully it has not gotten to this point for you and you were able to catch it quickly.

I went through this cycle over time.......

Slightly low fluid (like you would see with normal pad wear)..... topped up
Checked all fluids.... topped up

No visible leaks no excessive fluid loss. This cycle went on till one day brake pedal did not feel normal. Got under the hood notice fluid leak at seam where it bolts up with booster. After reading the horror stories on other threads on this site about master cylinder replacement with non OE brands and rebuilds. I bought an OE Master cylinder. Tore off the MC only to find my booster drowning in fluid. Took the booster off poured out the fluid and realized after pushing on the booster pedal shaft there still more fluid in it and when you stop holding the shaft down it would draw in any residual brake fluid still left in the housing. Worked just like a siphon. I got about a pint of fluid out and still did not get it all. Brake fluid was almost black from eating the seals and diaphram.

Not meaning to scare you or hype it up. But thoroughly check the booster too. If its more than just damp its only a matter of time before you will replace the booster. Better to bite the bullet once and do both then have to replace one and then the other later. ABS lines make it a little challenging from a space perspective there is not enough room to be able to remove the booster without disconnecting the master cylinder. Another reason it makes sense to do both at once if needed.

If you choose to still go the rebuild route, I am not aware of any generic O rings but this might help:

Brake Master Overhaul Kit With ABS (STC2903 Same Fit As Part # STC2903 ) - Land Rover kits from Atlantic British

Good luck which ever route you choose !!!

 

You can get a new TRW (they've owned Lucas for a long time) brake master cylinder PLM218 for a little over $200 on eBay right now. I bought one about a year and a half ago on Amazon and paid around $175 for it but those deals seem to be long gone.

I had a master cylinder fail on me once as I was going down a hill and learned my lesson the hard way. It's one part I don't like to cheap with on the truck and seldom sell them used unless I can see they are pretty new on the truck I'm parting.

 

Thanks folks, ill get on it !