Brakes and Clutch Bleed

Fellas, after all your help getting the carbs running well…I’m moving on to the brakes and clutch. I shined a flashlight down there and both the brakes and clutch hard line from the reservoir are disconnected! Called my father in law to ask how that happened…he had no idea.

So…here is a picture…but do I need to pull the master cylinder for the brakes off and clean/rebuild? Do I need to do the same thing with the clutch?

I have read on here about a couple tools to bleed the brakes…what’s the best way to do the brakes and clutch? Not sure what the next step is…

Looks like you need a couple cylinders rebuilt.
Open to the air like that, no telling what they’re like on the inside.

Based on the rust those lines have been off for some time ,there’s things you could try but trouble will be around the corner. To assess the system further you could pull a line From a front wheel cylinder if dirty fluid comes out oh oh remove and open the cylinder if it’s full of rust you’ll need to do the whole system.The whole system is probably contaminated rear end has to come out to do it right


Just did it this week
Sorry Jim

Definitely replace with new master cylinders, also suggest the three flexible brake cables be replaced as they will be falling apart on the inside and cracked on the outside, also the two flexible lines from the reservoir to the masters need replacing, also take a look inside both reservoirs for rusty crud, also you may need a new clutch slave cylinder.
There is also the brake booster to consider for a rebuild, it’s possibly seized solid.
And then there are the eight brake pistons which will definitely need new seals, or new stainless sleeves installed with SS pistons. The original brake pistons are alloy and corrode.
You may get lucky with just new masters, but later sticking brakes will haunt you.


Oh man…I thought you guys were going to say, just add some fluid and get driving! Ok, lot’s of work…seems like I start on the master cylinders and flexible brake cables. There is no fluid in the reservoirs. I think I will start there and then see what needs to be done. This part sounds like a big job: And then there are the eight brake pistons which will definitely need new seals, or new stainless sleeves installed with SS pistons. The original brake pistons are alloy and corrode.

I was going to say that just cleaning up those threads, put it together, pour in some fluid and giving it a try won’t make it any worse, with the caveat that you don’t leave your driveway. :grin:

Personally, I’d dismantle and check the entire hydraulic system if I found that, in that condition. They must have been disconnected for a reason, although why they would be left like that is anybody’s guess. There is water in your braking system, or at least there has been - brake fluid is hygroscopic. These are brakes, the bit that makes you stop - even if you’re prepared to take a punt on them, the bloke you hit might not appreciate it!


Guys…just getting back around to having a little time to work on this. Worked on it today…it appears the clutch slave cylinder is toast…so going to replace that. Do I replace the master cylinder too…or test the slave cylinder…and if that works, it’s good?
However, I was thinking about replacing the brake master cylinder, but all the ones from Moss (and other guys) have the lines coming into the cylinder from the top. Mine has one port in the front (see above pic)…so the brake line that goes into that would have to be extended and bent to fit the new cylinder. I think I have a Dunlop cylinder. Should I look for a Dunlop master cylinder?

Hi Greg…im refurbing my 1960 xk150…just started on the front brake master and clutch master and the whole pedal mechanism…i dont like the old steel hydraulic pipes…they rust internal and external…so replaceing all mine with cunifer…iv removed my masters and checked the bores…both are ok…suggest you strip and check yours…and make up new pipes…Steve

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Hi Steve,
Thanks for the message. I probably will eventually have to do the same thing you are doing, but for now just want to kind of ops check the system. But…the cunifer lines are probably the way to go. In my head, I don’t want to make all those fittings…but I know I probably need to. Did you go with the TRW Master?

Hi Greg…the bores of both my masters were of so ru usring them. …TRW are good quality as far as im aware…making brake lines is quite easy…but get a good pipe flare tool…Steve

Ok, thanks. I have a flare tool and it looks like the cunifer lines are sort of flexible.

Hi Greg…the cunifer isnt flexible but easy to bend to shape…for sharp bends use a small hand held pipe bender,…Steve

There is a special tool and technique to make the double flares.
brake line flaring tools
There are tools to make nice bends. One is line a coil spring with a flare on one end. The other looks sort of like a pair of channel locking pliers.

I did all my Mark V brake lines in cunifer.

Hi Rob, I have the plier type benders…and have the flare tool…so that should be good.
I had never heard of the cunifer lines…glad you guys are here.
Wow…maybe you could make my undercarriage look like yours. That’s cool. I supposed at some point I’ll have to do a frame off restore.

I also use Cunifer, and I use a pipe straightener before flaring and bending. It really tidies up the long runs, easily. A high quality bench- or vice-mounted flaring tool makes life much easier, but you need to be doing a lot for it to make financial sense, they aren’t cheap.

This is the flaring tool I use:

I’ve had it 35 years and it doesn’t owe me a penny. It does a perfect flare in seconds.


I have the same flaring tool, Roger - works very well. But I’d never heard of the pipe straightening tool before. Might have to get one!

There are several similar straightening tools. It does make a difference, leaving nice straight pipework - unfortunately you need one for every size of pipe. The XK is the only car I’ve ever done that doesn’t have 3/16 brake pipe. The Riley’s the easiest for pipe flaring… doesn’t have any, rod brakes…

The straightening to can only be used prior to adding fittings/flares as the pipe has to be slid into it…shame you cant clamp the straightener around a pipe…Steve

Your 120 is very similar to the 140. When you get the system assembled bleeding is simple. Open the wheel cylinder bleeder valve with the reservoir topped up and let gravity do the work. Do longest run to shortest and keep topping up the reservoir in between.