Brake Reservoir Hoses to Master Cylinder

(Greg) #1

1988 Jaguar before TEVES system. Nice simple system.

I just bled my brakes, and NOW I decide I want to replace those braided hoses between the Reservoir and Master Cylinder. I would buy German cloth braided brake hose.

Am I right to assume I can do this without bleeding the brakes again? Or would this introduce air into the system?


(scrimbo) #2

I did mine no bleeding…bought Volkswagen blue wrapped hose and clamps from BUGHAUS company…real cheap

(Greg) #3

Thanks. Is it all 7mm? You just cut to fit?

Suck out reservoir brake fluid, or drain via old hose?

(DavetheLimey) #4

Hi Greg,
I used Brembo brake reservoir tubing on mine You can get Tygon tubing from Amazon. Then it’s easy to see if your brake fluid is clean, and no bubbles.

(Greg) #5

Thanks, that’s a nice solution. What inside diameter? What are you using for clamps? And how did you get that narrow tubing over such a large barb on the plastic parts? Just heat it up?

(scrimbo) #6

I. use fuel inje
ction style hose clamps on most lines as they are less destructive to hoses

(DavetheLimey) #7

I.D. is around 6mm, I think.I used spring type clamps as there is zero pressure to worry about, and warmed up the tubing, no problem. The biggest concern is to make sure that the tubing stays well clear of the throttle linkage with whatever restraints you can devise.

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #8

Have you replaced your reservoir with one from a Mitsubishi yet?

(Greg) #9

I saw that in the book, but my reservoir is in great shape, and I’d rather leave it alone for now.

Can those clear tubes handle 15psi? Because I use pressure bleeder which fits nicely on reservoir top, when I bleed brakes.

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #10

The low fluid level switch works?

15 psi is nuthin’ on a hose that small.

(John) #11

Here’s my solution:

I used teflon tube.
And for fluid level I replaced original cork sensor with generic fluid level sensor:

(scrimbo) #12

Where do you buy a sensor??

(John) #13

Bought in in a local electronics shop

(scrimbo) #14

If I ever change my brake reservoir I might fabricate a new bracket of stainless steel…paint and brake fluid do not mix well…btw…model car enthusiasts use brake fluid to clean paint off of plastic cars…

(Greg) #15

I ended up ordering the Tygon 2375 hose for Brembo. It is 6.35mm to be exact. only $9/foot, I got two feet.

How dependable are our master cylinders? Mine is original from 1988, some surface rust, but no leaks. I assume it’s pretty easy and cheap to just replace the seals? Is it a good preventative job? Or do you just leave 'em alone?

But I’d like to polish mine so it looks as nice as yours.

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #16

They are quite dependably garbage. There are two issues with the OEM XJ-S pre-ABS master cylinder: FIrst, the fluid level warning switch looks like it was designed by a child with his Lego set. It makes other Lucas products look reliable. Even if the stupid cork float doesn’t cause problems, the contacts themselves might, getting corroded and failing to make connections. And this is a serious safety concern; it’s important to know when your brake fluid has left the building, preferably BEFORE you really, really need to stop.

The other problem is that brake fluid should not be exposed to the atmosphere because it absorbs moisture from the air, which lowers its boiling point and causes corrosion to brake components. Better brake reservoirs have a rubber diaphragm that sits on top of the fluid and allows the level to rise and fall while still sealing it off from the air above. Of course, the reservoir in the XJ-S is simply vented to atmosphere, so your fluid is absorbing moisture from the day you changed it.

The fix is simple: A reservoir from a Mitsubishi. There are apparently even a couple different Mitsubishi reservoirs that will work, a round one and a rectangular one. The round Mitsubishi reservoir has the rubber diaphragm, and it has a reliable fluid level sensor. Cost is nominal. You’ll have to fab a bracket to mount it. Perhaps the biggest issue is the brake line connections are seriously larger than on the Jag, 10mm I believe, so you’ll need to adapt the hose sizes down to connect to the XJ-S master cylinder.

(Bernard Embden) #17

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #18

Awesome writeup. The only thing I would add is that the Mitsubishi cap actually had a minor flaw with the diaphragm. They updated the design and fixed it. If you get a reservoir from a junkyard, you’ll need to either check that you got the later design or you’ll need to stop by a Mitsubishi dealer and pick up the updated part.

(Greg) #19

So I definitely understand the issues with the master cylinder reservoir. Converting to Mitsubishi is on my list of improvements over the next year or two.

But the actual master cylinder. It looks quite simple. Do the seals last a long time? Easy to take apart and refresh seals? Better to buy rebuilt?

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #20

The master cylinder is routine and reliable enough. If you want to upgrade, there’s supposedly a shop that will press in liners, brass I think. Arguably not really necessary, though, as the OEM master cylinder lasts long enough and isn’t difficult to R&R when it gets worn.