• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

86 XJ6 mystery brake fluid leak

Share this page

V

VinnyT

Freshman Member
Offline
My father is describing a brake fluid leak in his 1986 XJ6. The puddle is underneath the vehicle, but coming from the middle of the underside somewhere. The master cylinder is now drained. He knows he scraped the car twice going into the driveway.(Weird drainage ditch hump thing) Is there a coupling near the center of the vehicle for the rear brakes? I'm thinking of a mating block or union. I will be seeing him this weekend, but need a direction of what to look for. Any help is appreciated.

Thanks!!
 
yes there is, over the rear IRS cage, there are brake lines and rear calipers which are smack in the center over the suspension cage. You could reach them from below the car with a <span style="color: #FF0000">lot of safety precautions</span>, the XJ-6 weighs over 3 thousand pounds, so let me repeat: <span style="color: #FF0000">A LOT OF SAFETY PRECAUTIONS!</span>

Those rear Brakes are not a job for the inexperienced, best to let an experienced Jaguar technician repair it, (unless you are), spend the money required and avoid any possible danger or future problems. Brakes are a SAFETY item.

However, if they tell you that the rear Cage must be removed, just walk away and go elsewhere.

Depending on where you are, call different Independent Jaguar mechanics and tell them to give you a ballpark cost for brake work.

And that is ASSUMING that the leak is back there, but you don't know that it is! Best to get a visual and let them tell you. Don't tell them "I think the REAR brakes are leaking", because an unscrupulous mechanic might see an opportunity to make more money on repairs that the car does not need. Better yet, find a friend who is not out to get money from you, and let him tell you where the leak is. Can't be THAT difficult to find. But if you're going to put a friend under that car, remember that <span style="color: #FF0000">SAFETY is NEVER ENOUGH!</span> Put enough Jacks under the car, tie the hands behind the back of whoever is at the wheel so that the transmission is not engaged by accident! (engine needs to be running as someone starts the engine and applies the brakes and someone else adds brake fluid, while someone else looks underneath to see it leaking). Put wedges on at least 2 tires. It's never enough!

The Good News: you lost ALL the brake fluid? GREAT! that means you start out with fresh fluid, which probably needed to be changed anyway!

Last: if there's no leak found underneath, it's probably the Booster/Master Cylinder Seal, so it's leaking the fluid inside the booster, time to rebuild it or better yet, get a new one!

Good luck.
 
If indeed it is the rear brakes leaking, there are a few things to consider"While you are at it" Change the rear rotors anyway. The parts are cheap, and doing any of this twice is to be avoided. If the rotors are changed, go ahead and have the stub axles rebuilt. The seals probably want changing anyway.
If you are going to attempt rebuilding the rear calipers yourself, with out a lift, removing the rear subframe is not really a bad thing to do. It is ultimately safer as you will spend far less time under the car. If a shop does it, it is much easier to just disassemble it in place. It is hard to raise the car enough safely to get the axles apart to change the rotors on jackstands.
In my shop, to overhaul calipers, emergency brake pads and calipers, stub axle rebuilds, and rotor replacement is about 16 hours of labor.
 
Jesse, why replace the rear rotors? I mean, if the car is braking ok, why change them? after all, the Rear Rotors in the XJ-6 do very little work of braking the car, they're mostly for the Handbrake, are they not? The Front Brakes are the ones that do the real braking. Chances are that the Rear rotors are like new!

I would agree with a stub-axle rebuild if the Seals are gone, but again, only if absolutely needed. Ditto for the rear calipers. You know the saying: "leave dirty, dirty enough"? Before you know it, the rear cage has been removed, and things start getting complicated and going bad like an opened can of worms. I don't like to contradict people who make a living repairing cars and who are obviously experienced, (like you), but at least for me, removing the rear cage is a heck of a job and one of last resort.

Too bad you're not in Central Florida, good Jaguar mechanics
are few around here.

Ex
 
Back
Top