Hello folks,
In my never ending quest to get the bugs out of my 86 XJ6, recently my brakes have been failing intermittently. I'm guessing it is my brake booster since the pedal gets harder and the hissing sounds like a pissed off snake...but sometimes it seems to be OK.
Besides the master cylinder leaking a little where it attaches to the booster (I fixed the seal between the two and it now seems ok for that problem), the brakes have been acting up more now that it is getting warmer in the springtime. I guess I'm looking for a used or rebuilt booster since I'm not in a position where I can rebuild the original booster. If anyone has one for sale at a reasonable price, please let me know. Its a little strange that the problem seems to be temperature sensitive, but perhaps the membranes are stiffer when cold and not allowing the vacuum leak as much. When the brakes are first applied, they seem to stop pretty well but they get less effective the slower I get...maybe I'm using up the vacuum at low speeds (less than 10 mph).
Any and all help is appreciated, as always!

Jim M

 

Booster is most certainly the "hiss', and should be sorted asap.

The leaking of fluid at the master cylinder to booster joint, is the master cylinder internal seals leaking, and that should be replaced at the same time.

 

When I first test drove Nix, before any money had changed hands, I noticed the brakes seemed unusually hard to apply. There was a bit of assist, but not what I was used to in my work truck. I asked if the car had Power Assist Brakes, and was told rather bluntly it had independent rear suspension.

As I knew virtually Nothing about IRS at the time, what that had to do with my question escaped me but husband was eager to buy the car for me so I kept quiet (I Was quite smitten with the car).

There was no hissing and no fluid loss, but the pedal went down just a bit while sitting at a stop light. I knew the master needed changed and that was on the First List.

Before I got to that, the booster failed completely in the first 6 months; while topping a hill at 65mph on a strange road, to find a line of cars at a stop light at the bottom, heavy cross traffic and no place to take the ditch.

Fear and adrenaline are wonderful things sometimes, and I was able to get the car stopped safely without even throwing her sideways. As the master and booster were the same age (30 years) I changed both and discovered what 4 wheel disc braking should be! I've had no trouble since.
(';')

 

Elinor:


Was Nix' previous owner a politician? Classic, ask a question, he/she answers, a different question. Otherwise known as obfuscation!!! They have mastered the technique as a necessary skill for a politician !!


Up til I got my 41 Studebaker Champion tudor, my cars had durn near useless mechanical brakes. Wow, a huge amount of driving angst removed.


It seems that a PO replaced the master cylinder and booster, not long before relinquishing it !!! Great for me!!


But, ugh, the rear calipers not done.


Carl

 

No, Carl, as far as I know he was never a politician. However, I discovered he had just flat Lied to us about SO many things!

In the first 6 months, while I was working on this or that little neglected matter, I found myself stomping through the house shouting, "LIAR!! LIAR!!"
And husband would ask What now? and I would relate the latest thing he Had to know was "incorrect."

For a while it was like every single thing I touched needed work of some sort, and we hadn't even got to the major stuff yet. Of course, neither of us had owned any vehicle that has sat unused for 10 years (and we didn't know this one had, again, weren't told), let alone a Jaguar, so perhaps we could be forgiven our naivete'.

By this time, after all those matters, large and small, have been corrected, I would like to happen to meet him somewhere while I had the car just outside, and list all the stuff that we fixed. It wouldn't matter though, because almost None of it shows, and he got his money, and that's all he cared about.

We'd still have bought the car, but it would have been nice to not discover we'd been lied to.
(';')

 

Sounds like no difference !!!


Except for the fact that NIX was going to become yours, in whatever state, the following really matters not t you. But, for others, I'll comment.


In almost all jurisdictions, a used car sale is "as is". NO warranty of any kind. When you hand over the $'s and take the keys and papers, you are on your own. If it falls apart an instant later, your problem,. not the sellers.


However, fraudulent misrepresentation, ala "out right" lie is grounds for recisision,
aka "undoing the deal". Example, claimed rebuilt or new engine or transmission, when in fact not true, merely power washed.


But, sales "puffery" is not fraud. Classic, "old lady in Pasadena", when in fact a fleet car....


War story: In my former career, I investigated a case in involving a dealer's sale of a used 89 Ford Thunderbird. Buyer wanted a recision. Two grounds:


1. Failing to disclose that it was a former rental car.
2. That it had suffered front end collision damage.


Investigation found 1. to be true. But, ACV the same, and the car had no mechanical ills. As good as or better than a private party trade in. XLNT maintenace.


2. No collision at all. Proven by sophisticated frame machine. Fact. It had suffered sandstorm damage and the front clip was repainted. New WS as well. No effect on ACV. The repairs were well done.


Today, perhaps more of an issue. Diminished value by the mere fact that repairs, howsoever well done, reduced the ACV.


Carl

 

Jim - mine would hiss (sounded almost like it was sighing) like that on and off for a few years and then I had a rude awakening like LnrB's where I had to stomp hard with both feet and all my strength on the brakes to avoid ploughing into a line of cars. Unassisted brakes on a big car are no fun.

I tried an aftermarket booster (Cardone I believe) but didn't like the feel. I returned that and now have a used one from David Boger - been working great for a couple of years now and no more sighs.

 

 

One alternative....

Booster Dewey Power Brake Booster Exchange Inc.


Excellent reputation


Cheers
DD

 

Usually the rear of the master failing will damage the booster. A consistent hissing sound is a leak, the single hiss you hear on application in a good system is just air entering the atmospheric side of the booster.

Pull a vacuum on the booster and see if it holds

 

 

It was as if they was no boost at the beginning of the pedal travel, and then you had to push the pedal all the way to get anything, then it came in all at once. I guess it feels less linear than the stock booster.