Replaced the rear brake pads and calipers, when tested the rear wheels lock so I bleed fluid and locking released. Run again for a kilometer then rear wheels lock again. Please help. Thanks.

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Jaguar 2006 X-type 3.0 AWD (added by GGG)

 

What kind of car?


Cheers
DD

 

Hi Doug, thanks and apologies for not including as much info as possible. Its a Jaguar 2006 X-type 3.0 AWD, automatic tranny.

 

Followup to my previous post, I found out that all 4 wheels are sticking. I bleed brake fluid from all 4 wheels and it was okay for few kilometers then back again, all 4 wheels are sticking. Can anyone please help?

 

You will get more answers if you post under the specific model rather than the regional section. The X-Type (x400) section under Jaguar Models (modern) will most likely get you an answer. Good Luck

 

Welcome to the forum edapol2007,

I've moved your question from Canada Region to X-Type forum. The model forums are the place to post technical questions. Members here with the same model will be able to help.

Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some info about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

I had a similar problem with the linkage going to the master cylinder not coming all the way back out after it got hot.

You can test this by getting them to lock up, jack the car up, and make sure they are still locked, then loosen the bolts that hold the master cylinder to the booster. If that unlocks them you have found the problem area.

 

 

Thanks Graham, much appreciated.

 

I will try this Larry - I've re-bleed the brake system and still once it gets hot (running about 10 km with lots of braking) the brakes lock again (all 4 of them).

 

Hi Larry, what could i possibly do if the linkage does not go back? Thanks.

 

Larry, I loosened the 2 nuts connecting the master cylinder to the brake booster and heard an air leaking then brakes are free again. Tried driving but then back to the wheels sticking/locking again. I would like to check the vacuum hose from booster to manifold but how to remove that I don't know. Or can anyone suggest of what should I do? Thanks friends...

 

To check the hoses you spray some WD-40 type spray on and around the hoses as the car is running. If you hear a change in the motor RPM you have found a problem.

I would now look at the linkage under the dash for any binding, extra play, or rubbing on things. The pedal may be coming all the way up but not the linkage.

If it is possible to loosen or remove the master cyclinder to see how the linkage looks and feels.

 

Hi Larry-Cleveland, I was able to check the vacuum hose and it's working okay. I checked under the dashboard and nothing that is binding or restraining the rod to retract. But loosening the 2 nuts release the pressure and I can move again...I'm too puzzled now but thank you for your help. I wish that this issue be solved. Thanks again.

edapol2007

 

Hello, I have the same problem, and wondered if you have solved it, and if so how. Thanks rob

 

Hi Rob,

Tried everything we know, even employed the help of 2 experienced mechanics but no success. Their analyses points to replacing the Master Cylindet. I am awaiting the master cylinder I ordered last week. Will update this forum once the issue is solved.

 

Thanks, I have cleaned all calipers and replaced one, replaced servo, master cylinder and abs module (second hand) and still drag when engine running, unlucky if these had same problem. If I take the vacuum hose out they free. The only thing I can think of now is to adjust the length of the push rod in the booster, have you tried that.

 

I have not tried adjusting the rod inside the booster. What I noticed was when its locked, I loosened the 2 nuts holding the master to the booster and its free again. Then test drive, and once I travel about 10 km with lots of braking, then all 4 wheels lock again. I'm still not 100% agreeing with my 2 mechanics that its the master that's causing the issue but I bought online anyway. I will see once the new master is installed what it does, then will update you.

 

Ok guys after reading that the brakes released when the vacuum was removed is a good clue!

The booster has a rubber diaphragm in the center that attaches to the rod going to the master cylinder. When you start the motor and create vacuum it is equal on both sides of the diaphragm. When you push the brake peddle it opens a small valve to allow normal pressure air into the back side of the diaphragm. This imbalance of pressure is what gives you the added aide in applying the brakes. Ok class is over...

That said... it sounds like the booster valve is allowing in, a small amount, of normal pressure air in when it gets hot applying some pressure on the master cylinder rod locking the brakes.

I say booster is bad.