I guess this thread might be helpful to some folks.

So, to make a long story short - many X-type owners (including me) found themselves with a bad brake booster after front brakes replacement. Seems like it's a very common issue among X-types. Don't know what causes the booster failure, but nevertheless it tends to go bad.

Please keep that in mind when you do your next brake service.


Cheers

 

Could you be a little more specific on the symptoms of your booster failure to help me please? I have changed the front brake pads on my 2010 XF. I pushed the pistons back without opening the master cylinder or bleed nipples which I now know can cause issues with the seals etc.

I have clamped both front brake hoses individualy to test for air ingress at the calipers and the pedal still goes slowly to the floor (with the engine running), I have opened the master cylinder and checked for air bubbles coming up whilst the pedal is pumped to no avail. When the engine is stopped the pedal will pump up solid and not go down but as soon as I start the engine the pedal slowly drops.

Can anybody help me with this problem? I'm now at my witzend and exasperated with it. I don't want to send the car to the dealer as they'll charge a klondyke to repair it.

 

all 4 brakes were always applied after the engine is on. But they were released once you disconnect the vacuum line from the booster. Some other guys had slightly different symptoms but it all happened after the front brakes replacement.

I don't know why that happens, because before the brake job- everything (at least in my case) was fine.

 

purely a coincidence. they do fail and nothing to do with a pad replacement. they fail 3 ways.
leak vacuum and create a p0171, p0174 lean engine code for a check engine light.
hard pedal,
sticking brakes from a slow to release booster

 

That what I thought but I found records of at least 3 cases (+ 1 mine) which happened after a pad replacement. Nobody wrote that they had had any codes or leaks (neither did I). So it looks very odd to me too, but we have what we have.

 

Brake master cylinder sure i can see that. Booster no

 

Still can't believe it myself. But...it's exactly what I got.

 

I just recently changed my pads and rotors, and am having a rough idle problem. I just ordered new O-rings and a pcv valve, and if my problem still persists, I assume it will be the brake booster valve. Any advice on where to get them besides the factory? Thanks.

 

Autoparts warehoude; gaudin jaguar...ebay?

 

Mechanic says that during normal use, master cylinder piston only travels part way along the bore. Over time, the unused part becomes rusty/ full of crap. When pads are changed, wheel cylinders are pushed completely back. When job is finished, pedal is pushed all the way to the floor to seat the pads against the disk, resulting in master cylinder seal travelling through rubbish and becoming scored. Failure soon afterwards.

 

Necro-post, but I just had my brakes done and yup, booster failure. What causes this?

 

Brutal, just finished replacing booster hose and it went smoothly! However, I still have a problem braking. The brake pedal is very stiff and sometimes it kicks back. Could there be something more serious? I also get a computer warning stating "Cruise Control Not Available" (it goes away after a while) I've seen other threads with this problem could it be a damaged booster hose...? I hope is not the brake booster. Any Ideas?

 

I have replaced MANY(25-30) sets of pads on different cars and I use this technique and it never fails.
Remove pads and discs as usual, BUT open bleeder when pushing back the caliper piston,DO NOT force contaminated fluid back up the lines into the MASTER CYLINDER OR into the PROPORTIONING VALVE (used to equal pressure and flow to rear brakes). If the BLEEDER is froze remove the line, block the end of the hose with plug/rag what ever. FILL reservoir AND NEVER let it go dry (or you will have air in the system)
Now replace your pads/rotors as usual,check the reservoir making sure it;s full,
Now leave the bleed valve/line open and dripping UNTIL you don't see and bubbles come out.important!!
Close valve/line
start the car and push slowly on the brakes until the pedal is firm.(don't pump wildly,If there is rust in the master Cyl. that will scour the seals)
You should be done BUT you will have a MIL. most of the time Don't worry, It will go out after a BLOCK OR SO of test drive.
Now I SEAT the new pads BUT thats another post!
This technique uses a bit more fluid but fluid is cheaper than a MASTER CYLINDER AND you get all new fluid to start over with.
Rear brakes take a little longer to Gravity Bleed but the same applies.
TIP#2--Always use a SIX POINT socket or a six point BOX wrench opening the bleeder valve
Tip#3-- Check the rubber brake lines to the wheel cylinder (no cracks)
Tip#4-- Don't skimp or say GOOD ENOUGH. Your car is a missile WITHOUT brakes.

 

Does anyone have a brand of brake booster to recommend? I think mine is done. I've had the P1071 and P1074 come on every drive cycle for months now, but they go away after a few minutes. What's really happening is the car goes into limp mode for a few minutes every drive cycle, but then returns to normal operation after those few mins. Pep Boys said the brake booster has an internal leak. Parts and labor is $600.00 to R/R.

I watched a YouTube vid on how the brake pedal should behave when the car is running vs not running and the Jag failed every test

I happen to be up on my X Type vacuum leaks. I've been thru the vacuum hose threads here regarding the connections that are easy to reach and replace on top of the engine. I've replaced most of that. The IMT gaskets are 6 years old, but I doubt that's a culprit.

Here is the test I found:

Test 1: With engine off, pump the brake pedal 4 times and hold. Start the car and the brake pedal should sink. If it does brake booster is good.

Test 2: Start car and let idle for 2 minutes. Press and hold brake pedal. Turn off the engine. Pedal shouldn’t rise for 30 seconds. If it rises you have a problem with brake booster.

Test 3: Start car and let idle for 2 minutes. Turn off the engine. Pump brake pedal 3 times. The pedal should rise a little bit higher after releasing each time.

A far fetched idea is that there is simply air in the lines. I did have new rotors and pads installed at PepBoys 4 months ago. After the service the brakes were squishy and had low braking power. I thought maybe they left air in the lines or the pads needed some brake cycles to start grabbing better.

I've let them burn in for a while now and they suck. I only have real braking power towards the bottom of the pedal travel. ...a new booster sounds good, here comes the quintessential question; What else can be addressed at this time? Master cylinder? I imagine so

 

I would take the car to a company that deals mainly with brakes, and get them to bleed the brakes properly. Eliminate the easy stuff before replacing booster.

 

Any resolution to your brake problem? Did you get a new brake booster? New master cylinder? Figure out something else was wrong?

 

I had a new brake booster installed by Pep Boys (no master cylinder). It was about $600 for parts and labor. Definitely fixed the problem. Brakes work great and codes, at that time, went away. I was good for a few months, then in April I came up on a whole new slew of problems. Have been working thru those, misfires, fuel injectors, and sensor problems.

Gotta smile!

 

well guys heres the solution
,they dont go bad ,if one any has this problem all you do is remove the two bolts from the master cylinder , be careful not to drop the nut on the right ..now the reservoir has i think one bolt in the front now twist the interlock lift up and try and move it to the side ,you dont need to remove any hoses
now pull the master cylinder back, you dont need to remove lines ,its a little tough to pull out but you'll get it
once its out move to the side,now you see the hole for the brake booster ,have a friend push down on the brake pedal now you will see the stem
get a 7mm socket and a long needle nose pliers or something two grab the stem then put the socket on the end off the stem and turn clockwise in like 3-4 turns in. and voila no more problems with sticking brakes
ive done this on about 3 x-types worked everytime

 

Thanks Dennis, I'll give it a try. I don't know how that stem gets too long but I think that might be my problem. I noticed yesterday if the brakes are warm and I put the car in drive on a flat area and don't touch any pedals the car doesn't move, like if the e-brake was on. If I put my foot under the brake pedal and pull it up the car starts moving even though I don't feel any movement in the brake pedal.

 

you have the symptoms of some jag and ford owner has ,but its a simple fix ....you dont need any money just a 7mm socket ....you dont need to bleed any brakes