<!-- from fixya rte -->How do i bleed the air ouy of lines for top - 1999 Jaguar XK8

there is a particular method to bleeding brakes
IT is a 2 person operation and you start at the longest brake line first
If you have disconnect/replaced the master cylinder it is prudent that you loosen a line at the master cylinder and bleed the air out there first ( primes the master cylinder)
pump/press the pedal to the floor and hold it there as the bleed nipple is opened to let air out
close the nipple and repeat the process until only solid fluid comes out
move to the next wheel and repeat the process ending at the shortest line
at all times be aware of the amount of brake fluid in the reservoir because if you get the line with all the air the level will drop rapidly and will allow air back into the system if not kept topped up
Failing that get it to an accredited brake specialist shop and have them fix any faults and do the bleed

There is a special pump used to bleed the master cylinder first then after the master cylinder is installed you bleed the brakes and fill as you go it's a two-man operation

this is an indication that there is still air in the system and the bleeding process was inefficient. Bleed the lines at the master cylinder first by loosening off the lines and holding the pedal down until the lines are retightened. Then starting at the longest line first bleed the system finishing at the shortest line . Keep the fluid level in the reservoir topped up at all times.

take the bleed valve out completely, pump the brake. if it works change the bleed valve it must be blocked. also is the bleed valve at the top as have heard some people put the pistons on the wrong sides and the bleed valve is at the bottom this will not bleed up this way as air will still be in there.

It's most likely a vacuum line, look under your hood (close to the cowl panel) for a disconnected, cracked or broken vacuum line.

In some rear cases, it could be the vacuum switch (in dash). Or vacuum diaphragm (under dash).

Hope this helps you ???

Hello Vicno.

Bleeding brakes is easiest done with a helper to push the brake pedal.

If the master cylinder was empty, top it up. Have the helper push gently down the pedal while you crack the line fitting on the master cylinder enough that it allows air to come out. Generally it is a 1/2 to a 3/4 turn off the seat. Close the fitting when the pedal is down and then release the pedal. Continue this until no air is evident. Then do the other line fitting on the master. This operation will get the air out of the master and is easier than pushing air all the way through the system.

Make sure you keep the fluid topped up! If it goes dry you will need to start over.
And use approved brake fluid only! Anything else will ruin the complete system.

Next proceed to bleed the remainder of the system as described below.

If the master cylinder maintained fluid then you will need to go to the bleed screws on the wheel cylinders or calipers. Front brakes will have calipers, rear could be wheel cylinders or calipers, depending on how it was equipped.
Each one will have a screw with a hole in the center. this is the bleed screw. They are usually close to where the main line is attached.

Start at the right rear bleed screw and bleed the same as the master-------crack....push...close...release. Then go to left front bleeder and do the same. Then to left rear, right front.

Have the helper push the pedal hard after you are done bleeding to verify the fittings that were loosened do not leak.

If you would like further advise on this subject, please ask me here in a comment.
Thank you for using FixYa.
KL

First thing you need to do is bench bleed the new master cylinder.new master should have come with 2 plastic tubes and fittings.screw fittings into new master,fix tubes to fittings other end in to top of master where fluid goes.fill with fluid make sure the tubes are submergered in brake fluid for entire process.take a screwdriver and press plunger in rear of master.use short slow strokes to start you will see air bubbles in resovoir.slowly increase length of stoke watchin resovoir till no mome bubbles.now ready to install.Remove failed master,(loosen lines befofe removing mounting bolts)remove lines last.reinstall new master then remove bleeding tubes last install and tighten lines.Fill fluid replace lid,have a helper sit in car,loosen lines about half a turn.Have helper depress brake pedal slowly and hold down pedal untill lines tightened.when tight release pedal and repeat 5/6 times.fluid should come out of lines without any air when bled propperly.if failed master did not run out of fluid uyou should be finished.if pedal still soft/mushy will have to bleed a wheels also.use same proceedure but openening bleed screws not lines.may take many times to get rid of all air,you can see and hear the air exiting bleeders.keep an eye on fluid level while bleeding if u run out you are starting again

Any time the internal pressurizable portion of the brake system is breached, i.e. bad seals, broken lines, replacing ABS or master cylindar or blown out cylindars at the wheel you must bleed all the air out of the system. A proper bleed requires 2 people. one person operates the bleed screws while the other holds the pedal down. The screw operator is in charge they tell the pedal operator when to push. the pedal must not be released until the bleed screw is closed again or it will **** air back into the line.

to bleed the system you top it off with fluid then
Open a single bleed screw. tell the person to press the pedal and hold it. the bleed screw will sputter with air and fluid forced out. close the screw and then tell the person in the vehicle to release the pedal. repeat this as many times as necessary to get a steady stream of fluid with no air out. close the screw and that line is done move to the next. The bleed screws are located in slightly different spots on different cars but they should all be somewhere near the caliper or cylinder on the back side of each wheel. Obviously you can trace the brake lines to them.

newer ford trucks are a bear to bleed of air, your bleeder screw is on the line where it enters the transmission, or on the slave, you will see it close to where the line enters the trans.. best way to do it is fill the slave cylender, leave the cap off, and barely crack the bleeder, just so a drop comes out of it about every 20 seconds or so, and let it gravity bleed all night long, tighten it in the morning, and top it off.... like i said though they are tough to bleed, even if you have a helper.... if you do have a helper find the bleeder on the trans, have them pump the clutch about 10 or 12 times, have them hold against it, crack the bleeder, let the air/fluid out, retighten the bleeder, have them let off of the pedal and pump it up again.... tell them not to let off of the pedal until you tell them.. if they let off when your bleeder is open, it will **** air back in the system and you will need to start all over again... after pumping and bleeding 3 or 4 times, have your helper top off the slave cylender to be sure it dont go empty and draw more air in the system... bleed the system like that until you get a plain steady of fluid, and no air, and you should be good to go.. top it off and put the lid back on the slave... hope this helps more than it confuses you... it can be a little difficult to explain sometimes

if the car is fule injected thear will be valve that looks like an air valve on top of the engen on the fule line you can use this to bleed out the air in the line. do this with key on DO NOT RUN OR START the engen untill finished bleeding system and spiled fule is clend up and dry