I've replaced some section of rear brake line, I've bled nearside rear brake no problem, the offside rear different matter having trouble bleeding it, even tried to let gravity bleed it but still having trouble, could it be the master cylinder needs priming

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2006 X-Type 2.2 diesel (added by GGG)

 

Welcome to the forum Aplanir,

I've removed your duplicate post of this question from General Tech Help.

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Graham

 

Aplanir, I guess the first question that I would have is whether the connection is tight or not. It may seal just fine under pressure, but if you get a slight vacuum in the brake line (from when the brakes are being released), if you don't have a good seal, air can make its way in. I would start there first.

After that, if you are getting air into the system, the next place I would look is the bleeder valve on the caliper itself. But, I would expect that to leak if it is allowing air into the caliper. The only other possibility that I can think of is the seal on the piston itself. If you have some how managed to get a knick or something on that, that could also potentially allow air in without being a source of leakage (due to the seal being pressed hard up against a surface when the pressure is applied, but then relaxes when the piston is backing off). But, this should only occur if you have a ripped boot on the piston or you got dirt inside of the caliper when changing the brake lines. Unfortunately, if this is the case, odds are, replacing the caliper is going to be your best bet.

 

I read that each outlet pipe from master cylinder services offside front and offside rear or nearside front and nearside rear, I thought I might have bottomed out master cylinder and needed priming because air was still in one of master cylinders pistons

 

aplanir, if you have the reservoir full of fluid, you should have flushed enough fluid through the system to remove any air. If I remember the construction of the master cylinder correctly, both halves are on a common shaft. So, there is no "bottoming out" a side. If you want to see if there is truely an air bound condition, take the car out to a parking lot, keeping your hands near the steering wheel (but loose enough the the steering wheel can move some on its own), get up to say 30 MPH (50 KPH) and then get into the brakes in a timely manner, but end with your foot pretty good. If the steering wheel pulls one way, then you know that only one of your front calipers is stopping the car (the side the steering wheel pulls to). If the car pulls straight, then both front calipers are working properly.

 

I check brake line and a couple of flares wasn't good so took out one section I had replaced front to rear, and redid it there were no brake fluid in the pipe I changed, didn't have time to do front to nearside rear will have to do that saturday but when I loosened the connectors no fluid came out. brake fluid wont go through pipes the master cylinder reservoir is full to top, I loosened the outlet pipes 5 or 6 turns from master cylinder and nothing ran out, I've worked on brake system before on other vehicles I've had

 

I replaced both sections front to rear brake line there no airleaks connectors are good.
brake lines empty master cylinder full to brim, tried bleedin front driver side pumped it 30 times but no fluid will come through, I've been told master cylinder design dont allow it to bottom out so not that. I've tried bleeding with master cylinder cap tight and also just placed over top epic fail infact never had problem with any of my other cars/vans if I had trouble with other vehicles in past I'd bleed master cylinder by loosenig outlet pipes from master cylinder pump it about 5 times then hold brake down and tighten outlet pipe up.
so is there something I'm misssing?

 

On some cars I have found that they can draw air into cylinders in an otherwise good system when there is a vacuum. In those cases I would release the break pedal very slowly while bleeding the system. I would take a minute or more as I slowly released the break pedal. There is no problem with pressing the pedal fast, only the release cycle needs to be slow.

Pete.

 

does anyone know if the X type as a load portion valve? my son was saying it will explain why I cant bleed brakes because the car on 4 axle stands

 

I would use an "easi bleed" type of kit.
The easi bleed bottle is partially filled with brake fluid, and is then pressurised from your front tyre, through a pipe, and another pipe coming out of the bottle(that goes in to the brake fluid, is fed to a replacement master cylinder reservoir screw cap.
This method pressurises your master cylinder reservoir, and also supplies extra brake fluid, to replace the loss when bleeding your slave cylinders.


I remember some years ago, a old Vauxhall astra had to be bled this way.


Paul.