Brake Master Cylinder

David Lawrence · 14th November 2019, 02:49

The MOT guy should really know about this issue, most of them seem to, and dont normally fail it. Lets face it, you felt safe enough to drive it there for the test so it cant be that bad can it.

You will need a proper bleed to be done. I have had this appear on both of my cars after various bits of work when air got in to the system.

One car I fixed by a pressure bleed doing it myself. That is using a sealey pressure bleeder attached to the reservoir.

The second car just could not be bled by me, although i tried maybe 10 times. Jules had to fix it for me. I had thought he would need to use his T4 to operate the special ABS bleed mode, but what he actually did to fix it was a reverse bleed, pumping fluid in from the caliper bleed nipple, and drawing it out from the reservoir.

Your garage may have attempted bleeding in the normal way and had no success so concluded a faulty master cylinder, but this method is easy and should be tried. You have not indicated there are any faults with your braking, so all 4 corners will need doing. Search for a post by Jules as somewhere he documented the procedure in full, i think the pedal must be partially pressed during the process.

14th November 2019, 02:49	#10
David Lawrence This is my second home Rover 75 CDT-2001 Join Date: Jan 2009 Location: Wrexham, North Wales Posts: 3,606 Thanks: 195 Thanked 606 Times in 501 Posts	The MOT guy should really know about this issue, most of them seem to, and dont normally fail it. Lets face it, you felt safe enough to drive it there for the test so it cant be that bad can it. You will need a proper bleed to be done. I have had this appear on both of my cars after various bits of work when air got in to the system. One car I fixed by a pressure bleed doing it myself. That is using a sealey pressure bleeder attached to the reservoir. The second car just could not be bled by me, although i tried maybe 10 times. Jules had to fix it for me. I had thought he would need to use his T4 to operate the special ABS bleed mode, but what he actually did to fix it was a reverse bleed, pumping fluid in from the caliper bleed nipple, and drawing it out from the reservoir. Your garage may have attempted bleeding in the normal way and had no success so concluded a faulty master cylinder, but this method is easy and should be tried. You have not indicated there are any faults with your braking, so all 4 corners will need doing. Search for a post by Jules as somewhere he documented the procedure in full, i think the pedal must be partially pressed during the process.