Unresponsive brake pedal

[Siboy]

I just thought I would share a solution I've come across. Apologies if this has been covered, but I couldn't find it when i was in need.

 

I replaced the brake fluid on my newly purchased 51 plate Octavia VRS, after also replacing each bleed valves on the calipers and pressurising the system the brake only engaged for the last 10% of travel of the brake pedal. I have another VRS which engages the brakes almost immediately, so I knew it wasn't right; I was about to replace the brake master cylinder when I notice that it also has two additional bleed valves on the top of the BMC itself as well.

 

I have never seen that on any other car I've worked on, but when I bled those as well the brakes are now great.

 

Just thought this may save someone else some time and money!

[petrolbloke]

Same thing happened to my car last year, with the same solution:

 

 

[theo_k]

can you please post a picture with circled the bleed valves on the brake master cylinder?  Some of us are daft...

[Siboy]

The top and bottom are the black rubber caps over he two bleed valves. The middle picture shows where they are located from a top view of the engine (if the plastic housing wasn’t there). 

 

Both valves are are accessible without removing any engine components. Any problems just message me. 

[theo_k]

thanks mate, have to be honest I had no idea.  I am guessing the right order to bleed those if you are doing all of them, is to start from the furthest caliper, then leave the ones shown above for last, is that right?

[Siboy]

That’s he way I did it but remember the order of bleeding is dictated by which abs pump you have (pictures below for you, if you have a standard air box it will be harder to see); there are 5 or so different types. 

 

I had a look at a Haynes manual which set it out but sure someone on here will have the diagram to compare. 

[theo_k]

...right when I thought I got this!  I ll do some research and maybe I will ask again, thanks again though

[kentphil1]

Here you go, both seqences depending on which you have fitted.     Bleeding brake system with brake filling and bleeding device for vehicles with Mark 20 Special tools and workshop equipment required t  Brake filling and bleeding device, e. g. -VAS 5234- t  Vehicle system tester -V.A.G 1552- with diagnostic cable -V.A.G 1551/3, 3A, 3B oder 3C- or diagnostic unit VAS (only vehicles with ABS/EDL) t  Brake fluid → Chapter If one chamber of the brake fluid reservoir has run completely dry, e.g. leakage in the brake system, bleeding must be carried out using the brake filling and bleeding device, e.g. -VAS 5234-. Then the hydraulic unit is tested with the vehicle system tester -V.A.G 1552- in the function "basic setting" or with the vehicle diagnosis, measurement and information system -VAS-. Opening the bleeder screws on the hydraulic unit is not allowed on vehicles with ABS, ABS/EDL!   WARNING t  Brake fluid is hygroscopic, i.e. it retains humidity from the ambient air, and must therefore always be stored in airtight containers. t  Brake fluid must never come into contact with fluids containing mineral oils (oil, petrol, cleaning agent). Mineral oils damage the plugs and boots of the brake system. t  Drained (used) brake fluid must never be used again. t  Brake fluid is toxic, avoid skin contact. t  Because of its caustic effect brake fluid must not come into contact with paint. t  Rinse any brake fluid spills with a lot of water. t  Dispose of brake fluid in compliance with the applicable waste disposal and environmental regulations. t  Bleed the brake system on vehicles with ABS or ABS/EDL, as for vehicles without ABS. t  Only use new brake fluid in accordance with the specification → Chapter. A pre-pressure of 0,1 MPa (1 bar) is required to bleed the brake system.   DANGER! t  When replenishing brake fluid with a brake filling and bleeding device, it is important to ensure that the filling pressure of 0.1 MPa (1 bar) is not exceeded. t  Therefore the brake fluid pressure on the brake filling and bleeding device must be regulated down to 0.1 MPa (1 bar) → Operating instructions of the bleeding device t  If the filling pressure of 0.1 MPa (1 bar) is exceeded, proper bleeding of the hydraulic unit is no longer assured.

–  Unscrew cap -1- from the brake fluid reservoir

–  Connect the thread plug -1- of the brake filling and bleeding device e.g. -VAS 5234- to the brake fluid reservoir. –  Provide a suitable catch pan for used brake fluid. –  Remove the dust caps of the bleeder screws at the brake calipers. –  Switch on the brake filling and bleeding device e.g. -VAS 5234- and activate the system with a brake fluid pressure of 0,1 MPa → Operating instruction of the brake filling and bleeding device.

–  Fit the hose of the bleeding bottle-1- onto the corresponding bleeder screw. –  Slacken bleeder screw. –  Extract as much brake fluid as possible until even the smallest air bubbles have escaped. –  Close the bleeder screw and fit on dust cap. –  Repeat this procedure for all brake calipers in the prescribed sequence until the brake system is fully bled.   Note For vehicles with brake-power regulator move the rear wheel-brake lever of the regulator during bleeding. Bleeding sequence 1 -  Rear right wheel-brake cylinder/brake caliper 2 -  Rear left wheel-brake cylinder/brake caliper 3 -  Front right brake caliper 4 -  Front left brake caliper –  Inspect pedal position and idle travel at brake pedal. Idle travel: max. 1/3 of pedal travel. –  Repeat the whole procedure if necessary (several times), until perfect bleeding is achieved. Vehicles with ABS or with ABS/EDL –  Initiate basic setting → Chapter.   Caution Before the basic setting of the ABS control unit is performed, first of all the brake system must be fully bled until even the smallest air bubbles have escaped from the system. The air bubbles would penetrate into the ABS hydraulic unit when performing the basic setting of the ABS control unit. It is very difficult to remove these air bubbles from the ABS hydraulic unit. A characteristic feature of right-hand drive vehicles

If one chamber of the brake fluid reservoir has run completely dry (e.g. leakage in the brake system) or after changing the hydraulic unit, then the master brake cylinder must be bled via the bleeder valves after carrying out the basic setting -arrows-. Continued for all vehicles –  If necessary, correct the brake fluid level in the brake fluid reservoir. –  Disconnect the brake filling and bleeding device. –  Disconnect the brake filling and bleeding device from the brake fluid reservoir. –  Perform a test drive. While doing so, at least one ABS adjustment must be carried out on vehicles with ABS or ABS/EDL!     Bleeding brake system with brake filling and bleeding device for vehicles with ABS Mark 60 Special tools and workshop equipment required t  Brake filling and bleeding device, e. g. -VAS 5234- t  Vehicle system tester -V.A.G 1552- with diagnostic cable -V.A.G 1551/3, 3A, 3B oder 3C- or diagnostic unit VAS (only vehicles with ABS/EDL) t  Brake fluid → Chapter If one chamber of the brake fluid reservoir has run completely dry, e.g. leakage in the brake system, bleeding must be carried out using the brake filling and bleeding device, e.g. -VAS 5234-. Then the hydraulic unit is tested with the vehicle system tester -V.A.G 1552- in the function "basic setting" or with the vehicle diagnosis, measurement and information system -VAS-. Opening the bleeder screws on the hydraulic unit is not allowed on vehicles with ABS, ABS/EDL!   WARNING t  Brake fluid is hygroscopic, i.e. it retains humidity from the ambient air, and must therefore always be stored in airtight containers. t  Brake fluid must never come into contact with fluids containing mineral oils (oil, petrol, cleaning agent). Mineral oils damage the plugs and boots of the brake system. t  Drained (used) brake fluid must never be used again. t  Brake fluid is toxic, avoid skin contact. t  Because of its caustic effect brake fluid must not come into contact with paint. t  Rinse any brake fluid spills with a lot of water. t  Dispose of brake fluid in compliance with the applicable waste disposal and environmental regulations. t  Bleed the brake system on vehicles with ABS or ABS/EDL, as for vehicles without ABS. t  Only use new brake fluid in accordance with the specification → Chapter. A pre-pressure of 0,1 MPa (1 bar) is required to bleed the brake system.   DANGER! t  When replenishing brake fluid with a brake filling and bleeding device, it is important to ensure that the filling pressure of 0.1 MPa (1 bar) is not exceeded. t  Therefore the brake fluid pressure on the brake filling and bleeding device must be regulated down to 0.1 MPa (1 bar) → Operating instructions of the bleeding device t  If the filling pressure of 0.1 MPa (1 bar) is exceeded, proper bleeding of the hydraulic unit is no longer assured.     –  Unscrew cap -1- from the brake fluid reservoir   –  Connect the thread plug -1- of the brake filling and bleeding device e.g. -VAS 5234- to the brake fluid reservoir. –  Provide a suitable catch pan for used brake fluid. –  Remove the dust caps of the bleeder screws at the brake calipers. –  Switch on the brake filling and bleeding device e.g. -VAS 5234- and activate the system with a brake fluid pressure of 0,1 MPa → Operating instruction of the brake filling and bleeding device.   –  Fit the hose of the bleeding bottle-1- onto the corresponding bleeder screw. –  Slacken bleeder screw. –  Extract as much brake fluid as possible until even the smallest air bubbles have escaped. –  Close the bleeder screw and fit on dust cap. –  Repeat this procedure for all brake calipers in the prescribed sequence until the brake system is fully bled.   Note For vehicles with brake-power regulator move the rear wheel-brake lever of the regulator during bleeding. Bleeding sequence 1 -  Front left brake caliper 2 -  Front right brake caliper 3 -  Rear left brake caliper 4 -  Rear right brake caliper –  Inspect pedal position and idle travel at brake pedal. Idle travel: max. 1/3 of pedal travel. –  Repeat the whole procedure if necessary (several times), until perfect bleeding is achieved. Null balance of the brake pressure sender -G201- → Chapter. Vehicles with ABS or with ABS/EDL –  Initiate basic setting → Chapter.   Caution Before the basic setting of the ABS control unit is performed, first of all the brake system must be fully bled until even the smallest air bubbles have escaped from the system. The air bubbles would penetrate into the ABS hydraulic unit when performing the basic setting of the ABS control unit. It is very difficult to remove these air bubbles from the ABS hydraulic unit. A characteristic feature of right-hand drive vehicles   If one chamber of the brake fluid reservoir has run completely dry (e.g. leakage in the brake system) or after changing the hydraulic unit, then the master brake cylinder must be bled via the bleeder valves after carrying out the basic setting -arrows-. Continued for all vehicles –  If necessary, correct the brake fluid level in the brake fluid reservoir. –  Disconnect the brake filling and bleeding device. –  Disconnect the brake filling and bleeding device from the brake fluid reservoir. –  Perform a test drive. While doing so, at least one ABS adjustment must be carried out on vehicles with ABS or ABS/EDL!