VW passat 99 the brack is stuck while driving then towe to grage they said 2 calipers ( 1 front & 1 rear) stuck.they change 4 calipers ,4 rotors
and two hoses after installing there was no oil come out when bleeding.Mechanic said something wrong with ABS pump it doesn't start with the car.Take it to dealer said Master need to be changed.after changing master the dealer said the lines was leaking and hoses were iinstalled wrong.We staill waiting .can some told me the reson is it master or ABS pump and if they install hose wrong can this cause no oil when bleed.
Thanks
The master cylinder supplies the pressure to the brake fluid that travels between the maste brake cylinder resevoir and the brake caliper pistons (through the brake lines. If the master cylinder fails there will be insufficient compression of the brake fluid to make the calipers operate as designed. Leaks in the brake lines and/or cylinders is a possibility, and unrelated to functionality of the master cylinder. Also, pistons located in the brake calipers can form a corrosion ring on their inside walls if there is breakdown in the brake fluid or moisture that gets into the lines. Operating the vehicle when there is insufficient brake fluid in the master cylinder resevoir can also lead to air getting into the brake lines, causing bad working brakes. Air compresses more than brake fluid, and the master cylinder isn't designed to compress air in the brake lines. Sounds like a bad case of "lack of maintenance", as opposed to bad advice from the mechanics. That said, there's no excuse for bad installation. But, it's tough to improperly install a brake line since they are nothing more than hollow metal tubes. There should be no rubber connectors installed in the brake lines. When bleeding the brake lines one must remove all of the trapped air before you will see any fluid appear. If the valves in the master cylinder are not properly operating the master cylinder will not allow the brake fluid to get into the brake lines.
Hope this helps.
The master cylinder should only have one (1) fluid reservoir. The same fluid reservoir sends fluid to both the front and the rear brakes. There is a small valve that feeds each individual brake line as it leaves the master cylinder. Master cylinders can fail for a variety of reasons, but I've not seen an instance when it failed because the brake pedal was depressed to the floor several times ????
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Thanks.I forgot to say that the dealership mention that the master gone because the mechanic bleed it wrong he kept push the pedal all the way untill touch the floor and that made the seal in the piston to flip and that ruine the master .Can thios be the reason and can the master only send oil for rear only and doesn't send oil to front.I really appriciate if some body can advice
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