Bleeding the brakes..... 3 options to choose from ?

[IlovemyVW]

Hello all...

Been reading and looking at videos on bleeding the brakes. Its been 2 years since mine where bleed and they was done previously using the traditional method of pumping the brake pedal with two people.

It seems I can choose that option again, but some argue it places a huge demand on the master cylinder and the seals pumping the brakes like that. Then there is the option of the gravity system for bleeding the brakes which is a one man job or there is the pressurised system to bleed the brakes, again a one man job.

Im thinking I might try the pressure bleeding so I can change the entire brake fluid for new brake fluid, also means I can do it all on my own.

Its a Mk4 golf estate. Anybody got any comments on brake bleeding using the pressurised method, good or bad? Or any other comments on brake bleeding.

Many thanks for your contributions.

[Crasher]

We use pressure bleeding at a maximum of 1 bar as instructed in the manual. Pumping the pedal can encourage master cylinder seal failure and whatever you do do not let the reservoir run dry or you will be in a world of pain!

[IlovemyVW]

Would you say a 1litre of Quantum Dot4 would suffice in the pressure container to flush out all the old fluid, refill all the lines with new fluid and refill the resevoir?

[Crasher]

In theory yes, 1 litre is typically the amount you pass through to effect a change but I would be worried about being caught short so to speak, air getting into the system is something even we try desperately to avoid as eradicating it completely is such a fuss. My electric pressure bleeder (an old Sykes Pickavant machine, obsolete and if it breaks I don't know what I would replace it with) holds 20 litres of fluid. On the worse pain in the **** one have had to do, a 99 Golf 4 GTI, we got through 25 litres and one genuine master cylinder (its fourth, 3 by other people) before we got the brakes back which in the end turned out to be two faulty rear caliper brake hoses, damaged internally by someone clamping them. This was back in the early noughties when we were still learning these idiosyncrasies of the Golf 4.

[IlovemyVW]

Blimey.... sounds like a nightmare... having watched a few more videos Im torn now with just doing the brakes via the gravity bleed system.... just wanting to replace the fluid with new brake fluid using the most simple method without trauma like you have described.

When doing the brakes via a gravity bleed system and pumping the brakes, is the risk of damaging the seals the same as when you do it the traditional way and close the bleed valve after every pump of the brake pedal, or is the only difference between these methods being that when you close the bleed valve it ensure it draws fluid from the resevoir??

[Crasher]

The risk to the seals is from the deep travel you subject them to when pumping the pedal but failure during this is not common, about 10% in my experience. The most important point is not to let the reservoir run dry.

[Doctle Odd]

I use one of these works well too Sealey VS0212 Brake Bleeding Bottle 500ml | eBay