Bench Bleed?

nope...not at all... "bench bleeding" a remote reservoir mastercylinder is a waste of time if you don't keep fluid lines hooked to it when you are done "bench bleeding"(and plug the outlets)....by the time you get it from the "bench" to the car and installed, the fluid has already begun running out of the outlets and air makes it's way into the inlets.... I've never "bench" bled a vw master cylinder, and never will..... wasted time and unnecessary... My opinion, of course...

If you're like me and don't trust the manufacturer to put together a clean mc then you will want to take it apart and clean it. You don't know how long that mc has sat on the shelf; it could have rust in it. Secondly, and I haven't done any research on this, but do they put a preservative paste on the rubber seals? If so, you would want to remove the preservative before installing the mc. The mc has some small orifices, so it's a good idea to find out at least once if those orifices are clear. You don't want anything but clean brake fluid flowing in and out of all five cylinders. Bottom line: the brakes are the most important system in the car because you have to rely on them to stop the car, so peace of mind is more important than saving the time and hassle of giving the mc (and the wheel cylinders if they're new) a cleaning.

A word of caution before you start. A master cylinder is under a lot of spring pressure. When you pop off the clip that holds it all together make sure you have a rag around the opening so that the contents don't launch into space and bounce off the ceiling, wall, your face, etc.

You should change the brake fluid every two years. I think that's also a good time to go through the entire system and take apart and clean all of the cylinders. A quote from the Bentley manual: "change the brake fluid in your VW every two years. Brake fluid tends to absorb moisture from the air and after two years of service its water content may be enough to make replacing of the brake fluid necessary. Water can initiate corrosion in the system and may also cause the fluid to boil when the brakes are used very hard." If there's corrosion in the system it can eat holes in cylinder walls and possibly result in loss of brake pressure, meaning the car won't stop like it's supposed to.

Like Joey said about himself, it's my opinion but it's an opinion I formed pert near 30 years ago.

-- Randall

It is blister-packed, coated with some kind of oils and has has no rust on the exterior.

I am not about to take this thing apart.

Duh. No way.

I thought as much. One of the more expensive solutions to bench-bleeding is to fill a bucket with fresh brake fluid and just drop the friggin master cylinder in there and exercise it a bit. Way too spendy for me to even try. I do have a power bleeder and I'm not afraid to use it - at least now after the good advice. Thanks.

I also have dipped some fluid into the brake switch orifices using a toothpick. It seems to work.

Thanks for that, Chris!

John

John, Randall has some good advice if our parts were a bit crappier than they are at this point.... if it is a cheapie chainstore rebuild, I could see needing some extra attention, but I've even had decent luck with those....

BTW, I prefer gravity bleeding to pressure bleeding... easy and effective...

Ah, glad you asked. The old trick is to dip a slim toothpick in brake fluid and insert it into the orifice. Another is to use a syringe and needle to push a drop or two of fluid in there. I got lots of them as a 'side benefit' to home health care.