I'm fixin to go into my front drum brake system on a 69 Malibu to try an clean up some bad brake fluid, I don't know how contaminated the lines themselves are, but wheel cylinders are pretty crusty. Been reading a lot on the bleeding process and bench bleeding a new master cylinder and not sure how to approach this project. :confused:

If I replace the wheel cylinders, flexible rubber brake hoses, and master cylinder all at once, does this introduce too much air into the system and I'll have problems bleeding it all out (even if I bench bleed the m/c)? Now same question but what if I replace all the steel lines too?

Should I just replace portions of the system, bleeding between each part of the project (ie install new m/c and bleed, install wheel cylinders and bleed, install flex hoses and bleed. Somebody who's done this please give advice for least painful approach. Many thanks-Dave.

Dave.

Normally it really shouldn't be all that hard to do. Just replace whatever you want, all at once, then bench bleed the M/C (see the picture) and mount it. Finally bleed the system, starting at the longest line, working your way to the shortest line. Do this a couple of times and all air should be out.

In your all drum setup there is no combination valve, I think. If there is, you will need to push the front pin when bleeding the front brakes.

Watch for:
1. When mounting the brake shoes be sure to put the longest lining on the rear side (at each wheel).
2. The front and rear brake cylinders may be different. If so, the bigger ones belong in the front brakes.
3. During the bleeding, keep your mind on the M/C level, or you will draw air into the system again. Do not leave the M/C open, or fluid will squirt on your paint.

Hope this helps.

Rob

http://www.si.hhs.nl/~rob/images/scanned/313d_ass_bnch_bld.jpg

What Rob said, and as a second thought invest ($20 or so) in a set of tubing wrenches if you don't already have them.

For those that don't know, a tubing wrench is a 6-point box end wrench with a little "notch" cut out of the circle. The notch is just large enough to fit over the hardline that a particular size fitting would be on.
An inexpensive set should have a 3/8 - 7/16, 1/2 - 9/16, and 5/8 - 11/16 included. These sizes will cover most anything you'll run into.

Using these will reduce the chance of rounding over the fittings, and enable you to properly tighten the fittings. Might even save some knuckle skin as well.

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Second on getting the tubing wrench set. I don't know if anyone else has noticed - but as I've gotten older, the knuckle skin is in much shorter supply and more precious. It makes a lot more sense now to buy the right tool for the job than it did 20 years ago

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