I am going to be installing a new proportioning valve to finish my 1le disk upgrade, but I have a few questions. Will I need to drain the master cylinder before removing the pv? After installing do I need to bleed or set the pv or just bleed at the calipers?

Also, just to make sure, changing from disc/drum to 1le disc/disc, I keep the drum mc and change to the 1le pv, right? A few posts in a search said to use both the mc and pv from the drum car.

Thanks

 

I can answer a few questions.

Will I need to drain the master cylinder before removing the pv?
It would be a little less messy if you do. Take a turkey baster and suck all the fluid out from the resevoir. If you don't have one, get one at Target for about a $1.
Or, I just thought of something. Instead of draining the master, when you disconnect the lines from the input of the PV, if you had some kind of rubber cap that could be put over the end of the line to keep the brake fluid from running out that would be nice. That way you wouldn't have to worry about any air bubbles getting into the master.

After installing do I need to bleed or set the pv or just bleed at the calipers?
Only thing you need to do is bleed at the calipers. Some people recommed starting the farthest away from the master first... pasenger rear.

 

I'd definately get rid of the old fluid in there, wipe the "dirt" off the sides of the m/c, and then fill w/new fluid. Fluid doesn't really pour out of the m/c, it's a constant drip, so if you work fast, it won't really be messy. Break all the fittings free, first, then snub 'em back up by hand.

On a few of those fittings, while using the correct (isn't it 13mm?) flare nut wrench, I've almost stripped the nuts. Wound up using a Big (12 inch) open-ended adjustable snap-on wrench, and it broke them free without damage. Sounds backwards, I know, that a flare nut wrench would hurt them, but an open ended adjustable wouldn't- go figure.

Remember too that there's a right and wrong way to use an adjustable wrench. The "fixed" jaw should always bear the brunt of your strength against the nut. For instance, say you're looking straight at a nut, and you want to turn it counter clockwise. You'd hold the adjustable wrench so the fixed jaw was on the right, and hooked under the nut. The adjustable jaw snugs against the left of the nut. That way when you turn the wrench counter clockwise, the fixed jaw takes the "strength" on three sides to the nut. The adjustable jaw just keeps the wrench from falling off. Hope I explained that well- and I hope the fittings break free okay for ya.

And remember that brake fluid eats paint... use lots of old rags.. paper towels and old tshirts are better than newspaper; newspaper tends to let the brake fluid "puddle" instead of soaking it up. I'd put newspaper down first, then put paper towels/tshirts/towels down over top of the newspaper.

If you -can-... at the Pep Boys near me, I found their pre-flared brake lines. (They were hidden in the back, and I probably was in a staff-only area, but hey, screw it.) I grabbed lines from the "import/foreign" rack - apparently Pep Boys didn't know that GM used metric fittings since '84 - that fit the m/c. Then I took 'em home... I'd screw them into the m/c. I used my tubing bender to bend them back up into the m/c reservoir. That way, no fluid dripping out.

I did the same for the prop valve, too.

Yes, you keep the same master cylinder, and change the prop valve. The master cylinder is definately the same between both systems, and the prop valve definately differs. Changing the prop valve is the "right" way to do the swap. It might work otherwise, but it won't be the "factory" setup.

 

Thanks for the help guys, changed it this morning. Left the mc full and the cap on, only dripped 2-3 times. Going to bleed it now, and see if I can still stop.