TomP

Looks like I have to rebuild my master cylinder (check out the suspension board for that message!).. and I went through hell trying to bench-bleed the m/c when I swapped my rear drums for discs.

I'm thinking of picking up the Mityvac "Plus" (or special or ultra, or whatever) kit that lets you do everything... Eastwood wants $75 for it. I'm wondering though- is the mityvac worth it? How much else can I use it for? My car's fuel injected; I haven't worked on a carb'd car in a lonnng time (and probaby won't, from the looks of what my friends are buying now).

Plus, I'm still wondering about making my own pressure bleeder. The stock cap couldn't hold the pressure, but maybe if I made a steel cap... hm...

So should I drop the $75 bux or what?


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-Tom P (Hot rodded 1986 Firebird 2.8l)

lonsal

iTrader: (2)

The MightyVac is well built. But flush out the clear lines when done bleeding brake fluid and blow dry with compressed air. Mine clouded up a little. I'm very happy with mine. I paid about the same from LAPD (Los Angeles Performance Division) 877 THE LAPD, www.TheLAPD.com.

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90 RS Convertible
Owner: Top-Down Solutions
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TomP

Lon, thanks! Have you ever used it for anything besides the brake system? Also, how the heck does it attach to the m/c? The picture in the catalog shows a rectangular piece of plastic with two holes in it... I have no idea how the plastic glues to the master cylinder.

My "homemade pressure bleeder" was made with info from the internet- it was really slick; I got it to work directly on the brake lines. It was just a big bottle of brake fluid. In the cap, I put a quick-disconnect air compressor fitting, and a grommet with clear tubing coming out. When the bottle was pressurized (low psi, and running thru a water separator), brake fluid would come out of the vinyl hose. I had it attached to the line (from the m/c) for the rear brakes, and then to the front brakes, and it really moved all the old fluid out. I was impressed! (And at the time, it eliminated the possibility of "air in the lines or prop valve" as being my brake problem.)

I tried putting a hole in a spare m/c cap with a grommet, and pressurizing it, but the cap bowed outward in the center- brake fluid went everywhere. Too bad I was in the back of the car staring at the bleeder screw.. I finally heard the "drip drip drip drip" and found the garage floor covered with fluid under the m/c!

Anyway, I was thinking about attaching a metal plate to the top of the m/c, in place of a cap. I'd cut up a spare m/c cap gasket to seal the plate to the reservoir body. Then I think I'd hold the plate to the reservoir body (or wrap around the whole m/c body) with c-clamps, or maybe hose clamps, or mechanic's wire, or....

Does the Mityvac's reservoir plate hold itself in place because the Mityvac uses vaccuum?

Thanks...

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-Tom P (Hot rodded 1986 Firebird 2.8l)

greearhr

The miti vac is great for checking vacuum pots, EGR's, and bleeding brakes. I don't think you can blead the master cylinder with it though. You have to pump the piston in and out to open and close the ports.

Bear Tracks

TomP

So the Mityvac won't work directly on a m/c, then. I found out what that plastic plate's about...

Mityvac calls it their auto-fill system. Seems like it comes with two small black caps that fit over a brake fluid bottle. The plastic plate (with the holes in it) is fitted to one of these small black caps. I then think that the whole thing (fluid bottle, cap, plate) is inverted, and placed on top of the master cylinder. The caps must have a check-valve to allow fluid to drip out if a suction (vaccum) is present.

So does this mean any pressure bleeder won't bleed a master cylinder? Am I stuck with bench-bleeding the damn thing? What if, when I put the m/c rebuild kit in, I fill the bore with brake fluid? Would that assist in the bleeding procedure, or just make a mess?


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-Tom P (Hot rodded 1986 Firebird 2.8l)