98 v70GLT Front Caliper toast? Leak when depressing...

[TRuck]

....ugh. okay, thanks.
@ abscate; not questioning you, but so i understand...
here comes an ignorant question; how does air get to the left rear caliper when i did not take it off or open it up? air travels through entire system that fast from the front?

[abscate]

In theory, it shouldn't. In practice, it might. If you can't bleed the rest of the system, then you have air somewhere, and the 'one you can't crack' is the best bet. If you can't crack the bleed valve, you might be able to bleed it by cracking the brake hose and spewing brake fluid out onto the Wall Street Journal, new edition, thereby actually bringing value to this new 'paper'


That being said, after all the admonishments that you have to have two people to bleed brakes, I often successfully bleed them by setting the bleeder just tight enough for pressure to be built in the the circuit, running the hose up into the strut spring so that the air doesn't go back into the system, and then just quickly depressing the pedal, then s-l-o-w-l-y releasing it.Im done this on Volvo, BMW, VW and trailer brakes. If i get a spongy pedal, I call the boss and we have a marital bleeding session.

Im a scientist, so I don't mind being questioned, btw.

[TRuck]

so when you "hang" the hose in the strut spring you also have something there catching the fluid?

When using this vacuum bleeder (and it happened back when i did the two person method) the tube from bleeder valve to the "catch can" never gets the bleeder hose entirely full of fluid from caliper to catch can. The fluid is flowing obviously, but there tends to be only half the hose solid/full of fluid OR it is at both ends...near caliper & near catch can. Do I need to elevate bleeder tube?
At times I get little bubbles in the tube....i kept bleeding it until they disappeared. but never had the hose completely fluid from one end to the other.

[rmmagow]

Motive Pressure Bleeder or co-operative other has been the only way I've gotten a good bleed. The vacuum method never worked well for me. Speed bleeders are supposed to work ok, but I don't trust them either.

[dosbricks]

Yes, better to have some upward loop in the bleed hose so air bubbles travel up before the fluid drops into a catch can. Also, just crack the bleed valve a little bit--don't open it one or two revolutions which could allow air to be drawn past the threads via the venturi effect--something that might be exacerbated with a vacuum bleeder.

[abscate]

You can open it wide to push all the dark, old fluid out...but once you are really bleeding out air, it just needs to be open a few half turns like dosbricks says.

[Roadrunner]

In changing the brake pistons, (calipers) I have had some luck in just filling them with a hand oil pump.
Then bleeding the rest of the air out. In pumping the pedal I have heard that it can cause more problems because the end of the slide is now corroded because of lack of use. If you do know how one can make a pressure pump using simple garden parts for your car. This way just open the bleed value and watch for the fluid. I will re-find that how to make a home made presser brake pump then I will re post.



Cheers

PS is it me or are other folks being dropped and requiring to log in again to post or change a search?

[TRuck]

thx much guyz.
will be a day or two before i can look at this rear bleeder, and then try again.
perhaps I was opening bleeder too far...about 1/2- 3/4 revolution. And will try with tube going up.

@rmmagow did you get yours sorted out?
thanks

[Ozark Lee]

I normally modulate the bleeder screw from open to closed as I use the Mityvac. Open as I squeeze the trigger and closed when I release it just to make sure that I keep a fairly uniform vacuum on the brake fluid as I suck it out. The bleeder screw only takes about 1/4 turn to do its job. As far as technique goes I use a small boxed end wrench that I put on the bleeder screw before I hook up the hose. That way it stays in place and I don't have to fiddle with trying to line it up every time.

...Lee

[rmmagow]

My brake grief is going to need to see a mechanic perhaps. I ordered new hard lines but I also ordered a set of gearwrench flare wrenches and will give it one more shot. The hard lines may actually be easy to do, I haven't looked closely at the routing. I got pretty annoyed getting beat by a little job but the car is 16 years old so I guess there's always going to be something burning me.