PMB's method of brake bleeding Options

[tomh]

PMB has a tech tip on "gravity bleeding" your brakes. What it doesn't explain is the way to bleed a caliper with 2 bleeders.
Did I miss something or do just use only one of the bleeder ports.

[colingreene]

what do you mean two bleeder ports, two like my S calipers where its one on each side or like the rear early calipers with a top and bottom.
Only the top would need to be opened the bottoms are not used.

[tomh]

I have two on each, top and bottom.
So only use the top bleeder? What's the reason for two then?

[Breaker]

Bleed first from the top. Why the top bleeder? Because air is less dense than brake fluid, and it's easier to chase air out the top, it would just get stuck otherwise.

As for the bottom bleeder: when the circuit is bled, no air left, you can bleed the bottom, it's worth it, just take a look at the sludge that comes out from a car where the bottoms were not bled often. You can't get air out from there, but you can drain out old brake fluid, and you should.

[rgalla9146]

I have two on each, top and bottom.
So only use the top bleeder? What's the reason for two then?

....so the caliper can be used on either side of the car

[tomh]

Explained that way it does make sense.
I have never gravity blead brakes but it sounds easy and i got no helper so here i go.
Thanks for the help.
I'll BE BACK

[wndsrfr]

Explained that way it does make sense.
I have never gravity blead brakes but it sounds easy and i got no helper so here i go.
Thanks for the help.
I'll BE BACK

No affiliation, but take a hard look at "Speed Bleeders"....have to take them all the way out if gravity bleeding, but really really make fluid flushes quick and easy with one person. My track car gets fluid flush every 6 months, so I've btdt many times.

[bandjoey]

How do you use speed bleeders with one person. ?

[GregAmy]

How do you use speed bleeders with one person. ?

They have an internal check valve. Air and fluid goes out, but the check valve keeps air from coming back in. So you hook up the bottle, crack the bleeder quarter turn, then jump in the car and slowly cycle the brake pedal.

I used to use them on the race and street cars, but had limited success. I found that unless I put some kind of sealant on the threads (Teflon paste, for example) then air could get sucked in past the threads. In the end it's just easier for me to nicely ask the wife to work the pedal while I work the bleeders (plus it's a good excuse to take her out to dinner after at my fav gastropub).

[Rob-O]

Or a pressure bleeder. That way one person is sufficient and you don't have to worry about air past threads and what not. The pressure pot sits at the reservoir and pushes fluid through the system. You sit at the wheel and open the bleeder valve.

I have this one...

Basically you add brake fluid to the jug. Close jug. Then screw the cap onto the reservoir. Pump the handle a few times (I think 15psi IIRC). Not too much psi as you don't want to blow out any seals. Then sit at each wheel. This thing comes with a length of hose that you attach to the bleeder valve. fill a jar 1/4 of the way up with brake fluid. Put other end of hose in jar with brake fluid. Open bleeder valve. Bleeder device pushes air through the system, through the caliper and into the jar filled with brake fluid. This way you don't have air going back into the system. Pretty easy...

[GregAmy]

I've never had good luck with a pressure bleeder. Either makes a mess (almost always), over-fills or under-fills the reservoir, and leaves excess fluid in the tank that I'll either have to pour back in the can (don't like to do that) or toss it (don't like to do that).

The Wife Method works most excellently (and between race and street cars, mine and friends, I'm flushing something monthly) and my method comes with most excellent post-flush beer and food. (IMG:style_emoticons/default/wink.gif)

BTW, I've had decent success gravity-bleeding, but always feel compelled to follow up with a quick follow up regular-way.

Try different ways, see what works best for you.

[BillC]

I use the Motive Power Bleeder, but I use it "dry". I don't put any fluid in the bleeder, just use it as a pressurized air reservoir. Still does the same job, but no mess when you unscrew the cap. The only potential drawback is that you have to keep checking the car's reservoir and re-fill it before it runs low (same as with the Wife/Assistant method).

[80cap]

Does the Motive Power Bleeder cap fit 914 brake reservoir ?
Brian

[siverson]

> Does the Motive Power Bleeder cap fit 914 brake reservoir ?

Yes and that's what I use with no problems.

-Steve

[Eric_Shea]

Dual bleeders are a method of creating a caliper that can be used on multiple vehicles. The Opel GT used the same calipers as the 914 with a different handbrake angle. This allowed ATE to make one caliper that would fit multiple vehicles (left or right) and have one machining program for all. Rear calipers, as an example, cannot be used on either side of the car. The Opel would have them mounted behind the axle and the 914 in front of the axle... making 914 left calipers, Opel right calipers. (IMG:style_emoticons/default/huh.gif)

That said; bleed the "bottom bleeders" first just to make sure you have all of the residual air out of that passageway. It will only be a very small amount if any. Once that's done, you can basically close them off and forget about them. You really just have to open them up and let them drain a few seconds, then you're done with them.

We use the Motive Power Bleeder in the Coachwerks shop. I think it's the best way to get fluid past the pressure regulator etc.