brake bleeding - proper procedure ?

[p7387]

hey guys
i replaced rotors, calipers and hoses on my 87 2wd, the front brake reservoir (larger one) drained down to empty during the process of the job, the rear brakes were not touched. now it is time to bleed the brakes. i did a search on "brake bleeding" and a detailed answer was given by "vile z" back in 1/07. never having done this before i am not sure about certain details. obviously the first step will be to fill the reservoir, but i am not sure if i will gravity bleed myself or use the two man pump and hold method.

gravity bleed ?
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>after the reservoir is filled do i need to put the top back on and depress the pedal a few times to push the fresh fluid to the new calipers and than remove the top and gravity bleed? or can i just fill the reservoir with fluid and let gravity feed the fluid to the new calipers?

>do both front calipers have to be gravity bled at the same time or do i do the passenger side first and than the driver

>MUST the clear hose used be suberged in fluid at all times or can it just drip into the container

two man pump and hold method ?
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>does the hose need to be submerged in fluid or can it just shoot out


regardless of which method is used
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>MUST the master cylinder or the bore be bled first?

>MUST all four wheels be bled even if only the front brakes were changed?

>does the fact that the brakes are "power" brakes have any affect on how things are done?
does anything "power" related have to be connected or disconnected during the process?

>what is the story with the possibility of the proportioning valve becoming upset and seeing the brake light come on when the the battery is hooked back up

Brakes are a serious issue so i just want to be crystal clear on proper procedure and sequence

thanks.

[Lt.Del]

you don't have to bleed all brakes if you just worked on front ones.  Get a partner and  have them pump the brakes and hold pressure on pedal while you loosen the farthest wheel bleed screw from the master cylinder---front right (passenger side).  After you tighten it back up, only then should your partner pump brakes again 3 or 4 times and hold again.  Loosen screw, tell partner to hold pressure on pedal.  tighten, repeat.  Keep an eye on the resevoir---don't let it run dry of fluid or you will be doing this again and again and again.

After 5 or 6 times, do the other side.

eventually there will be enough pressure on the pedal indicating all the air is out of the lines--the pedal should then seem firm.

the hose doesnt need to be submerged.  I just let it squirt out...can get messy, or just have some sawdust or rags laying around to absorb fluid.  Power brakes procedure is no different. You can have engine running when you do this if you wish for the power assist, but, i don't bother.

[low budget]

Here is what I use and have had great success with it.  It is also pretty cheap.  AutoZone carries these...

http://www.lislecorp.com/divisions/products/?product=66&division=1&category=1

[VileZambonie]

If you replace the master cylinder you need to bench bleed it before you install it. Pressure bleeding is the best method but requires special tools. The one man vacuum bleeding set up for a hand held vacuum pump is essentially a glorified gravity bleed. If you have an assistant that can keep pressure on the pedal while you operate the bleeder screws it will go much quicker. Make sure those rear brakes are clean and properly adjusted before you begin.

[bake74]

     As mentioned, I perfer the "2 man" bleed over the self bleeder kits, It seems I always have better results doing it the pump pedal and hold method. 

[zieg85]

What I would do is fill the master and open the front bleeders.  Loosely put the master lid back on.  Have someone slowly press the brake pedal to the floor but don't mash it, hold it and close both bleeders, let up the pedal and repeat.  If you don't mash it the proportioning valve shouldn't move.  When the air is out pump the pedal and then bleed the RF first.  I can't stress enough to not mashing the pedal to the floor.  Fill the master back up, lock the lid down and you should have a good pedal.  My $.02

[Dr_Snooz]

I always work alone, so I have to bleed alone. I'm also poor, so special tools and what-not are not an option. I use the clear plastic hose that came with my vacuum pump. I put it over the bleed bolt and then route it up over something before letting it drop into my catch pan. Loosen the bleeder bolt, pump until the fluid comes out clean and then re-tighten the bleeder. For whatever reason, routing the hose up will allow all escaping bubbles to go up and not be sucked back into the caliper/wheel cylinder. It works great for me. It's also in my price range.

[ToddN]

Great post and good timing as I will be doing this very soon.

[VileZambonie]

Zeig,

The problem with actuating the pedal with more than one bleeder open is you don't get the same volume and air can easily reamain trapped. You may never feel it in the pedal but when your brakes get hot and the brake fluid ages the result is moisture absorption in the fluid, lower boiling point a you could end up with brake fade or loss of braking in that circuit all together. If you're going to bleed them manually, do one at a time.

[zieg85]

Zeig,

The problem with actuating the pedal with more than one bleeder open is you don't get the same volume and air can easily reamain trapped. You may never feel it in the pedal but when your brakes get hot and the brake fluid ages the result is moisture absorption in the fluid, lower boiling point a you could end up with brake fade or loss of braking in that circuit all together. If you're going to bleed them manually, do one at a time.

Yes I know, what I described was to get the majority of the air out, then one at a time...as I mention RF above.

[Lt.Del]

working solo, i've bled brakes by myself many times.  I have different size pipes and such always laying around.  I'd pump the brakes.  Put a pipe up against the seat and brake pedal, get one with a very tight fit so when i relieve the pressure at the bleeder, the pipe, thanks to the cushion aspect of the front of the seat pushing down upon the pipe which in turn pushes down on the pedal, the pedal is forced down to a degree.  Tighten up the bleeder and repeat. It takes a little longer but it works.  I have to stress that the pipe, with much effort, can be lodged between the front of the bench seat and pedal in such a way that it will force the pedal down and keep enough pressure on the pedal as to not fall out of the place. Sometimes you have to place a rag on top of the pipe for two reasons, to keep tension and to protect the vinyl.  It works everytime for me.