Bench bleeding MC with plugs

[ksagis]

Question for the brake experts, when bench bleeding a MC with the plug approach, how little of a stroke indicates its fully bled?

For example, is 1/8 to 1/4” of stroke expected when applying maybe 35 to 50 lbs of pressure to piston?

 

[toddz69]

It's been awhile since I've done it, but I think I usually get almost no stroke, like 1/16" or less when its fully bled. @Apogee can give a better answer.

Todd Z.

 

[Broncobowsher]

No, that is an air bubble being compressed. It should be near rock solid. Tiny stroke as the pistons cross over the transfer ports.
Typically bench bleeding isn't done with plugs. It is done with bleed lines looped back into the reservoir. Move the fluid, and air bubbles until they are worked out.

 

[DirtDonk]

I agree, and that’s how I’ve always done it. However, there are several members here, who swear by the plug method.

 

[bronco italiano]

Has anyone tried the "reverse bleeding tool". I bought one and have yet to try it.

 

[toddz69]

Has anyone tried the "reverse bleeding tool". I bought one and have yet to try it.

Is that the one that looks like a big syringe? I have one but haven't tried it yet either.

Todd Z.

 

[ksagis]

How long does one generally need to stroke it (no jokes…)

I’ve probably been doing it for 30 minutes and still have about 3/16” of stroke before it stops. But I didn’t tighen the plugs super tight for concerns of liberating plastic in the threads. They might be leaking some air.

 

[toddz69]

How long does one generally need to stroke it (no jokes…)

I’ve probably been doing it for 30 minutes and still have about 3/16” of stroke before it stops. But I didn’t tighen the plugs super tight for concerns of liberating plastic in the threads. They might be leaking some air.

That's one reason I like the plug method - I usually get results quickly - usually done in a minute or two, whereas the looping the lines back into the master goes on and on and on...

Todd Z.

 

[DirtDonk]

I remember the old days. When parts were more cooperative…
Never had bench bleeding take more than a few strokes.

But hey, that’s just a personal problem…

 

[73azbronco]

so the method of using lines back into master cylinder, no plugs needed, not a thing anymore?

 

[DirtDonk]

Yeah, it’s still a thing. Just that there are different schools of thought. Some use one method, some use others, some use both.

 

[ba123]

I did the lines regular method (with the lines into the res and worked great. I don't know the plug method. I generally believe in doing things as the manufacturer says to in things like this cause it works. I feel like if there were a better way they would tell you to do it that way. No joke.

The lines to the res method makes sense to me. I like to SEE progress and watch those bubbles go away, but they both should work.

 

[ba123]

Has anyone tried the "reverse bleeding tool". I bought one and have yet to try it.

There is someone on here that likes reverse bleeding, don't remember who, but I don't like the idea off putting fluid at the exit end of my lines. Seems wrong and seems like it would increase the chances of contamination. . My view is that's the dirty end. Like eating out of your rear, I wouldn't do it. Food goes in the clean side.

Sorry, bad visual, I know. I'm a germophobe.

In addition to that, you need to add fluid at FOUR different points instead of just one. My way, with the motive bleeder, you make ONE single connection, never disconnect, fluid and everything clean, it all goes out with one single pressurization and done withing a few minutes and perfect.

Why try to change something that works so well? Maybe a little work to set it up just right how I did it, but worth the effort. @bronco italiano I'm happy to help if you need it.

 

[Soylent]

There is someone on here that likes reverse bleeding, don't remember who, but I don't like the idea off putting fluid at the exit end of my lines. Seems wrong and seems like it would increase the chances of contamination. . My view is that's the dirty end. Like eating out of your rear, I wouldn't do it. Food goes in the clean side.

Sorry, bad visual, I know. I'm a germophobe.

In addition to that, you need to add fluid at FOUR different points instead of just one. My way, with the motive bleeder, you make ONE single connection, never disconnect, fluid and everything clean, it all goes out with one single pressurization and done withing a few minutes and perfect.

Why try to change something that works so well? Maybe a little work to set it up just right how I did it, but worth the effort. @bronco italiano I'm happy to help if you need it.

I have the Motive system with the plate for the Wilwood master. To be clear, you are bleeding one corner at a time starting at rear passenger. Not bleeding all four corners at the same time right?

 

[cldonley]

Has anyone tried the "reverse bleeding tool". I bought one and have yet to try it.

I've used that method on airplanes with a lot of success. Never really tried it on a regular motorized vehicle.

There is someone on here that likes reverse bleeding, don't remember who, but I don't like the idea off putting fluid at the exit end of my lines. Seems wrong and seems like it would increase the chances of contamination. . My view is that's the dirty end. Like eating out of your rear, I wouldn't do it. Food goes in the clean side.

Sorry, bad visual, I know. I'm a germophobe.

In addition to that, you need to add fluid at FOUR different points instead of just one. My way, with the motive bleeder, you make ONE single connection, never disconnect, fluid and everything clean, it all goes out with one single pressurization and done withing a few minutes and perfect.

Why try to change something that works so well? Maybe a little work to set it up just right how I did it, but worth the effort. @bronco italiano I'm happy to help if you need it.

If you purge the fittings a bit before bleeding, you don't have to worry about debris getting into the system.

Matco makes a system that uses pressure across the bleeder valve using a compressor that draws fluid through the brakes without pumping. Works well, you can do it without a helper and you don't have to worry about the whole back bleeding contaminating the system. Just gotta make sure you don't run the master cylinder dry. https://www.matcotools.com/catalog/...der-vacuum-800ml?referer=ZVNlZ21lbnRfMTQ0NjU4

 

[ba123]

I have the Motive system with the plate for the Wilwood master. To be clear, you are bleeding one corner at a time starting at rear passenger. Not bleeding all four corners at the same time right?

I bought the motive plate and didn’t like how it looked like it would work so I sent it back. I bought a replacement willwood cover, which has two breather holes to allow air in so the gasket can go down and take up the empty space.

I drilled and tapped one to fit an air hose quick connect, and the other side I drilled and tapped and put a plug.

I cut all but the outer part of the gasket so it just seals the outer ring.

I put a quick connect fitting on my kotive hose.

And yes, I just do one wheel at a time, but you only need to pump to like 20lbs one time for a completely dry system. Let to e air out at the pass rear, then drivers rear, then pass front, then drivers front. Then done.

I did write some on my build thread page 4 or 5.

 

[73azbronco]

I have a reverse bleeder, use it on GMC, BMW, Jeep, one vehicle it does not work for me? an EB. Don't know why, but I do get to spend more time with the wife as brake pusher, while I bleed each corner.

 

[fluffybunny]

Has anyone tried the "reverse bleeding tool". I bought one and have yet to try it.

I used one (syringe type). You need to make sure that you have a good seal around the port or brake fluid will squirt out of the sides and make a mess. It works but I went back to the kit that loops back into the m/c.

 

[EPB72]

I've used that method on airplanes with a lot of success. Never really tried it on a regular motorized vehicle.

If you purge the fittings a bit before bleeding, you don't have to worry about debris getting into the system.

Matco makes a system that uses pressure across the bleeder valve using a compressor that draws fluid through the brakes without pumping. Works well, you can do it without a helper and you don't have to worry about the whole back bleeding contaminating the system. Just gotta make sure you don't run the master cylinder dry. https://www.matcotools.com/catalog/...der-vacuum-800ml?referer=ZVNlZ21lbnRfMTQ0NjU4

For the last 10 years or so for bench bleeding a MC the syringe and modified plug method is my go to, but all methods mentioned can work...... Mount MC in vise with a catch pan fill MC with clean fluid, Fill the syringe from one of the res. remove any air from syringe inject slowly in the port .{ you will see the air turn to a steady stream of brake fluid in MC res}once or twice for each port is all it takes ,,, then I plug both ports with my thumb and middle finger and cycle the piston ,usually its good to go but if the piston moves more then a 1/16 then I let some fluid escape past my fingers and reseal ports while releasing the piston,95% this all it takes......My experience with the tube method and the janky plastic fittings is the fitting can sometimes allow air to be sucked in and you sit there cycling the piston and see air bubbles indefinitely .. ..I have the vacuum bleeder mentioned they work but with caution, they can actually pull air into the system { usually at the wheel cylinders} , so if using to exchange fluid and then fallow with manual bleeding maybe necessary.. I'll add that if bench bleeding a new MC cylinder and you can't get the results on the bench .. It can and does happen that you just got a defective MC ..

 

[DirtDonk]

Yeah, the plastic stuff is really junky. And unlike many of the things we deal with today, it has been for more than 40 years!
You need to either be very lucky, finicky or clever, or just make your own from hard fittings and tubing.

Paul