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Brake bleeding / dummy light update

CopperBronco

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Aug 13, 2021
Messages
389
I replaced my leaking prop valve and bled my brakes for the first time ever… a little hesitant as a newbie but a few remaining questions. How much fluid should go in my master cylinder? There is no max fill line, see photos of it after I filled it.

What’s the best way besides the brake pedal feel to make sure I got all the air out? I’d love some diagnostic tips and tricks.

Lastly, the rubber on my Motive power bleeder seal that attaches to the Master Cylinder turned blueish in color and left a little residual in my master cylinder. Should this be concerning? All new at this and don’t want to get brakes wrong :)

Thanks!
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DirtDonk

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Your level looks fine. Could even get it a little closer to the top, but frankly that would probably just lead to more leaking out the gasket over time! Really though, it looks good from here.
As for that gunk that got in? NOPE! I can't see it, but you really don't want anything in the brake system but nice clean fluid. In most cases something getting in does not do any harm or cause any trouble down the line. But I don't know enough of your material to know. So I worry...

Is the "blue" stuff that got into the master just a dyed liquid mixing with the fluid? Or is it hard material? If liquid, I'm guessing it's not a problem other than reducing the temp rating of the fluid or whatever. If a new unit that's strange. Might check the instructions to see if they say anything about it. If it's an older used model, could it be just some different colored brake fluid from the previous use?

As far as using the pedal to feel, the answer is basically yes. Of course the first line of defense is to stop seeing bubbles coming out from the other end. But a full firm pedal is really a good sign and the one most used by most.
Did you also tap all the hard lines up by the master, and the master itself (and new valve) with something hard like the side of a wrench, to dislodge any stuck air bubbles that would then work their way up and out of the master?
It's just something I've always done after bleeding and have almost always gotten one or two little bubbles purging out the master reservoir.

Paul
 
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CopperBronco

Sr. Member
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Aug 13, 2021
Messages
389
Your level looks fine. Could even get it a little closer to the top, but frankly that would probably just lead to more leaking out the gasket over time! Really though, it looks good from here.
As for that gunk that got in? NOPE! I can't see it, but you really don't want anything in the brake system but nice clean fluid. In most cases something getting in does not do any harm or cause any trouble down the line. But I don't know enough of your material to know. So I worry...

Is the "blue" stuff that got into the master just a dyed liquid mixing with the fluid? Or is it hard material? If liquid, I'm guessing it's not a problem other than reducing the temp rating of the fluid or whatever. If a new unit that's strange. Might check the instructions to see if they say anything about it. If it's an older used model, could it be just some different colored brake fluid from the previous use?

As far as using the pedal to feel, the answer is basically yes. Of course the first line of defense is to stop seeing bubbles coming out from the other end. But a full firm pedal is really a good sign and the one most used by most.
Did you also tap all the hard lines up by the master, and the master itself (and new valve) with something hard like the side of a wrench, to dislodge any stuck air bubbles that would then work their way up and out of the master?
It's just something I've always done after bleeding and have almost always gotten one or two little bubbles purging out the master reservoir.

Paul
Thanks Paul, the blue I discovered was something off the packaging of the motive bleeder, it was brand new, looks greenish in color, but very little got in. So not too worried… maybe some sort of packaging grease or lube? No idea…

As for watching air bubbles leave the bleeders down by the tires / calipers, my connection wasn’t great so air bubbles were leaking in from the connection, but I also had about 15 PSI coming from the master cylinder… I know all the dirty stuff came out, brake fluid was black when I discovered it from PO… but not anymore :)

Thanks for tip on tapping the lines, hadn’t done that.
 
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CopperBronco

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One other question, got it all put together and all seems to be good after test drive except looks like I have a leak coming out of lid of the Master Cylinder… it has the wire clamp and goes on super tight, so kind of confused as to why it’s leaking… any ideas anyone?

Do I have air bubbles in front brake lines causing it shoot around when I apply the brakes? Or do these seals just fail over time? Couldn’t see this leak before although it could have been there, had a decent fluid leak and parts were super dirty… easy to see now though. Any advice much appreciated.
 

m_m70

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Or do these seals just fail over time?
everything will fail over time............LOL

Seriously though, the top of your master cylinder (where your seal mates to) looks pretty corroded/dirty/not flat anymore/etc.. I would try to get that cleaned up and back to flat being very careful not to get any debris in the cylinder.
 

DirtDonk

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Black fluid is good. Once it's out of the system and in the bin! Glad you got it flushed out. Sure wasn't doing your parts any good.

Those things leak unfortunately. Lots of discussions about it over the years, but I admit I don't remember reading any for a couple of years now. Some people have resorted to a big screw-clamp (or two) wrapped around the lid and the body of the master to put more tension on it.
You can bend the wire bail if yours is the least bit loose, but that is rarely a fix unless your leak is absolutely minimal. If you're seeing leakage after just a few applications however, it's more than minimal.
Do what was suggested and clean the rim up a bit. And post a pic of the rubber seal/boot thingy too. Maybe it's past it finally.
How hard is the bail to snap into the grooves?

Oh, and yes sometimes air in the system makes the fluid geyser squirt higher than normal. But you'd also likely have a squishy pedal as well.
Most, but not all master cylinders and brake systems give a little bit of a burble into the reservoir. Sometimes when you press the pedal, but most often when you let back up. In some cases it will literally splash out of the master. Usually though it takes the form of a kind of "mound" pumping up in the fluid.
If it's minimal it's nothing to worry about I've found.

Paul
 

Steve83

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Jul 16, 2003
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Memphis, TN, USA, Earth, Milky Way
...looks like I have a leak coming out of lid of the Master Cylinder.
Remove, disassemble, clean, & dry the cover & diaphragm; inspect the rubber & cast iron for gouges/cuts/damage; fill the fluid in the reservoir nearly to the top edge; reinstall the cover, and pinpoint the leak (if it's still present).

I prefer to reverse-bleed all brakes, as explained on this page:

(click this text)


This page shows the last eB brake job I did:

(click this text)
 

DirtDonk

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Any use of speed bleeders? About to do brakes on mine.
Like the idea, but never had any luck with them. Probably did not use them correctly or something. Not very high-tech, so not exactly sure what I could have done wrong, but it was a bit of a pain.
Part of it was air leaking in past the threads when I got them loosened up. Must be a very fine line between too loose and just right.

That said, I bought another pair recently just because I don't find willing slave... uh I mean partners to push the pedal very regularly.
This is a new kid on the block though, and looks slick: https://www.fenderlizard.com/
Even at $219, it seems like a decent bang for the buck. Not a cheapie tool, but I bet it gets the job done. Watched it in action on Motorhead Garage this weekend.

Speaking of which... Alex Borla passed away last month. Not a lot of Broncos sporting Borla exhaust, but he was a big name in the auto industry anyway.

Paul
 

Rustytruck

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Messages
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The cap bail wire must be very hard to push over to seal. you can tweek it some to add tension. remove the cap and look at the impression in the gasket look at the impression on the gasket leak prone areas with show if your getting good compression I have had to tweek some caps to get them to seal. use to be able to buy the Caps and gaskets at the auto parts in the Help product line. when working on you master cylinder put some foil on the wheel well to catch spilled fluid so you dont ruin your paint. foil makes a good catch because it is easily formed around obstructions. I place a paper towel on top of the foil.

I use a motive pump bleeder and a shuttle valve block tool because I have no helpers.


 

ntsqd

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Ideally you flush your brake system every two years to replace the old fluid with new. Knowing it and doing it are two different things! ;)

This is my infamous "peanut butter bleeder" system. Looks like this:
i-vkhjmHD.jpg


Those are 1/8" copper tubes J-B Weld Puttied into the cap. One tube goes nearly to the bottom of the jar and the other you can see where it stops. The long tube gets a section of vacuum hose long enough to reach the highest bleeder while sitting on the ground. The short tube gets the rest of the spool of vacuum hose.

This jar can be used two ways; if you hook the short hose to bleeder just barely cracked open and you put enough brake fluid in the jar to cover the end of the long tube, then you can slowly (!!!) push the brake pedal by hand while watching for bubbles. The fluid above the end of the long tube means that no air will be pulled back into the brake system on the return stroke of the pedal.

The second way that you can use this is to connect that long hose to manifold vacuum, and connect the short hose as above. Start the warm engine and crack the bleeder. No more pedal pumping or hand vacuum pumps! Credit MISF for this one.

One thing to know, manifold vacuum is strong enough to pull air past the bleeder's threads making it look like you're never going to get the air out of the system. I usually remove them and pack the threads with brake system assembly lube (can get it from amazon if your LAPS has no idea what you're asking for) or with dielectric silicone grease. If you use the dielectric grease you need to be very careful to not get any where it can get into the system, AND there is no substitute grease. Using any other type of grease is an exceedingly BAD idea. Petroleum products of any type are not compatible with a brake system's rubber parts.
 

.94 OR

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Is there any type of swivel union that could be used adjacent to the bleeder valve? I have a piece of clear tubing that fits over the bleeder nipple and runs into a clear plastic soda bottle that I use to catch the fluid, but with enough twists it pops off the bleeder. I'd love to have a swivel of some sort so it would stay on better.
 
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CopperBronco

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Aug 13, 2021
Messages
389
The cap bail wire must be very hard to push over to seal. you can tweek it some to add tension. remove the cap and look at the impression in the gasket look at the impression on the gasket leak prone areas with show if your getting good compression I have had to tweek some caps to get them to seal. use to be able to buy the Caps and gaskets at the auto parts in the Help product line. when working on you master cylinder put some foil on the wheel well to catch spilled fluid so you dont ruin your paint. foil makes a good catch because it is easily formed around obstructions. I place a paper towel on top of the foil.

I use a motive pump bleeder and a shuttle valve block tool because I have no helpers.

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This is what I bought, worked nicely. And thanks for tips, I cleaned up edges and installed new MC rubber piece and no leaks so far! One other question, since front and rear brakes are separate systems, you can bleed them separately, no? I keep reading start at rear passenger, to rear driver to front pass to front driver. But if I think I have air just in fronts I could bleed those separately, no? Or when you re-bleed you have to do all of them?
 
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OP
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CopperBronco

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Like the idea, but never had any luck with them. Probably did not use them correctly or something. Not very high-tech, so not exactly sure what I could have done wrong, but it was a bit of a pain.
Part of it was air leaking in past the threads when I got them loosened up. Must be a very fine line between too loose and just right.

That said, I bought another pair recently just because I don't find willing slave... uh I mean partners to push the pedal very regularly.
This is a new kid on the block though, and looks slick: https://www.fenderlizard.com/
Even at $219, it seems like a decent bang for the buck. Not a cheapie tool, but I bet it gets the job done. Watched it in action on Motorhead Garage this weekend.

Speaking of which... Alex Borla passed away last month. Not a lot of Broncos sporting Borla exhaust, but he was a big name in the auto industry anyway.

Paul
Thanks Paul, I actually just put in JD headers and dual exhaust. I put in Borla mufflers because they’re quieter and my Bronco is just rhino lined and no insulation, almost deafening going down the freeway, didn’t need Flowmasters adding to the problem, although still tempting :)
 

DirtDonk

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The whole “starting at the furthest point“ aspect is for major bleeding only. If you have air suspected in only one corner, or if you work on just that one corner, you can bleed just that one corner.
 

DirtDonk

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And I just made a major improvement to the noise level inside my bronco two days ago. I used specialty under coatings on the outside of all of the panels that are part of the interior. From the rear floor pan especially rear wheel wells, to the rest of the floor pan and especially the front foot wells and lower portion of the firewall. Very noticeable difference.
I’d almost say a HUGE difference, but I’d probably be exaggerating slightly. 😉😁
Still, very happy with the results.

As I mentioned in another thread I’m a big fan of seeing body color in those areas when I crawl underneath. I like blue wheel wells and floor pans in my case. But I had to have more sound deadening and I don’t have the interior done yet. So black it is!

Much easier for those with their bodies and other stuff still separated. But I made the best I could with everything assembled. About the only areas I was not able to to get very well were the back floor pan under the gas tank and the full transmission tunnel because of my big transmission.
Well worth the effort though.
 

Rustytruck

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Feb 24, 2002
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Is there any type of swivel union that could be used adjacent to the bleeder valve? I have a piece of clear tubing that fits over the bleeder nipple and runs into a clear plastic soda bottle that I use to catch the fluid, but with enough twists it pops off the bleeder. I'd love to have a swivel of some sort so it would stay on better.
zip tie the hose
 
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CopperBronco

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And I just made a major improvement to the noise level inside my bronco two days ago. I used specialty under coatings on the outside of all of the panels that are part of the interior. From the rear floor pan especially rear wheel wells, to the rest of the floor pan and especially the front foot wells and lower portion of the firewall. Very noticeable difference.
I’d almost say a HUGE difference, but I’d probably be exaggerating slightly. 😉😁
Still, very happy with the results.

As I mentioned in another thread I’m a big fan of seeing body color in those areas when I crawl underneath. I like blue wheel wells and floor pans in my case. But I had to have more sound deadening and I don’t have the interior done yet. So black it is!

Much easier for those with their bodies and other stuff still separated. But I made the best I could with everything assembled. About the only areas I was not able to to get very well were the back floor pan under the gas tank and the full transmission tunnel because of my big transmission.
Well worth the effort though.
That sounds like a lot of work. Did you strip it and then spray? Curious what coating you used? I was thinking of cleaning up surface rust with wire brush, then a fast etch rust eater/ paint prep spray, and then some sort of coating. Mine has some old coating on it, but it’s old. I’m waiting til things warm up so I don’t have to have it in the garage and fumigate my children with rubberized undercoating. I was experimenting with rust bullets Low VOC coating, expensive, but fumes were nothing like 3Ms rubberized undercoating.
 

DirtDonk

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Not much work the way I did it. It’s still messy, but I probably spent all of 45 minutes doing the whole job.
That’s why I mentioned it’s great if your body is already separated from the other junk, but mine’s all assembled so I just took a little time and sprayed it where I could.

I did make a mistake though, in that since I was in a rush to do it in a small open window of time that I had, I forgot to lay some plastic or cardboard over the exhaust tubing! Yes, it smells pretty bad when it’s burning. :)😱

Rather than lay cardboard or plastic down on the driveway, because I knew it would probably get a little messy, I parked on the street where a little spotting of rubber and tar would be mostly hidden if it dripped. Glad I wore gloves and glasses.
Should’ve worn coveralls though…😩

I used three different brands, so I can’t really say that one is better at sound deadening than the other, or if one is a thermal barrier and another is not. But they all three sprayed differently.

I had an old can of Bondo brand and sprayed easily and smoothly more like paint than undercoating. Very little mess.
I recently bought a Rustoleum can because in the text it said good for sound deadening. It sprayed on with more texture, but not quite as thick as I remember under coating being 30 years ago.
More recently I bought three cans of Boom Mat brand specifically, as you can imagine, because of the name and what it claims to be. It probably is the best of the three, but is also by far the messiest to do on your back to an already assembled vehicle. very liquidy and splatters a lot, and also builds up around the nozzle so if you don’t have gloves on your hands will be black.

Driving it again today extensively I would have to say I probably dropped about 25% in temperature through the floor and 50% of sound transmission.
My front floors are mostly bare with just the remnants of an old one piece floor mat remaining. The entire interior is done in rhino (sorry, Raptor) liner color matched to the body. It’s a great covering, but in spite of its mass does not dampen sound very effectively. Very surprising in fact. Either that or it would be unbelievably loud without it!
Soon I will have another layer of protection in the form of an underlayment of insulation along with either the full coverage sport mat or carpet.

If I was doing it to a body without all the stuff, I would probably use a higher end product such as lizard skin. Or like some do, make their own.
I’ve been a proponent of theirs for years and from all reports it seems to work as advertised. Works out to be quite a bit more expensive than just buying 10 cans of undercoating, but I would have to believe that their product is also way more effective.
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CopperBronco

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Got it, thanks! One other question, I installed a brake light warning switch in my 66 Bronco, just connected the one wire off prop valve pigtail to the purple wire on the dash light warning switch, and then the red wire out of the dash switch to the threaded end/bolt of key ignition. Is there any way to test/validate it’s working? Hard to test something that is meant to stay off. I had heard it should flash when you turnover the key like my turn signals do, but mine didn’t do that. I looked at wiring diagrams and I don’t think I have an emissions solenoid to junction with, and it looks like that junction goes back to ignition anyways, but also the alternator. Also original diagrams show two wires coming out of the switch on the prop valve, but the one I ordered from Toms only had one. I’m assuming if you have an OEM harness you’d just solve the one wire into the two on the factory harness, is that right? Diagram attached…

Also curious how it grounds, I was told the prop valve/ brake warning switch grounds through the frame or body near the prop valve itself, which mine is up on the driver fender grounds through the body, but I have an undercoating on the fender. So curious if that would cause it not to light up when I turn the key. I have solid grounds from body to frame, etc… Wondering if I need to splice in a ground wire somewhere?
 

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