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Old 11-12-2019, 08:06 PM   #1
Mini-Skoolie
 
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Brakes...What am I missing?

Just replaced all hard brake lines(hydraulic ), bleeding them now and having a heck of a time. Not my first rodeo on brakes over the years, just seems weird that I cant get the air out. working on a pressure bleeder system now. see how that goes.

Any words of wisdom?

Russ
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Old 11-12-2019, 08:20 PM   #2
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Make sure all your flared connections are seated properly and hold pressure.

Start with the cylinder furthest from the master cylinder.

Get a piece of tubing that fits snugly on the zurk fitting. Get a jelly jar and put some clean brake fluid in it. Connect the hose to the zurk fitting and put the other end in the brake fluid.

Confirm the reservoir if at the full mark and replace the cap.

Have someone pump up the brakes and then hold the pedal to the floor. Crack the zurk fitting to let out any air. Repeat until no air comes out, making sure to keep the reservoir full.

Move on to the next farthest cylinder from the master. And so on.
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Old 11-12-2019, 08:38 PM   #3
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After replacing all hard lines I like to fill the fluid, leave the cap off, and open the right rear bleeder first. I wait until I see fluid running out, close it, and go to left rear. Repeat for right front and left front. With the engine off and someone stepping on the brake you should hear the electric brake pump running. With a bleeder open this should easily push fluid through the system with no pumping at all.

At 6:27 in this video you see me bleeding a hydraulic brake system and can hear the pump running as the pedal is stepped on........

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Old 11-12-2019, 10:02 PM   #4
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Basically what we have been doing, starting in back and bleeding each wheel. couple 3 times, and still a squishing brake peddle and warning buzzer and light.

The last time bleeding, couldnt see or hear any air out the bleeders, thought we were good to go. nope! still squishy and warnings. blehhhh. Gonna check all fittings again, (didnt see any leakage before), extra close this time to see if we are sucking in air.

Theres nothing special about the electric boost is there, nothing to bleed there right?

I have an idea about pressuring the fluid tank, low pressure, to get a constant flow and pressure in the lines.

Oh, didnt use any glass jar to see any minute air bubbles, will try that tomorrow also.

Of course all this in balmy Wisconsin!

Thanks
Russ
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Old 11-13-2019, 08:25 AM   #5
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What kind of brake booster does it have hydra max?
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Old 11-13-2019, 09:42 AM   #6
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Not sure of the booster, other than its way newer then the bus. all the hoses off the booster are fresh and clean. Bought the bus like that.

Any way I could tell what booster I have, pretty tucked up along the floor and beams.
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Old 11-13-2019, 10:35 AM   #7
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I had a similar problem last when I changed my hydromax booster and the master cylinder I had apparently lost the two little valve springs between the master cylinder and the resivore and so it was not building any pressure to bleed the brakes I had tried vacuums and pressure bleeding to no avail
Also sometimes when you lose fluid it gets an air bubble in the antilock brake motor and you have to pressure bleed it out . I've never actually had this happen but I've been told so from multiple sources
Another thing is to be sure and bench bleed the master cylinder
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Old 11-13-2019, 01:17 PM   #8
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Been looking up pressure bleeding, think im going to try that, low psi compressor connected to reservoir cap. That should give me a slow steady fluid flow, taking those nasty bubbles out with it.

Im assuming that this will bleed out the master cylinder also?
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Old 11-13-2019, 01:30 PM   #9
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Quote:
Originally Posted by Danjo View Post
Make sure all your flared connections are seated properly and hold pressure.

Start with the cylinder furthest from the master cylinder.

Get a piece of tubing that fits snugly on the zurk fitting. Get a jelly jar and put some clean brake fluid in it. Connect the hose to the zurk fitting and put the other end in the brake fluid.

Confirm the reservoir if at the full mark and replace the cap.

Have someone pump up the brakes and then hold the pedal to the floor. Crack the zurk fitting to let out any air. Repeat until no air comes out, making sure to keep the reservoir full.

Move on to the next farthest cylinder from the master. And so on.
They are bleeder valves, zerk fittings are for supplying grease to joints.
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Old 11-13-2019, 07:20 PM   #10
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another old school idea that after no luck i have used is to gravity bleed?
let the system bleed itself at least at the calipers.
fill the master with fluid and open the back bleeders a little and let them leak without touching the brake peddle then close them and top off the fluid and open the front two bleeder valves and let them leak.
of course you can put a hose into a jug to collect the leaking brake fluid at each cylinder.
you can put the cap over the master cylinder to try to keep dirt out of it but if trying the gravity drain then it cannot be sealed or it will create a vaccum where the fluid doesnt drain.
as a fluid that is heavier than air the fluid sinks to the lowest points and the air bubbles rises to the master cylinder which is the top of the brake system.
if that doesnt do it and have a new booster then i can almost say you have a bad vaccum line to your brake booster.
the only other idea could be with a new booster is that the installer didnt check pushrod length and adjust or change the new to match the original.
you said you havent noticed any leaks?
so the rest are guesses? good luck
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Old 11-14-2019, 11:15 PM   #11
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Got some work done today, 30 degs outside so tee shirt weather! Got my cap adapter to pressurized the system to 10-15 psi, worked great. Started out close to the master cylinder wheel bleeder, massive air pushed out. Then went on to bleed normally, far back wheel, next back wheel, etc.... No air. Checked all my connections for drips again, nothing.

Sooooooo still a soft peddle to the floor and brake warning light and buzzer. Im thinking the master cylinder is malfunctioning, o-ring or something. Will pull it off and find a replacement somewhere. Any tips on installing this creature?

Jolly? mentioned something about vacuum line, with the electric pump, is there one? never looked. Also, new master cylinder push rod length? not a clue about that.
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Old 11-18-2019, 05:17 PM   #12
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Update and a oh **** question!

Well, seems to be working, did a pressure bleed and got good peddle and no warnings.

However, I found a way to text the master cylinder, take off the brake lines and plug them at the master cylinder, hard peddle, no warnings test, good to go.

My oh **** moment, reconnecting the hard lines to the hoses, then to master cylinder, I cant remember which goes where, front brakes to what port on the master cylinder?
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Old 11-18-2019, 06:12 PM   #13
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hopefully someone with a tc2000 and hydraulic brakes will offer advice.
but can you post pics of your master cylinder and lines in place.
never seen one with rubber lines in between the master cylinder and the hard lines?
normally the hard lines are pointing you to there positions but that is not with soft lines in between?
pictures would help all of us help you.
have you checked wheel cylinders for leaks or the rubber lines that go from the hard lines from the master cylinder to each wheel cylinder?
to help first pictures of your master cylinder to help get the lines connected properly cause you didnt mark or identify them yourself before disconectting them and then if possible the inside tire under bus picture of the bottom of tire at each brake drum.
are you solo or do you have someone that is or could help?
hydraulic brakes can only be a one person show if you know everything about them and have the tools and equipment to do it.
help us help you
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Old 11-18-2019, 06:26 PM   #14
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Quote:
Originally Posted by russsh View Post
Update and a oh **** question!

Well, seems to be working, did a pressure bleed and got good peddle and no warnings.

However, I found a way to text the master cylinder, take off the brake lines and plug them at the master cylinder, hard peddle, no warnings test, good to go.

My oh **** moment, reconnecting the hard lines to the hoses, then to master cylinder, I cant remember which goes where, front brakes to what port on the master cylinder?
more from me?
well seems to be working with good peddle and no warning?
was the bus running?
master cylinder tested plugged with no lines attached?
was the engine running?
what did you do a pressure bleed on and its working without the lines attached assume the master cylinder with no lines attached but ports plugged.
did the brake pedal hold or slowly sink to the floor with the master cylinder plugged? was the engine running?
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Old 11-18-2019, 08:26 PM   #15
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Master cylinder is new-ish, was there when i bought the bus. The lines from the reservoir and lines to the hard lines are also new-ish. (see pic)

No leaks at wheels or connections. Just did a pressure bleed, good peddle and no warning lights or buzzer. no pics needed here.

just a brain fart after testing master cylinder, (took off hoses, put plugs in, isolated and tested master, worked as expected, very hard peddle no squishy),
If you look at the pic, my question is are the front and back lines right?
Attached Images
File Type: jpg Master Cylinder.jpg (196.1 KB, 10 views)
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Old 11-18-2019, 08:32 PM   #16
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Originally Posted by Jolly Roger bus 223 View Post
more from me?
well seems to be working with good peddle and no warning?
was the bus running?
master cylinder tested plugged with no lines attached?
was the engine running?
what did you do a pressure bleed on and its working without the lines attached assume the master cylinder with no lines attached but ports plugged.
did the brake pedal hold or slowly sink to the floor with the master cylinder plugged? was the engine running?
Bus tested off, and tested running. Pressure bleeding, modified cap to the resevoir, 15psi gave me flow out the bleeders, both off and running, the electric motor and hydro-stat pump both seem to be working.

Brake peddle is holding. The only question is the lines going to the master cylinder, which is front and back/
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Old 11-18-2019, 10:37 PM   #17
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Quote:
Originally Posted by russsh View Post
Master cylinder is new-ish, was there when i bought the bus. The lines from the reservoir and lines to the hard lines are also new-ish. (see pic)

No leaks at wheels or connections. Just did a pressure bleed, good peddle and no warning lights or buzzer. no pics needed here.

just a brain fart after testing master cylinder, (took off hoses, put plugs in, isolated and tested master, worked as expected, very hard peddle no squishy),
If you look at the pic, my question is are the front and back lines right?
Is this pic upside down?

My hydro system different looking -- 4 wheel disc, the front and rear discs are the same part.

I also have combination hard/flex lines coming from the m/c to the hardlines on the chassis -- I think this is to handle the vibration & chassis flex instead of using coiled hard line like you'd see on a p'up truck, or car.
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Old 11-18-2019, 10:52 PM   #18
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Pic is from bottom, the brake lines are coming out the side, the supply lines actually come off the top, if that makes sense lol
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Old 11-21-2019, 10:45 PM   #19
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All is well. Brakes are back in business, working as expected.

Thanks everyone for your help

Rus
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Old 11-21-2019, 11:00 PM   #20
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Pic is from bottom, the brake lines are coming out the side, the supply lines actually come off the top, if that makes sense lol
So your m/c has a remote reservoir?

Very different from my hydro-boost. Mines really just like a p'up truck's, but on steroids...
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