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Cant get front brakes to bleed...

BIGCHEVYTRUCKDRIVER

BIGCHEVYTRUCKDRIVER

1/2 ton status
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After installing 10 bolt in front of my truck the same calipers that I had wont bleed. Ihave pumped 2 quarts of brake fluid through them and still no pressure. I let the master cylinder drain completely through the lines hanging down for 3 days in between axles. Anyway to "benchbleed" master cylinder and calipers on the truck ? Any other thoughts appreciated.
 
First off, do a bench bleed on the MC if you've let the lines hang for 3 days I assume the MC was empty? Secondly, please decribe how you are bleeding them.
 
Mudstud said:
First off, do a bench bleed on the MC if you've let the lines hang for 3 days I assume the MC was empty? Secondly, please decribe how you are bleeding them.
Click to expand...

+1

do all 4 wheels, right rear, then left rear, right front, then left front.
 
Pump them up, hold, crack bleeder, pedal to the floor, close bleeder, repeat. There is fluid coming out just not pressurized. What is the proper method for the benchbleed on the master cylinder. I have bled brakes many times using this method but have no idea about the m,aster cylinder bleed.
 
i have had masters go dry and suck in the nast crap in the bottom of the bowl. then when you refill and blead the master never comes back to 100%.

in these bad masters its time for a new one and start over with good results.
 
If your MC has drained entirely then yes a bench bleed should solve your issues. You can do it on the truck. All you need is a bleeding kit which is nothing more then a couple soft lines with plastic fittings. Put them on the MC and fill with fluid and slowly push the brakes till there are no more bubbles. If your MC sit nose high- I'd try and jack the back of the truck up to where it sits more level before you begin bleeding. There are lots of instructions on line about how to do the process if you need help.

46605DS4Marchjp_00000019793.jpg
 
One thing I wanted to mention is that since you were going to reuse your calipers from your old axle you shouldn't have disconnected them to begin with.
 
Mudstud said:
If your MC has drained entirely then yes a bench bleed should solve your issues. You can do it on the truck. All you need is a bleeding kit which is nothing more then a couple soft lines with plastic fittings. Put them on the MC and fill with fluid and slowly push the brakes till there are no more bubbles. If your MC sit nose high- I'd try and jack the back of the truck up to where it sits more level before you begin bleeding. There are lots of instructions on line about how to do the process if you need help.

46605DS4Marchjp_00000019793.jpg
Click to expand...

Bench bleed like this. My new master came with plugs and said that is how you bench bleed, no hoses. I think the hose approach will work better. Most auto parts stores sell cheap kits to do this properly. Basically it jsut lets you reuse clean fluid during the bleed process.
 
OK so went to Kragen today and they said they dont bench bleed like this anymore? :confused: The guy said just take the lines off and pump the **** out of them for a little bit until air stops coming out then hook up the line quick. Then bleed the individual brakles. Does this make any sense to any of you?
 
if you can't find those kits just buy 2 short brake lines and bend a curve into them and let them dump back into the master. Short brake lines in steel should be under $10 for the pair.
 
dont know the sizes, but did you have him check and see if a new master comes with the hose type bleeding kit. Bought a new master ~6 months ago from autozone, think it was like $18, came with the hose style bleeder kit and the master had a lifetime warranty.

Anyway, if you are doing this on the truck you will get fluid everywhere and kill your paint. I usually clamp them in the vice and use a stubby philips screwdriver in the indentation on the back of the MC and, ahem, stroke it fully and slowly until the bubbles stop coming out of the hoses (I see a new sig line from that).

If it just has plugs or you are doing the old one on the truck with one line connected, compress the cylinder, put your thumb over the open line, let off, then push, clamp your thumb over the hole, and release. Continue for all eternity (or you cover everything in fluid)
 
Trouble shooting time

I had a similar problem on my ’74. First you need to isolate the problem.

Bench bleed you master cyl. Reinstall

Clamp off the front break lines.

Bleed the rears. Pump it up. Do you have pedal? Will it maintain pressure? Are you getting clear fluid though the rear, no air.

If it has PB check your pedal with the engine running so there’s vacuum to the booster after bleeding with the engine off.

Yes to all? Check the front calipers, the bleed screws need to point up. If they point down the calipers have been reversed. L on R, R on L. They will bolt up this way but the system will not maintain pressure.

If the system isn’t holding pressure with the lines clamped… You probably have a bad master. Bleeding these by pushing the pedal to the floor can ruin the seal on an older truck.

My project was apart for months getting done in spare time, so when I rebuilt the front end and installed the new lines and calipers they were reversed. Everything bolts up so I had no idea what was wrong. A budy was helping me bleed them for the 100th time and noticed the problem.

Hope that this helps.

Cheers.
 
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