Jump to content

Bench Bleeding M/c In Car????


JIPJOBXX
Go to solution Solved by JIPJOBXX,

Recommended Posts

Well a friend of mine has help me put new brakes on my Dodge and he used that special tool to get the shoes within specs of the drum and thats done! Now I have a problem with air in the system.  Here is what I sent a friend about where I'm at in this evolution.

 

Dam, double dam I still have mushy brakes!!!! Funny this morning I separated the front from the back brake system and of course bleed the M/C before this evolution. I tried the brakes out before I remove fme device (Plug) and the front brakes worked great! So then I removed that FME plug and reattached the back brake line and bleed those lines. I just wonder if when I removed that plug could I have reintroduced air into M/C? I tried to find something on bleeding the M/C and how to replace the lines that are removed for the bench bleeding. Does the M/C after bleeding haft to have the pedal set in place on the floor or leave in the up position? Well I'm going on line in a few minutes and ask that on the board.  I have bleed the brakes till the cows have come home and still they are mushy!!!!!! Can someone here give me the details on how to bleed an M/C in the car just want to double check and see if I mist something.  Thanks Jon

Link to comment
Share on other sites

I have a booster can that I use for bleeding the brakes but for some reason I still cannot get the mushy out.  Tomorrow I will try again but instead of trying out the front brakes with the rear line not attached I will just hoke up both lines at the same time and see what happens?  Of course I will have my pressure bleeder in place.

Link to comment
Share on other sites

If you can't get the mushy out you might have a pin hole leak somewhere.

 

I think pressure bleeding is the way to go: Makes it a one person job and a pretty easy one at that. With that said, I still need to go around all the wheels a couple of times to get all the air out.

Link to comment
Share on other sites

First off I could never bench bleed my master cylinder in my car because my bench is much too big to fit in my car. Now that I have covered that bit of nonsence lets get down to the rest of the nonsence.

 

If I read your posting correctly you are removing the front and read lines from the master cylinder one at a time and attempting to bleed your brakes. Why? The brake system is a closed system meaning that any time you remove one of the lines from the back of the master cylinder you have opened the system thus allowing air into the system.

 

You say you have a power bleeder? You need to insure all the brake line fittings are tight with no leaks, then connect your power bleeder to the top of the master cylinder (insure that your master cylinder is full of fluid) and pressurize the system.

 

Start bleeding first with the right rear, then left rear, then right front, and finish with the left front. Make sure that your master cylinder never runs out of fluid. Once you have finished all 4 wheels then repete the process in the same order. Once done then disconnect the power bleeder and check your pedal. It should be firm. If it is not then check your entire system for leaks. 

  • Like 2
Link to comment
Share on other sites

Don I know sometimes I use the wrong words but what I ment by bench bleeding the M/C is that I want to start at point zero and go from there.  So I fill the reservor with clean fluid having already removed the two lines that leading to the rear brakes and front.  In the process I have two rubber tubes that lead back up to the top and reservoir and bleed the M/C till all the air is extracted from that part of the system.   Now I reinstall both hydraulic lines and install my portable pressure can with hyd brake fluid and pump till I have around 10 to 14 lbs.  I then go to the rear brake and bleed till I see no air and continue around to the last one which is the drivers side front wheel cylinder.  I have done this and checked to see if I could see any leaks on each hub and none to be seen.  This morning I'm going to do the same process but pressurize the M/C and crack the first two fitting oft the M/C and bleed what ever air might be trapped in there. And then go through the procedure that I described already.

 

Now I was wondering could my oil be contaminated with air bubble from to much pressure on my portable pump? 

 

Like I described in my opening statement I split the system into to part by blocking oft the back line with a brass plug at the M/C  and bleed the two front brakes and when finished I removed the pressure can and both front brakes work excellent!!!! This shows me the M/C is working correctly but when I installed the back lines and bleed them I went back to the M/C and that was when I got a mushy pedal again.  Any ideas of whats happening? 

Link to comment
Share on other sites

Don is there any reason for a pitcher to get 150 million dollar contract? Did you know that the average baseball player makes over 3 1/2 million dollars a year? Not bad for sand lot baseball. Guess that why a beer cost almost 10 dollars!!!!!!!!!! Just my two cents worth

Link to comment
Share on other sites

Don is there any reason for a pitcher to get 150 million dollar contract? Did you know that the average baseball player makes over 3 1/2 million dollars a year? Not bad for sand lot baseball. Guess that why a beer cost almost 10 dollars!!!!!!!!!! Just my two cents worth

 

NLA

Edited by Plymouthy Adams
Link to comment
Share on other sites

Well just rebleed the whole system again and still the same soft pedal. Could this problem because of the new brake shoes install not making contact with the hubs properly? I'm going back to just seperate the hydralic lines and just test to see if the front brakes will have a soft feel to them. I noticed that yesteday befor I installed the rear line with a brass plug in place to keep the hyd fluid from leaking out the M/C while under pressure. Just wondering can the M/C cause this soft pedal to happen if the O ring or seal is leaking by?

Link to comment
Share on other sites

Well I just came in from seperating the rear brakes from the front brakes and they work great when the front two brakes are hooked up to M/C but when all four are hooked up then I get a spongy pedal. What can cause this effect? Could it be that the drums are to large for the new shoes? Any answers? I think I will go out and hook up the rear brakes and see what happens with the front ones not attached to the system. Will get back with you guys.

Link to comment
Share on other sites

Just doesn't make since??? Has anyone had this problem?<br />When M/C is only attached to the frount brakes the pedal is perfect<br />When M/C is only attached to the rear brakes the pedal is perfect<br />When both frount and rear brakes lines are attached the brakes feel mushey<br />Check brake shoe cleareances and they are perfect. Even took the car out for a spin and applied the mushey brakes to check out wear pattern of brake shoes and there perfect.<br />Have bleed the system numerous times and bench bleed the M/C also.<br /><br />What is happening I do not have a clue??? Going to take the M/C out and check it out-just to clean it up and check the seals.

Link to comment
Share on other sites

No it kind of stay the same. Just a different type of problem??? I will continue to bleed the system tomorrow and see if I can get any extra air out of the system. I have bleed down the brakes probably six or seven times. But I do notice that the car is starting to stop better not great but at least stops. I would like to get to a point where the brakes at least causes the tires to skid.

Link to comment
Share on other sites

does anyone have an a clue why when you disconet one set of brakes the other set works just like there suppose too? If you do then please state something so that I can have an idea of what to do to get all four brakes up and working properly. Thanks

Link to comment
Share on other sites

it works because ALL the fluid from a single stroke on the master is only going to half of the wheel cylinders, basically putting twice as much fluid down those big 1/4 inch lines you have on it.  You either have to double the volume of fluid a single stroke will put into the lines or reduce the volume needed to keep the lines filled.  Get some 1/4 to 3/16 reducers, replumb with 3/16 line and the problem will go away.

Link to comment
Share on other sites

reducers will not change his problem....a bit of reading on hydraulics, line, lengths etc etc and the dynamics of fluid  flow..will go a long way understanding what folks are trying to help him with

All that studying will make my head hurt, but if I must, I will. 

Link to comment
Share on other sites

Trying to work through Pascal's theories.  Should be room in my head to get around most of it and understanding it won 't cause me any harm.

Link to comment
Share on other sites

It wouldn't matter if the brake system was plumbed with 3/4" pipe, once it's full of fluid i will still only require the necessary flow to extend the wheel cylinder pistons. The only thing that would change that would be the piston stroke. More stroke = more fluid needed = longer pedal travel. However, Jon's statement was regarding spongy pedal. This would indicate that he still has air in the system. Apparently it's still in the rear part of the system since when he blocks off the rear he gets a good pedal. I have to wonder how these lines were disconnected and reconnected for the tests without introducing more air into the system? I think you need to get your hands on a good pressure bleeder and bleed the system again.

 

Merle

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.

Terms of Use