88 bronco its been sitting for 5 yrs and the pedal goes to the floor but it still stops and has break. When i pump to pedal with it not running it doesnt build pressure. Does my master cyl need replacing or do my breaks need bleading or is there something else wrong. I tried bleeding that piece that is bolt to the frame and no air came out just fluid so i imagine all the other spots are like that too but i cant get the bleeders out and i dont want to break them if thats not whats wrong. Theres no leak because its still full of fluid all the lines were in great shape.

 

First thing…. get some PB Blaster, Kroil or other good penetrant. Spray all the brake bleeders and line fittings for several days BEFORE you attempt to bleed the brakes.

Be patient… they will loosen up but you have to keep spraying them everyday.

 

I have sprayed them but just recently.

 

Second thing: blow out all brake lines and fill with fresh fluid, then bleed.

 

Soft pedal? or pedal that over travels?

Soft pedal due to air in the system the pedal would pump up.

Pedal that simply travels too far and does and does not "pump up" and is solid at the end of travel would have nothing to do with air.

Does it pump up engine "running"? (pumping pedal engine not running is great exercise but otherwise a waste of effort/time).

If it pumps up bleed the system replacing the old fluid in the process, old fluid can cause a spongy feel yet still have no air in the system. Pedal would be high/normal position yet feel like pressing against a spring no solid feel at end of travel.

If doesn't pump up check the rear shoes, make sure they are correctly adjusted up to the drums, make sure all rubber lines are all in good condition.

And yea would no doubt benefit from a fluid change as part of the "fix" regardless of other issues it may or may not suffer from at the moment.

 

Yes it doesnt build pressure while its running or not. It goes to the floor then there is a little pressure. I bled one rear wheel and there was no air in it. So i guess i have the pedal that travels too far.

 

Sounding like air isn't the problem then nor a leak.

Check out the rear brakes common for them to be out of adjustment to point pedal over travels, only takes one of the two worn down didn't self adjust to create the condition.

Can eliminate the master cylinder as the problem by sold plugging both line ports, if master is good pedal would be solid. Gotta get into lines to do that so keep that in mind, lines at the master and then of course system would need to be bled front and rear including RABS valve after test so would have to free up all bleeders (here in the rust belt I tend to replace them once get them loose/out).

I'd start by pulling rear drums have a look see, free up self adjusters if necessary replace shoes etc whatever it needs. Might not be a problem but won't know until you look.

 

Alright ill pic one side up at a time. I have never done rear brakes before so what do i look for besides unevenly worn shoes.

 

Quick and dirty test is simply take a screw driver and through the slot in the backing plate scoop the star wheel fore and aft test for shoe adjustment. Push wheel all the way aft then try and move it forward, if it moves and moves quite a ways the shoes are out of adjustment and need attention/definitely related to excessive pedal travel.

If can't move it at all or very little the shoes are or very near right up to where they should be.

Other test lift rear wheels off ground, have someone slowly press brake pedal down while you spin wheels, if pedal makes it to floor or very near it before stopping you from spinning the wheel? the shoes are well out of adjustment.

Both test results are questionable as neither fully account for every possible condition but also reason they are quick and dirty type tests!

If the shoes are properly adjusted and have some miles on them, you'll have to back off the self adjusters to remove the drums. If not good chance the drums will slide right off maybe catching ridge just a little bit.

 

Alright so i took one of the drums off and since i have no idea what im supposed to be looking for i pushed the brake with the drum off and nothing happens at all. Not a single movement back there. And the shoes are evenly worn and there not worn much at all.

 

Ok so after all this i think it is my MC. I took the brake line off to see if it would squirt out. None barely did. So i took it off and i have another one to replace it. My question is it necessary to bench bleed my MC and if it is how do you do it. Or can i bolt it back on fill with fluid and be good to go. If this is the actual problem.

 

Yes, you will need to bench bleed a new MC. In all probability, the MC will come with instructions and the two plugs you need to bleed it. All you'll need is a vise, fluid, and a wood or brass dowel.

Be sure to blow out all that old fluid in the lines before bleeding the system.

Inspect the rubber brake lines for cracks and bulges. Steel lines for rust.

Roy

 

This isnt a new one. I have several off parts trucks that ive saved. So i guess i still need to know how to bleed it.

 

Here is how:

Master cylinder bench bleeding procedure

You will need two plugs which screw into the MC outlet ports.

People have had an assistant cover the ports with their thumbs...but, the plugs seem the way to go to me. There are also other approaches to MC bleeding.

I have replaced two MCs somewhat recently and used the method described by Cardone...it was easy and fast.

Roy

 

Alright so i replaced the mc and i have a lot more break than what i had. But still needs a little bleeding. Thanks a lot for help everybody it was greatly appreciated.