Brakes start to go to the floor last week checked fluid was fine. The rubber boot inside was distored and would not go on correctly so I got another in good shape and put it on, hoping maybe a vacuum leak. Brakes got worst today so I pulled one front wheel and tried to bleed it no fluid came out. The rubber boot was distorted again. Guessing I need to disconnect front lines see if there clogged then flush the entire system.

Thing is I have a disk brake system I have been want to get on for awhile so I don't want buy any more parts than I have to get the drum brakes going unless they can be used on the disk brake swap.

Been awhile since I've done any major brake work so where should I start? Unclog front lines then flush system and bleed. Thanks.

 

Hmm just open the bleeder push brake peddle. Master maybe leaking look for fluid stains on power booster. Check rear wheel for leaking fluid on wheels or backing plates. The rubber seal in the MC cover sucks down to feel the well ti help keep air out of the system. So it's leaking some where. MC leaks can also go into the p/b booster and hard to find find not look for a leak..
orich

 

Will a new master cylinder work with disk brake conversion, there only like 18.00. Think that worries me is the mc boot is distorted like a chemical burn distortied. I'm wondering if all rubber part are like that, want to flush but don't know if I should try to flush with new mc or use old one first flush then check the rest of the system. Going to check for leaks this morning.

 

Any one know the correct order for brake bleeding on a 1970 f-100. Did some searches looks like I can get a new master bleed on truck then hook up brakes and flush out system. Of course I should check wheel cyclinders ect for leaks first. Does this sound like the correct order.
Check for leaks get new parts as needed, wheel cyclinder ect.

Put on new master cyclinder bleed then hook up lines and bleed system.

Is that correct order, I'm I missing anything? Thanks

 

Do you have p/b on that truck now or standard? if just standard check at rubber dust boot in cab where mc push rod goes into mc for any wet or sign of brake fluid. The mc cover are design to do that reverting outward just push it back into cover. P/B MC were not the same at one time, not sure any more can't remember if they still had the push-rod that was fixed in the mc for non p/b mc...Where as the p/b mc just bolts to the mc. and push rod is in mc.. orich

 

on any car or truck start bleeding with the farthest wheel from master cylinder (passengers rear) and work your way closer to m/c
no pressure sounds like a typical m/c failure to me , rebuild kit is cheap and easy to do

 

The rubber cups inside the m/c are shot(allowing pressure to bleed past) and/or the bore is pitted, sounds like the rubber seal on the cap is gone too. Typical. You can rebuild the master cylinder, but for the money and ease just get rebuilt model. If the bore is too bad(pitted-worn), then it's junk anyway.

Get new M/C and bench bleed it(usually comes with little hoses to do this), get air out of it, bolt on and then bleed system, starting in the back(farthest) and work forward. You'll be good to go.

I would bleed the system extra long to get rid of as much old fluid as possible.

 

No- the correct master cylinder for your drum-drum application will not work properly in a disc-drum application.

 

Ok thanks for all the replies, system is power brakes. I order a mc will have to pick it up tomorrow. Guess I won't be able to use in disk brake swap but it is only 18.00 bucks. The mc rubber boot is distorted like there is another chemical in there causing to really curl up. I guessing the flush should get all the old fluid/fluids out. Was hopeing to look at today but have to go work so I will start first thing in the morning. Hope I don't have to buy new/rebuilt front wheel cylinders. Thanks for the help been awhile since I've done any drum brakes. Just have to pick up a new mc when I get around to the disk brakes.

Seems like it just never ends, first electric problems now the brakes. Should be running good and safe once I get this done. Then maybe I can get back to some upgrades again. Anything else to look for on brakes let me know, thanks again!

 

It's like other things, it can snowball when you least expect it.

If bleeders come loose, and lines are in good shape it should be an easy fifor now).

 

Just how are you going to flush the system ? Also what your going to be using?
If your just going to pump new B fluid through the lines your ok. But don't use anything else your you'll be in for a complete system rebuild. And never mix SYNTHETIC with standard regular dot 3 or 4 fluids cause you'll be flushing the whole system lines out an rebuilding everything. Synthetic when mixed with standard fluid turns to a a light gel that will lock up your system..orich

 

I was going to use dot3, system has not been flushed since I've owned it. I can only assume po used dot 3 or 4. What is B fluid, should I flush with that first and then add dot 3? Did not know about the geling, good to know for the future. Thanks.

 

Well there's a no cost way is just let it self bleed all of all 4 wheels cyl. After installing new mc. Best to bench bleed if not bleeder tubes. Keep mc full then once all cyl are filled with fluid and bleed. This is when you need a helper. Pump brake peddle a few times and hold it with a heavy foot pressure then open each wheel cyl bleeder fast & close fast repeat about 3 time to all 4 wheels cyls, You should have clear clean fluid coming now unless you have a lot of rusted lines or crap in the cylinders that may need rebuilding. If you live in the real cold parts of the US you maybe it's time to replace the all the tubing. I'd replace all hard lines.
I live in Calif where we have very little cold winners. Then I was doing my brakes ABOUT 5 yrs ago, I notice what looked like a little rust starting in the rear steel tube while changing the rear rubber b line going to the axle tube. So re-tubed the whole truck for about $25 bucks But the two lines from mc to the proportion block that cost $57 bucks for the two mc lines with new hard ward on each end. The old line nuts where getting kind of rounded out on the shoulders. I just laid each one out and bent it to the same loops around a tin can and bent to match the old mv lines. Work great plus I cleaned and reset the proportion valve brake warning switch and so now the waring brake light in the cab is off and working correct. Only took me 25+ yrs to get around to fix that...

 

Though about replacing the lines but I think I will only replace what is needed for now. Right now I'm busy landscaping but should slow down a liittle in a month and hope to do the disk brake conversion then. That should give me the time to replace anything as needed correctly. I have the proportion valve from the donor truck so that would be a good time to replace those lines, good idea with tin can. I live in Atlanta GA so maybe the lines are not to bad, famous last words. Thanks for the help, plan on doing the brakes sunday.

 

When bending tube around a tin can do it with a can that's not been open or it will crush it, I could not find the 4" PVC I had but the can worked. The shop wanted 15 bucks X 2 lines for each loop bend. Said no thanks, I'll do it myself...
orich