Can you bleed brakes on a slope?
 

The brakes in my 77 F250 4x4 have deteriorated. The pedal goes almost all the way to the floor with no resistance. The truck will stop, but it's a bit unnerving.

I've never worked on brakes before, but it seemed like a classic case of a bad master cylinder. I ordered a replacement and picked up one of those vacuum pump kits. Bench bleeding the master cylinder and replacing it seems very straight forward. I'm not so sure about bleeding the brake system though!

My driveway is a bit of a slope. It's not very steep, but it's definitely not flat. Can I succeed with this if the truck is not flat? If it will work on a slope, would pointing the truck one way or the other be better?

I would not think a gentle slope would hurt... though it would be a bit harder to get air out of the downhill side.

If you plan to jack it up and it is safe to do so, you can just set one end lower and level it.

Or... I always prefer to bleed the brakes once, let it settle so any little air bubbles can combine and do it again. You could do it the first time facing one way and second time facing the other. After the first bleed, you should have decent pedal... the second time is to make it as good as possible.

I would suggest you get a cheap Chilton or Hanes manual and get to reading on your brake system, like how to bleed them. Then I would suggest you join you FTE state chapter and get some experienced help with your brakes. They are not a learn as you go system..

Brakes either work absolutely as they should and when they don't, you should stop (if you can lol) driving the vehicle and get them fixed. PERIOD!

Washington Chapter - Ford Truck Enthusiasts Forums

Bench bleed m/s is easy, self bleeding and getting it right not so much. Having a pedal pusher (and hold) sure makes it go faster and better.

Oh and since you are pushing fluid during the bleed process, being on a slope does not matter, it only matters to keep the fluid in the m/s full all the time.

My quicky thoughts are that because it is a closed system, you could bleed the brakes with the truck standing on its nose .... or roof. The only drawback in that theory would be the master cylinder of course. (and yeah,I know,sometimes under ideal conditions ya' can't get the darn air out). Just sayin'. gary

I my opinion yes being on a slope makes a big difference, my 79 was on a slope after i redid the brake lines , i bleed the brakes for hours over a few days and was at a complete loss. i thought maybe that was why and i jacked up the back so it was higher than the front and the brakes bleed in minutes.

that`s my experience so i would say yes. air bubbles rise !

The air needs to get out through the bleeders. If the slope prevents that then some will be trapped.

If you are gravity bleeding the system, then yes a slope matters. If you are bleeding the system by pumping the master and holding while someone lets the air out, then it shouldn't matter at all.

A vacuum system works OK either way as well, but I find that it takes a little finesse to get a vacuum bleed to work right. Loosen the bleeder/nipple too much and it seems like you can pull vacuum from around the threads, reducing the effectiveness of the vacuum. Don't open it enough, and it doesn't work either. Having a helper pump the brakes is the best in my opinion and what I prefer if someone is around, but I've been able to get a decent bleed with a vacuum as well (air powered venturi bleeder system, not the little "Mighty Vac").

If you purchase one of these, you can bleed the system all by yourself (no buddy). They work great. I personally wouldn't worry about being on a slope...

Air bubbles rise if the master cylinder is higher than the back the air stays at the top. Maybe it's not impossible but makes it a lot harder to bleed . From the front to the back is a long run. May as well give yourself the best advantage as you can.

Good discussion! Thanks for the pointers and encouragement. I do have something like the mityvac but I'm still hoping to get a friend over to lend a hand.

I will point the nose downhill just in case.

Thanks again, I'll post my results in a few days.

Let use know how you make out!

Well, finally some good weather and a little free time. I managed to get the new master cylinder bench bled. LMC sent me a Cardone replacement MC. Things went just as described in the instructions.

Onto removal of the old MC. I wire brushed around the brake tubes and sprayed a little PB Blaster on them. The threads broke free but the tubes were completely frozen in the fittings and started to twist :( I tried to wiggle back and forth on the fitting, but it was just too seized up... I figured I was screwed either way so I tried to tighten them back up and the front tube broke. At this point I decided I could at least get the new MC installed, so snap went the 2nd brake pipe.

I'm starting to think every fastener in this old truck is frozen solid. Getting the old MC off the booster took PB, a breaker bar, flame, swearing and an impact gun. Both nuts will have to be replaced.

It looks like I'm now in the same boat as this guy https://www.ford-trucks.com/forums/1...e-options.html

My question is should I replace the brake booster now that everything is torn apart and until I can get new brake lines, the truck isn't going anywhere... The booster itself is rusted quite a bit and splined rod that comes out of the booster is pretty rusted on the end that goes into the MC. The part of the rod that was inside the booster is clean and shiny.


https://cimg0.ibsrv.net/gimg/www.for...e3765a81b2.jpg

And for the curious, this is what the old MC looks like

https://cimg5.ibsrv.net/gimg/www.for...36fde27599.jpg

May be one reason a lot of trucks got parked on the back 40, back in the day. It's almost impossible to replace just some or part of the brake system, the original parts are more prone to failure because of the restored hydraulic pressure e.g. a new master cylinder may blow out old hose or new shoes mean the wheel cylinder cups may start to leak. And then there's the original hard steel line. You can see where this is going, right?

On the booster, I did not change mine with new MC but kinda wish I did... even though it works fine. The working part inside the booster is rubber. I have to believe time takes a toll.

It is not too hard to repair the brake line and get her rolling. That said, nice pre-bent replacement line sets are not too expensive from the vendor of your choice. I like in-line tube. If you do the lines, best to go ahead and do the flex lines since they are likely frozen also.

Also a tip... if the brake line is frozen hard to the nut or will be scrapped anyhow, just nip it off with bolt cutters. Saves time and you can use a socket on the tube nut.

My experience...

I replaced front pads on trashed rotors to try to get by for a few months, bled the brakes while I was at it. Mushy pedal, not a lot of stopping power.

Replaced master cylinder (no booster on mine), bled brakes again. Good for a couple days and mushy again...

At that point I shelled out for all new parts: front rotors, bearings, calipers, and pads again. In the rear new shoes, spring kits, wheel cylinders, and drums. Also new hard lines on the rear axle and all new flex hoses.

Bled brakes, adjusted shoes, bedded in the pads/shoes, adjusted shoes again. SOLID pedal and awesome braking power.

Don't waste time chasing your tail, 40 year old braking systems should be gone through 100% front to rear.

Thanks for all the suggestions as always :)

I've gone ahead and ordered a new brake booster.

Still need to deal with the lines. Can I just put new fittings on the existing lines? The first one broke right at the fitting and I cut the 2nd one off right at the fitting. Seems like there is plenty of play/extra tube to reach the ports on the master cylinder.

You can do anything you want, but weigh for yourself the likelihood of having to go back through it again. And again. I don't mind maintenance and repair but once is plenty at least when it comes to brakes.

Good brake work cannot be done half assed or piece meal and you want to keep the peace at home. Marathon brake bleeding sessions are not good. Not telling you to remove the radiator cap and drive a new truck under it, but think how pissed off you'll be if the hard lines start blowing or start shedding 40 years worth of old rust and sediment into your nice new wheel cylinders. Once you start looking at all new wheel cylinders, drums, master cylinder, hoses, (Nod your head "Yes") another $50 on top of that and bending up some hard line is an easy decision. Good brakes are worth the extra effort.

Wow, has it really been 3 months since I decided to tackle the brakes! Guess those "slow" build threads have nothing on me.

After some time tracking down various fasteners and pins and wavy washers, I cleaned up and painted the booster bracket and got the new booster in and brake pedal reattached.

I got some new brake fittings and some line from the local parts store and the basic tools to bend and flare the lines. I made a semi satisfactory double flare on my first try, but decided to try again. Each time got a little worse... until the POS flaring die broke on the 4th attempt.

I then ordered the fancy Eastwood flaring tool... I told myself if it just needed to work once to pay for itself. Let me tell you, it lives up to its reputation. What an awesome tool. Perfect flares.

I think the hardest part may have been getting the new fittings threaded into the proportioning valve. What a pain!

I got everything bolted back up and things were looking up. Time to try and bleed the brakes. I removed the rear passenger wheel and hooked up the little vacuum gadget per the instructions and got a whole lot of nothing. Remember, the truck is on a hill with the rear higher than the front. The brake system has been open to the world for many days. Having never done this before I wasn't sure if I was just doing it wrong or if there's so much air in the lines it will just take a while... The vacuum holds and I pumped it up to 25 mm/hg but still no sign of fluid. I even tried pulling the bleeder rod out of the proportioning valve, but it didn't make a difference.

So, I thought before I gave up and come posting for help, I'd just see if I could get fluid to bleed out of the front to make sure I was using the vacuum thing correctly. I removed the passenger side front wheel and carefully applied even, strong pressure on the bleeder screw and was feeling pretty good when it started to slowly move... until the top sheered off.

I think Steven@nd and Tedster9 are right... once you start on old brakes you just keep going. :(

Any advice on replacing the calipers? I'm assuming trying to get the remnants of the bleeder screw out is not worth the effort. Any reasonable upgrades to do at this point or just go with remanufactured versions of what's there?

I'm sorry to hear about the bleeder screw. That's a bit of a disappointment. Your last paragraph about sums up my experiences. Perhaps others may have additional suggestions, but I'd probably do what you said. I suppose that the remnants of the bleeder could be extracted by a knowledgeable person using all the facilities of a machine shop. Years ago they charged me $20-25 for a standard exhaust manifold bolt extraction from a head when I was able to find someone capable of doing it successfully without damaging the original threads. I would expect that working on a bleeder would be even more difficult. Whatever you go back with might benefit from having some anti-seize compound on the threads. If the manufacturers would do this for the exhaust manifold bolts, etc. a lot of grief could be avoided on disassembly.

inline tube makes a great brake line kit that's who I ordered from I'll have to dig up my receipt but I'm certain it was 200 or less for a full stainless brake line kit shipped to my door.
I have yet to install it but I did inspect the tubes and all the flares are perfect and the hardware looks to be of good quality.

New stock calipers are not expensive, maybe $30 each. Not worth the effort to extract a broken bleeder or rebuild in my opinion.

As to upgrades, as long as you are not auto crossing the stock brakes are more than adequate. Properly adjusted and in good condition, my 74 with no booster will stop on a dime.

For the front, Cardone reman calipers have worked well for me. For the hard lines, bend up and flare new when the old ones look bad or twist off has also worked well. If the flare joints do not leak under pressure, they are good.

For bleeding, the mityvac may help get it started, but a helper pumping the pedal with bleeder open always seems essential to me.

Did your new booster include a new or reman MC? The new/reman MC will need "bench bled" before bleeding the brakes which can be done on the bench or in the truck. Also bench bleed may be required if your older master ran dry.

Yep - a new master cylinder is what started all of this :) I did a bench bleed on that and it all seemed good and bubble free when I mounted it on the booster.

I will get a helper for the next round of bleeding.

I'm going to order new calipers/brackets/pads and flex lines for the front. I'm good with running my own hard lines now that I have that Eastwood flaring tool!

I should probably order new master cylinders for the rear drums while I'm at it just to make an offering to the brake gods...

The brakes did seem to work fine when I first got the truck and the upgrades to the F-350 double booster and rear cylinders and Thunderbird calipers up front seems more popular on the F-100s and F-150s. I think I'll just focus on getting it working again for now.

Thanks again everyone. I'll keep posting progress as I make any... maybe this will be of help to some future newbie?

Definitely go with new wheel cylinders in the rear, they are about the cheapest parts of the system!

The bleeder rod on the proportioning valve is for bleeding the front calipers. Should be pulled out when doing the fronts. I use a pair of needle nose vice grips to hold it out when doing mine although Ford has a dedicated tool - a "spring clip" for it. Haven't been able to find a dealer that has it.

Have you blown out the lines? Sometimes a goober or two will block the lines.

Gravity is your friend here...Since she's on a hill you can use it to your advantage - attach a clear hose to the nipple, emptying into a Mason jar or a clear beer bottle. Open the M/C cover and watch the flow...careful not to let the M/C empty completely. When you have a good flow (no air bubbles) bleed as normal.

Ok - installed the new calipers and pads on the front last night. Everything went as advertised except the bolt that goes into the bottom of the bracket to hold the spring loaded locking key in place was significantly shorter on the passenger side than the driver's side. The driver's side bolt looked exactly like the replacement. I just reused the existing bolt from the passenger side. I don't know why it was so different.

Then we went to bleed the system. I had a helper this time so we started with the brake pedal version and the rear passenger side. Nothing. We tried the vacuum pump. Nothing. We tried swearing at it. Didn't help.

We moved to the front passenger side and again couldn't get anything with the pedal. We could kind of get a little with the vacuum pump but not really what you'd expect. Then I crawled under and messed with the proportioning valve rod and we started getting fluid with the vacuum. Still nothing with the pedal. We went through a bottle of fluid and still couldn't get bubble free... We tried the diver's side front caliper with the same results. Bubbly fluid and lots of it. It was getting dark so we packed it in for the night.

I decided to try just gravity bleeding the front this morning. I got good streams of fluid out of both calipers in front and took out an inch or so of fluid into the bottom of a gatorade bottle and tightened down the bleeders. I want try the same with the back, but the truck is on a slope, so I'm going to have to spin it around.

With the engine off I have a nice firm brake pedal. With the engine running, I have no pedal. Zero resistance - straight to the floor :(

The brake warning light is on. I see no leaks anywhere.

I was thinking I should have front brakes at this point - certainly enough to spin the truck around in the driveway so I can gravity bleed the rear?

The H beam hold down bolt - Ahhh, the PO strikes again! They should be the same but as long as it's working, swing with it.

Yes, you can use gravity to your advantage on bleeding anything - fronts, rears, a sliced finger, mowing the grass on a hill, pinchin' a loaf, etc....

Be sure to bleed those brakes normally after the gravitational pull of the Earth has done it's thing.

Engine running, no pedal: How's the vacuum line to the booster and the swivel joint connection? The pedal to M/C rod is the right length?

All the new parts I've purchased have been exact replacements for what was there. So I'm pretty sure the booster and the M/C connections to the brake pedal arm and the length of all those parts is correct.

I pulled the vacuum tube off the booster and it hangs onto my palm about as hard as a shopvac... (and the engine barely idles with that tube not sucked onto something).

Let me know if you want some fresh eyes on it. You can reach me at our Seattle area code, 6192889. If you're a reasonable drive away, I'd be happy to help.

Wow mmoe, what a generous offer! I am down by Seward Park south of I-90.

You're pretty close. I live on Orcas on the west side of Beacon Ave, so only a couple minutes away. Let me know.
-Mike

Thanks to the overwhelming generosity of mmoe and his budding mechanic son (who knows way! more than me), the brakes are bled to a point of drivability and I took the truck out for an around-the-neighborhood tonight and a trip to the gas station.

Mike, I can't thank you enough -- publicly! Folks on this forum are generous of their experience and time (and opinion!) and apparently the saintly ones will drive to your house to help you.

The rear drums/shoes/etc need to be replaced, but the truck stops now with its shiny new calipers on the front and new booster and master cylinder.

The brake light is shining brightly on the dash. Do I need to crawl under and crack the hex nuts on the end of the proportioning valve with a helper in the cab? Is there any other way? Are there other reasons why the brake light might stay lit all the time (it was off before this whole saga began).

No, you don't need to fiddle with the proportioning valve under the vehicle. The reason the brake warning light is on is because after bleeding the brake system, the pressure differential metering and proportioning valve are off center. It should only light up in the START position.

To re-center: Make sure the connection (top middle of the prop valve) is secure. With the key in the ON or ACC position, push on the brake pedal. This should center the valves and the light should go out.

If it stays on then there may be a shorted or broken brake warning light switch or grounded switch wires.

Glad you're back on the road!

Plug is nice and seated into the proportioning valve. Brake light does not come on when key is in ACC. Brake light is on when key is in ON and START.

Pushing the pedal with the key in either ACC or ON had no effect on the light.

Guess I can finally get back to my wiring gremlins :) -- rear side markers don't work. Reverse lights don't work. All other exterior lights seem to work a-ok.