tmatador

70 model F85, front disk rear drum. The car set for years, I changed the front calipers rear wheel cylinders, brake booster and master cylinder. When I tried to bleed the brakes the front passenger side is the only one I can get any fluid to to come out the bleeder. I'm just doing it the old way by pumping the pedal. I can't see any fluid anywhere so I dont think its leaking. Is there something I don't know or something else I need to replace?

Thanks!

66ninetyeightls

Did you bench bleed the master cylinder before you put it on the car?

MDchanic

Yup.

1. Bench bleed master cylinder with cylinder LEVEL (it sits at an angle in the A-bodies).

2. Follow along to be sure fluid is getting through the system to where it needs to be.

- Eric

tmatador

Hmmmmm... Learn something new everyday!

Thanks!

MDchanic

The M/C should have come with "bleeder plugs" of some sort.

The newest ones seem to just be plain closed plastic plugs, which seem to work fine, though you'd think they wouldn't.
The older ones were plastic plugs with attached tubing that you ran back into the reservoirs.
You could also create some in any number of ways, including using ends of old tubing.

How you set it up to do the job doesn't matter, so long as it's level.
I remember once years ago bench bleeding one in a parking lot using a hammer - butt end of the handle against the piston, head against a tree, pushing the M/C in and out against the tree until the bubbles stopped.

- Eric

rustyroger

I've bled brakes (and clutches) for years by simply removing the M/C cover, opening the bleed screws in turn and letting gravity do the work.
The M/C needs to be properly bled first btw.

Roger.

tmatador

Well I pulled the master cylinder off and bench bleed it, but still got no fluid to the rear wheel cylinders.Took the master cylinder off again and submersed it in bucket full of brake fluid just to make sure I had all the air out of it, still no fluid to the rear. Distribution switch maybe? The switch was working just a few days ago cause when I changed the front pads and the calipers were compressed all the way the brake light came on when I first pumped the pedal and then the light went back off after a few pedal pumps. Now when I have one of the rear bleeders open the brake light does not come on and it should right?

Thanks!

Junkman

I will start with the simple.
1) Did you replace the original rubber lines?
2) Did you replace the rear cylinders, and if so, did you fist blow out the steel lines to make sure that they are not clogged? If the car has sat for a long time, there is a good chance that the steel lines have rusted internally, and that rust is causing a blockage.
3) Did you purchase cylinders that were made in some far off land? If so, the cylinders might be defective and are not drilled properly.

I would suggest that you check the hose over the rear end by loosening it, and have someone step on the brake pedal. If no fluid comes out, then there is a blockage somewhere between the distribution block and the rear of the vehicle. As for the brake light switch, it should return to a neutral position once you have the brakes bled. If not, then you can always break the connection and step on the brake pedal to move the contact to the neutral position. My bet is on a clogged rubber hose.

MDchanic

Are you pressing down the little button on the metering valve that sits under or beside the master when you bleed it?

- Eric

tmatador

Nope, I did'nt know there was such a button. I will see if I can find it tomorrow afternoon as well as check the line from the distribution block to rearend to make sure it isnt clogged.

Thanks for the help everyone!

MDchanic

Here's that metering valve:


BT-6710 is the tool to hold the button down. Vise Grips work, too.

This may do it, but it may not.

- Eric

Lady72nRob71

Never knew this but makse sense. How long does it take? Maybe I will do mine like this!

BosMobile

x-2,JUNKMAN!{AGAIN}I would check the lines themselves,they get rusty,espesialy if a car sets along time,as stated.I would take a real good look at those brake lines,rubber and steel.One of them babies blows on the highway,and your along for the ride.It's always a good idea to go ahead and make sure all the fluid is new and clean.You've already spent the money on the parts,but nasty fluid could even cause those new parts to clog with rusty fluid.I,m thinking a cloged line is why your having trouble bleeding them.Northern cars will be more probable to have the rusty steel lines.There's alot of preasure on the brake system.Your new M\C would come with the directions to bench bleed it,which is a mandatory procedure.Good luck with your project,Later,BO

67 Cutlass Freak

I know this may sound stupid, but check the bleeder screws in the new wheel cylinders. Pull them out and blow through it to make sure it passes air. I have had new ones that were not drilled properly. Try to borrow a vacuum brake bleeder. They're not that expensive. You should always start at the furthest point from the master. If you can't borrow a vacuum bleeder, try removing the right rear bleeder and hold your finger over the hole while a friend slowly pumps the brake pedal. You should feel air pressure, or fluid pressure, when the pedal is depressed, and a vacuum upon release. Do this until the fluid flows nicely. Do not let the master go empty. If you don't feel any pressure go back to the master and crack the lines there. Make sure you have good pressure on each. It's a very good possability the lines are rusted internally if they were allowed to be exposed to air or moisture while stored. If the system was intack and full of fluid, I believe it is less likely the lines have rusted internally. If your proportioning valve is stuck, Ive had good luck with unsticking it, by opening the RR bleeder, starting the car, and slamming on the brake pedal. If you still get nothing remove the lines going to the front wheels and to therear differencial at the proportioning valve. Open the bleeders one at a time and blow through the lines with compressed air to check for a clog. If they are all clear, remove the lines goin' to the proportioning valve from the master cylinder. Check for good fluid pressure on both. If you have good pressure there but can't get anything out of the P valve, and can't get it to reset, replace the prop valve. If you did not get good pressure at the P valve, replace the obstructed lines coming off the master cylinder assuming you actually did have good pressure coming off your new master. Man I hope this novel helps you. Good luck. Please keep us posted.

Aceshigh

Yep.....the one from Harbor Freight is WELL WORTH the $$$.
Just need a compressor and this thing SUCKS the fluid from the Master cylinder down each brake line to the end point.
Just have to keep an eye on the Master fluid level at all times so you don't suck it dry on accident and end up with air in your system.

I've bled both of my classics to put clean new fluid in all of the lines on both cars.
Only $25 and just like the Vacula which is 4x the cost.
http://www.harborfreight.com/brake-f...der-92924.html

rustyroger

About 15 minutes per wheel Rob. I normally get on with other jobs while this is going on, like changing oil & filters, plugs, lubing hinges & locks, tea break (remember I'm doing this in England!) etc.

It doesn't work on Rolls Royce and some Citroen models though.

Roger.

Lady72nRob71

Maybe I will do it this way first - less messy it seems! I will just keep topping off the master as it drains out. I f that dont work, I will use the vacuum pump.
Let's see - 15 minutes.... That is about a beer's break, so in 3 beers, I will be done!
I still have some tea I brought back from London years ago - great stuff!

rustyroger

Use boiling water to make your tea or it won't brew properly. I remember asking for tea in the USA once and the waitress brought a cup of hot water and a tea bag!.

The English habit of tea drinking gave us a head start in the industrial revolution - tea has a mild antiseptic property which helped supress outbreaks of communicable diseases in early overcrowded industrial sweatshops and slum housing.
A little gem to impress your friends with!

Roger.

66ninetyeightls

But it also caused over working of the pinky finger muscles leading to injury and loss of work hours. This was one of the major causes of the "Great Slump" in the 1930's!!!!

LOL

Lady72nRob71

Hmmmm--- Looks like I have been drinking wronly-brewed tea for a long time!
Here in TX, I make refigerator iced tea. put two big tea bags in a pitcher of water and stick it in the fridge overnight. Works well!

In summer we can make sun-tea instantly, but I prefer to leave out the heat.

MDchanic

I've used the gravity-feed technique too a few times (when the "helpers" were too lazy...) - the best way is to set or affix the drain bottle at a level higher than the part being bled, that way the air bubbles rise up and out of the line and stay there.
You set it so the tube is below the surface of the fluid in the bottle, then you can give the pedal a slow pump - all the way down, then all the way back up - every now and then to push out a little more.
This is the type of bottle I've used - kind of small, but they're cheap:



Thanks for that Harbor Freight link, Aces - I think I'll have to get me one of them things soon.

- Eric

tmatador

Well I pushed the button on the proportioning valve that is mounted on the master cylinder and still no fluid to the rear wheel cylinders. Thats all I had time to do today, I will check the lines tomorrow to make sure none of them are clogged up.

Is it possible that the distribution switch is closing the rear brakes off when I open one of the bleeders on the rear brakes?

Lady72nRob71

Welcome to the brake bleeding hell club...
I cannot get any fluid out the left rear cylinder but get plenty out the right rear one. I stuck a drill bit in it and it is not blocked...

Also, I found that those vacuum bleeders suck. Suck air that is, from around the threads of the bleeder screws, so there is a continual stream of little bubbles and you do not know when to stop bleeding. I ran through two bottles of fluid (and half a bottle on the floor when some DA left the front right screw open...) Still have a sponge pedal...

MX442

Yes. If you lose pressure to one side of the switch, a pressure valve can close causing no fluid to pass. You need to disassemble or replace the switch.

oldsguybry

pass the tea....bag

tmatador

The rubber hose that goes over the rearend was clogged.
I got a new distribution switch and all new lines. Just got to figure how to get the new lines on with out demolishing them, I bent the old ones up pretty good taking them off.

BosMobile

Well,i for one ,am glad you,ve found your problem.You i guess could simulate the routes and bends with the old lines.I've never replaced all the lines on my olds ,but on other makes i've delt with ,you just do the neatest job possible.I think you'll be fine,and safe.I like to partake in the "tea drinking" as well,I'ts probably not the best on fix the brakes day.Enjoy your ride,thats why i do it!Good luck,later,BO

frankr442

I bleed my brakes with a stick and a battery. Set a clean battery on the floor in front of pedal. Open a bleeder. Push pedal down and hold with stick against battery. Close bleeder and slowly release pedal. Repeat a few times and you'll get a good pedal. Works for me when working alone, and dosn't take very long.

ah64pilot

I know the problem has been found but just for any guys following this that don't know...the rear brake line is ONE line that splits to two at the junction block on the rear differential. If you get fluid out of one side of the rear, the blockage is not in front of the junction block rather it is in the side of the line that won't bleed, between the wheel and the junction block.

I know most everyone knows this, but some guys don't. Just thought I'd throw it out there.

MX442

That is a great tip to isolate any blockage location. Just so we're all on the same page, the OP was asking about the distribution switch. I see what you are saying, I was answering in general as a loss of pressure front vs rear. I thought that it was possible for these to lock or stick when pumping the pedal with no pressure? I believe that older single reservoir systems they actually locked to keep from losing pressure to the good side (front/rear). When I read this post, I did not pay attention to the fact we were talking about a 1970.
Just so we are all clear on nomenclature, from the 1970 service manual:
The distribution switch gives the warning light due to front/rear differential pressure. The Metering valve momentarily delays rear brake application on disk brake only applications, 1968-70. I think this was changed in 1971, however I don't care to research this. (Use at your own risk, YMMV ).