The Stovebolt Site Forums The Shop Area Driveline completely new brake system lots of problems.....

well i have a completely new brake system in my 54 3100 and am having major problems trying to bleed it.

the system is:

-new 7" power booster with corvette dual reservoir master
-front is 85 s10 new calipers, new stainless hoses, new pads
-rear is 88 ranger 10" drums, new wheel cylinders, hardware and shoes
-brand new 3/16 lines throughout the entire truck
-2lbs residual valve for the front and 10lbs for the rear
-no proportioning valve

the master was correctly bench bled prior to installation!
been checking for leaks but really hard to do when there is no pressure what so ever in the lines. i have one of those speed bleeder kits which hooks up to your air compressor and i let it run on one front caliper for about 20 min, went through roughly 3 large bottles of brake fluid and there is still lots of large air bubbles coming out. have tried everything from a buddy pumping the pedal to gravity bleeding still have way too much air in the lines. anyone have any tips or suggestions?! at this point i'm considering just taking it to a shop, been messing with these brakes for 2 months now!!!!

note: on this first pic the line for the front brakes is hooked to the small reservoir on the master, i have since corrected this and the front line is now hooked to the larger rear reservoir
Picture 1
Picture 2
Picture 3

Are you using DOT 3, 3-4, or 5?

With DOT 5 I have had problems before. Especially when by myself. One thing I do is step on the pedal hard for about 3-4 times, then barely depress the pedal and "mini pump" it or tickle it right when the bubbles come out of the master cylinder. Repeat that over and over again and it might slowly pump up.

I'm sure you already know this but, never let the master cylinder get empty or you will get more air in the system.

Not that this should effect the bleeding process, but shouldnt you have a proportioning valve with the disc/drum combo???

You might try jacking the front of the frame as high as you can then bleed the rears. Try to get the master cylinder as high above the drums as you can. This may help get the air out. Also, tighten the rear shoes up tight against the drums just so you know any movement in the pedal is air and not brake shoe travel.

Rustednut has a good point, where is the proportioning valve? I installed a adjustable one at the rear on my truck so I could limit the pressure to the drums. My would lock up the rear brakes to easy. Its easy to adjust with just a twist of a knob. A few test stops dialed it right in. Joe

Good point on the drum adjustment too. I'd bet on that helping you out. You may have too much clearance from the pads to the drums (are your drums still within specs?) If they are, like Joe H said, adjust the pads till they lock up the drums. Then back them off so you can just hear them drag when you turn the drum by hand.

If you are getting bubbles in the resevour (like you said), you are letting air out of the system. If you are having problems bleeding the system, just exercise some patience and tickle it like I mentioned above. If nothing else is working for you that is.

I recently worked my way through a brutal brake job and learned many things of what not to do.

Forum Posted "New brakes don't work anybody please help"

1. If i was you, i would NOT take it to the shop. Because you will get it eventually and then you'll know it's right.

2. Vacuum bleeding systems did NOT help me since I had so many leaks I was consistently sucking air into the lines. Can't detect leak if no brake fluid mess. To fix leaks need pressure system. If NO leaks vacuum would work.

3. Speed bleeders helped me do it by myself but they needed modifing to fit properly.

4. IMPORTANT: Remove all drums and ensure all is good then adjust shoes out against drums as far as possible before started.

I don't know nuttin about disk brakes so can't comment there.

Gee & I was going to say it was because he used F**d rear brakes

Make sure the pedal to master rod is adjusted up. If the masters plunger isn't moving full stroke, you'll never get good pedal. I firmly believe in power bleeding too,
Scott

I agree, you have at least one leak that you are sucking air through. Pressure bleed them so you can find the leak.

i have almost the same set up as you do.
i hand bleed by pumping the old fashioned way
start w/ the longest /furthest wheel to the shortest
note i did not bench bleed my set up and used one large bottle
use one or two proper flare wrench(s) to tighten all threaded unions.
hopefully you have double flares on all your 3/16'' lines & unions.
just to make sure your disc bleeders are above the hose line, NOT below as shown in pic's.
hope yours works and soon

Cool,,,,On the brakes,,,Don,t know what a speed bleeder with the air is so put it in the corner and get a friend and bleed the old way longest to closest,,fill master pump brake until some pedal there hold brake open bleeder until brake on floor close bleeder then release brake from floor repeat as many times as needed at each wheel check master often for fluid..This will work if you have all mechanical,s correct...doc

Looking at the pic of your front calipers it looks to me the brake line is going to the top of the caliper...maybe your calipers are installed on the wrong side..you need the bleeders at the top or above the line to get the air out..air rises so bleeder needs to be at the top to get the air out...check this first ...Ive seen a case where a guy put his rear cylinders on upside down..same problem..Hope I can help ya..
James

I would add in the proportioning valve too, then bleed longest line to the shortest line. Ensure there are no leaks, otherwise you are wasting your time and brake fluid. I prefer the old fashioned two person method, (brake pedal up, open the bleeder, brake pedal down, close the bleeder, repeat as necessary.)

I would also recommend that when you undertake a project such as this, is to find a vehicle in the wrecking yard, and pull all of the components off (ie.. prop valves ect), buy new components for the same vehicle, and assemble them in the same manner as the donor vehicle. I found a 76 chevy 1/2 ton pickup with manual front disks and drum rears... it also makes it easy when you need to replace something later on...

Yea, those calipers are installed wrong... the bleeder goes on top.

hey guys thanks for all the responses. i got the brakes working this passed weekend. ended up running all new lines for the 3rd time except i bought the pre-flared stuff in diff lenghs and just worked it, not a single leak! also had to bench bleed my master once more as there was air in it. the front calipers were swaped so the bleeders were on top before. spent about 3 hours bleeding them with the vacumn pump and a friend and we got them working great. rears don't lock up so no need for a prop valve here.

thanks again!

Negative.....on not needing a prop valve! I know you're not going to want to hear this, but you're headed for some seriuos braking control problems.

I'll bet a dime that at the moment, the rear brakes are not adjusted down far enough so that they are getting a bite. What you're running now, is basically front brakes doing 90% of the work. Might be okay under normal driving, but when you have to brake hard, especially on wet pavement you'll see what I mean. No...you don't want to see what I mean!!!

Adding the adjustable prop valve (Summit Racing SUM-G3905 $36.)is going to prevent you from having a VERY unpleasant experience down the road. On both my trucks I have the valve cranked down fully and backed off 2 turns. I've got mine mounted so I can adjust them from inside the cab, down at my right heel. With all the varying road temps and rain we see down here, I've been able to fine tune my bias to compensate and can safely navigate in heavy traffic. Pic in Webshots albums.

Obviously it's your call.....but I'd hate to see you have to eat up half a Camry or a Lexus to get the message.

Dave

thanks for the reply and concern, the rear drums are adjusted full out. but i'll look into adding a prop valve into the system since you put it that way! lol can never be too safe

HE'S RITE...iT'LL KICK YA IN THE BUT ...bin-THEREDUNDAT..EVEN MY 65 WITH E/Q VALVE ...SLICK = "OOPS"

Take it to a empty parking lot and do a few 50 mph hard stops. Really stand on them and see what happens. You need to know this before heading out on the road anyway. I fined tuned my doing this. Keep at it till you know which direction the truck is going to go. Joe

I have to side with Dave & ambear, it is absolutely necessary to have a proportioning valve in this system. These trucks are light in the rear and will try to swap ends on you in a panic stop or inclement weather.
Fred