NO BRAKES! Everything new or rebuilt....

[free4u2nv]

Need help guys.... My car just wants to criuse and never stop!
I have installed all new brake lines from front to back - hard and soft-no apparent leaks. Have installed new rebuilt front calipers and pads. New rear wheel cylinders and brake shoes. adjusted. New vacuum hoses and booster inlet valve. Put on a mastercylinder, that I got from ebay, which the guy said was rebuilt. Also new warning switch on mastercylinder. New emergency brake cable.
I have bled the brakes over and over in the correct order and I am not getting anymore air. The left back does not seem to have much pressure to it though. Still, I have no brakes. I can get the peddle to pump up slightly to where my toes on one foot fit between the peddle and the floor. This is the most peddle I get. I took the car for a short drive in a safe area to see how the brakes act and it is as if I have NO brakes at all- they dont slow the car down at all let alone stop it!
So, what do you guys think??? Need help. At a standstill and banging my head on the wall! Junk mastercylinder?? I have the cars original booster still installed.......

[baz]

im just guessing (long distance diagnostics are never easy) but
1 are the rubber rings in the M/C in the right way , did you look or just take the guys word its rebuilt
2 have you adjusted the hand brake up correctly as if its not the pedal can need to have more travel than it has to take up the gaps in the drums
3 what order did you bleed the brakes initi needs to be
front furthest away from the booster passenger side for you ),then front nearest(drivers side ) then rear shortest pipe(passengers side again i think ) then the last one

the orig servo/booster would not matter
as even if it did not work the brakes would , just a lot harder to push down

[ungermm]

Originally Posted by free4u2nv Need help guys.... My car just wants to criuse and never stop! At a standstill and banging my head on the wall! Junk mastercylinder?? I have the cars original booster still installed.......

My quess would be the master cylinder. But 1st, I would suggest that you pull the drums off the rear wheels and recheck to make sure everything is still in their proper place and no leakage. Also, did you adjust the parking brake and does it work? Jerry

[free4u2nv]

ebrake is adjusted to 8 clicks. I took the guys word for it that the mastercylinder is rebuilt...rubbers all appeared new. Have already taken back drums off and all is still intact.

[baz]

8!!!!!!!! should be 3 - 4

[free4u2nv]

really??? My book said 10....

[baz]

really

bight at 3 be fully on to the point you have to strain to get it off at 5

[free4u2nv]

will adjust to 3 clicks tomorrow and see what happens..... I first had it at 10 clicks but there was the strain you are taliking about so dropped it back to 8. This makes a big difference in the functioning of the other brakes?

[baz]

it is all dependent on how the drum end is adjusted
if they are set up wrong (too much travel before the pistons contact the shoes ) then the M/C uses all its fluid to push the rear pistons out till they make the shoes contact the drum
then they can move the front pistons out to grab the discs
if its wrong the pedel is soft and goes to or nearly to the floor and you have no brakes to speak of

if they are right and its just the cable that is loose to 8-10 clicks it would not affect the action of the hydrolic brakes

[free4u2nv]

thanks. Back to it tomorrow. Will see what happens.

[namba209]

I just went through this drill on Willit?, twice, and here's what I did to get good brakes. Adjust the rear brake shoes, individually, with a loose brake emergency cable. The front drum shoes are adjusted so they just start to drag when the wheel is turned in the forward direction, then back the adjustment off a very slight amount. Adjust the rear shoes the same, but with the wheel turning in the reverse rotational direction. Next pull up on the emergency brake handle 3 clicks and adjust the cable, again until the rear shoes just start to drag on the drums. Release, then pull up on the emergency brake handle and count the clicks, it should be no more than 8. Then check to see if you can turn the rear wheels, if you can turn one or both, reposition the cable in the horseshoe by pulling up on the brake handle numerous time, then readjust the cable. Baz is correct in that the front brakes are actuated after the rear brakes during initial brake pedal application. Because the front brakes are self-adjusting, the rear brakes have to be adjusted first, then numerous applications of the brake pedal is required to get the pistons adjusted in the calipers. HTH.

[Anonymous D]

It's necessary to "bench bleed" a master cylinder,
prior to installation. This means adding fluid,
and moving plunger (using a dowell) about an
inch forward -- repeat a few times, so that
the m/c squirts out any air trapped inside
(along with some fluid). This also aids development
of a fluid pressure to the brake lines.

Reference:
OMC Blitz newsletter
Article on master cylinder rebuild
June 2004

[azopelnut]

Don't know if you are talking GT or Ascona/Manta but recently I had a similar situation with a rebuilt MC. I took it off and looked in the rear of the MC and noticed it was rebuilt with an incorrect shaped snap ring (the piece that keeps that piston from flying out the back end). The pedal plunger made just enough contact with the ring to drive it into the MC and wedge it about 3/4" into the bore. This prevented the piston from returning all the way back. I changed the 10 cent snap ring and everything worked as it should.

[blancojp]

most likely you still have air in the lines. I would do a gravity feed first to load up the lines a bit and then the famous pump and evacuate. It does not matter how well your rear brakes are adjusted if they get mostly air instead of fluid.

[Manta Rallier]

My first impression of the problem is that of not having bled the master cylinder first. This has to be done, period. If not, you can sometimes bleed the system all day long and still have a soft pedal.

Take the MC off, rig up some short lines to feed the brake line outlets back into the reservoir (you can cut off some short pieces of replacement brake line with a correct sized fitting on the ends and then extend these with cheap rubber hose, and route back ot the reservoir) and then clamp the MC flange in a vise. Then slowly pump over and over. (Don't jam the piston in hard.) Keep doing it 'til no bubbles appear from the hoses feeding back into the reservior, then do it some more. It could take many dozens of strokes; you will continue to get a tiny bubbles for quite a while and you need to get them all out.

Then put it on the car and re-bleed everything else.

You can sometimes bleed the MC on the car, but it takes a very long time and uses up a lot of fluid. Also, the slope of the mount of the MC sometimes makes it not successful. Putting the MC in the vise gets it level and helps get the air out of every nook and cranny in the MC.

Good luck!
Mark B.

[Paul]

I've had great success using the Mighty Vac(?sp). Even starting with a COMPLETELY empty brake system.

[free4u2nv]

adjusted ebrake cable to 3 clicks, readjusted rear shoes, rebled system. Nothing changed. Going to try to take the MC back off and do the bench bleed then follow some of the advise the rest of you have gave. THANKS for suggestions. Very frustrated with this. This should have been the easy part after all that I have done to this car!!!!

[namba209]

When you bled the brakes, did you get clean fluid or old ditry fluid out of the cylinders/calipers? If the fluid is old looking, it could be you still have air in the line. I would bleed them all until you get no air bubbles and clean brake fluid out of each one. The latest method of bleeding the MC is to block off all outlet ports, and slowly depress the MC piston numerous times until no air bubbles come back through the MC reservoir. It's a little easier than running hoses from the ports back to the reservoir. My experience with a vacuum pump was not that great, I was pulling air in through the wheel cylinder cups because of their shape and design. JMTCW

[heimue]

Something that came to my mind, and it may or may not apply to the GT brakes: A friend of mine got a new MC for his Chevy Nova, put it in, bled it and got NO brake action. After a while we found out that the connecting rod between brake pedal and booster needed some adjustment. Basically before adjusting, the MC was pushed in only a fraction of what it needed to be, just enough to open the connection in the MC from the reservoir to the output lines. It was enough to pressure-bleed his system, but not enough to create any pressure. After the adjustment was done, the stroke was long enough to create the brake pressure. One sign if this is the case on your brakes: Open one front bleed screw, press the pedal and watch the amount of fluid coming out. If it is only a little bit, then your pedal stroke might not be enough. I'm not talking about the total stroke, but the one that actually presses in the piston of the MC.
In any way, even without MC or with dry lines, your e-brake handle is supposed to get you some brake power to the rear wheels. It's a pure mechanical connection, and if it doesn't work, something in the rear brake shoe adjustment is fishy.

Dieter

[SpringGT]

As long as you are to the point of taking the MC off, take it apart right fast and check the quality of the rebuild. Check to see that all of the cups are undamaged and installed right. Put some light in the cylinder it and make sure that the bore has a uniform honed surface with no shiny, wear-spots where fluid might bypass. If it was rebuilt by the ebay seller, he may have only replaced the "rubber" parts and didn't refurbish the cylinder. Just a thought.
Bob

[caramiciu]

hello,
I need to chage my rrear drums (73GT).The ones I have cannot take one more grind.
Any ideas as to where i can buy a set.Aside from OGTS and OpelUSA, I could not find any.I have a hard time payig the $70-90/each.
I should be able to get some for $40-50 each.
Any help would be appreciated
thanks