CoupeDTS Posted August 19, 2012 Report Share Posted August 19, 2012 On my 70 Calais the brakes went out last week. they barely worked then after a few more times pushing they just went to the floor with ease. WIthout the booster hooked up they still went to the floor just not as easy. And without any leaks I figured it must be the master cylinder. I put a new one on, I got the bleeder kit to bleed the master cylinder and I pumped until no more air was coming out of the hoses going back into the resevoir. Then I started to bleed the brakes. I have a check valve setup with a clear hose attached to the bleeder. THe back brakes barely pushed any fluid out. The fronts bled great, lots of dirty fluid came out and then the air and clear fluid until no more air. But still both back brakes would not do anything. I took the back hardline off the master cylinder and blew compressed air through with both back bleeders open and all the fluid blew out and then air, so its not blocked. Now I cant get anything out of the back bleeders, the fluid is not going down in the back resevoir. Fluid drips from the back master cylinder port when the hardline is disconnected and it worked when i bench bled it so it seems the master cylinder is good. Whats going on? I see other cars you have to adjust the proportioning valve but this car there is no adjustments or levers. For now i parked on a hill and left the master cap loose and the back bleeders hoping it will gravity bleed. Am I doing something wrong? * 1966 Deville Convertible * 2007 Escalade ESV Black on Black * 1996 Fleetwood Brougham Black on Black V4P -Gone* 1983 Coupe Deville Street/Show Lowrider -Gone* 1970 Calais 4dr Hardtop GONE* 2000 Deville DTS - Silver with Black Leather and SE grille GONE* 1999 Seville STS - Pearl Red GONE Link to comment Share on other sites More sharing options...
CHL2T Posted August 20, 2012 Report Share Posted August 20, 2012 Remover the back bleeders and ream them out with a piece of wire, if that doesn't do it, remove the back wheels and have a look at the wheel cylinders they may be rusted and crusted up and in need of a rebuild...... Don't let your first ride be your last ride in a Cadillac! Link to comment Share on other sites More sharing options...
rockfangd Posted August 20, 2012 Report Share Posted August 20, 2012 i had similair problem with my k1500. Problem was I didnt realize master was the problem because it went over the coarse of time. I had the same problem. fronts bled great, rears would trickle. I replaced lines, cylinders, and no matter what they wouldnt bleed. master was the issue. New master and voila. Now 2 things. I have seen bad masters right out of the box And also I dont bleed the fronts till the backs have been bled. if not you may have to start over. I wish you the best of luck. It can be a PITA. Also I agree. check the bleeders to be sure they are not clogged GM FAN FOREVER Nice, clean, luxury= fine automobile Link to comment Share on other sites More sharing options...
CoupeDTS Posted August 20, 2012 Author Report Share Posted August 20, 2012 Ya I took the bleeders out and ran air through them too. The gravity thing I think is working a little atleast a little fluid is coming out now, ill know more tomorrow. Sounds like I'm doing all I can * 1966 Deville Convertible * 2007 Escalade ESV Black on Black * 1996 Fleetwood Brougham Black on Black V4P -Gone* 1983 Coupe Deville Street/Show Lowrider -Gone* 1970 Calais 4dr Hardtop GONE* 2000 Deville DTS - Silver with Black Leather and SE grille GONE* 1999 Seville STS - Pearl Red GONE Link to comment Share on other sites More sharing options...
CoupeDTS Posted August 20, 2012 Author Report Share Posted August 20, 2012 Tried rebleeding the master cylinder, ran air though the lines with the bleeders open again, still not moving fluid. So I hooked up a vacuum and clear tube to the back bleeder and fluid and mostly air came out, never a clear stream so somhow its sucking in air. There's no lines leaking or wheel cylinder so I suspect the reman master cylinder. I had the store order up another, ill redo everything and see if there are any different results. * 1966 Deville Convertible * 2007 Escalade ESV Black on Black * 1996 Fleetwood Brougham Black on Black V4P -Gone* 1983 Coupe Deville Street/Show Lowrider -Gone* 1970 Calais 4dr Hardtop GONE* 2000 Deville DTS - Silver with Black Leather and SE grille GONE* 1999 Seville STS - Pearl Red GONE Link to comment Share on other sites More sharing options...
rockfangd Posted August 21, 2012 Report Share Posted August 21, 2012 please keep us updated. They are fairly common to be bad right out of the box. sometimes they have sat on the shelf for a long time and then when they get iinstalled it damages the seals GM FAN FOREVER Nice, clean, luxury= fine automobile Link to comment Share on other sites More sharing options...
CoupeDTS Posted August 22, 2012 Author Report Share Posted August 22, 2012 That's very possible since nobody in town had one of these. After inquiring a lot of people they say with some its important not to press the plunger in more than an inch because it will ruin the seals. There was a warning about that in the instructions but I wasn't sure if I was pushing it in more than an inch. Nevertheless with the next one ill be more careful and more knowlegeable so hopefully it works. For those of us with newer cars, one thing I've learned from the videos is you don't have to bleed furthest to closest like u do on older cars because each corner now is a seperate system or proportioned right at the master cylinder. Nifty. * 1966 Deville Convertible * 2007 Escalade ESV Black on Black * 1996 Fleetwood Brougham Black on Black V4P -Gone* 1983 Coupe Deville Street/Show Lowrider -Gone* 1970 Calais 4dr Hardtop GONE* 2000 Deville DTS - Silver with Black Leather and SE grille GONE* 1999 Seville STS - Pearl Red GONE Link to comment Share on other sites More sharing options...
rockfangd Posted August 22, 2012 Report Share Posted August 22, 2012 I only push the piston a little bit several times when I bench bleed the master, Now on the other part it still applies to systems with proportioning valves because if you bleed the fronts first you wont be able to bleed the rears GM FAN FOREVER Nice, clean, luxury= fine automobile Link to comment Share on other sites More sharing options...
CoupeDTS Posted August 23, 2012 Author Report Share Posted August 23, 2012 Well I installed the next reman master today and an hour later was cruising. This time I only pressed the brake down an inch or so when bleeding the master and the same when bleeding the brakes. Everything worked out great. So for any future reference, DON'T put the pedal to the floor or press the master in all the way * 1966 Deville Convertible * 2007 Escalade ESV Black on Black * 1996 Fleetwood Brougham Black on Black V4P -Gone* 1983 Coupe Deville Street/Show Lowrider -Gone* 1970 Calais 4dr Hardtop GONE* 2000 Deville DTS - Silver with Black Leather and SE grille GONE* 1999 Seville STS - Pearl Red GONE Link to comment Share on other sites More sharing options...
rockfangd Posted August 24, 2012 Report Share Posted August 24, 2012 excellent. Glad to hear it. Brakes can be very complicated especially when the new part is faulty GM FAN FOREVER Nice, clean, luxury= fine automobile Link to comment Share on other sites More sharing options...
CoupeDTS Posted August 24, 2012 Author Report Share Posted August 24, 2012 Other mechanics say they press the master cylinder in all the way with no problems. Well I warned them its possible to ruin them that way either if the seal in them is old or it could be model based. Either way better be safe then sorry and just pump the pedal a little, it still gets the job done. * 1966 Deville Convertible * 2007 Escalade ESV Black on Black * 1996 Fleetwood Brougham Black on Black V4P -Gone* 1983 Coupe Deville Street/Show Lowrider -Gone* 1970 Calais 4dr Hardtop GONE* 2000 Deville DTS - Silver with Black Leather and SE grille GONE* 1999 Seville STS - Pearl Red GONE Link to comment Share on other sites More sharing options...
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