I am having weird issues with the brakes on my '69. The car had non functioning brakes when I bought it. Everything is new/rebuilt except for the metal lines themselves. The driver's side caliper will not bleed no matter what I do. It was rebuilt a 2nd time and the company could not find anything wrong with it. The caliper does appear to work though, when you step on the petal the shoes contact the rotor.
2nd issue is, The passenger side is leaking a lot from the house where it goes into the caliper. Do I need two crush washers, a different kind of washer? And, of course, I have almost no brakes, pedal goes to the floor. I'm stumped.....
On the front left frame rail there is a proportioning valve....I'm wondering if your opening this valve up when you bleed the brakes....
Here's one for sale on eBay right now, just so we can see what it looks like. From underneath the car I hang a small vise grip off that small stud on the bottom. This valve needs to be open when bleeding the brakes....
https://www.ebay.com/itm/193551287167
Somebody else will weigh in with a better description of what needs to be done....
Mike
What is the"house" where it goes into the caliper? Some calipers require a copper washer on both sides of the fitting. Did you bleed the rear first?
I'd crack the lines at the calipers and hit the pedal to see if anything comes out. Tighten the lines before releasing the pedal. This will let you know if the bleeding problem is the master/line, or the caliper.
You say things are replaced but does that include the rubber lines?
Jeff R
Quote from: Dave Shepherd on August 30, 2022, 07:07:38 PMWhat is the"house" where it goes into the caliper? Some calipers require a copper washer on both sides of the fitting. Did you bleed the rear first?
I think he meant to spell 'hose'.
Lots to add to this. The master is a bear to get all the air out of it on the bench. You need to put it in a vise almost straight up where the outlet ports are at the top for the air to get out. Then you need to put in pipe plugs while you bolt it to the booster. From there, bleed out each section of hard line from the top to the bottom at the calipers and wheel cylinders.
I've never had so much trouble bleeding brakes as on 69 & 70 cars. Calipers need 2 brass washers. One on each side of the hose block and be sure the hole in the bolt is clean.
Good info, BigFins, but the washers are copper.
Thank everyone for the replies. Yes, I meant hose and yes all rubber hoses were replaced. No I haven't opened the proportioning valve, that's probably part of my problem :P Also I didn't realize I need two copper washers right now there is just one on each. What do you mean "washers on either side of hose block"? I had the master cylinder in a vise and did what you said, it bled fine.
If these are the metric type hose, flat block, hole in the middle, feed bolt screws into the caliper. They must have a copper washer on either side.
I take it this is the proportioning valve. How far is this thing supposed to open? Several turns?
And this is what I have for brake hoses, not the type with the hole in the middle. Two washers here?? (this is where it leaks, just on the passenger side not driver)
That style does just use a single washer. I have had issues with those leaking too lately, I think its just low quality parts. Makes you feel safe when its thing like brakes eh?
I'm not a 69 expert but to me that looks like perhaps some sort of drum to disc conversion? The caliper doesn't look right to be especially and the hex bolts look really not stock but I'm more used to the 70's so maybe they are correct?
Quote from: Cadillac Nut on September 02, 2022, 05:52:53 PMI take it this is the proportioning valve. How far is this thing supposed to open? Several turns?
Yes that's the proportioning valve....the pin on the bottom is what opens the valve....It's been awhile since I bled my brakes but I remember the pin is pulled down not turned, It's spring loaded inside the valve....Maybe twist it back and forth a little to get it moving....It doesn't pull out very far to open and I usually hang a vise grip from it to keep it open as I bleed the system.....Don't force anything here....
Your hoses look like they need just one crush copper washer there....
Mike
It's the stock 69 brake set up. I'll replace the washer but kind of scary if parts are really that low quality now. I was able to twist the valve back and forth a little, I'll use the vise grips like you said to pull it down and try it tomorrow and see what happens
Interesting, I didn't know they ever used hex bolts, I thought the floating calipers started out with the Allen heads.
What method(s) of bleeding have you tried? Have you tried just leaving the bleeders open for a few hours and see if gravity will fix it? Are you sure the pedal is fully returning all the way up? If something is keeping the MC from fully returning it won't bleed or act correctly. Could also be a mismatch between the booster and MC causing it not to fully return. To test that you can usually loosen the bolts between the booster and MC so there is a gap just for testing.
Are you sure that pin is pulled down? Mine does not move up or down at all, it will turn slightly.
Everything bleeds fine except driver's side caliper. The pedal returns normally I don't think it's a master cylinder issue or I would be having bleeding problems on the passenger side too
The proportioning valve seemed to be stuck, I did finally get the pin to go up and down, and hung a vise grip on it like suggested. No change. No matter what, no fluid will come out of the driver's side bleeder. The passenger side bleeds fine, however when you close the bleeder and try to bleed the driver side, it eventually starts leaking from where the crush washer is (at this point am putting a lot of force on the pedal). I know that fluid is getting to the driver's side as it will drip out of the hose if you remove the hose from the caliper. I'm stumped.
Quote from: Cadillac Nut on September 03, 2022, 04:07:55 PMThe proportioning valve seemed to be stuck, I did finally get the pin to go up and down, and hung a vise grip on it like suggested. No change. No matter what, no fluid will come out of the driver's side bleeder. The passenger side bleeds fine, however when you close the bleeder and try to bleed the driver side, it eventually starts leaking from where the crush washer is (at this point am putting a lot of force on the pedal). I know that fluid is getting to the driver's side as it will drip out of the hose if you remove the hose from the caliper. I'm stumped.
I'd leave the proportioning valve open and then remove the drivers side bleeder out completely....will fluid leak out of the caliper by gravity?....maybe the bleeder is clogged or defective....blow some air thru the bleeder while it's out...With bleeders open a substantial pressure on the pedal wouldn't be needed....
Mike
Ok so some progress, I did remove the bleeder and I stuck a small pin in there. Pumped pedal, fluid finally came out. Put bleeder back in, fluid came out and bled caliper as normal. I assume it was obstructed somehow? Bled passenger side. Closed bleeder valve. Started up car, applied brakes as normal. Pedal goes to floor. Any ideas what to do now?
Didn't see this in the posts, but have you successfully bled the rear, this the first step in the process.
Yes, the rear bled fine.
It's time to start all over again with the bleeding.....If you don't have a power bleeder then this is a 2 person operation....one in the car at the brake pedal and one under the car opening and closing the bleeders....your proportioning valve has to be open....
Start at the right rear, furthermost from the master....bleeder gets opened someone pushes the brake pedal down.....air and or fluid comes out.....brake pedal held at the floor until you close the bleeder....keep do that process until just brake fluid comes out of that bleeder....go back to master and refill with fresh fluid....
Continue with left rear then right front then left front....don't let the master run out of fluid.....Then close proportion valve and see if you have brake pressure.....if you still don't, I'd look hard at the new master cylinder as being defective....
Wish I was there to help...
Mike
Well bled the car again, the rears bleed fine like before. Proportioning valve was open. The fronts very tough to get all the air out, went through a lot of brake fluid. I think I got all the air out. Pedal does the same thing, maybe a slight improvement. Step on it and it goes to the floor. I don't think it's a bleeding issue now. Master cylinder? What else could it be? I have never had so many issues with brakes before and I have worked on a lot of cars :o
Pinch the front hoses off, see if the have a pedal, post back.
What bleeding method(s) are you using?
Pinch off both brake hoses near the caliper? How do I do this, with a zip tie? I am using the regular 2 person bleeding method like described above.
Use needle nose vise grips, if possible, clamp them closed as far from the caliper as you can. Even better is plug the port on the master that goes to the front brakes, an inverted flare pipe plug will work. Same size as the line. The see if you have some pedal.
I plugged the front port on the master cylinder. Now, I have pedal
So that tells us that something in the front has a leak and or has air in it. Can you keep moving forward plugging things? Like being able to isolate the sides?
I'll try pinching off each side with a vise grips. Would this indicate a master cylinder issue?
Couple of possibilities here, air getting into one or both of lines supplying the front brakes, or if the master is sectioned off front to rear, could be air trapped in the portion that feeds the ft brakes. Your getting closer to a resolution here.
I clamped off each side with a vise grip, as tight as I could. No pedal whatsoever. It's a dual pot master cylinder. I must have gone through a quart of brake fluid trying to get the fronts bled. Thanks for the help guys
The fronts never seemed like they bled 100% even though I went through so much fluid. I can here gurgling sounds when I am bleeding them (not sure if that means anything but seems a little odd)
If you have any 'leak' it's also opportunity for air to be introduced and therefore no bleeding can take place.
Once the leaks are addressed the bleeding takes place with the rear farthest from MC. I like to use clear aquarium hose fitted over the bleeder into a clear reservoir. Open the bleeder and have someone depress the pedal only. Watch for fluid/air activity exhausting thru hose. Tighten bleeder and then raise pedal.
Technically air can be introduced via loosened bleeder, so to avoid that, I try to only depress the pedal for bleeding.
I also bleed right at the master cylinder by pumping the brakes and holding the pedal down, then crack the line at the master and fluid/air will exhaust while pedal sinks. Tighten line BEFORE allowing pedal to return.
Monitor fluid level at all times in reservoir or all gains will be lost.
There are no leaks that I see. That's exactly how I am bleeding the brakes (with clear tube) and it has worked for every other brake job I have ever done. I did bench bleed the master cylinder. I will try bleeding just the fronts at the master cylinder. Something is going on with the front brakes that isn't normal.
I have done as suggested and bled at the master cylinder and both front calipers. They seem like the bled okay this time,but still no pedal. To me I would think this is a master cylinder issue. Could the proportioning valve have anything to do with it?
Since you are running out of other things to try maybe loosen and install temporary spacers between the booster and MC just to make sure its returning fully? Maybe the front and back are not perfectly aligned and the fronts are having an issue because its not fully returning?
Are those MC's hard to come by or expensive? Since you have tried everything else maybe try a new one? Are you sure you have the correct one for disc brakes? There were still a lot of drums around in 69.
Since 69 is still fairly early in disc brakes I'm not sure what the prop valve was actually doing. Many of them are mostly working with the rear.
No, they aren't, I ordered another one which should come Thursday. I need to get the brakes working ASAP as this car is blocking in another one. I matched up the casting part number on the old master cylinder to the new one so I'm sure I have the right one. At this point I don't see it being a caliper or brake hose issue.
Is the proportioning valve rebuildable on these cars? I cannot find a new one anywhere.
Pretty sure you could fabricate some lines and adapt a generic GM style disc /drum valve if you feel that would fix it, I don't think that is the issue though, let's say it was blocking off the front, yes you couldn't bleed the front as no fluid could pass the valve, but you would have a pedal.
I sent the proportioning valve in to be rebuilt, I found a rebuilder. It has to be either the valve or the master cylinder.
I'm still siding with the MC having air in it. I invented new cuss words when I did mine. Once I had all the air out of the MC, the brakes came right in. I went through 2 quarts of brake fluid before finding out the MC was air locked. Fluid flowed through everything, just as it's supposed to. Still no pedal.
I filled the MC to the top, put on the cover, removed it and placed it in the bench vise standing straight up. I pushed the piston up from the bottom and expelled more air. Light taps with a hammer and a few more burps. After that, I installed pipe plugs in the ports and reinstalled the unit, then bled the entire system again. Great pedal, seated the pads and shoes, then made final rear adjustments. Stops on a dime and gives 9 cents change.
But I have rear brakes, block off front port on master cylinder and I have rear brakes. So I don't think the master cylinder has air in it or I wouldn't have any brakes. I did exactly what you did to the master cylinder. before I installed it and got all the air out I'm waiting for the proportioning valve to come back. After that I am replacing the master cylinder with another one, bleeding everything again and then will post back with the results.
Wanted to give an update, after obtaining a replacement proportioning valve and having that one rebuilt, and then bleeding the brakes again, I now have brakes that work excellent. One wheel I had to bleed twice, these brakes are a little tricky to bleed. So the issue was my proportioning valve. Thanks to everyone who helped
Quote from: TJ Hopland on September 02, 2022, 06:02:38 PMThat style does just use a single washer. I have had issues with those leaking too lately, I think its just low quality parts. Makes you feel safe when its thing like brakes eh?
I'm not a 69 expert but to me that looks like perhaps some sort of drum to disc conversion? The caliper doesn't look right to be especially and the hex bolts look really not stock but I'm more used to the 70's so maybe they are correct?
Cadillac for 1969 was 100% disc brakes.
When I had a pedal to the floor problem a few years ago, it was the master cylinder.
Garrett: Thanks for taking the time to follow up with the final outcome. Many people have long strings, with lots of contributors, problems eventually get resolved, but everybody following along never finds out what really worked to find the problem. We are ALL still learning. Thank you! Joe Gibeault
I didn't want to leave people hanging, a lot of great info was provided. Hopefully this will help someone in the future working on one of these cars.