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1961 Cadillac Series Sixty Fleetwood. Brake question

Started by Alexandre.j.basulto@gmail, October 31, 2021, 02:49:14 PM

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Alexandre.j.basulto@gmail

Good afternoon Cadillac and LaSalle friends,
    Recently,  I have been working on my car and I have made some good strides with minimal issues.  However,  I have reached a point of concern and question.  I replaced all of the brake lines, rebuilt the rear brake cylinders,  replaced the front brake cylinders,  rebuilt  the master cylinder,  and brake booster.  With the assistance  of a neighbor  we bled the brake system last night.  There is resistance  as you press down on the brake pedal.  All of the drums lock up and or hard to spin.

Issue-
   When I turn the car on the brake pedal has minimal  pushback and travels to the floor. As for the drums they all spin freely when the brake pedal  is pressed down. All of the vacuum  hoses are connected  and secured.  There are no leaks or drips anywhere. it's holding brake fluid. My gut tells me it's the brake booster. But I wanted to reach out and post about this.

so if there is anyone who has mechanical experience  within the the Pearland,  Texas feel free to reach out. Naturally,  your time will be compensated.   Thank you all looking forward  to your feedback.  If you prefer  to call my number is 346.804.2613. 

Alex Basulto
   

Big Fins

I just experienced this exact same thing with a full brake re-work on the '69 Fleetwood. Everything was bled to the best of my abilities. I bench bled the master and let gravity do the lines and most of the wheel cylinder and caliper bleeding. I still had no pedal. Pumped it up and pressure bled it all. Everything was right, the calipers would lock the fronts and the rears would spin free. I bled and bled and bled for an entire quart of brake fluid.

I posted my problem on my own site and was rewarded by a one sentence answer. Air in the master. Removed it and bench bled it again in varying positions. Lot's of air out of the rear section of the master.  ??? Reinstalled it and wore out the wife's legs again bleeding the entire system. Lot's of air out of the rear lines.

A nice pedal. A little lower than I would like, but solid just the same. I pulled the wheels and readjusted the rear shoes and now there is a pedal as good as factory with no premature lock up after seating everything in.   
Current:
1976 Eldorado Convertible in Crystal Blue FireMist with white interior and top. (Misty Blue)
1969 Fleetwood Brougham in Chalice Gold FireMist with matching interior and top. (The Old Man) SOLD!

Past and much missed:
1977 Brougham de Elegance
1976 Eldorado Convertible
1972 Fleetwood Brougham
1971 Sedan de Ville
1970 de Ville Convertible
1969 Sedan de Ville
1959 Sedan deVille

Cadman-iac

Alex,
John is correct, it's air trapped in the master cylinder. When you bench bleed it mount it in your vise so that the outer, or forward end, is higher than the booster end by about half an inch or a little more.
This allows the air to travel to the top of each half of the master cylinder and makes it the first thing that gets pushed out of the ports. Use an adapter fitting for a return line on both ports with clear hose if possible.  This way you can see the air coming out of the ports too. (Most master cylinders come with the adapters and hose now).
I've learned the hard way too about having to tilt the master cylinder as you bleed it. Good luck with it.

   Rick
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

Alexandre.j.basulto@gmail

Thank you both. Another issue arose today. The reservoir is losing fluid but there are no visible  leaks from the brake components or lines. My only guess is that it's back filling into the brake booster. The reservoir  was filled three times from my first post. When I rebuilt the brake booster the internals looked in great shape. I just ordered a delco Morin brake booster kit and another master cylinder  overhaul  kit.

When I took off the brake booster it was 1/3 filled with old brake fluid, rust, and grime. Not sure if that is by design?  Or should the booster system remain free of fluid??

The Tassie Devil(le)

In a word, Yes.   The Vacuum Booster should be free from brake fluid, so it would look like the seal in the back of the Master Cylinder is leaking, and the vacuum is sucking it out.

Not sure, but is it possible to install the rear seal backwards?

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

wheikkila

I would also invest in a vacuum bleeder. They are about 60.00 but well worth the money. Your wife will also like it.
Thanks Wayne

Cadman-iac

#6
Quote from: The Tassie Devil(le) on October 31, 2021, 09:11:14 PM
In a word, Yes.   The Vacuum Booster should be free from brake fluid, so it would look like the seal in the back of the Master Cylinder is leaking, and the vacuum is sucking it out.

Not sure, but is it possible to install the rear seal backwards?

Bruce. >:D

  The rear seal "could" be installed backwards I guess, depending upon the design, but it should be obvious which way it should face.
 

Alex,
  From your statements, I'm getting that you rebuilt your own master cylinder yourself then, is that correct? If so, did you inspect the bore of the cylinder for any scoring or pitting? Sometimes there are small defects such as those right at the contact area of that rear seal, and you can have a leak there into your booster without any external evidence of it. If the rubber seal between the booster and the master cylinder is in good shape, the leak will be hidden from view. And I think you can have some vacuum also drawing your fluid into the booster when you press the pedal. If you find that it is leaking into your booster, you need to check it for fluid on the inside. It collects in the can and will deteriorate the rubber diaphragms over time.

If you purchase a replacement master cylinder assembly, try to get a new one, not a remanufactured one. The quality of a reman is often questionable, as the cores they start with are somebody else's junk in most cases.
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

Alexandre.j.basulto@gmail

Good evening,
     Yes. I did and do the work on my own. Normally,  I'd  source  this out to a reputable local shop. I was fortunate to have retired last year at a relatively young age at 36 year old. Since  then I have opted to do the work myself and learn. This is the only hurdle that got me truly bewildered. I also noticed  that the vacuum  operated door lock no longer work (they all worked with no issues. Nevertheless  I'll get back at it tomorrow.  I ordered a new rebuild kit for both the booster and master cylinder.  I shy away from rebuilt/  reproposed items from past work experience  within the petrochemical industry (i.e. pumps, valves, and seals). They tend to be someone else's headache. 
  When I took apart the booster other then the old rusty sediments that traveled from theater cylinder  over the past six decades. Everything  looks great. That is why I made the decision  to reuse the same components.  Maybe I should of done the right thing and made the proper  investment. But hey we live and learn we do it with classic  American  luxury  style.

Big Fins

I don't see it stated in your posts, but did you hone the bores in the master and wheel cylinders? That essentially polishes the bores to remove any stuck on residue and any light pitting without oversizing the bore.
Current:
1976 Eldorado Convertible in Crystal Blue FireMist with white interior and top. (Misty Blue)
1969 Fleetwood Brougham in Chalice Gold FireMist with matching interior and top. (The Old Man) SOLD!

Past and much missed:
1977 Brougham de Elegance
1976 Eldorado Convertible
1972 Fleetwood Brougham
1971 Sedan de Ville
1970 de Ville Convertible
1969 Sedan de Ville
1959 Sedan deVille

Alexandre.j.basulto@gmail

Those were done as well. I took medium followed by fine sand paper.  These were done on the rear. The front wheel cylinders  were all replaced (New). I may take them off and do it to them as well.

Cadman-iac

Quote from: Alexandre.j.basulto@gmail on November 01, 2021, 11:27:17 AM
Those were done as well. I took medium followed by fine sand paper.  These were done on the rear. The front wheel cylinders  were all replaced (New). I may take them off and do it to them as well.

Alex,
Definitely inspect your front wheel cylinders, but if new, they should not need to be honed. If they are leaking, then yes, by all means do that.
  Rick
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

Big Fins

Like the rest of us, I tried to post more information, but alas, could not.

You need to hone the master and wheel cylinders that you did not replace. DO NOT use sand paper for a multitude of reasons. The most prominent being uneven surfacing. The sandpaper will score the bores and allow brake fluid to by-pass the pressure cups. Honing will give you a nice smooth surface for the cups and pistons to ride in.

You can get these honing tools at any auto parts store for just a few dollars and they use a drill for actuation. Use brake fluid as a cutting agent for the stones and run the hone in and out of the bores at an even pace. You will get a nice surface that way. The new ones shouldn't have to have anything done but bleeding them.
Current:
1976 Eldorado Convertible in Crystal Blue FireMist with white interior and top. (Misty Blue)
1969 Fleetwood Brougham in Chalice Gold FireMist with matching interior and top. (The Old Man) SOLD!

Past and much missed:
1977 Brougham de Elegance
1976 Eldorado Convertible
1972 Fleetwood Brougham
1971 Sedan de Ville
1970 de Ville Convertible
1969 Sedan de Ville
1959 Sedan deVille

Cadman-iac

   To second what John has said, definitely use the honing tool for this, as mentioned, the paper method will yield uneven results,  even if you are using an extremely fine grit. And once you've done the honing, you need to clean the bores thoroughly of any film or filings.
   Best of luck on your project. Well worth the effort and time.

Rick
CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"