Author Topic: 1957 CDV Brake Job - Assistance  (Read 177 times)

Offline jfaurschou

1957 CDV Brake Job - Assistance
« on: October 20, 2018, 09:17:51 PM »
So I was in need of a brake job on my '57 CDV. I knew the MC was going out, it was leaking fluid from the boot, so I knew it was compromised and probably needed to be re-sleeved.  So I removed the old Master Cylinder and Sent it off to  a shop here locally, they deal specifically in older cars, brakes, steering and other components. They came highly recommended. The Master Cylinder was cleaned, re-sleeved with a stainless steel insert and rebuilt to original specs. I got it home, installed it and proceeded to bleed the system based on the manual's directions. I bled the whole system, flushing out the old fluid until I got clean fluid in all cylinders and through the booster first, then re bled it to get any excess air out. He's the frustrating part, I'm not getting any pressure. Pedal goes right to the floor without any hint of the shoes engaging. I removed the MC once more, and bench bled it, and re did the whole process again of bleeding (minus flushing the old fluid out completely). Same results. I've scoured the internet and forums trying to find a solution and none seem to be found.
My next assumptions are:
Is the Brake booster bad and needs to be rebuilt?  I'm looking into this but I'm not exactly sure how to test these. The shop that rebuilt my MC can do this. 
Is there a leak somewhere I can't see? Can't tell as yet, but I'm constantly checking the lines and distribution blocks to see any leaks and none I can find currently.
Is the rebuilt MC not don't correctly? Again, hard to say, It seems to be functioning properly but this type of brake system, with separate MC and Boosters has got me confused.
Need to use a different brake fluid? Read to use DOT3, and that's what I've been using.

Any help or suggestions would be awesome, I've been lying on my back under the darn thing for the past two days pounding my head into the concrete, my wife is starting to get concerned...


Jared
1957 Cadillac Coupe deVille
1987 Mercedes-Benz 560sl

Offline Roger Zimmermann

Re: 1957 CDV Brake Job - Assistance
« Reply #1 on: October 21, 2018, 03:41:45 AM »
How do you bleed the circuit? Manually (pumping with the brake pedal) or with a bleeder?
As you certainly saw, the booster must be bled too. Do you get brake fluid when you open one of both bleeding screw at the booster while pushing on the brake pedal?
It could be that the booster was improperly rebuild; difficult to see on the PC!

Offline David King

Re: 1957 CDV Brake Job - Assistance
« Reply #2 on: October 21, 2018, 07:21:53 AM »
As I recall, there is a sequence to bleeding the system and first couple of bleed points are the booster.  You have to get the high elevation air out first.

David
David King  CLC 22014 life member
Founder & Director of the Eldorado Brougham chapter
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Offline jfaurschou

Re: 1957 CDV Brake Job - Assistance
« Reply #3 on: October 21, 2018, 10:07:37 AM »
As I recall, there is a sequence to bleeding the system and first couple of bleed points are the booster.  You have to get the high elevation air out first.

David

Yes, the sequence I followed was in the manual. Booster first, (top, then bottom bleeder screws) then start with the cylinders, Passenger Rear First, Then Driver Rear, Passenger Front, Driver Front Last. I followed this each time I bled the system, and still getting no pressure.
1957 Cadillac Coupe deVille
1987 Mercedes-Benz 560sl

Offline jfaurschou

Re: 1957 CDV Brake Job - Assistance
« Reply #4 on: October 21, 2018, 10:12:38 AM »
How do you bleed the circuit? Manually (pumping with the brake pedal) or with a bleeder?
As you certainly saw, the booster must be bled too. Do you get brake fluid when you open one of both bleeding screw at the booster while pushing on the brake pedal?
It could be that the booster was improperly rebuild; difficult to see on the PC!

I have been using a Vacuum Bleeder kit. This was useful draining the old fluid which was pretty dark, and had some water in it as well. But I'm going to try again today and have my son in the drivers seat pumping the pedal and see if that make a difference. I'll try opening the bleeder screws on the booster while pumping the pedal and see the results, but I did get fluid flowing from both screws on the booster with the vacuum pump. The booster did not get rebuilt, just the MC, but I'm thinking that's the next step.
1957 Cadillac Coupe deVille
1987 Mercedes-Benz 560sl

Offline walt c

Re: 1957 CDV Brake Job - Assistance
« Reply #5 on: October 21, 2018, 03:34:50 PM »
   jfaurschou,
  I've been playing this game forever and sometimes air will NEVER bleed out it seems. Before you rebuild the booster (no reason to) try this. Using a small rubber mallet, tap on the lines at various places in the system. By the way, I have 2 or 3 vacumn bleeders (along with a pressure bleeder for forcing fluid in the reverse direction) and have never had a successful bleed with them. After using them I always have to go back to the second person bleeding. (I've had words with my wife MANY times!) Air can be a bugger! Have you tried to pump the pedal (slowly pausing between pumps) with the bleeder valves closed? (before going to the bleeder valves)My method of second person bleeding calls for the second person to pump 3-4 times with the bleeder closed, then on the next pump crack the bleeder valve open with a short hose running from the valve into clean fluid,then,close bleeder immediately before the 2nd person hits the floor with the pedal. 
  A friend of mine (also a mechanic) once took on the job of bleeding the front brakes of his Harley.(only approx 4foot of hose) He came to work that night with his eyes red from being up all day (we were on midnite shift) and NEVER could get pressure in his MC! That was years ago and I believe he did a reverse direction bleed in order to get pressure.....air can be a bugger!....good luck!....walt...tulsa,ok

Offline South_paw

Re: 1957 CDV Brake Job - Assistance
« Reply #6 on: October 21, 2018, 05:41:34 PM »
Same results here with a vacuum bleeder. Didn't work. Had to do it with my wife pumping the pedal. God she hates do that chore.  ;D
Lou
1956 Eldorado Biarritz
CLC Member since 2001 (Unlisted in Directory)



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Offline Willits

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Re: 1957 CDV Brake Job - Assistance
« Reply #7 on: October 22, 2018, 12:20:23 AM »
Same for me with the vacuum pump.   I've never had any luck using it.    I put speed bleeders on mine so I can bleed the brakes without a helper.   
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Offline Caddy Daddy 55

Re: 1957 CDV Brake Job - Assistance
« Reply #8 on: October 22, 2018, 08:17:44 AM »
What are speed bleeders?

Regards,

Bob K
Bob K
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1955 Fleetwood aka Annie

Offline walt c

Re: 1957 CDV Brake Job - Assistance
« Reply #9 on: October 22, 2018, 09:10:51 AM »
Speed bleeders are essentially a "check valve" that will allow brake fluid to pass in one direction only....good addition for any/every brake system....walt...tulsa,ok