1957 cadillac Series 62 Brake problem

[TBZ_57_Series_62]

I recently lost all brake pressure, looked and saw fluid was low. After refilling the fluid, there still was no pressure whatsoever. Also if I pump the brake, i feel no change in pressure and cannot see any fluid squirt (from a leak). I suspect it's the master cylinder but I'm hoping one of you can tell me if I'm looking towards the right part. It's there any way to test/know if the part is bad?
Also I'm wondering if anyone knows what the exact factory correct master cylinder should be and if anyone knows how hard a rebuild would be. I tried to find any marking on the matter cylinder,  but without taking it off i did not see anything... hate to take it off if it's not the issue.

As always, I appreciate any help, anyone can give.

Thanks
Ted

[Walter Youshock]

Have you had any brake work done on this car?  How long have you had it?  How familiar are you with the hydro vac booster?  Do you have the shop manual?

[TBZ_57_Series_62]

I have had the car about 3 years...  have not had brake work done. (though i did buy parts to do the shoes, springs, adjustment screws and wheel cylinders... just have not had time to revamp). Lines look quite new and when i looked at the shoes (about 2 years ago) they were in good shape.
I know about the booster, but i am only familar with the basic function... (could my problem be the booster? Should I look into rebuild of the booster (how hard is the rebuild? ))
I do have the original shop manual and parts book.

Ted

[Walter Youshock]

Personally,  I'd have the entire hydraulic system done.  Send the booster and master out for a rebuild and either have the wheel cylinders sleeved or replace them.

The hydro vac is the one thing I would not tackle on my car.  It's bad enough removing, remounting and bleeding it.

With a single master setup, you really need every part up to perfection.

[TBZ_57_Series_62]

Do you know where to get the Hydro Vac Rebuilt and what it might cost?

Is the Master Cylinder fairly easy to rebuild myself?  I have rebuilt the Fuel Pump, ran all new fuel line, rebuilt Power Steering pump and Water Pump myself (as well as other things), so I am somewhat mechanically minded.

I had already figured on doing the wheel cylinders and the spring kits when I had the system apart, that why I don't have to worry those will fail anytime in the near future.

Thanks for the advise and help.
Ted 

[Walter Youshock]

I had mine done by Ed Strain in Florida.   If you have the shop manual,  you can see what it takes to rebuild it.  It should be in the $300 to $400 range.
  What concerned me the most was rust on the inside of it.  Since its a "wet" booster (fluid actually travels from the master into the booster and then out to the lines), it's possible it is contaminated.

The master isn't bad to do.  It's mounted on the frame and is pretty easy to remove,  rebuild and replace.

[TBZ_57_Series_62]

This may seem like a dumb question... i see many people talk about resleeving the master cylinder when rebuilding. Is it necessary or how do i know if it's needed to resleeve?

Ted

[Walter Youshock]

If it's pitted from moisture or rust, it would have to be honed and should be sleeved.   Sleeving would return the original bore size and the effectiveness of the plunger and rubber parts would be maximized.  Same goes for wheel cylinders.

[Caddy Wizard]

It has been noted several times on the Forum, but it bears repeating:  brake fluid is hydrophilic, so it absorbs moisture out of the air and causes internal corrosion in the lines and in the cylinders.  The lines can look brand new from the outside and be corroding dangerously on the inside.  Brake fluid should be flushed very regularly on an old car, preferably every two years or so.

BEST PRACTICE FOR MAXIMUM SAFETY:
Sleeve the wheel cylinders and master cylinder with stainless steel or brass sleeves to prevent them from corroding again.  Replace all hard lines with stainless steel lines (even if the old ones look good from the outside).  Send the booster off to be rebuilt (Ed Strain does a good job).  Replace the rubber hoses.  Make sure the shoes are correct for the particular car (for example, 54-56 shoes are supposed to contain a 1/2" groove in the leading shoe, a feature often missing in replacement parts).  Be sure to do the "major" brake adjustment and do it correctly.    Brakes will work impressively well.


GOOD PRACTICE FOR GOOD SAFETY:
Same as above, but use new wheel cylinders without sleeving them.  Use a new master cylinder (again without sleeving).  Install new hard brake lines, but use the plain steel.  This is cheaper and works okay, but is not as good in the long run.


IT'LL PROBABLY WORK FINE, BUT YOU ARE GAMBLING WITH YOUR LIFE
Re-use the old hard brake lines because "they don't look bad" and aren't leaking at the moment.  Rebuild the wheel cylinders and master yourself, even though they are pitted.  Same for the booster.  Since this is a "single circuit" brake system, if corrosion pops a hole in a brake line, you will know it instantly when the pedal goes to the floor and the car won't stop.  If that happens, please remember to use the parking brake and hope you don't hit anything hard.  Make sure your car and life insurance is up to date.


Sorry if this seems heavy-handed, but I am passionate about doing brakes in a way to minimize the risk of catastrophic failure.

[Jon S]

I would add that recommendation to use LMA Brake Fluid (Low Moisture Absorption).

[jackworstell]

If air got into the master cylinder when the fluid went low........... sometimes you can have an "air lock" in the master cylinder and it won't pressure up even if you fill it back up with fluid.   You will have to remove the air and bleeding brakes in the usual manner may or may not do the trick.    You may have to remove the discharge tubing from the unit and install a temporary section of flexible tubing   ......and run it back into the master cylinder reservoir.......then pump the unit.     On pressure stroke air will bubble out into the reservoir and on release stroke only fluid will be pulled back into the unit

I've had to do the on a number of occasions.

Jack Worstell   #7558

[TBZ_57_Series_62]

I'm having the booster and master rebuilt... how do i bleed the booster and what is order for bleeding the whole system? Just want to be sure this is done correctly.
Thanks
Ted

[Dave Burke]

Hi Ted,

The bleeding procedure is noted in the shop manual - basically I have a power bleeder that attaches to the master cylinder reservoir.  I got it through Amazon.com and it works great - it makes the job easier.  You start with the power booster, and bleed the screw closest to the firewall first, then the one towards the front of the booster.  You may want to repeat this a couple of times and even if you are using the booster, pump the brake pedal a few times to help the fluid through.  I use a piece of clear neoprene tubing to conduct the fluid out of the bleeder valves into a collection jar.  This allows me to see air bubbles and the color of the fluid (you can get this tubing anywhere - I got mine at Lowe's and it is a good snug fit on the bleeder nipple but allows me to keep the bleeder wrench set onto the nut part).  Bleed until there are no air bubbles and the fluid is clear.  Look for bits of contaminant floating in the fluid - that can indicate other problems such as corrosion in the lines.  Once you have bled the brake booster satisfactorily, you bleed the rest of the system by starting with the most distant wheel (passenger rear), to nearest (driver front).  You should only need to open the bleeders about 1/4 to 1/3 of a turn to get them to work - if they do not, replace them.  Most auto parts stores carry replacement bleeders.  Finally, go online to Amazon.com and order a bunch of rubber bleeder screw caps - they will keep crud out of your bleeders.  I rebuilt my own booster and recently replaced the lines on my 1957 SDV with stainless.  I may end up sending my booster out for a professional rebuild, but at the moment I am too busy driving the heck out of it.  17K miles over the last year!

Hope that helps:

Dave Burke
CLC# 27968