Repairing the Treadle Vac Master Cylinder and Brake Booster of my 58 Eldorado

In June I bled the brakes of the 58 Seville because it needed some fresh fluid, and the fluid level was a little low in the reservoir of the Bendix Treadle Vac master cylinder.
Now as I wanted to drive it out of the garage, I found a puddle of brake fluid under the car.
So I went on to search where it was coming from.
I suspected a leaking wheel cylinder, but could not find any traces of fluid coming from the wheels. After some more searching, I eventually found out that fluid was dripping out under the brake booster along the push rod. When I checked the fluid level it was only half full.

So I knew that the Treadle Vac would need a full rebuild…
I ordered a rebuild kit at Cadillac Parts LTD. They offer a kit to rebuild everything from the booster to the master cylinder. As I found out, the gasket for the reservoir did not fit from their set and some other correct smaller rubber parts are also not included in the set. So remove everything carefully from your unit as you might have to reuse some parts for your rebuild. I contacted them about the wrong parts and they immediately sent me the correct parts by mail. Great customer services - I would order from them anytime again!

As I had never done a full rebuild I asked my Cadillac friend Lucky for help - knowing that he can repair almost everything, and that he had done this job during the full restoration of his awesome 58 Biarritz before.

He was so kind to offer his assistance and invited me to his fantastic work shop where he is restoring his cars.

So I carefully removed the whole unit from my car and visited Lucky´s workshop.

With his skills he managed to rebuild the whole unit within a couple of hours. As it turned out a bad O-ring caused fluid to leak into the booster.
Due to all the brake fluid the finish of the Bendix unit suffered a lot, and so I decided to strip everything on the outside down to bare metal to repaint it.
So I took everything apart once again to make sure to do it perfectly.
I ordered some great spray cans from Eastwood to get the perfect look to match its appearance to when it was new.
Originally the master cylinder was not painted at all - but left in bare cast metal. Of course it started to collect surface rust very quickly - even on new cars back in 1958.
The booster originally was painted in semi gloss black.

Eastwood has a product called "Brake Gray" which I used to emulate this look. It comes extremely close to bare metal, but of course the paint protects the metal from rust. This paint is also resistant against brake fluid. I first primered the master cylinder with self etching primer two times before two coats of brake gray were applied.

For the brake booster I ordered Eastwoods Chassis Black extreme primer and satin black paint - painting turned out really fine! See pictures below

To make bleeding brakes easier and a one person job I also ordered a set of speed bleeder screws. (SB3824-SS)

The unit still in the car - before removal
Removal has started
The unit out of the car - before rebuilding it.
Out of the car
In Lucky´s workshop with the rebuild kit I got from the USA
My friend Lucky at work
Lucky´s fantastic work shop
The Bendix master cylinder fully disassembled

Everything disassembled

This O-ring was leaking and caused the problem.

The new o-ring in place.

The vacuum cylinder
As you can see the paint suffered from the brake fluid - a repaint was necessary after the rebuild.

I started to wire brush the paint off - took it apart once again after this picture.

The master cylinder in primer.

After painting it with "Brake Gray" - great stuff.

The master cylinder with paint
The booster in bare metal before primer. I used Eastwood Extrem Chassis Black primer and paint.

In primer

Speed Bleeder screws
Speed Bleeder screws and bag
The new Speed Bleeder screw in place
The reassembled unit back in the car.


Outlook to the 2012 season - doing the first repairs 2012

As we had a nice sunny, dry winter day today I decided to re-arrange the cars in my garage so that I can start doing some work on them during the remaining cold winter nights.

The following work is planed for the next few months before the cars will be put back on the road in May 2012.

1971 Mark III

1967 DeVille

  • needs new front wheel bearings (I already have the spare parts)
  • will try to find a rebuilt OEM Bendix master cylinder and vacuum booster. These are very difficult to find. Everybody seems to offer Delco Moraine parts only. I have replaced my original booster and master cylinder 2 years ago and I´m not quite happy with the power assist of the new units. It seems that the after market master cylinders from Delco have a smaller bore diameter and therefore you will have to depress the pedal with more force. There is a discussion going on on the topic of finding the correct booster and master cylinder in the CLC forum - check it out for more detail! If you know where I could find a correct Bendix booster and master cylinder or where I could get my original core rebuilt, please let me know!! The parts number for the Bendix Master Cylinder is #1489981 and for the Bendix booster it is: #1489071
  • re-adjust the gear indicator as it's slightly out of line.

1967 Eldorado

  • I will remove the starter motor and have it rebuilt - it sometimes is acting up

1958 Eldorado

  • It needs some new front wheel bearings as well. I already bought the parts.

I will of course post the repair progress here on my website

A new garage?

The biggest planned project for 2012 will be to find a solution for my storage problem. I hope to be able to build another garage or to rent one. I will have to find a solution until the spring of 2012. I´m dreaming of building a building which can hold 8 Cadillacs, but I do not know yet if I will be able to afford it...

Car Shows

I hope to attend and visit the „Klassikwelt Bodensee“ from May 17th to 20th and of course the best meeting in Europe - the Cadillac BIG Meet August 25th to 26th. I will also hopefully make it to some local shows here in Austria.

As we had a dry winter day I took the cars out of the garage - they fired right up after some months of sleeping

The Mark III was moved to the back of the garage, so that I can start working on the other cars first

Little Elliot loves Daddy´s cars as well ;-)