Taking the Brakes Apart

Brake parts - the front brakes are in the box on the left.

Since the car had been sitting for over 30 years, the brakes did not work at all. This weekend was the start of the process of getting the brakes working - dis-assembly.

The front wheels are the most complicated. There are two cylinders at each wheel. I managed to get them completely disassembled in one fairly long day. The first wheel took the longest since I had to figure out how to do it. The second wheel went a lot faster.

I also needed to remove the rubber brake lines which had swelled closed over the years. This was the biggest problem. The nuts that held these lines on were stuck and took a lot of force to get undone. One wrench had to be on the inside of the engine compartment and another wrench had to be on the wheel side. Nita helped with this and the driver's side line came apart ok.

The air log is the big thing at the top of the picture.

Removing the rubber line from the passenger side was hard. The only way I could get a wrench on the nut inside the engine compartment was to remove the air log. This is a big aluminum tube thing that collects the air from the air cleaner and distributes it to the two carburetors. It took awhile to get the eight nuts and screws that held it on. Then I could get to the brake line nut. It was stuck and, in trying to get it loose, I broke the steel brake line. Oops! Now I have to get another one which will cost about $60.

While the air log was off, I was able to fix a leak in the fuel system. One of the nut that held a fuel line onto a carburetor was loose and I couldn't get to it with the air log in the way. Another problem fixed!

Once the front brakes were out I spent an hour or so cleaning all the parts. I couldn't get the pistons out of the wheel cylinders. It was getting dark so I gave up on that. Later that evening I looked up how to remove stuck pistons and got some good advice.

This morning the plan was to take the rear brakes off. This went really smoothly. The rear brakes only have one cylinder per wheel so there are a fewer parts. The rubber brake lines were stuck but, this time, I just cut them with a knife to make them easier to remove. I should have done this with the front wheels but didn't think of it. It turns out that the rear right wheel cylinder was new. It must have been installed when the restoration process stopped 30 years ago. I will still have to take it apart to see what the inside looks like. It could be ruined by rust after sitting so long.

One of the front wheel cylinders

The next project was to try getting the stuck pistons out of the front wheel cylinders. First I tried compressed air. I put the cylinder in a vise and held a cardboard box in front of the opening in the cylinder. I fired up the compressor and shot 90-psi air into the opened bleeder valve and the piston popped right out into the box. Perfect! It worked the same way on the next cylinder.

Compressed air didn't work on the last two cylinders. I used a grease gun instead. The end of the grease gun hose was the same thread and diameter as the hole in the cylinder so I threaded it in and pumped the handle. The piston slowly moved forward until it plopped out into my hand. I only had enough grease to do one of the wheel cylinders.

The problem with the grease gun method is you have to get all the grease out of the cylinders. Grease is not compatible with brake fluid.To do this I scraped out as much grease as I could using my finger. I used a rag to get more grease out and dropped the cylinder into a can of parts wash. Finally I sprayed carburetor cleaner through every hole and wiped it down with a clean cloth. That should be good enough.

With the pistons out of the cylinders I could inspect the bores. They were all pitted and ridged too much to get away with simply honing them. Bummer. What I think I will do is send them out to a place that puts stainless steel sleeves in them. This will be better in the long run since the stainless won't be susceptible to rust pitting.

I also need to order some parts. I need one of the steel brake lines and I really should get a master cylinder rebuild kit. I didn't take that apart yet. It is not easy to get to. I think, for the rest of this project, I will bring the car to a shop in town so we can put it up on a lift. That will make re-assembly a lot easier.

The front brake shoes look new.

My brother, Randy, found a couple of boxes of Mercedes parts at his place and sent them to me. Inside were several wheel cylinder rebuild kits and one complete rear wheel cylinder. Cool! This will save me some money. I also discovered that the brake shoes are good and the front ones are new. Nice! I hope that, when I get the front cylinders sleeved, that the rebuild kits are the right size. If so, I will be getting off easy.

I need to be able to roll the car around so I put the wheels back on, even though all the brake parts are out of it. It really rolls easy! Now I have to be careful to not push it into something. No brakes at all now, not even the emergency brake.