Installing Porsche 356 drum brakes on a VW

If the car is new to you, do yourself a favor and replace ALL the brake lines, no questions asked. The old ones are a pain to work with, can cause major problems if they fail, and new ones are relatively cheap considering how important they are in the big scheme of things. Rubber lines can fail internally without giving notice externally. Having a problem with your brakes dragging? Could be the old lines giving you grief. Also, on these old VWs if one line fails, the entire system fails. If you're going to be doing brake work on one of these cars, you should consider changing it over to a dual circuit system. (I recently did this to my car)

If you are going to be replacing the master cylinder and/or front brake lines, remove the gas tank first. Yes, you can replace this stuff without removing the tank, I've done it. But in hindsight it's pretty easy to remove the tank, and you have such better access to everything with it gone. (Besides, then you'll be more apt to replace the fuel line too, and it probably needs it!)

Why Porsche parts? I wanted to use them because they're an old hotrod trick from back in the day. There were also aftermarket disk brakes available for the wide-five bolt pattern. I've seen a few sets for sale, but have forgotten the brand name now. (Maico?) They are pretty cool, but parts are more scarce, and I already had the Porsche parts when I found them! I suppose if you're doing an Okrasa special, they'd be worth looking for. Another option for those who like wide-five wheels is the modern disk brake conversions. These days they're likely cheaper and certainly easier than locating and rebuilding a set of 356 brakes.

There are also disk brake conversions that utilize the later style 4-lug pattern. If you don't mind converting to the later style wheels, these are probably the best-buy from a performance standpoint. I think most of them are only offered with dropped spindles though? This is probably a bonus to most people. And finally, the later Ghias had disk brakes factory installed. Doesn't help the link pin crowd much, but if you car has ball joints it's another source for parts.

Porsche 356 drum brakes are more or less bolt-on to the early VWs, but it should come as no surprise that Porsche parts are more expensive than VW parts, in some case MUCH more expensive.

I'm only doing the front brakes, mainly due to cost. There is another choice for an upgrade at the rear though, Type III parts can be modified to fit and offer a larger swept area. It's not exactly a bolt-on modification (some machining required) but it's not too involved. The process has been described in numerous books and magazines; pick up a copy of "VW Beetle Restoration Handbook" from HPBooks if you're interested.

Tearing the 356 brakes apart is pretty straight forward but there are a few tricks I learned. I left removing the bleeder screws until last. More on that later.

The first problem to present itself was how do I get the wheel cylinders apart? 356 front wheel cylinders only move one piston, i.e. the piston goes into a blind hole. This means I needed to find a way to push the piston out. Thinking back to a trick my dad showed me, I used a grease gun to force the piston out. This is messy, but the risk of damaging anything is about zero, and using a grease gun is very controllable, with little chance of blasting anything (including brake fluid) across the shop when it finally lets go. Compressed air may seem like an obvious answer, but I have bad memories of a little incident with a piston in a brake caliper and a certain someone's finger being in the way when the piston finally came out.

The trick is to find a way to pump grease into the cylinder to push the piston out. While it may be possible to replace the bleeder with a grease fitting, there's an easier route. The fitting on the end of my grease gun uses the same threads as the brake line, so I took the grease gun fitting off and screwed the brake cylinder on in it's place. With the cylinder screwed onto the gun, I simply pumped the piston out of the bore.

With the piston, spring, and various rubber pieces gone, I was ready to remove the bleeder screws. First I cleaned all the grease out of the wheel cylinder. Then, I put the cylinder in a smooth-jawed vise and twisted the bleed screw. Twisted it right off in fact. Ok, not a big deal. Bleed screws are cheap, right? Still, it may be a pain to get the stub out of there, so for the next one I got out the propane torch and lightly heated things up. This time, the screw turned right out. I hadn't heated it much, so I figured I'd try the next one cold. Snap. Broke another one. I heated the fourth one, and it came out no problem. For the real test, I then heated one with the broken bleeder screw and grabbed it with a vice grip. It turned right out, as did the other broken screw.

Moral of the story: Heat the cylinder where the bleed screws are inserted before trying to remove them. Porsche's are not VW's. When I went to replace the screws I had broken, I found that you can buy about ten VW bleed screws for the price of one Porsche part, and they aren't interchangeable.

The Porsche backing plates will bolt directly to the VW spindles, so there's no need to change the spindles. You can use the Porsche spindles, but I've heard this will require a different tie rod. I sold the Porsche spindles to help offset the cost of the parts so I never found out how to make it work.

Once the backing plates are bolted up, install the Porsche wheel cylinders and other parts. One note on the bridge pipes that connect the two wheel cylinders: I bought some generic metric line at the local auto parts superstore, intending to make my own. After bending the first one I noticed the flares on the new lines were formed differently than on the original line! Not good, so I ordered a set from a Porsche supply house. Even at twice the price of the generic lines they're still cheap. The generic lines probably would have worked, but why chance it?

In doing a trial fit of the Porsche drums on the VW spindles, I found the Porsche inner wheel bearings won't fit on the VW inner race (the one on the spindle; we used to call this the "cone" at the bike shop I worked at). The VW bearings seem to fit the races in the Porsche drums, so it is possible to mix and match bearings and races to get everything to work. I'm not going to describe how to do this though since, in my opinion, the best way to make it all work is to convert over to roller bearings and be done with it. The kits made to convert a VW from ball bearings to roller bearings will work perfectly with the Porsche drum. Your favorite VW supply house will have the kits to do this. Install the kit parts in their respective locations and the Porsche drums will fit right on to the VW spindles. Once the bearings are installed you can put the drums on the car and get to work bleeding/adjusting them.

A typical process with drum brakes is to adjust the star screws until the shoes rub slightly and then back off a touch. If you try this with the Porsche brakes you're going to have problems getting a good feel at the pedal. After your initial adjustment of the star wheels, you are going to go stomp on the brake pedal and the shoes are going to seat on the drums and reposition themselves on the wheel cylinders. Now the next time you press on the brakes, the pedal will go to the floor. You may spend a bunch of time trying to bleed the brakes to fix the soft pedal but it won't get any better until you readjust the shoes.

I've heard some people tighten the star wheels down tight to seat the shoes, and then back them off about four notches. I preferred to adjust the shoes with the front end in the air and the wheels off, setting them to barely rub and then applying the brakes a few times, then rechecking. Before I did this I was convinced I needed to bleed the brakes more. After I did this I was pleasantly surprised to find the initial bleeding had done the trick and I now had what felt like great brakes.

And finally, if this mod interests you, get a 356 service manual and familiarize yourself with the braking system.