DDK - Die Deutschen Klassiker

3 years ago I replaced all the rear brake cylinders with repair kits. I didn't replace the cylinders they had not actually been causing problems but with a rear brake not coming off properly and dragging it turned out to be a flexible hydraulic pipe. The pipe was old and the bore was closing inside and disrupting fluid flow. ( All flexibles were then changed)

Since then all has been great with the brakes until.... a week ago I noticed a small area of my painted garage floor had lifted. right by my passenger side rear wheel. Then I saw a dribble of hydraulic fluid on the inside of the wheel!

I did wonder first of all if it was an axle oil seal but it proved to be the wheel cylinder. Now that just was a start of my problem because when I tried to remove the metal hydraulic brake line from the back plate I turned the location nut but also the pipe at the same time result broken pipe! ( luckily the linings were not affected from the leak)

I decided to order in the end a variety of items, a new repro wheel cylinder a couple of oil seals, some split pins for the castle nut and right and left metal brake lines.

I then thought or wondered how many of you with 356 cars do the rear brake work themselves? I reckon PRS have seen just about every brake problem many times over but when you have a leaky cylinder to drive anywhere especially a long way to get to them is risky indeed!

So I took a few pictures of my work on the brakes. This system works for me but no doubt guys at PRS have other ways of working. I have the normal garage ( no post lift ) and use a hydraulic jack and axle stands.
How many of you have thought how do I get that nut off the drum and get the required 260 ftlbs torque to do it up with normal tools? I know 30 years ago it made me ponder.

1).So your car is driving fine and the brakes are okay but you want to see inside the drum. Before you start removing the split pin I mark with red marker the hole the pin goes into, the relative position on the brake drum and also at the top of the drum I mark the drum and the back plate.
In theory ( my thinking!) if when I replace the nut to same position it should be okay.

2). I made a breaker bar 30 years ago ( I had access to machines) The dimensions allow with a 36mm socket with 3/4 inch drive to be used in conjunction with a long 5 foot steel pole. A photo shows the tool and I attach also a drawing if you should want one made. ( It was only mild steel from memory and has never twisted)

3). I leave the car on the floor block the wheels in the direction I apply force and put the handbrake on. Then remove the nut.

4). My T2 car does not have drip pipe in case the axle oil seal fails. There is a chamber as part of the drum with exit hole for oil. A photo shows this.

5). The nicely shaped but broken metal hydraulic line is shown in a photo. Stoddard can supply all the formed lines. Maybe also PRS?

6). The photo shows the assembled new cylinder in place. I find it best to keep both brake shoes the top bar and spring together on removal. (undo the handbrake lever nut on removal but when replacing the shoes bolt the handbrake lever in place ready to insert on the cable.

7) For the first time in 40 years I have found an easy way for securing the brake shoes to the backplate. I never thought of using small moles to grip the slotted location across its diameter and then compressing and turning the pin to lock. ( see photo )

I also apply a very light film of copper grease to the castle nut location to stop siezure problems.

9). An important part of using the braker bar and long pole is to make sure the 3/4 inch drive is horizontal when applying force. I support the 38mm diameter on the cradle of my hydraulic jack to make sure its in good contact with the nut. ( also as guide if you take you weight say as in my case 140lbs you can measure along the pole till you see 22 inches from the socket which should give you the required 260 ftlb torque if you stand on the mark. ( It should line up anyway with the marks you made on the drum.
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Great stuff Roy, adding this to the technical links sticky

The actual Torque recommended rating for an `A` is 267 Ft/lbs (Workshop Manual Page R10)

Porsche revised this for `B`s and `C`s to 400 Ft/lbs (Workshop Manual Page R83)

I can see absolutely no reason why the Tightening Torque on a `A` should be any different to a B or C (everything except the Brake Drum is the same construction)

Bearing in mind that most of the Drive Shaft Nuts that we see do NOT spin freely on their threads, this will also generate a loss in clamping pressure

If you leave these drums loose you will eventually end up needing a New Drum or a New Drive Shaft or both

We tighten everything to 400 Ft/lbs and having reached that point if the split pin hole does NOT line up we tighten some more - NEVER loosen

DO NOT use impact Guns to tighten nuts - you have no idea what torque you are tightening to

Hey Mike,

I have always followed the 356A factory manual as you say 253 -267 ftlb
and also the "Elfrink " book page 179 which states 255 - 265 ftlb.

The Elfrink book has not?? updated torque values to over 400ftlb for "b" models with drums.

My drums have come off maybe 8 times in 40 years and the castle nuts can be easily turned on the thread. With 400ftlb and the fact the nuts are castle headed is it not possible the threads are truncating under the force?

I really hope my wheels stay on the car! with my torque loading and I do not wish to cause anyone any trouble by implying torque figures that are wrong I just followed the factory and Elfrink.

I would say in 40 years use my car has driven many thousands of miles without touch wood failure of axle items, oilseals, and until recently!! brake cylinder problems.

Why would they increase from 260 to over 400???? thats a massive difference.

Roy

I am only quoting what the Porsche Workshop Manual States

Yes - it is a big jump - so we must assume that they had a reason

Porsche issued Service Bulletins to all dealers if changes affected earlier models but my bulletins only go back to 1963, so not much use in this instance

I ought to just add the following warning

DO NOT USE VW Seal Kits - the Flat Thin Washer that abuts the face of the Wheel Bearing is too soft - try bending it - if you can bend it throw it away and buy the correct Seal Kit

As this forms part of the assembly that you are trying to Torque up - it will distort at the loads that we are talking about and there is a good chance that you will end up with a loose Brake Drum and all the expensive damage that that does

In addition we have also seen `O` Rings that are the incorrect section, which in turn lead to oil leaks and ruined Brake Shoes - VW Parts are no longer VW Parts there is a better than 50/50 chance that they are made in some `Rinky Dink` country with no quality control

My same criticism applies to Kin Pin and Link Pin Sets - buy German - buy Febi

These jobs take a lot of time and effort - it makes no sense to save a couple of pennies and then have to do it over

End of Rant

Sensible points regarding seals etc. I should make the point quite clear about the torque setting on the castlenated nut holding on the rear brake drum.

1). Mike is correct that the Porsche factory "B"manual state "B" versions
have 400ftlbs torque. ( the "A" version has the lower value above in the books but no doubt can accept the higher torque if you wish to apply it.)

2). I have tried to find out if anyone has the actual reason for uplifting the torque value from "A" to "B" drum braked cars. A number of people reckon its due to the lower lower value possibly presenting some spline wear if the drum female spline form moves against the faces of the shafts male spline. ( sorry if that looks a little rude ) if the nut is not tight enough.

Also the power transmitted to the back wheels increased with models over the years and if the car is used in rallies or racing again it might have influenced their decision.

So, although it would seem some think an "A" driven normally should be okay (as mine has been ) with the original figure, it will according to them be acceptable to increase it as Mike says. ( A tight nut is better than a loose one!)

I hope that this later information will be kept in place on the "sticky" regarding rear brakes. ( take the advice of those who work daily on these problems)

You never stop learning something about these cars!

Roy