356 Front Axle Rebuilding Service

[Curtis Batchelder]

Jim
Would you also be capable of installing and fitting new bushings (n the Torsion Bar Tubes (Top & Bottom, Inner & Outer)?

Curt

[Al Zim]

BEFORE YOU START! Grease the lower torsion bar tube on each side. If the grease comes out brown you need to clean the torsion bar tube AND carefully check the trailing arm bushings. USUALLY* we have to drive the car 3 times to make sure the suspension has settled to allow a permanent setting.
BUSHINGS to fit the spindle into the link pin carrier! are ONLY USED ON THE PRE "A" CARS.
If all goes well this usually stretches out to 3 days,
Fill the steering box.
Replace the tie rods. NOW BOTH ARE ADJUSTABLE!
To align the 356 correctly you will have to reset the bushings on the torsion bars. Sorry I forgot some of this. al
***CURTIS*** The trailing arms have roller bearings FROM 1956 ON if they are worn new ones and their races will have to be installed.
THAT IS WHY NO ONE DOES THIS! Because everything is perfect! Al
*** I know most of the cars that we see have (possibly excessive) worn out front ends! This year , 2024 we have not restored any front ends*** 17 August 2024

[Curtis Batchelder]

Al
I have a 53' Pre A 9/53, it is my belief that the on this model year the trailing arms have bushings (inner & outer) on each trailing arm (8 total), Am I incorrect in this case? My torsion bar tubes are to small for the roller bearing(s).

Curt

[Curtis Batchelder]

AL

Detail from Stoddard.

[Al Zim]

CURTIS: I have no experience on Porsche vehicle front suspension manufactured prior to 1956. Your picture of the plastic bushing looks like a VW part which
I have learned were used on all PRE A CARS. Al

[Curtis Batchelder]

Al,
Sorry I 'm having difficulty with transfer of the complete image & text.

Curt

[Jeff Adams]

Hi Curt

The Stoddard plastic bushings will not fit your pre A 356. The inside diameter of the torsion bar tube, as well as the outside diameter of the bushing, is a little smaller than the 356A and later cars. By about a millimeter if I remember right.

Bushings from a 1965 and earlier VW Beetle are pretty much the same as the pre A 356 so you can get new ones from a VW parts shop. I just checked Wolfsburg West and they have them part number is 111.401.315. The original Porsche part number is 356.41.118 and not available.

The VW bushings are a Bakelite material as original with a small inside diameter that is meant to be reamed to size after installation. Similar to the bronze king pin bushings which are also reamed to size and alignment after installation. The special reamer used for this job is not a common tool but works perfectly when setup right. Ideally, especially for the home mechanic, a bushing that is the correct inside and outside diameter size for a "plug and play" install would be available. Unfortunately I don't think this is the case with anything out there to get the just right Porsche fit and alignment we are all looking for. It also helps to have a bore gauge and micrometers to measure the car and parts to determine sizing before install. I have seen many cars with out of round torsion bar tubes, which translates to an out of round bushing inner diameter once installed. An undersize bushing and reamer can correct any out of round and alignment errors after install.

The inner bushings used on 356A and later cars is currently available from Porsche, part number 644.41.103. These particular bushings are also Bakelite like the originals. I have purchased and inspected these parts and found the inside diameters are a little too big. Meaning, you could install these new parts and have the installed inside diameter be bigger than the worn out bushings you just removed. Our remedy here has been to buy a log of suitable Bakelite material and have our machine shop custom cut new pieces on the lathe. Then, ream to size after install with the same tool used on the pre A cars. The Stoddard plastic bushings are also a little too big on the inside diameter, they must have reverse engineered the dimension from the Porsche part.

[Wes Bender]

Jeff, that's one of the most complete and informative posts I believe I have ever read on the forums.

[Brian R Adams]

Wouldn't be Bakelite, but given precise dimensions, could not a serviceable bushing be 3D printed with a modest hobby printer?
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[Al Zim]

Brian: It was unfortunate that in the early days of the 356 Porsche a plethora of VW parts were used! Because Porsche was under capitalized! Porsche's goal was a performance vehicle similar to what he developed prior to WW2. Obviously as his (and his cars) increased in performance (read cash) his team was able to improve their reliability as well as their safety! It is not my desire to bring Porsche's successes in their automotive endeavors into this conversation. Mr. Karl Ludvigsen has done an EXCELENT analysis in "Excellence Was Expected" The first book of this series. (warning it is a LOOONG book and its size dictates that it should be read resting flat on a kitchen table). It will probably tale you over a month to read this book and scribble notes in the margins of the pages.
Remember you will need 3 different sizes for reaming the king pin to the correct dimensions because old age has crept into the suspension. Do not use the plastic spacer that comes in the king pin kit it was not correctly designed to support the suspension. You may have to make tooling to correct the spindle.
FINALLY::: HOW ARE YOU GOING TO DO A PORSCHE ALIGNMENT ON THE VEHICLE. ***THIS DOES NOT WORK ON YOUR GARAGE FLOOR*** I did not address what most other shops (which I will bet includes the factory restoration shop).
You want to do this in plastic bushing made by a computer? Why it is a VW part and a cheap one at that. Al Zim

[Brian R Adams]

HOW ARE YOU GOING TO DO A PORSCHE ALIGNMENT ON THE VEHICLE. ***THIS DOES NOT WORK ON YOUR GARAGE FLOOR***

The 356 trundles along just fine with no hand-wringing over alignment at all! Just a bit of front toe-in which is easily verified with the simplest of methods. Keep the steering knuckles greased and link pins adjusted. Unless you notice obvious handling quirks, or unusual tire wear, just drive it.
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[Al Zim]

BRIAN: Its your car in your garage! Repair it as you wish. When a car leaves ZIMZ We assume financial responsivity I am also assuming personal responsibility if the vehicle something fails. You cannot have your business close because of part or assembly malfunction. al

[Martin Benade]

My single kp reamer works perfectly, matches the kp.

Brian, you forgot the rear toe-in and alignment.

Having no bent parts or body, with a little thought and string, tape measure and a plumb bob, a perfect alignment can be done. It’s not magic, just measurements.

[Brian R Adams]

Brian, you forgot the rear toe-in and alignment.

No, just ignored it.
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[Martin Benade]

If nobody messed with it, it’s probably still correct.