Correct use of Spring Washers
 

I thought I had seen a discussion on this once before, but can't find anything with a search.
I'm in the process of re-assembling the F&R suspensions on my 73.
I'm trying to make sure that all the fasteners are correct.
I've noticed in many cases, the factory manual specifies bolts with spring washers alone, or bolts with flat washers and split lock washers. For example, Volume 5, assembly group 4 (Front Axle) page 2.1 - 3/1 calls for spring washers on the M12 bolts to the pan, and the M10 bolts to the Steering Rack. Page 2.1-4/2 shows Flat & Split Lock washers on the Sway bar mounts.
Does anyone know if there are guidelines for when to use which washer combination.
Sorry if this seems a bit anal, but these fasteners would be among my least favorites to come loose.

Thanks for your help.
Joe Frantz

Re: Correct use of Spring Washers
 

don't know if there are any Porsche guidelines for the nuts/washers, generally.. but the parts catalog has a blow by blow description of everything.............Ron

this is for '74-'77.. the microfiche was photostat, then scanned..

http://forums.pelicanparts.com/uploads/frontwash.jpg

Ron,
Thanks for your help.
The picture is a little tough to make out, but it definitely looks more complete than the repair manual.
Joe

Yep.. just wanted to give you a dose.. the parts book for my car comes in a microfiche that costs maybe $30.. they are a great reference for assembly of a project.. it took a few hours for me at the library to turn out a stack of photostate copies of each page.. and a big stack of dimes

I too, have tried to understand the logic to the Porsche's use of lock washers and other fastener locking methods on the 911. There are to my knowledge cotter pins, helical lock washers, spring washers, Schnoor lock washers (a type of toothed Belleville washer), prevailing torque lock nuts (either a plastic insert or a deformed thread geometry type), nuts with a flange or sleeve for upsetting or staking, locking tab washers, the infamous stretch bolts and Loctite thread locking compund. I haven't seen or heard of any lock wire being used on a production vehicle but there may have been. Except for a few cases there seems to be little rhyme or reason (based on looking at the factory parts catalogs which I too try and follow) to the locking method used for a particular fastener. I suspect the many methods used were simply a matter of the designer's preference or what was cheapest or the latest technology or simply what proved to work. The exceptions I note are the high temperature insert locknuts used on the engine (valve covers, etc.); note that the OEM locknuts have a black, brown or blue insert and are not white like common nylon Nylocks. The white nylon nylocks will soften and creep under the higher engine temperatures. On really hot parts around the exhaust there are some all metal prevailing torque (distorted thread) nuts. In addition, these all metal prevailing torque nuts are used on the intake runner studs. Stretch bolts are used where a maximum and predictable clamping load is desired. One fasteners I desire to further secure (but still remove someday) I'll degrease the threads and use a bit of blue Loctite on. Cheers, Jim

Update - Loctite now makes a special Blue that will set up fine on oily surfaces.

I'd bet PAG just tossed a new summer intern at each separate area and that person used whatever they learned in school...