cv bolts/gaskets early 75 targa

[47silver]

I am planning to replace both wheel rear bearings and have 2 questions that i could not find answers to in the search.
75 targa (early model).

1. should i replace the cv joint bolts?
2. should i replace the gaskets

Any advice is appreciated.

[Kelly Bell]

Absolutley! The bolts need to be replaced everytime you remove them, and the gaskets should go without saying. You will ruin a few gaskets while putting them on!

Good luck!

[47silver]

wow $7.25 for each bolt? are they stainless? special..do they screw themselves in?

[randywebb]

They are special high strength bolts. (12.9)

They do NOT need to be replaced each time, BUT inspect each one very carefully - use glasses or a magnifier and look closely at the threads and the place where the allen key fits into the head of the bolt (cap screw). That place is called the wrenching feature, at least by Jim Sims -- and he should know.

DO replace the Schnorr washers (the toothed rings that bite into the moon plates).

Do clean everything very careflly and avoid any grease on the threads or anywhere on the cap screws (like under the base). Use Q-tips & brake cleaner. It isn't fun...

IF the bolts are 30 years old, you might want to just replace them on general principles.

Do a search for more info.

[randywebb]

oh yeh - be sure to use the right torque and to re-torque them after 100 miles.

[47silver]

thanks for the comments....30 years? wow i keep forgetting how old this vehicle is..

[Nine9six]

Originally posted by randywebb
They are special high strength bolts. (12.9)

They do NOT need to be replaced each time, BUT inspect each one very carefully - use glasses or a magnifier and look closely at the threads and the place where the allen key fits into the head of the bolt (cap screw). That place is called the wrenching feature, at least by Jim Sims -- and he should know.

DO replace the Schnorr washers (the toothed rings that bite into the moon plates).

Do clean everything very careflly and avoid any grease on the threads or anywhere on the cap screws (like under the base). Use Q-tips & brake cleaner. It isn't fun...

IF the bolts are 30 years old, you might want to just replace them on general principles.
oh yeh - be sure to use the right torque and to re-torque them after 100 miles.
Do a search for more info.

Just as Randy spelled it out...After all thds are cleaned and ready for reassy, I use blue loktite, and have never had an issue with loosening or backing out CV bolts. 100 and 500 mile rechecks have confirmed this procedure.

[47silver]

great information...and will take my good ole time doing it properly...i hate being stranded.

[Grady Clay]

Naah,

I’m sure our host is less than the PCNA $7.25. I just queried my local supplier (* below) and these M10x55 are $26/C, $0.38 each in 16-24 quantity or $0.65 singly.

Just to be clear, your 911 has how many CV bolts at each CV joint? What size? (A M10 fastener uses an 8 mm Allen wrench and a M8 fastener uses a 6 mm Allen wrench.) What is the OD of the CV joint? Are there bolts at all four CV joints? How thick is each CV joint?

The proper term for this fastener is an “M10x55 (or whatever length in 5 mm increments) socket head cap screw class 12.9.” The Porsche parts are available in the specified length (say 48 mm) but cost a great deal more.

It is possible to shorten the fasteners but this isn’t a “hack saw operation.” The big issue is the “lead-in” thread that allows proper engagement of the fastener into the flange threads. Careful inspection of a commercial fastener will clearly show this. These are rolled (not cut) threads. The other important issue is to absolutely not damage the fastener in the process.

While long, there is a lot of good info in this thread:
Pelican rcecale, Randy’s classic thread.
”Reconstructing Constant Velocity (CV) Joints”
It is worth the time to read.

The lock washers are Schnorr Bellville Spring Safety Washers. This site has a lot of good technical information.

*
AAA Metric Supply
60 Lipan St.
Denver, CO 80223
303-892-9000 (-12 for info).

I assume you have searched and read all the threads about replacing your rear axle bearings. There is a lot of good info. You could do everyone a service by posting links and your critical review. There isn’t the minutest detail that isn’t worth discussing.

Best,
Grady

[47silver]

Grady:

Mine is an early targa (0148) 1975 with about 55k miles on it. I do not think that the wheel bearings were replaced but the engine was out (rebuilt), new clutch etc by previous owners. and although a lot of work was done on the engine, I do not think that the cv's were replaced so i am assuming that the bolts are 10x48. the cv boots look like they are in good shape but i was thinking of replacing them also and repacking them with the appropriate lubricant.

I was going to order all new bolts from pp but they are listed at 7.25 each on the site which gave me pause. 1.50 each even 2 bucks but 7.25...i hope that you are correct and it is a misprint.

the washers are about .5 each so no big deal.

I have a pretty good camera and if it would be helpful to anyone eles i will try to document what i am going to do pretty thoroughly and write it up with a material list, tools, time etc. That is my objective, but in the thick of the job i tend to keep moving until it is done and then say, oh, i should have taken pictures,,
i found this to be the case when i recently did a pedal cluster interior refit...too few pictures too late in the process.

but i am glad that you suggested it so i will verify what type of cv and bolts are there.

[Grady Clay]

YOU BET

While there are quite a number of threads (Pelican and other), I have never seen a comprehensive “start-to-finish” detailed set of instructions on rear wheel bearing replacement. That naturally includes servicing the axle CV joints and boots. As you can see form any search, there is a big deal issue with CV joints coming loose. Most of the time it only damages some perfectly good Porsche parts. It can also cause a 911 to go out of control. The goal is to devise a good set of instructions for this common procedure.

The Porsche Workshop Manual for the 911 Carrera (’84-’89) has pretty good descriptive procedures, it isn’t commonly available for earlier 911s. The goal could be to combine Factory procedures with more detailed instruction to cover all 911s since ’69. (The SWB rear bearings are significantly different and pretty well covered in Vol. I.)

Aside from the issues with the axle half-shafts (which are pretty well covered), there are several other. First is the rear shock lower mounting bolt is usually not easy to remove. Next is the service/parking brake assemblies (which need maintenance), the not unusual damage to the parking backing plate-bearing retainer and finally the issues removing and re-installing the wheel bearing. There has been a lot written about the conversion to the aluminum trailing arms that should be linked.

If these tasks are done correctly they will last another 30+ years. If slipshod, there can be an immediate problem.


Where are you in Pittsburgh? I lived just east of Schenley Park when I was at Carnegie Tech (CMU). I really need to go to Spring Carnival next May.

Best,
Grady

[47silver]

sent a pm

[47silver]

checked the cv bolts today and they take an 8 mm allen head socket, so a previous owner must have upgraded to a newer cv. THe boots look pretty good too, so i expect that they not original cv.s.

[Jim Sims]

"so a previous owner must have upgraded to a newer cv"

Not necessarily, the design went from the four 10 mm bolts (8 mm hex key) to the six 8 mm bolts (6 mm hex key) during the 1975 model year production run. How many bolts does one of your CV joints have?

[47silver]

not sure about the quantity will look in the am. the parts and tech ref catalog indicates that my targa #0148 is an early 75 so i thought it would use 900-067-128-01-OEM bolts which are 10x48 and use a 12 point socket. the ones i on the car are allen bolts and use an 8mm allen head socket. Will an allen head socket fit into the 12 point? I reached under the car and used a socket that fit nicely into the bolt...it sits pretty low.

I put it in the air tomorrow and find out what the heck i have.

thanks

[randywebb]

no no no - don't mix 12 & 6 pt drives.