Carrera 3.2 CV to transmission bolts - washers?

[ErrorMargin]

I have an 84 Targa narrow body.

I had the transmission rebuilt by CMS and am now getting ready to reinstall.

Do the CV joint to transmission Allen bolts need washers? Mine did not have any.

The PET shows some kind of weird plate that would go under two bolts. Is that what I need? Do all the bolts get these?

What is the latest thinking on what to use here to ensure proper bolt torque and to ensure they do not back out?

[Spetrow]

I also have an 84. Mine looked to be original w/o moon plates. When installing new axles & CVs, I used snor washers with the 8M bolts (6mm hex). Torque to 42NM as per the specs. No locktite.

[HarryD]

You want use Schorr washers. A decent hardware store has them or there is always Belmetric.Com or McMaster.com.

[walt]

Schnorr Washers.

[HarryD]

Walt. I stand corrected.

I am referring to the washers that are serrated on both sides and are concave.

Grady Clay had this to say on the topic:

Originally Posted by Grady Clay

tshebib,

I recommend that you replace all of your CV joint bolts with new, known quality, correct length, 6-point internal hex bolts.
You can replace them one-at-a-time so to not disturb the CV joint seating against the flange.

The correct strength grade is “12.9”. These are NOT hardware store bolts.
The bolt threads should protrude through the flange by 1-2 (1½ is ideal) threads.
Make sure your Allen socket tool is in perfect condition.
Make sure your torque wrench is calibrated.
Use new Schnorr safety washers. The raised center goes toward the bolt head.

Does your 911 have the ‘moon’ 2-hole washer plates? If so, use them.

Inspect the tin cover seating surface for the Schnorr washers. These should have a good, flat surface to grip if no ‘moon’ washers.

Do not grease the bolt threads.
Inspect the threaded holes in the flanges for debris or rust.
Clean threads with a wire brush, ‘brake clean’ and compressed air. (Position the hole being cleaned ‘down’ to protect the lip seal. I additionally use a piece of cardboard, cut to fit.)

Do not use 12-point bolts, they are difficult to reach the required torque and ‘strip’ more easily.
Do not use bolts that are threaded the full length, they are probably not the correct strength grade.
The correct bolts must have the “12.9” stamped in the head of the bolt. Do not accept a bolt with printed “12.9”.


To clear up any possible confusion:
There are two different bolt sizes used for two different size CV joints.
The 108 mm OD CV joint uses a M10 (10 x 1.5 mm thread) bolt with an 8 mm internal hex. This is a “10 mm” bolt. The M10 bolts should be torque to 63 ft-lbs.
The 100 mm OD CV joint uses a M8 (8 x 1.25 mm thread) bolt with a 6 mm internal hex. This is an “8 mm” bolt. The M8 bolts should be torque to 33 ft-lbs.
Never confuse the ‘wrench size’ with the ‘bolt size’.
Never confuse the torque specs, either a bolt will break or become loose.
Always re-torque the bolts after 100 miles or so. Check at periodic maintenance.

Best,
Grady

[Geneman]

brilliantly concise by master Grady .... rip

[ErrorMargin]

Originally Posted by HarryD

You want use Schorr washers. A decent hardware store has them or there is always Belmetric.Com or McMaster.com.

I see that Schnorr has both the S washers at Class 8.8 and the VS washers at Class 10.9. They do not seem to offer a Class 12.9 washer.

The VS washers are thicker than the S washers.

Should I go with the VS washers?

https://www.schnorr.com/serratedsafetywashers
https://www.schnorr-group.com/en/products/safety-washers/safety-washers-type-vs?tx_avschnorr_productfilter%5Baction%5D=resetDis c&cHash=970ec54066808b6e60597bf61e8042f4

[Cevan]

The PET does not show any washers for '84-‘86, only the plates. Mine never had any washers. Is this wrong?

[mepstein]

Originally Posted by Cevan

The PET does not show any washers for '84-‘86, only the plates. Mine never had any washers. Is this wrong?

The plates are soft and grab the head of the bolt. I think it works but personally, I like the schnorr washers better. Properly torqued, they don’t come loose.

[Ian Comerford]

I think we need to know whether you have the cv boots with the thick flanges or the thin steel version? The moon plates are best for the thin steel version as they support the thinner steel and reduce distortion, loss of torque. Belt and braces with the thin steel version would be moon plates and Schnorr washers. If you have the thick flanges then just use Schnorr washers and ensure you torque them up

[winders]

I would use moon plates regardless of which washers I decided to use.

Schnorr washers (10.9) are good and are what I use on 10mm 12.9 CV joint bolts.

However, if I had 8mm bolts, I would be using Nord Lock washers. See here:

https://belmetric.com/nord-lock-washer-hv465-steel-quenched-tempered-zinc-flake/?sku=WNORD8

Heck, I really should be using Nord Lock washers with my 10mm CV bolts....

[Spetrow]

I went back and checked - I used a Nord not schnorr. Being a mechanical engineer i don't see the value of skinny moon plates for load spread in this application. As others have found, a positive locker is needed. I applied torque seal to check for de-torque movement. I see improper install (under torque) is the issue due to the use of a long 6mm hex flexing and or 3/8" extension twisting. low initial compression can cause the bolting to back out.

[ErrorMargin]

Originally Posted by winders

I would use moon plates regardless of which washers I decided to use.

What is the benefit of using the moon plates?

I'm assuming you are using the lock washers in between the moon plate and the bolt.

Originally Posted by winders

...if I had 8mm bolts, I would be using Nord Lock washers.

...

Heck, I really should be using Nord Lock washers with my 10mm CV bolts....

Originally Posted by Spetrow

I went back and checked - I used a Nord not schnorr.

What is the difference between using a Nord vs a Schnorr? Is one much better than the other?

[Spetrow]

I'll answer mine (Nord vs. Schnorr) the S is like a serrated washer and the Nord works like a ratchet. The import item is - S should be used up to a 10.9 fastener but the N will do the socket head cap screw 12.9. https://www.nord-lock.com/learnings/knowledge/2013/comparing-nord-lock-x-series-with-serrated-spring-washers/

[winders]

I use the moon plates because the metal of the flange is so thin that it distorts over time. The moon plates spread the load and do not distort.

Yes, the washers go between the bolt head and the moon plate. Where else would you put them considering their job is to help prevent the bolt from backing out?

I am not using the Nord Lock washers on my setup because they aren't necessary. I have 10mm bolt and I have never had a 10mm bolt loosen when properly installed and torqued. If I had 8mm bolts, I would be using the Nord Lock washers. Well, actually, I would get rid of the 8mm setup and replace it with a 10mm setup...

Spetrow provided the information on the differences between Schnorr and Nord Lock...it is night and day. If you have 8mm bolts, don't bother with Stage 8 fasteners or safety wiring. Use Nord Lock washers and make sure everything is super clean when installing the fasteners. Make sure there is no CV grease anywhere near the threads of the bolts.