ZF LSD swing axel question

[Eddie DVK]

Ok bought a ZF LSD (swing axel) which looks nice on the outside, but is there a way of testing if it is ok to use.
I saw that there are new lsd plates for IRS ZF available (on the samba Bruce T), but don t see this for swing axel ZF s.

Need help.

Thanks in advance

[Bruce]

VW showed measuring the break-away torque.  Get the busted spade of an axle from a drag racer, weld a socket to it and install with fulcrums.  Lubrication will affect the readings greatly.

Take it apart?  Beware, the number one cause of swing axle ZF failures is due to the dummy that previously assembled it wrong.

Can you post the 10 digit ZF part number engraved in the housing?  Starts with 4061 00x xxx

[Felix/DFL]

Congrats, a ZF LSD for swing axle is a rare part nowadays.
You will really see how it's condition is when you see the state of discs...

For a start check technical bulletin  2/1968:

https://www.thesamba.com/vw/archives/manuals/techbulletins/h1.php

A good read, print out and study before loosening any screw!
Post some pic's here, and listen to bruce 
repeat listen to bruce...

Best greetings, Felix

[Eddie DVK]

Can you post the 10 digit ZF part number engraved in the housing?  Starts with 4061 00x xxx

I will make some pictures sunday, and post it here.

A good read, print out and study before loosening any screw!
Post some pic's here, and listen to bruce  
repeat listen to bruce...

Best greetings, Felix

That was my plan.  

Oooooh already made some pictures... I forgot... number is not complete visible.

[pupjoint]

mine

[pupjoint]

was going through the bulletin, in order the adjust the ring gear with the VW297, it says i have to disaasemble the LSD, get the admustments done, reassemble the LSD .

anyone here does that as i am a bit worried about opening the diff, in case i break something and cannot get replacement parts.

if i dont use the VW297, it is a lot more work? any ideas?

[Eddie DVK]

Mine does not have a number on top like the picture above.
It has an engraved number on the side.
I could not get the number in one picture, but the number is 4061 001 014/L140 786
There are numbers on bottom en top, but those don t start with 4061 …





Hope this usefull

Edit: the other numbers are 301070 and 301069 (or 301089?) Left of the numbers is a kind of marking I can not read..

[brewsy]

Interesting.
By the looks of the ramps it looks like its a two way locker.

Id have expected a 'stock' unit to be one or at least 1.5 way

Marc

[Eddie DVK]

Interesting.
By the looks of the ramps it looks like its a two way locker.

Id have expected a 'stock' unit to be one or at least 1.5 way

Marc

I am new on this topic so, how can you see if it is a 1.5 or 2 way lock..
Is it in the number?

Regards Edgar

[Bruce]

By the looks of the ramps it looks like its a two way locker.
Id have expected a 'stock' unit to be one or at least 1.5 way

What are you talking about?

[Bruce]

It has an engraved number on the side.
I could not get the number in one picture, but the number is 4061 001 014/L140 786

Edit: the other numbers are 301070 and 301069 (or 301089?)

The ZF part number of your diff is 4061 001 014.  This means it has bi-metallic discs with the 4 extra shear pins, and it's for 8 bolt ring gears as you can clearly count.  This is the most common version of swing axle ZF.
The L140786 is your diff's serial number.
The other stamped numbers are just the meaningless part numbers of the housing. Since all ZF diff's part numbers start with 4061, they didn't bother to stamp those into the housing parts. Otherwise their full number would be 4061 301 070, etc.

Wallace's diff is an older diff that was originally made for 6 bolt ring gears, then later drilled for 8 bolts. Those diffs use the same technology bi-metallic discs, but without the 4 extra shear pins. Your diff's part number will likely be 4061 001 006.

If you plan to take it apart, please wait for instructions.  If you don't, I guarantee you will destroy the bolts. GUARANTEED!!!  In the past I have ruined many bolts.  Now I can get every one of them out without damage.

Have you found an axle spade to make a tool?

[Eddie DVK]

The ZF part number of your diff is 4061 001 014.  This means it has bi-metallic discs with the 4 extra shear pins, and it's for 8 bolt ring gears as you can clearly count.  This is the most common version of swing axle ZF.
The L140786 is your diff's serial number.
The other stamped numbers are just the meaningless part numbers of the housing. Since all ZF diff's part numbers start with 4061, they didn't bother to stamp those into the housing parts. Otherwise their full number would be 4061 301 070, etc.

Wallace's diff is an older diff that was originally made for 6 bolt ring gears, then later drilled for 8 bolts. Those diffs use the same technology bi-metallic discs, but without the 4 extra shear pins. Your diff's part number will likely be 4061 001 006.

If you plan to take it apart, please wait for instructions.  If you don't, I guarantee you will destroy the bolts. GUARANTEED!!!  In the past I have ruined many bolts.  Now I can get every one of them out without damage.

Have you found an axle spade to make a tool?

Thank you Bruce.
Have a spade, but did not test the lsd yet. Will test it, before I will open it..
And if I will open it, I am sure to not do anything without asking you first. If you don t mind.

Regards Edgar

[brewsy]

Bruce and Edgar,
Look here:
http://www.intothered.dk/simracing/differential.html
Under the 'impact on handling' section.

The style and shape of the ramps dictate whether the locking works under acceleration or deceleration and can directly influence the handling of a car.
For something like a T1 which is renowned for snap oversteeer if power is removed mid corner (lift off the throttle) Im very surprised its not setup to be a 1 way.

However this guide seems to indicate the opposite of what Ive read on the subject so far. Any reps from Salisbury or ZF around to explain further?? 

Cheers,
Marc

By the looks of the ramps it looks like its a two way locker.
Id have expected a 'stock' unit to be one or at least 1.5 way

What are you talking about?

[Eddie DVK]

Ooooh ok.
I know now what you mean, but a ZF LSD works on acceleration and deceleration.

[brewsy]

Yup,
According to that person it seems like a 45:45 setting.

Ooooh ok.
I know now what you mean, but a ZF LSD works on acceleration and deceleration.

[Eddie DVK]

Ok have found a extra axle to test the LSD.
But have a question I don t really understand how to test it..
I saw the samba manual... but not that does not help me further.
I understand you have to turn it with torque, but do I block the other end of the LSD than or what.

Thanks in regard.

[Mats Herrlander]

No.
Just simply put the diff. in a vice and measure the brake away torque (with a torque wrench).

[Eddie DVK]

Ok that part I get, but i think my english is not that good.
So what does brake away torque mean, the force that is needed to turn the diff, or the force that is needed to block the diff?

Thanks in advance.

[Mats Herrlander]

You want to measure the torque needed to overcome the friction of the discs.
If you do the same procedure with a standard diff. you get zero torque.
Buckel up the diffrential in a vice, insert the spade into one end of diff., turn the torque wrench (and change torque), untill "you find the click". Now you found the torque value. Should read around 3 kpm / 30 Nm, but can read 2, 5, 9 ... what ever, depending how well stored and maintained the diff. has been.

[Eddie DVK]

You want to measure the torque needed to overcome the friction of the discs.
If you do the same procedure with a standard diff. you get zero torque.
Buckel up the diffrential in a vice, insert the spade into one end of diff., turn the torque wrench (and change torque), untill "you find the click". Now you found the torque value. Should read around 3 kpm / 30 Nm, but can read 2, 5, 9 ... what ever, depending how well stored and maintained the diff. has been.

Thank you,
I think I got it now.

[Eddie DVK]

You want to measure the torque needed to overcome the friction of the discs.
If you do the same procedure with a standard diff. you get zero torque.
Buckel up the diffrential in a vice, insert the spade into one end of diff., turn the torque wrench (and change torque), untill "you find the click". Now you found the torque value. Should read around 3 kpm / 30 Nm, but can read 2, 5, 9 ... what ever, depending how well stored and maintained the diff. has been.

Ok have tested the diff, it starts to 'click' at 25 NM, is this ok?
Or is this to low?

Regards Edgar

[Bruce]

I'd say it's good.
When you're turning it, is it smooth, or jerky?

[Eddie DVK]

Hi Bruce,

When turning it, it is smooth..
Would you recommend opening it or leave at is.

Thanks for replying, much appreciated.

Regards Edgar