Diff lock - not locking?

[Alistair C]

Following the diff lock thread - I've noticed mine isn't.

The little triangular light on the switch comes on when the switch is pressed, but the Green LED on the diagram doesn't light - nor does the ABS light come on.

Doesn't look like it's duff lighting..... so any suggestions?

Cheers,

[ottawa coupe]

mine is doing the same thing right now. i'm going to have time to take a peek on thursday or friday. my guess is the mechanism at the diff is rusty and needs to be freed up.

[A1QSHIP]

Difflock

Most likely yor will need the vacuume servo that actuates the difflock mechanism.
To test the lock system you can access the vacuume lines to the actuator from underneath the rear seat. There will be three plastic lines colored
1) violet, from intake manifold, vacuume supply to control module.
2) blue, to unlock servo for difflock actuation.
3) yellow, to lock difflock actuator.
I may have the functions of the blue and yellow vacuume lines crossed but if you have the engine running and a vacuume gauge hooked to either line you will figure it out.
The voilet line should have a vacuume whenever the engine is running. If not, check at the rear of the cylinder head for a violet line and the connection to the intake manifold. This rubber connector sometimes break (20v N/A).
Apply a vacuume to either the blue or yellow lines leading to the actuator and see if it will hold a vacuume. If not, you will need the servo assembly.

[Alistair C]

Most likely yor will need the vacuume servo that actuates the difflock mechanism.

Good diagnosos.
Twas indeed the vacuum lines which had become disconnected beneath the rear seat squab. Two minute job!

If only everything with the S2 was so easy!

cheers.

[Jas11n]

Good diagnosos.
Twas indeed the vacuum lines which had become disconnected beneath the rear seat squab. Two minute job!

If only everything with the S2 was so easy!

cheers.

Which side of the diff is actuator/mechanism on? offside or nearside?
Tested mine last night, wouldn't turn on, left it and got in today and it's miraculously on, but won't switch off
Switch is ok, lines under seat ok, and I can hear the vacuum servo clicking on and off whilst operating the switch.
Now to check under the car but not sure which side of the diff it's on.
Anyone help, cos car is grounded till this is sorted.

Thanks
Jas

[DJones]

Try driving the car back and forth with a slight bit of steering, left to right it may be that the teeth are wedged i.e. just to tight in the position it is currently in, should not be to much of a problem. You could always go underneath and manualy disengage it.

[Jas11n]

Thanks for the reply, I've had the car out for a drive, gave it some stick on and off the throttle, round corners and all over. Still stuck on and didn't switch off above 15mph either
Getting dark now so it will have to wait till tomorrow, whip a rear wheel off and see if I can see which side it's on.
Any clues as to how to free it off manually?

Ta
Jas

[DJones]

It must have an air leak, from memory there are two pipes that go to the servo unit one sucks it one way i.e. on and the other sucks it off (so to speak..) disconnect both and whilst swithcing on and off check that the pipes suck. Whilst the pipes are off you should be able to manually turn the diff lock off.

Hope it helps..

[Jas11n]

Thank you kindly
Have worked out it's on the nearside of the diff on the coupe and avant.
Will have crawl around in the slush tomorrow, what fun

Jas

[S2central.net]

Thank you kindly
Have worked out it's on the nearside of the diff on the coupe and avant.
Will have crawl around in the slush tomorrow, what fun

Jas

Yep - if you apply VACUUM to the 'unlock pipe' (which is blue from memory) then it should do the trick. You can do this with a MityVac if you have one - if not - just bypass the difflock controller piping with a section of suitable tubing from the PINK line under the rear seat (after the 1-way valve) to get your source of vacuum from the engine as it idles.

Your locking mechanism may itself be stuck, but more likely is a frayed hose... You might need to bypass/replace the wee section of blue pipe under the car.

Paul

[Jas11n]

Right, tis now sorted.
If any of you have the same, then check things mentioned above first.
My vacuum pipes were ok. Problem was traced the the joint between the vacuum solenoid and the selector fork itself. This was all rusted up and stiff as hell.
See pic below for the joint I'm talking about (arrowed)
My fix was to remove the circlip arrowed, and drive the connecting pin out. Cleaned it up with sandpaper and then applied some moly grease to the joint and reassembled it. Works like a good un now.
The difflock actuator and mechanism are located on the nearside of the diff on all models of the S2/RS2. Only one difference between the Avant and the Coupe is that the Avant will have a heatshield covering it as it's exhaust passes close. The Coupes exhaust is routed over the other side of the diff.

Thanks for the replies
Jas