Electrics: 70: Spinning key syndrome - method to fix

[SwedishBus]

It's been a while since I posted, mainly because the pair of V70's are running reasonably reliably at the moment. One issue that has been creeping-up on the V70_TDI (1997MY) is the issue known as "spinning key syndrome", ever since this poor car was loaned-out to a less-than-mechanically-sympathetic user for a few months.

The symptom is that the key does not seem to "pick-up" the internals of the lock/switch/steering-lock/parking-cable-release, when it is first turned from the "0" position towards the "1" auxillary position. This means that the car cannot be moved if the problem occurs badly. Once the key "picks-up" the rest of the assembly, then all is fine until the key is turned back off to the "0" position, even if it isn't removed.

The problem is exacerbated by the bad-habit by some drivers of not releasing the pressure of the steering-lock detent when first turning the key after the steering-wheel has locked (turned with the key out), thus putting more load than necessary on the key-barrel. This is almost certainly what has happened to my V70, and once it starts, it just gets worse and worse.

The problem is caused by the mechanism inside the key-barrel that is designed to prevent the barrel being forced round by means other than using the proper key. It is masked a bit by a secondary mechanism that locks the key-barrel to the internal shaft (that then turns all the gubbins around, such as the switch, etc.), which is a pin that is designed to take the loads off the anti-forcing mechanism, once the key has left the "0" position. The anti-force mechanism is often full of oil & grit, and this exacerbates the issues, but there is also a bit of wear on this mechanism with time, and that accelerates when the steering-lock is abused by uncaring driver-style/s!!

It is said that the problem is just down to "worn steering-barrel", and that the only fix is to replace the whole assembly with a new or unworn secondhand unit. This has many problems, as a) the parts are hard to come-by, b) the key will be a different cut to the rest of the car's locks, c) the transponder in the key needs swapping-over, d) the whole replacement process is expensive; the new assemblies are retailing at circa £350 at the time of typing this.

The issue is caused by the anti-force mechanism, and not the key tumblers themselves, and therefore it is incorrect to say that the lock-barrel is worn. Also, it can be fixed with a bit of care, time, and a few tools. If (as I am) you live in the middle of nowhere, then this is an invaluable fix for a very common problem - Volvos seem to be prone to this issue over many years and models.

I will try to post a sequence of articles to detail how to strip and repair the steering-lock.

[SwedishBus]

There are plenty of good articles about this elsewhere, but something that is omitted from many of them is that the shear-bolts, that secure the two halves of the lock assembly around the column, are fitted at the factory with micro-encapsulation. Mine were. This makes it an utter PITA to get these bolts out in service, as they are effectively locked-solid via their threads in the main barrel assembly.

At the outset, I would recommend not even bothering to try and drift these round or grind them out with a Dremel. If you do this, as I did for my job, then you preclude the best option of all;

Centre-punch with either a manual punch&panel-hammer or an automatic dot-punch tool. The snapped-off heads of the bolts are quite soft, and there is a moderate amount of access for a punch and a cordless drill. Start with a small drill-bit, something like 3mm, then go for a larger one, around 6mm, then finish-off with an 8mm bit. If you get the drilling dead-centre, the bolt head will just snap free of the threaded portion. Try not to drill too deep, as the better the "stud" sticking out of the barrel assembly after removal, the easier it is to get a decent pair of locking-pliers onto it.

As you can see from the photos, I made a right old mess getting my barrel assembly off the column, and that is because I believed the YouTube videos that suggested that these shear bolts can be drifted round (they usually can on other makes of car), and thus had nothing clean to drill into after I had cut flats on the sides of the sheared-heads for this (failed) method. I will be honest and say that I sweared the roof off the workshop, when I found Volvo had used micro-encapsulated shear bolts on this car. It just isn't needed, and makes this job much harder, for no gain in security. Not the best bit of design.....
V70_ignition_barrel_removed.jpg

V70_barrel_clamp_removed.jpg

The shear bolts can be replaced by M8 x 20mm cap-screws (Allen-headed screws) as the shear-bolts are just a metric course thread M8x1.25. The caps just clear the die-cast upper clamp pockets around the fixings, unless you have mashed the metal, like me....

I would also consider removing the steering wheel the next time I did this; the access to the two forward-facing Torx screws for the clock-spring unit, that attach it to the upper clamp casting, are a bit of a fiddle behind the wheel. I had to use a shortened T25 bit to get in there, and even then that involved needle-nose pliers to turn the screws out.

[SwedishBus]

The top part of the clamp can be put out of the way whilst the main barrel assembly is worked-on. Broadly-speaking, the ignition key is not required for any part of this job, and therefore it should be removed and also put in a safe place. I kept mine to-hand whilst I was modifying and building-up the barrel assembly, but that was only to keep checking that everything turned smoothly, and that there was no hint of jamming.

barrel_assembly_preparation.jpg

The steering lock cover plate "A" can be loosened, but cannot be removed until the tumbler assembly has been withdrawn from the barrel.

Likewise, the plastic keeper "B" for the location where an automatic-transmission park-cable would normally locate cannot be easily removed at this stage (it will pull out under force).

However, the small cap on the side of the barrel body "C" can be drilled with a small bit (circa 2mm) after centre-punching, and that will allow a self-tapping screw to be inserted, then pulled with pliers, to remove the cap, spring just underneath, and a stepped plunger beneath that. They are all small, so work in a clean area where you can see where they have rolled/sprung! If the option is taken (see later post) to completely remove the steering lock pawl, then these parts are not needed again.

steering_lock_cover_removal.jpg

The cover-plate has to be released from the die-cast body by carefully cutting the peened-over material on the casting at three points. Although it is not strictly necessary to remove this plate to effect a repair to the anti-force mechanism, it makes life much more easy for cleaning and access during reassembly, and if you are going to remove the steering lock pawl, then this plate will have to come out anyway.

[stevepcar]

Thanks for this info. Can you just clarify what the bad habit is that causes the problem please. I want to make sure I do not do it?

[SwedishBus]

Originally Posted by stevepcar

Thanks for this info. Can you just clarify what the bad habit is that causes the problem please. I want to make sure I do not do it?

What I believe has happened with my car, and I have seen people doing this on other cars;

The car is parked, key removed, and the steering wheel is turned a little to engage the steering-lock. This means that the pawl has clicked into its engagement slot on the steering column itself. The implication at this stage is that there is a side-load on the pawl as the car sits, which is normal, because the steering wheel movement to get the lock to engage will have left a bit of elastic force on the front tyres to the ground - there is always a bit of friction between tyre and ground, even on ice.

When the driver comes back to the car, the correct way to operate the key is to feel the steering wheel by turning, to release the side-force on the lock-pawl. There will be a neutral-point between the lock acting clockwise or anti-clockwise, maybe a few degrees at the steering wheel rim. If the steering lock is not engaged, then fine, and if it is engaged, holding it at the neutral point will mean that as the key is inserted, then turned from position "0" to position "1", the internal mechanism of the steering barrel does not have to overcome the drag that would have otherwise existed when lifting the lock-pawl out of the steering shaft slot. A new car may be fine to disengage the pawl under load from the steering shaft/tyres, but an old Volvo with fragile steering lock is most definitely not!

HTH,

[SwedishBus]

One of the trickier bits to removing the tumbler assembly is to find a way of compressing the circlip that retains it within the barrel, just inside the key-end of the casting.

To access the circlip, first there needs to be a series of holes drilled through the casting, just over the top of the clip. About 4x holes seems the optimum, equispaced around the circumference of the barrel. I used a 3mm drill bit, and the dimension to drill back from the front face of the barrel, measured from the key-end, is between 6mm and 7mm. If you opt for the low end of this dimension, it can help to keep the clip depressed as the tumbler is removed forwards.

V70_barrel_no_drill_zone.jpg

Before drilling the holes, there is a caveat! One region of the tumbler houses the long, thin keeper bar, which is steel, and this occludes the circlip, which has ends that abut this keeper - so no point drilling there anyway. As indicated on the picture by circles, I found this out the hard way, but no serious damage was done. The main thing is to stop as soon as the drill-bit breaks through the barrel casting and touches the circlip, which is fairly easy to achieve as the circlip is made of tough spring-steel. The best displacement of holes seems to be at 90degrees intervals around the circumference, starting at 45 degrees from the keeper area.

V70_tumbler_removal.jpg

Once the holes are drilled, rather than struggling to find a spare pair of hands, or more, and risking injury as everyone fights to get in there, I used blunted-off self tapping 4mm screws, and drove them in to compress the circlip down. If you start at one of the holes opposite the keeper-bar, it will give the best probability of the circlip being able to compress and extend towards the keeper-bar (a natural obstacle to unlimited travel of the clip around the groove). Put the screw in until there is some resistance to turning, then back-off a quarter turn, to allow the tumbler assembly to come forward. Do this for all four holes, then access through the back of the barrel assembly from where the electrical switch would sit, and lightly tap the tumbler unit out with a panel-hammer and broad drift (to obviate damage to the switch drive-dog). Once the tumbler unit has shifted forwards enough to get a broad screwdriver blade between its shoulder and the barrel casting, remove all the screws whilst keeping pressure on the tumbler to stop it dropping back into its home-position. Then continue to tap the tumbler assembly out - nothing will ping outwards or be lost, so just drive the whole lot out.

Once the pieces are all out, you should have the following scene;

V70_tumbler_and_drivedog.jpg

The tumbler assembly "A" is the bit that needs the work, the main drive-dog piece just needs a wash and dry, to clear it of grit and debris, so no further dismantling there. The bottom plate "C" can now be withdrawn out of the steering lock aperture, the parking cable adapter or the plastic keeper "D" should now come out of the housing, and the keeper-bar "E" can be washed and dried for reassembly later.

It is a good idea at this stage to take a fine file to the outside of the barrel casting at the four holes used to compress the circlip; each hole will have raised a collar where the self-tapping screw has bitten-in to the metal, and this needs to be filed back down flush to the casting. The filing operation will generate some metal dust, so better to do this now, rather than after everything has been washed. If there are raised areas of metal, the transponder receiver collar may not slide over the repaired barrel assembly as well as it should, and might get damaged in the fight to free it again.

[SwedishBus]

With the tumbler assembly held gently in a vice, it is now possible to examine what has been happening with the spinning-key syndrome. The dog that is seen in the photo below is able to move independently from the shaft on which it sits, that which attaches to the rear of the tumbler assembly itself.

V70_tumbler_dirty.jpg

From the photo here, you can deduce that grit has played a fairly big part in the failure of this unit - this assembly has already been power-flushed through as a complete key-barrel unit, yet there is still a fair amount of oily grit and silt still present here. As an aside, the action of using a compressed fluid canister of release-oil straight through the key-slot, flushing the whole barrel assembly through several times, did make a difference, but it was still nowhere near being reliable to go back on the car. It would work in an emergency by the side of the road, but not over the course of several weeks/months/years.

The crucial areas shown on the photo above are that the whole tumbler assembly is timed to position "0" on the key, and that this aligns with a cutout in the tumbler outer casing. This cutout plays an important role in the control of forces once the key has reached position "1" onwards, as there is a free-sliding pin that locks the dog to the tumbler primary shaft, and that pin is driven in towards the shaft by a ramp on the working-end of that cutout. Prior to this, the whole drive-path is taken through the anti-force mechanism (later post) and that is where the key-spinning occurs. If you can get past that point, you are up-and-running to drive.

V70_anti_force_dogclutch.jpg

It is fairly easy to get the drive-dog off the tumbler assembly; just pop the C-clip off the tumbler primary shaft slot (catch the clip, but if you lose it, it isn't important after the modifications needed to fix a spinning-key). The drive-dog will just lift off, and its sliding pin will probably drop out onto the floor a this stage. Again, if it gets lost, not the end of the world......

[SwedishBus]

It's worth getting everything cleaned at this stage. As well as making everything easier to handle, it also obviates grinding and cutting dust/debris from sticking in parts that it is not wanted.

I use a small tub (yoghurt 500ml pot will do) with brake & clutch solvent filling the bottom of it. To agitate the whole mix, I use a 3/4" paint-brush to work the solvent into the crevices, but I found it was almost superfluous, as the solvent is so effective on this sort of thing. Holding onto each part with a firm grip, I also used a compressed air line to blow the solvent and any loose grit out of the insides - a bike pump would probably work just as well.

I cleaned everything seen so far, tumbler assembly included. No harm will come to the tumblers by washing them all out, and they can be lightly lubricated with a dry-lube film at a later stage.

[SnineT]

Great write up, if only you'd done it last week as there's been a user here recently struggling with this and your work shows the whole shooting match I was trying to describe blind to him.

[SwedishBus]

Once everything is cleaned-up, it is possible to first see where some of the wear-problems have occurred; it was not easy before;

anti_force_dog_wear.jpg

The anti-force drive dog here has two internal slots at 180degrees to each other, and they rely on having their full height available for corresponding pegs to engage with them, and turn the mechanism enough to get it locked by the main sliding-pin at key position "1". In my case, one of those slots was obviously chipped near the top, and this could have been either an effect of problems within the peg system, or the cause of the spinning-key-syndrome in the first place.

Looking closely at the back of the tumbler assembly without the anti-force dog in-place, it can be seen that the drive for the key through to the rest of the barrel mechanism relies on just two sprung pegs, which seemed very loose on my lock.

V70_anti_force_cams.jpg

The pegs "B" have springs that push them out radially to engage in the slots on the anti-force dog. The action of pushing the key into the key-slot will move the centre shaft upwards (as viewed) to push those pegs into engagement with the slots. Just visible are two rollers "A" that can act radially inwards on those pegs. If too much force is needed to turn the key, the rollers will push the pegs back and out of engagement with the drive-dog slots. At this point, the tumbler and inner shaft will continue to turn without resistance, and on their own, whilst the drive-dog is left behind. As it is this drive dog that engages with the piece of the lock that transmits all the torque through to the parking-cable cam, the steering-lock cam, and the electrical switch dog on its end, in-effect the tumbler mechanism is now disengaged from the rest of the locking barrel; the key spins.

The theory behind the repair is to lock the anti-force drive-dog to the tumbler inner shaft, and that is essentially how the mechanism would work anyway, once the whole lot had successfully turned together past the key position "1" region on the tumbler outside casing, as the sliding-pin within the anti-force dog would be driven into its corresponding slot that exists on the tumbler inner shaft.