Bush Removal!

The title of this page should generate some internet traffic......

Since AK supply new suspension wishbones all round, there is no real need to remove any of the bushes from the front wishbones when stripping down the front suspension.

The only bushed parts that need to be reused are at the rear - being the "pendulum" and the wishbone tie, both of which support the rear lower wishbones and the differential unit.

I had assumed that new bushes would be required all round as a matter of good practice.  However as per my post on the rear suspension strip down I discovered that the bushes in the rear wishbone tie are a non-serviceable item (you can no longer buy them either separately or as part of a replacement wishbone tie part), so DO NOT REMOVE THESE BUSHES!!

So the only bushes that I actually need to replace are in the "pendulum" bracket.

Pendulum bracket

So what is a bush?  In simple terms (?!) it is a sort of vibration isolator found anywhere where there is a joint in the suspension system of a car.  They cushion the movement between two solid parts, helping to avoid shocks and vibration and making for a quieter and smoother ride.

The bushes as fitted to the Jag suspension are of the metalastic type, which consists of an inner and outer metal sleeve with an rubber core in-between.  They are also an extremely tight fit in whichever part of the suspension they are mounted and typically quite hard to remove, especially in older vehicles once rust and road debris have done their bit!

Although I did not need to remove the bushes from the front wishbones, I decided to have a couple of practice attempts in preparation for the rear pendulum.

I am fortunate enough to have a 10 ton hydraulic press in my garage which I thought would be man enough for the job and indeed on my first attempt one of the front wishbone bushes simply popped out with no problem what so ever.  The second attempt was not so successful; having cranked the jack on the press up to what I felt was worryingly close to breaking point, there was no sign of any movement.

Plan B involved using a hole saw with a suitable diameter to cut into the rubber between the two steel sleeves.  This allows the removal of the inner sleeve and then using a cold chisel and a large hammer, one end of the outer sleeve can be hammered inwards with freed the remains of the bearing sufficiently that it could be easily removed with the press.

The one draw back of Plan B is that it generates a lot of smoke and covered my working area with little globules of burnt rubber that stick to everything and are a pain to clean up...

New hole saw (left) - after bush removal (right)

I also found that all the bushes are slightly different sizes which would require the purchase of a large number of different diameter hole saws.  So I needed a Plan C.

In the end Plan C was much the same as Plan A, except that when I reached the point where I thought the press was going to break, I closed my eyes, protected my most valuable body parts, and cranked the jack handle a couple more times!

This generally resulted in an almighty bang - which thankfully was not the press breaking, but the bush shifting in the mounting, after which it pressed out relatively easily.

A naked bush!

Pendulum bracket with all bushes removed

Black Friday (Thursday?!) Bargain

Having slightly (?!) grazed the rear lower wishbone inner fulcrum shafts with my angle grinder while trying to complete disassembly of the rear subframe (Rear Axle Strip Down - Part 4, I had reconciled myself to the fact that I was going to have to buy replacement shafts.

Original fulcrum shaft - with "slight" nick
from angle grinder...!

I had previously checked that it was possible to buy these, and while they are available,  original or OE fulcrum shafts are not cheap!  When I checked SNG Barratt had OE items listed on their website at the time for just over £130 - EACH!!!  

This was going to be a significant dent in my planned expenditure.  However I have to thank another fellow Cobra builder, James, who having read my blog, got in contact to tell me that he had spotted that SNG Barratt had discounted the fulcrum shafts by £113 - so they were only £20 each!  

Needless to say I got straight onto the SNG website and ordered two - saving myself £226.  That's my Black Friday (Thursday) bargain for the year.  Excellent service from SNG; I ordered them yesterday lunchtime and they arrived today. Happy days!!

£266 worth of fulcrum shafts - for the bargain price of £40!

Project Snake goes Global!!

Sometimes the power of internet amazes me (and scares me in equal measure!).

Last weekend I was browsing Facebook and found the AC Cobra group page - which although mainly for owners of real AC / Shelby Cobras, is also open to owners of replicas and generally anyone with an interest in these amazing cars. Once my request to join the group had been accepted I posted an introduction to the group including a link to my blog.

Since then I have had just shy of 300 views to the blog - in less than a week!  The audience has been from all corners of the earth with views from US, Australia, South Africa and Europe and of course the UK.

So welcome to all those who have taken the time to visit my blog.  I hope its of interest and that you keep coming back to see how the project progresses.  I'd welcome any comments or feedback on the content (I'm a blogging newbie) and of course any tips / advice etc will all be grateful received.

I think I can say that Project Snake has gone global (but not viral....yet!!!!)

Thanks all.

Rear Axle Strip Down - Part 4

The last major part of tearing down the rear axle / subframe was to remove the lower wishbones and fulcrum shafts from the wishbone tie.  This part of the rear subframe can be seen at the top of the photo below.  The 'pendulum' (the rectangular looking bracket at the left) was removed from the front of wishbone assembly by Simply Performance when they removed the diff for refurbishing.

Lower wishbone assembly (top)

As has become usual with stripping down the rear, this was not as straightforward an operation as I had hoped.

Firstly the lower wishbones have been designed so that they pivot on the fulcrum shafts only at each side, the middle section of the shaft is partially exposed to the elements and of course gets extremely corroded.  The engineer in me fails to understand why anyone would think this was a good design!!  The previous design of the XJ40 suspension appeared to have recognised this problem by having a spacer tube over the central section of the fulcrum shaft which at least (if properly greased) would give some protection to the shaft.  For some reason the later design made no such consideration. So the long and short of it was that the fulcrum shafts were well and truly rusted into the lower wishbones.

When I had helped fellow AK Cobra builder Richard with his body and chassis delivery, he had advised me that AK no longer need the wishbones as exchange items and that he had resorted to cutting the wishbones off the fulcrum shafts.  So I didn't bother trying any other method myself, I simply reached straight for my trusty angle grinder!

The first part of the operation to cut away part of the front of the wishbones was  relatively easy - some straight passes with the grinder and some assistance from a cold chisel and I managed to free up the front part of the fulcrum shaft.

Front sections of both wishbones cut away

Corrosion of fulcrum within pivot section
as well as exposed central section

Cutting the rear section of the wishbones was not quite so easy.  I was worried about damaging the wishbone tie (which needs to be reused) with the grinder so couldn't cut along the line of the fulcrum shaft.  Instead I tried to cut through the front section at an angle. 

Unfortunately this part of the wishbone is quite thick and of course is a solid casting and took a lot of grinding to cut through.  I was never imbued with a great amount of patience and on the first wishbone I managed to nick the fulcrum shaft with the angle grinder (actually it wasn't a nick, it was a bloody great gouge....).

Deciding that this shaft was now effectively scrap (and having checked that I could actually source a replacement one) I simply cut the end of the fulcrum bolt to free the wishbone from the tie.  I then managed to hammer the shaft out of the wishbone.

One scrap fulcrum shaft...

The other side was slightly more successful.  I managed to cut the front of the wishbone at a slightly better angle which meant that I was able to hammer the wishbone off the shaft without resorting to butchering the fulcrum shaft (although I will probably buy replacements for both sides having knackered one side).

Ironically I could have done this much more easily.  When Simply Performance removed the diff from the subframe, they also removed the two bushes in the wishbone tie that the diff mounting bolts pass through.

Wishbone tie with diff mounting bushes removed

These bushes are not available as a replacement part.  In fact bizarrely neither the inner or outer bushes on the wishbone tie are available as a replacement part (several fruitless internet searches eventually confirmed this - although the bushes for the pendulum which mounts the front of the diff are all available!) and neither is the wishbone tie itself.

Ben at Simply Performance was happy to provide a replacement wishbone tie free of charge (as part of their guarantee that all parts can be refurbished) - he also sent me a set of spacer tubes (from the old style XJ40 rear suspension) as I had noticed in the AK build manual that these are required.

Replacement Wishbone Tie (middle) with
all bushes present and correct!!  XJ40 fulcrum
shaft spacer tubes supplied by Simply Performance

So for fellow builders out there - when you do manage to separate the rear wishbone tie DO NOT ATTEMPT TO REMOVE THE BUSHES!!  

So of course I needn't have been so careful in cutting off the rear part of the wishbones to try and protect the wishbone tie, as mine turned out to be scrap in any case.....

Oh well - all the main parts have now been stripped down.  Now to clean, derust and refurbish all parts that are going to be reused.

An exploded rear end!!

Rear Axle Strip Down - Part 3

Today's job was to dismantle the rear drive shafts and universal joints.  The stub axles and the differential flanges will be reused.  The main driveshafts are exchanged with AK Sportscars for a pair of shortened items.  The universal joints themselves will be replaced with new items.

Rear Driveshaft

The universal joints consist of a 4-legged 'spider' with a roller bearing cup on each leg.  2 legs are located in the driveshaft and 2 legs in the stub / flange axle end.

Universal Joint - Photo courtesy of SNG Barratt

Having read through the AK Manual I assumed that to take the universal joints apart would be the reverse of installation so that if I could push the bearing cups out of both sides of the drive shaft or axle end then the spider would simply fall out.  Well it sort of worked like that, but as with everything so far on the rear end strip-down, it didn't go quite to plan.

The first step was to remove the circlips that hold each of the bearing cups in place.  Despite both ends of the driveshaft being caked in a fair amount of grease all the circlips proved to be either wedged or rusted into their housings.

Doesn't look too bad but circlip was stuck fast

The removal technique involved spraying with penetrating oil, application of a blow torch to heat up the half shaft and then another application of penetrating oil to cool the circlip and hopefully persuade it to loosen up.  Some additional persuasion in the form of a hammer and cold chisel on the clips eventually allowed me to either use a pair of circlip pliers to remove the clips or to lever out the clip with a screwdriver.

Using a screwdriver to pry the circlip out

I removed the clip from one side and used a socket with a slightly smaller diameter than the circlip on the other side in my hydraulic press to push down on one bearing cup to push the other side partially out of the stub axle.  I used a 32mm socket under the shaft to allow the bearing cup to push part way out of the bottom of the axle end.

Pushing bottom bearing cup out part-way

With the bearing cup on the top pushed in slightly removal of the circlip on that side was much easier using circlip pliers.  I then turned over the driveshaft and used the press to push down on the driveshaft to partially press the other bearing cup back out of the stub axle.

Top bearing cup pressed part-way out - pressing the bottom cup out

With both cups now pushed partway out I thought that would be sufficient to enable the spider to be removed from the stub axle.  I was wrong....

However there was now sufficient play on the spider to enable me to insert a screwdriver into one of the bearing cups and so I thought I could try and drift out the cup.  That didn't work either although it did crush the top of the cup enough that some of the roller bearings fell out into the bottom of the cup.  This had the effect of filling up the bottom of the cup so that when I put the shaft back in the press I managed to pop the cup out of the bottom and release the stub axle from the spider.

(During disassembly of some of the other universal joints I did manage to drift out a couple of the bearing cups with the screwdriver - but most of them did require the above technique to remove them)

Success!!

Separated stub axle

  

Half shaft with stub axle removed and spider still in place

The other bearing cup was then easily pressed out of the stub axle.  Removal of the spider from the drive shaft followed a similar process although the absence of the stub axle meant that I needed to be a bit more creative with holding the shaft in the press to get some leverage to push the bearing cups out.

Pushing out top bearing cup

Spider removed

Pressing out the final bearing cup

I then used the same technique to remove the differential flange and universal joint from the other end of the driveshaft. 

On one of the ends I managed to pop the top of one of the bearing cups whilst pressing it out which gave a good picture of the end of the spider and the roller bearings in place (see photo below).

Roller bearing assembly with spider leg and grease gallery visible

Both drive shafts are now fully separated.  Next and final job on the rear is to separate the lower wishbones from their pivot shafts and the wishbone tie.

Rear Axle Strip Down - Part 2

The next step in dismantling the rear hub carriers was to remove the brake shield.  This needs to be cut down as part of the AK build so the fact that the edges were all rusted and knackered did not matter.  My main issue, as I mentioned previously was that the holes for the handbrake shoe retaining pins are distorted and oversized on both sides and don't look like they will hold the pins in place for long! - so I will need to come up with a fix at some point

The shield is held in place by four torx head screws (2 upper / 2 lower).  The first side came undone relatively easily using a spanner on the shaft of a torx-head screwdriver to loosen the screws.  The second side proved more troublesome.  The two lower (larger) screws came out no bother but the smaller upper screws would not shift.

Attempting to undo them with the spanner / torx screwdriver combination eventually stripped the head sufficiently that I could not get any purchase with the torx driver.  Plan B was to cut a slot in the top of each screw with a dremel and try again with a large flat-bladed screw driver.  That didn't work, so Plan C involved buying an impact screwdriver from Toolstation.  Unfortunately that didn't work either.

Plan D involved using a blowtorch to try and get some heat into the aluminium hub carrier and using a hammer and cold chisel to try and drift the screws out.  I thought I was getting somewhere when the screw started to turn after a few clouts with the hammer.  At this point I switched to the impact driver and slowly but steadily the screw started turning......

Well the screw head started turning - after two turns the head sheared off leaving the rest of the screw thread still in the hub carrier.  It was a similar story with the second screw.

Today's tools include a blowtorch, impact driver, hammer and cold chisel.

The result being sheared off screw heads....

So another job to add to the list later which will involve trying to drill out the rest of the screws and re-tap the holes.

With the brake shield off, I could then remove handbrake retaining clip and cable and then the inner and outer oil seals from both hubs together with the bearings.  The outer bearing races were drifted out quite easily.  The inner races required me to purchase a new 1.5kg club hammer as my dad's old and trusty hammer was just not up to the job!

Farewell to my dad's trusty club hammer - welcome Mjolnir!!

I removed the lower fulcrum sleeve and taper bearings by using a socket to knock one end of the sleeve out of the bearing which enabled the sleeve with one bearing attached to be removed and the other bearing could then be pried out easily with a screwdriver.  All the bearings and seals looked in quite good condition from the outside but removal of the second shaft was accompanied by a large pile of rust.  One bearing was completely rusted up - good job these will all be replaced!

One rusted up hub fulcrum taper bearing (and one not so..)

And the accompanying rusted bearing race

I'm a bit stumped how to get the taper bearing races out.  There are two slots (visible in picture above) behind the race but I can't work out how to get any kind of drift in behind them to knock the races out.  I don't want to try and pry them out from the front in case of damaging the aluminium hub carrier.  A pause for thought is required.

Rear Axle Strip Down - Part 1

Well if stripping down the front axle was a relatively straightforward affair, then tearing down the rear axle has been anything but!

Rear axle components prior to stripping-down

The first stage was to remove the rear brake calipers and caliper carriers and pads.  As with the front axle the carrier bolts were a bit stubborn but a combination of breaker bar and air spanner managed to get them out.

Rear Brake Caliper and Pads removed

This enabled removal of the rear disc rotor which was accompanied by a pile of knackered handbrake pad linings falling onto the floor!  Fair to say they were completely shot!  More worryingly on the offside hub, the pins holding the handbrake pads in place were bent and had pulled through the brake back plate.  Not sure how to address this - but will put it on the list of things to sort.

Remnants of Handbrake Lining

Brake Rotor off - Loose Handbrake Pads due to missing pins..(found them on floor subsequently looking rather bent......)

Next stage was to remove the large nut from the end of the drive shaft to allow removal from the hub.  Not only is this bad boy torqued up to 220lb/ft but it also is a locknut with some cinches in the thread to grip onto the thread of the drive shaft.  In other words it is a complete sod to remove.

It was also at this point that I realised that Simply Performance, having partially disassembled the rear subframe when they removed the diff for refurbishment, was not as helpful as I first thought. With rear hub carriers separated from the lower wishbones I just could not get enough weight on the carrier to be able to get any decent leverage on the nut.

In the end I had to reassemble the carriers onto the wishbones so that the subframe weight could provide some additional ballast to resist the leverage of trying to undo the nuts.  With the subframe placed on a wooden pallet, a pry bar wedged under the edge of the pallet and and between the wheel studs, my weight on the subframe and with some pre-heating of the axle end with a blow torch, I eventually managed to get enough leverage on the nut to get it to shift!.  At one point I was convinced the swivel pin on the end of my breaker bar was actually going to shear before the nut moved but it did finally shift.  Final removal was assisted with the use of my air spanner.  Then I (simply!!) had to repeat for the other side.

Removal of the drive shaft from the hub could then be undertaken using a 3-legged hub puller and an impact wrench which was a relatively straightforward affair.  By then supporting the hub carriers on a couple of pieces of wood and using a suitably sized impact socket, I knocked the end of the hub out of the rear spacer / ABS ring which allowed removal of the hub.  This also gave access to the rest of the handbrake mechanism to remove the adjuster, springs and remnants of the brake shoes.

Rear Carrier - hub and handbrake shoes removed

Next stage is to finish disassembly of the hubs