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!!