Powder Coating Fest - Part 2

In between getting on with the assembly of the front and rear axles, I have been continuing to clean and powder coat many of the donor parts in readiness for reassembly.

The budget sandblaster has been busy - now powered by my new 3hp /100-litre air compressor, which was a present to myself for a recent major milestone birthday.

Bigger is better!

I also have also tried out some different blasting media.  

I was quite happy with the results using the Wickes Kiln Dried Sand; well at least with the first bag I had bought.  When I bought the second bag, the sand was more like builders sand, quite soft and slightly damp, and just clogged in the nozzle of the blaster.

So I splashed out on 25kg of Fine Glass Grit from Amazon and 25kg of Fine Aluminium Oxide from Frost.

I have had some great results with the aluminium oxide.  It strips paint, rust and clag off in next to no time.  It's far more brutal than the sand, both on the metal parts and on exposed skin!  

Aluminium Oxide blasting media

The glass grit is a more gentle blasting media and is good for removing light rust and cleaning up the machined surfaces of some of the donor parts.

Fine Glass Grit blasting media

HEALTH AND SAFETY TIP - As with the sand it is important to wear eye protection but I found it necessary to upgrade to a full set of enclosed safety goggles (after learning the hard way that aluminium oxide grit is very sharp and will find its way into your eyes while just wearing an ordinary pair of safety glasses).  Also with both the aluminium oxide and glass grit, I would recommend a good quality dust mask; both media have a lot of very fine particles which I have no doubt are not good for the respiratory passages.

The pictures below show one of the rear stub axles before and after blasting.  The aluminium oxide cleaned off all the old paint in less than 10 minutes (the kiln dried sand would have taken over an hour) and then I used the glass grit to clean up the splined shaft and threaded end of the shaft.

Prior to a good gunking!

Post gunk...(zip ties used to identify parts from offside driveshaft)

After 20 mins of the budget blaster with Aluminium Oxide / Glass Grit media

After my problems with the front hubs and the development of further rust/corrosion between blasting and powder coating, I decided to try out Eastwood's After Blast Metal Prep.  

A gallon of SlartyAfterBlast...

This stuff is supposed to clean and degrease freshly blasted metal and also contains phosphoric acid to etch the metal surface and leave a zinc phosphate coating to prevent flash rusting and give a good surface to aid adhesion of paint or powder coat.  It's not cheap, at £45 a gallon from Frost, but if it does the job and saves me sandblasting everything twice, then I guess it will be worth it.

I bought a cheap spray bottle and used it to spray the parts with the After Blast.  The instructions say to leave it for 2-5mins and then to wipe off with a clean cloth to remove any excess contaminants and excess spray.

The inboard Drive Shaft Saddle after After Blast treatment...

A couple of tips for using this stuff:

1) Do make sure any excess liquid is wiped off - if it's allowed to sit on the part it  develops into large blobs of zinc phosphate coating

2) Avoid machined surfaces - since the spray etches the surface of the metal you want to avoid getting any spray on these surfaces and it will change the surface texture (i.e it's no longer smooth and machined!)

I made these mistakes the first time round on one of the inboard driveshaft saddles and ended up having to clean up the areas with a brass wire wheel in the angry end of the drill.

But the stuff does seem to work - I blasted the inboard driveshaft saddle a couple of weeks ago and no further rusting / corrosion had developed by the time I got round to powder coating.

Below are a few pictures of various parts in preparation and after powder coating.  

Rear Hub and Stub Axle prior to blasting

The backside of the Rear Hub after blasting...

...And the front face

Hub getting an After Blast bath (avoiding the machined surfaces)

Inboard Driveshaft Saddle fresh out of the oven

Freshly coated Hub and Drive Shaft ends

Differential - Part 2 - Being Granted Two Wish(bones)....

With the differential unit in place, next on the list was to install the rear wishbone tie. A simple task from looking at the AK Build Manual.  Well...not quite!

First up was to install the donor mounting bracket, which is simply slid over the main rear differential bolts.

Wishbone tie (top), Mounting Bracket (middle) and Compliance Buffers (bottom)

Mounting bracket installed...

I then applied copper grease liberally to the main rear diff bolts and installed the inner compliance buffers (the ones with the big hole which fits over the main bolts); these are installed with the flat edge towards the outside of the chassis.

Inboard Compliance Buffers installed...

All nice and straightforward so far!

Next on was the wishbone tie; this is installed with the side marked "Jaguar" facing towards the rear of the chassis.

Wishbone tie in place - I see a problem looming...

The outer compliance buffers are then installed again with the flat edge facing outwards.

Hang on!  There's no thread of main rear diff bolts protruding out of the assembly to get the M12 Nylocs onto! WTF!!

Bugger...!

After much head-scratching, drinking of tea, internet research, taking it all apart and reassembling (hoping for a different result), and a teeny bit of swearing, I was none the wiser and I still had no protruding thread onto which to attach a nut...

The problem it seemed was simple; the flange on the back of my compliance buffers seemed to be too thick/big to allow the buffer to sit tightly against the wishbone tie.

This doesn't look right...

Then I remembered something fellow builder Richard had said to me when he was round and I had shown him some of my first attempts at powder coating; which happened to me a couple of the metal compliance buffers.  Richard had said that his buffers/spacers were completely different; they were rubber with a metal insert.

So I had a closer look at the AK Build Manual and the buffers/spacers in the photo in the manual looked completely different from mine.

These are not my spacers! - Photo courtesy of AK Sportscars Ltd

Then I had a lightning bolt moment and I dug out the original wishbone tie that I had received from Simply Performance with my donor axles; remember the one that I had assumed was missing the inner bushes.

Well, guess what - the flange on the back of my metal buffers/spacers seated exactly into the recess in the wishbone tie where the inner bushes should have been fitted.

Fits like a glass slipper!

A quick email to Jon at AK and he confirmed that some of the Jag rear ends did come with a solidly mounted wishbone tie.  So it was a good job I kept the original wishbone tie and even better, I had decided to powder coat it as well! (Although the finish was not as good as the tie that I thought I was using - so I might need to consider recoating it at some point).

Armed with that knowledge, I tried reassembly with the original wishbone tie, and this time it all went together beautifully and I ended up with a goodly amount of thread from the main rear diff bolts sticking out to get the M12 Nylocs and washers onto.

Looking more promising...

Result!

So after several hours attempting a job that should literally have taken five minutes, I need a lie down...or a beer...or both!

Differential - Part 1 - Differential Equations

Having done as much as I can do for the time being on the front end build, it was time to start on the rear end build.

The first task was to press some new bushes into the newly powder-coated pendulum bracket.  The replacement bushes were ordered from SNG Barratt as follows:

More bits courtesy of SNG Barratt

To (hopefully) make the installation a little easier I left the pendulum bracket out in the sun for an hour or two to warm up nicely and put the new bushes in the freezer for a few hours.

Bushes and chips for tea?

I lightly greased the bush housings in the pendulum with copper grease and then pressed the new (cold) bushes into place using my 12T press and a suitably sized impact socket as a drift.  Note that one side of the bush housings on the pendulum has a bevelled edge which helps hold the new bush in position and guides it into the housing when starting to press it in.

Greased bore - note bevelled edge to ease bush insertion...

Pressing bushes into place

All bushes replaced

Next, it was time to unbox the rear differential unit.  The diff is a Salisbury Power Lock (limited-slip) unit with a 3.58 final ratio.  This was fully refurbished by Simply Performance when I purchased the donor axles and has sat in a large box occupying a large space on my garage floor ever since.  The unit is also bloody heavy and I needed some help from Sam to lift it out of the box and onto the cup of my 3T trolley jack.

Shiny refurbished differential unit

The pendulum bracket is then fitted over the nose of the differential with the side marked "Jaguar" facing towards the front of the car.  The upper bushes of the bracket slide onto the shafts at the front of the diff; these had a generous application of copper grease prior to installation.

Pendulum Bracket in place

The rear upper differential bolts are M12 by 70 bolts which are supplied by AK, with M12 washers to sit under the bolt head and 35mm by 14mm washers which are used as spacers between the diff and the chassis.  I assume the 35mm diameter washers are supposed to fit into the recesses on the top of the diff unit but mine did not seem to sit properly and allow the M12 to pass through so I ended up having to flat off the bottom of the washers on the bench grinder.

Rear Diff Bolts and Spacer Washers - Photo courtesy of AK Sportscars Build Manual

"Modified" Spacer Washers

With some careful (skilful?) control of the jack, I managed to raise the differential unit up and slide it forward into position relatively easily (just remember to rotate the input yoke on the diff so that it passes through the aperture in the chassis first).

Then it was just a case of securing all the fasteners (M10x1.25 nuts on the diff nose studs, M16 Nylocs with 1.25" by 5/8" washers on the front diff studs and M12 Nylocs and M12 washers on the rear diff bolts) to hold the diff in place and allow removal of the jack.

Differential installed!

I haven't fully torqued up any of the fasteners at this stage, mainly as I haven't worked out which are the correct settings from the Jaguar XJ40 Haynes Manual yet.  However, from reading Richard's blog and the trouble he had getting the differential tie bar into place, I figured leaving the diff fasteners not fully tightened might allow some play to get the diff tie bars fitted.

Watch this space!

Front Axle Part 6 - Finally getting to the Hub of the matter...

I finally managed to find some time to make some progress on the actually build last weekend with the re-assembly and fitment of the front hubs.

I'd previously placed another order with SNG Barratt for the service parts needed as shown below.

Contents of Wheel Bearing Kit from SNG

Prior to attempting to install the new bearings I gave the hubs a final clean out to get rid of any final remnants of sand from the blasting prior to powder coating.  I read on the internet about masking off bearing recesses etc when sand blasting to avoid any contamination with blasting media.  Unfortunately I read that after I had sand blasted my hubs......And sure enough there were some traces of sand clinging to the cast areas in the middle of the hubs.  A final clean-out with some cotton buds soaked in WD40 and a blow out with the airgun and I think (hope) I managed to remove all traces of grit / sand that might lead to a very short bearing life!!

Cleaned out and grit free....(fingers crossed)

I recycled the old bearing races to use a drifts to assist in installing the new races.  Firstly I cut a slot in the old races using an angle grinder with a cutting disk so that the old races wouldn't get stuck in the bearing recesses - the slot allows the old race to be compressed slightly so it can be pulled out easily.

Old bearing races modified to assist with installation of new races

It was then a simple task of seating the new races into their respective housings and using the old race and a large hammer to gently tap the races into the hub until they were fully seated.

Inboard race prior to any gentle tapping....

Modified bearing drift...

Finally got the boy off the X-box to help out!

Inboard race fully installed and seated...

....followed by outboard bearing race.

With races installed it's time to get greasy!  Armed with a tub of high performance bearing grease and a large box of disposable gloves I set about packing the central part of the wheel hubs between the two bearing races with grease making sure I got plenty of grease in and any large air pockets out! 

Grease - does exactly what it says on the tin....

Having formed a large grease "dam" behind the bearing races, I packed the inboard roller bearings with grease, making sure to get all the spaces in the bearing cage as full of grease as I could manage.  The inboard bearings are then placed in their bearing races and the outer grease seals pressed into place (I used a large block of wood and the large hammer to press the seals in fully).

Hub cavity packed with grease

Inboard bearing cage greased and in place

The stub axle on the front uprights then got a generous coating of grease as well and then the hubs can be slid onto the stub axles.

A well lubricated shaft........(sorry...)

The outboard bearings were then packed with grease as above and pushed into their bearing races.  The D-washers from the original donor car were then placed over the end of the stub axle and a new locknut screwed onto the end.

Outboard bearing race inserted in place

D-washer and lock nut in place

The recommended procedure is then to tighten the locknut to 16Nm / 12 ft-lbs to seat the hub onto the stub axle and then while rotating the hub assembly in the forward direction tighten further to 27Nm / 20 ft-lbs.  The locknut is then slackened off half a turn and then retightened hand tight only.  The assembly was finished off with a new locknut retainer and split pin.

All torqued up with new nut retainer and lockpin installed

That's the front end finished for the moment, pending installation of the brakes.  Time for some rear end action now!

Completed hub assembly